engineering integrity issue 31
DESCRIPTION
Issue 31 of the Engineering integrity Society journalTRANSCRIPT
w
EIS31September 2011
JOUrNAL OF tHe eNGINeerINGINteGrItY SOCIetY
ENGINEERING INTEGRITY
NEWS F
ROM:
SMA
RT MAT
ERIALS
,
B.S
.I.,
FOR
MULA S
TUDENT
TECHNI
CAL PA
PERS
INDUST
RY NEW
S, EVE
NTS
prOdUC
t NewS
the telescopic Cantilever beam: part 2 - Stress Analysis•
eIS website: www.e-i-s.org.uk
EIS 31 Covers v01.indd 1 22/9/11 14:13:10
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INSTRUMENTATION, ANALYSIS & TESTING EXHIBITION
THE SILVERSTONE WING, SILVERSTONE RACE TRACK, TUESDAY 6th MARCH 2012, 10.00-16.00.
Engineering Integrity Society
The 2012 EIS exhibition is being held in the recently opened international exhibition centre at Silverstone, which provides superb new visitor and exhibitor facilities. Entrance to the exhibition and all technical activities are free. There will be complementary refreshments for visitors.
,
ExhibitionThere will be 50 exhibitors presenting the latest advances in technology in, aerospace, automotive, motor-sport, rail, power generation, and medical industries. Visitors will be able to discuss these developments, and their applications, with exhibitors in an informal atmosphere.
Technical ActivitiesThere will be open forums held during the day including:
- Kinetic Energy Recovery Systems (KERS) - CAE Predictions vs Physical Testing - Vision and Lasers Systems - Application of Electric Actuators
Guest panels comprising experts from industry will expand on the technical developments andtake questions from the floor.There will be workshops in signal processing together with selective technical presentations.
ExhibitorsIf you are interested in exhibiting please contact the EIS Secretariat.
VisitorsIf you are interested in attending please pre-register for the event which will ensure you reserve a place at the technical events.
For further information, or to pre-register please contact the EIS at: [email protected], or visit the EIS website at www.e-i-s.org.uk
EIS 31 Inners v01.indd 1 22/9/11 15:47:08
INDEX TO ADVERTISEMENTS
Amber Instruments ................................................... 40
Bruel & Kjaer ............................................... Back cover
CPD Dynamics ......................................................... 40
Data Physics ..................................... Inside front cover
Ixthus Instrumentation ..................... Inside back cover
Kemo ........................................................................ 40
M+P International .............................. Inside back cover
Micro Movements ........................................................ 2
Team Corporation ...................................................... 2
Techni Measure .......................................................... 2
EIS 31 Inners v01.indd 2 22/9/11 15:47:10
ContentsInstrumentation, Analysis & Testing Exhibition 2012 .......................................................................................................... 1
Index to Advertisements ...................................................................................................................................................... 2
Editorial ................................................................................................................................................................................ 5
Technical Paper: The Telescopic Cantilever Beam: Part 2 – Stress Analysis .................................................................. 6
Technical Article: Mechanical Testing of Micro Specimens and Semi-finished Micro Products ..................................... 18
Report on EIS Forum “Seven posters - is that three too many?” ..................................................................................... 23
Corporate Sponsor Application Form ................................................................................................................................ 23
Industry News ....................................................................................................................................................................24
Product News ....................................................................................................................................................................28
Personal Membership Application Form .......................................................................................................................... 30
Profiles of Company Members ......................................................................................................................................... 31
News on Smart Materials and Structures ......................................................................................................................... 32
News from Formula Student ............................................................................................................................................. 33
Diary of Event .....................................................................................................................................................................33
Challenge to Improve the Process from design to product ............................................................................................. 34
News from British Standards ............................................................................................................................................ 35
“Open Access”, another instalment .................................................................................................................................. 36
Group News ......................................................................................................................................................................37
Committee Members ........................................................................................................................................................38
Sponsor Companies ......................................................................................................................................................... 39
Front Cover: Courtesy of Institution of Mechanical Engineers
FORUM FOR APPLIED MECHANICS (FAM)
The EIS is a sponsor member of the Forum for Applied Mechanics (FAM), which provides an interaction between a
number of organisations in the UK where there is an interest in applied mechanics, both experimental and theoretical.
Current sponsor members of FAM are the EIS, NAFEMS, IMechE, BSSM, IoP and the BGA (British Gear Association).
The FAM website contains details of events being held by the sponsor members, together with a direct link to the
sponsor members’ websites. Some of these events may be of interest to you or your colleagues. Access to the FAM
website can be gained either directly www.appliedmechanics.org or via the EIS website ‘Links’ page.
3EIS 31 Inners v01.indd 3 22/9/11 15:47:10
HONORARY EDITOR:
Dr Karen Perkins
MANAGING EDITOR:
Mrs Catherine Pinder
Anchor House, Mill Road,
Stokesby, Great Yarmouth, NR29 3EY
Tel. 07979 270998
E-mail: [email protected]
EDITORIAL BOARD:
Paul Armstrong
Brian Griffiths
Dr Fabrizio Scarpa
Norman Thornton
EIS Secretariat:
Engineering Integrity Society
18 Oak Close, Bedworth,
Warwickshire, CV12 9AJ
Tel & Fax: +44 (0)2476 730126
E-mail: [email protected]
WWW: http://www.e-i-s.org.uk
EDITORIAL POLICY:
Engineering Integrity contains various items of
information of interest to, or directly generated by, the
Engineering Integrity Society. The items of information
can be approximately subdivided into three general
categories: technical papers, topical discussion
pieces and news items. The items labelled in the
journal as technical papers are peer reviewed by
a minimum of two reviewers in the normal manner of
academic journals, following a standard protocol.
The items of information labelled as topical
discussions and the news items have been reviewed
by the journal editorial staff and found to conform
to the legal and professional standards of the
Engineering Integrity Society.
COPYRIGHT
Copyright of the technical papers included in this issue
is held by the Engineering Integrity Society unless
otherwise stated.
Photographic contributions for the front cover
are welcomed.
ISSN 1365-4101/2011
The Engineering Integrity Society (EIS)
Incorporated under the Companies Act 1985.
Registered No. 1959979
Registered Office: 35 Wilkinson Street,
Sheffield, S10 2GB, UK
Charity No: 327121
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PRINCIPAL ACTIVITY OF THE
ENGINEERING INTEGRITY SOCIETY
The principal activity of the Engineering Integrity Society, is
the arrangement of conferences, seminars, exhibitions and
workshops to advance the education of persons working
in the field of engineering. This is achieved by providing a
forum for the interchange of ideas and information on
engineering practice. The Society is particularly committed
to promoting projects which support professional
development and attract young people into the profession.
‘Engineering Integrity’, the Journal of the Engineering
Integrity Society is published twice a year.
EIS 31 Inners v01.indd 4 22/9/11 15:47:11
Editorial
5
Welcome to the 31st edition of the EIS
journal. With hurricanes blowing away
the last vestiges of summer we have a
bumper edition for you, containing two
papers and an extended range of news
sections, including the new ‘product
news’ giving industry the opportunity to
announce key technology releases.
The first paper, ‘the telescopic cantilever beam: Part 2’
describes the stress analysis performed for a telescopic
cantilever beam and follows from Part I published in the
last edition. The second paper, ‘Mechanical testing of
micro specimens and semi finished micro products’
provides user experience of test frame design specifically
for the purpose of small scale testing. Something close
to our interests at Swansea, we are often asked to assess
a new material capability based on minimal material
avai labi l i ty before a ful l scale melt is produced.
Development of new al loys often starts with the
manufacture of small buttons of experimental alloy and
a preliminary mechanical assessment is required from
a quantity of material more commonly utilized for a single
mechanical test. The development of tests techniques
for gaining a range of mechanical properties from
minimal material represents a technological challenge.
Smart materials also hit on a pertinent point with regards
to new exotic materials. Many advanced alloys nowadays
consist of the rare earth elements that offer improvements
in temperature and mechanical capabi l i ty. Future
availability and access to these elements is paramount
and forms a key part of new alloy development.
The Industry news section again provides an interesting
mix of topics with a range of green issues, robotics
featuring in several guises and the application of phase-
change materials in the development of ‘brain-like’
computers. Perhaps these computers will develop more
understanding than the two chatbots who made the
national news recently when their conversation rapidly
descended into an argument.
Despite our perennial concerns about the shortage of
engineering graduates, recent research from
Birmingham University suggests that many engineering
graduates are joining their psychology colleagues
behind the counters of fast food restaurants. The authors
of the study note the contrast between their findings and
the experience of employers in the sector, suggesting
that the shortage is really one of quality STEM graduates.
Perhaps the private sector has yet to accept that education
standards are constantly improving!
With the new University tuition fee regime starting next
year this has been a bumper year for recruitment in many
institutions. The past couple of years of ‘plenty’ have
allowed entry requirements to be raised, but whether or
not the actual quality of the intake has improved remains
to be seen. The over emphasis on rote learning at A-
level leaves many students, not just the weaker ones,
struggling to genuinely understand material, let alone
analyse a problem they haven’t been given a model
answer for. In the new market lead system the student
will be king and University administrators will be straining
every sinew to improve their student satisfaction ratings.
In this environment it is a brave or foolish lecturer who
denies the customer the spoon feeding they crave. At
least employabi l i ty wi l l a lso be a headl ine key
performance indicator.
Finally, the group events are proving extremely popular;
with attendance at a record high. It is encouraging to see
that many attendees were from the young engineers keen
to advertise their work.
Karen Perkins
Honorary Editor
EIS 31 Inners v01.indd 5 22/9/11 15:47:11
ENGINEERING INTEGRITY, VOLUME 31, SEPTEMBER 2011 pp.6-17. ISSN 1365-4101/2011
Technical Paper
The Telescopic Cantilever Beam: Part 2 – Stress AnalysisJ. Abraham, D. W. A. Rees and S. Sivaloganathan, School of Engineering and Design, Brunel University, Uxbridge, Middlesex,
UB8 3PH
Abstract
This paper is an extension to a Part 1 analysis of the
deflection for a telescopic cantilever beam [1]. The Tip
Reaction Model, proposed in that paper, establishes
reactions at the tips of the overlapping portions as the
mechanism of transfer of the external loads between
sections of the telescopic beam. In Part 1 a three-section
telescopic beam was analysed for deflection using these
forces within a repeated integration method. In Part 2 the
bending and shear stresses for the three-section cantilever,
are obtained both analytically and numerically. A check upon
stress levels is provided from a parallel study upon an
equivalent, two-stepped, continuous beam. Graphical
presentations of the beam stresses, found from applying
the two methods to each structure, are self-validating. That
is, the continuous beam theory provides a check upon
numerical stress levels from FEA and, in turn, FEA provides
a check upon the analytical stresses calculated from tip
reactions within a telescopic beam. The fact that
comparable stress levels were found confirms that the
analytical technique proposed is perfectly adequate for a
telescoping beam, just as the classical theory is adequate
for continuous beams. Taken together, Parts 1 and 2 provide
an analytical theory for bending of a discontinuous beam
that did not exist heretofore, thereby obviating the need for a
numerical solution.
1.0 Introduction
Continuous structures balance the application of external
loads with an internal resistance within their material which
is commonly called stress. For a beam in particular, resisting
moments arise from its internal stress to oppose the
bending moments that the transverse loading produces.
For example, consider the simply-supported beam with self-
weight w/unit length subjected to four concentrated loads
W1 ... W
4 shown in Figure 1.
Figure 1: Moment of resistance within section at x-position
To understand how the material in the beam resists the
external loads it is seen that the beam sags beneath the
applied loads. Sagging creates a compressive stress within
longitudinal fibres lying in the upper half of the section and
tensile stress within fibres in the bottom half. A neutral
(unstressed) plane MN divides each half as shown in Figure
1. The equivalent compressive force acting on the upper
area MEFN is given by ‘C’. Similarly the equivalent tensile
force acting on the lower area MHGN is given by ‘T’. The
external loads applied and the effective shear force S acting
on the plane EFGH are assumed to be concentrated on the
vertical plane of symmetry, as shown. The forces that act
over length AX of the beam are therefore: (a) a vertical reaction
RA at A, (b) external concentrated loads W
1and W
2, (c)
uniformly distributed load w acting over the length x , (d)
shear force S offered by section EFGH, (d) a compressive
resistance C and (e) a tensile resistance T. The magnitudes
of the forces C and T are equal and, since they act in
opposing directions, separated by a distance d, they form
the section’s moment of resistance:
MR = Cd = Td (1)
Taking moments about O gives the bending moment due to
the external forces
(2)
In continuous beams we may equate (1) and (2) when
applying the principle that the moment at a given section
due to externally applied loads equals the moment of
resistance at that section. However, the same principle
cannot be applied to telescopic beams within the
discontinuous region between overlapping sections,
especially where there is a sizeable gap between them. To
overcome this the authors proposed [1] their Tip Reaction
Model, the principle of which is summarised in the following
section.
1.1 Tip Reactions
The tip reaction model assumes that in a telescopic
cantilever beam the overlapping ends have concentrated
reactions that transmit the effects of the loads applied to the
top surface of the cantilever assembly. Consider the three-
section beam assembly shown in Figure 2. The fixed beam
AB has an overlap of length CB with beam CD. The outer
beam EF also has an overlap of length ED with beam CD.
Tip reactions exist at the contact points C and B between
6EIS 31 Inners v01.indd 6 22/9/11 15:47:12
beams AB and CD. Similarly, tip reactions exist at the
overlapping ends E and D between beams CD and EF. In
addition, Fig. 3a shows the external loading applied to the
assembly which is a combination of self-weight and a
concentrated end-load. Thus, each of the three-sections
bears the loading shown in Figures 3b-d.
Figure 2: Telescopic beam assembly with three sections
Figure 3: Telescopic assembly showing tip reactions
within individual beams
In Figs 3b-d each beam section is shown separately as a
free-body diagram. Within each diagram the tip reactions
are the forces applied to each section from its neighbour.
Thus, the end-section exerts upon the middle section a
downward force at D and an upward force at E (see Fig. 3c).
The middle-section exerts equal forces upon the end-
section at D and E but in opposition to these (see Fig. 3d).
That the tip reactions must remain in equilibrium with the
applied loading enables these reactions to be found [1].
Consequently, the internal shear force and moment within
each length may be calculated from the reactions instead of
the moment of resistance used normally for a continuous
beam. The shear force and bending moment variations
along each length are converted to their respective stresses
in the following section. The stress magnitudes are
compared with those obtained from a finite element analysis.
The analyses were carried out on a telescopic cantilever
assembly consisting of three hollow sections the details of
which follow. Comparable stress levels were anticipated
from a further validation which compares magnitudes
between the ‘moment of resistance’ theory and FEA for a
continuous stepped-beam of similar dimensions and
loading.
1.2 Bending Stress
The longitudinal bending stress in a beam is calculated
from the bending moment M by a standard expression [2]:
y
I
M=σ (3)
where I is second moment of area of the beam section and
y is the distance from the neutral axis at which this stress
applies. Consider the beam assembly shown in Figure 2
and assume that it is fixed at end A and carries a tip load at
F. Due to self-weight and the tip loading applied there will
be tensile stresses in all three beam sections above the
horizontal of symmetry (neutral plane) and compressive
stresses below the plane of symmetry. For each section
depth:1d ,
2d and 3d , the beam is represented by the
vertical plane of symmetry upon which the maximum bending
stress occurs at their top surfaces. These are found from
Eq. (3) as:
1
1
12I
dM ×=σ ,
2
2
22I
dM ×=σ and
3
3
32I
dM ×=σ
(4a-c)
The d- and I-values are referred to a chosen geometry given in
the following section. The bending moment M in Eqs 4a-c
varies within the length in a manner provided by an M-diagram
constructed from the applied loading and the tip reactions.
1.3 Shear Stress
Figure 4: Shear stress parameters at depth position y1 for
section x-x
ENGINEERING INTEGRITY, VOLUME 31, SEPTEMBER 2011 pp.6-17.
7EIS 31 Inners v01.indd 7 22/9/11 15:47:12
Consider the uniform cantilever shown in Figure 4. Let a
transverse shear force S apply vertically along the section
X-X at a distance x from the fixed-end. It is required to find
the shear stress within section X-X at a distance y1 (at EF)
from the neutral axis as shown. The area above EF is a and
the distance from the centroid of this area to the neutral axis
is . Given a uniform breadth b for the cross-section, the
transverse shear stress at the required position is found
from [2]:
(5)
Equations (3) - (5) may be applied to both telescopic and
continuous beams when M and S are known. In what follows
M and S are converted to their respective stress distributions
from within the diagrams that show the variations in M and
S over the length. The method of constructing S- and M-
diagrams for continuous cantilever beams, carrying
combined concentrated and distributed loading, can be
found in many texts [2-5]. The F- and M-diagrams for a
telescopic beam may be constructed separately once the
tip reactions for each of Figs 3b-d are known (see Part 1 [1])
and then superimposed to find their net values within the
overlaps.
2.0 Case Study Formulation
The following three investigations have been made
i. To calculate the bending and shear stresses from the
tip reactions in a telescopic cantilever and compare
these with the results of a Finite Element Analysis
(ABAQUS).
ii. To calculate the bending and shear stresses for a
comparable, single-stepped cantilever and compare
these with a Finite Element Analysis.
iii. To compare the stresses between the telescopic and
continuous cantilevers as provided by the analyses in
(i) and (ii).
Note that for (i) – (iii), the continuous cantilever, being a
simpler structure to solve, offers greater certainty that
realistic, agreeable stress levels will be provided by each
technique.
2.1 Model Geometry
The model telescopic cantilever beam assembly consists
of three hollow square steel sections, each 1 mm thick,
with outer dimensions: 25mm x 25 mm x 1000 mm,
22 mm x 22 mm x 1200 mm and 19 mm x 19 mm x 1200 mm.
A load of 30 N is applied at the end of the beam assembly.
Beam CD and AB have an overlap of 400 mm and beams
CD and EF have an overlap of 300 mm. The second moment
of area about the neutral axis for the cross-section of beams
AB, CD and EF are 9232 mm4 6188 mm4 and 3900 mm4
respectively. Their linear densities (distributed self-weights)
are 0.007536 N/mm 0.006594 N/mm and 0.005652 N/mm
respectively.
2.2 Area Properties
Consider the hollow, square rectangular section shown in
Figure 5. The outer side depth is d and thickness is t for
which the following relationships apply
Figure 5: Hollow, square tubular section
Cross sectional area:
A = (d 2 - (d - 2t)2) = 4t(d - t)mm2
Volume of a section, 1 mm long:
V / L = A = 4t(d - t) = 4t(d - t)mm3 / mm
Self-weight (density) of 1mm3 of steel (taking g = 10 m/s2)
Self-weights of 1 mm long beam sections (distributed loads)
35)1085.7(
−−× Nmm mmNtdt /10)(14.3
4−×−=
(4)
Second moments of area for a hollow square section
( )12
)2(44 tdd
I−−
= (5)
Equations (4) and (5) provide the I- and w -values for the
section dimensions d and t given in Table 1.
ENGINEERING INTEGRITY, VOLUME 31, SEPTEMBER 2011 pp.6-17.
8
y
EIS 31 Inners v01.indd 8 22/9/11 15:47:13
×
Figure 6: Telescope beam assembly for FEA
3.1 Telescopic Beam Assembly for
FEA
In practice, telescopic beam sections
slide upon and react their loading
through these wear pads. Hence, four
wear pads are introduced to make the
FE analysis correspond with the
analytical approach. Wear pad 1, of 0.5
mm thickness and 5 mm wide, is glued
the inside of the free-end of beam 1 as
shown in Figure 6. Similarly, wear pad
2, of similar dimension, is glued to the
outside end of beam 2. Wear pad 3 is
glued to the inner end of beam 2 and
wear pad 4 is glued to outside end of
beam 3, as shown.
3.2 Finite Element Analysis for the
Assembly
With the details of the telescopic beam
assembly model provided in 3.1, Table
2 shows the finite element analysis
procedure adopted by ABAQUS. The
left-hand side shows the flow chart and
the right-hand side gives the detail.
3.3 Finite Element Analysis of Single-
Stepped Beam
Normally telescopic beam sections
have a 1mm gap between sections to
facilitate easy sliding. This clearance
needs to be allowed for within an
equivalent, continuous stepped-
cantilever. In Fig. 7, the end view 1
shows sections built up from the inner-
section, which results in the outer-
3.0 Finite Element Analyses
Two separate finite element analyses were conducted.
The first applies to the assembled telescopic cantilever
carrying a tip load of 30 N. The second applies to the
single, stepped cantilever with comparable section
dimensions under a similar load.
Table 1: Tubular square-section properties
Table 2: FEA (ABAQUS) for the telescopic beam assembly
ENGINEERING INTEGRITY, VOLUME 31, SEPTEMBER 2011 pp.6-17.
9EIS 31 Inners v01.indd 9 22/9/11 15:47:13
section having a smaller dimension: 23mm × 23mm having
retained a 1 mm wall thickness. For the present analysis,
the stepped section is reduced down from the outer-section,
so that the resulting inner-section will have the larger
dimension: i.e., 19mm × 19mm for the end-view 2 in Fig. 7.
Referring to Fig. 8, the maximum bending tensile stress
for the assembly occurs along the top surface. The
maximum shear stress occurs along the neutral plane.
These maxima are used as the comparative measure for a
scaled-down model under a tip load of 30 N.
Figure 7: Equivalent continuous stepped-beam (third
angle projection)
3.4 Finite Element Analysis of
the Continuous Cantilever
Details of the continuous
stepped-beam, provided in
section 3.3, were submitted to
ABAQUS for FEA. Table 3 shows
the FE procedure as a flow chart
with detailed explanations given
on the right-hand side.
4.0 Stress Analyses for the
Telescopic Cantilever
The maximum bending stress
comparison between the two
techniques refers to the mid-
width position at the top surface.
This follows the line
A1C
1B
1E
1D
1F
1between sections
in Fig. 8. The maximum shear
stress comparison refers to the
mid-thickness of the walls lying
upon the neutral plane. This
follows the line A2C
2B
2E
2D
2F
2 for
one wall in Fig. 8.
4.1 Force and Moment
Diagrams
A sample of the shear force and
bending moment calculations
required for one of the individual
Table 3: FEA for the continuous beam
Figure 8: Sectional view of the continuous stepped-beam
sections is outlined in Appendices A1-A3. Firstly, in A1, the
tip reactions are calculated from the formulae given in Part 1
[1]. In A2 the shear forces and moments are calculated from
the tip reactions and the applied loading for the beam ACB.
The resulting S- and M-diagrams appear beneath this
separated beam in Fig. 9. In A3 the bending and shear
stresses are calculated from applying Eqs 1-3 to the required
ENGINEERING INTEGRITY, VOLUME 31, SEPTEMBER 2011 pp.6-17.
10EIS 31 Inners v01.indd 10 22/9/11 15:47:14
positions in this beam’s section. Because of the reduced
scale in the model, units of N and mm are used throughout
in all these calculations. Similar calculations apply to the
remaining beams for which full details have been given
elsewhere [1]
Figure 9: Shear force (N) and bending moment (Nmm)
diagrams for each beam
4.2 Bending Stress Distributions
Figure 10 compares the bending stress distributions
obtained analytically and numerically (thin and thick lines
respectively). The unreinforced beam lengths AB, CD and
EF are shown for which the stress axis refers to the
maximum bending stress at their mid, outer surfaces.
These stress values were obtained at 50 mm intervals along
the top of the beam sections, as shown in Appendix A.3.
FEA values of bending stress were obtained in the manner
outlined in Table 2. The stress dips from FEA at lengths of
600 mm and 1500 mm can be explained by the presence of
wear pads; they decrease the stress concentration in the
overlap area between sections. Before and beyond each
overlap the bending stress in each is seen to diminish from
its greatest value at the fixed-end to zero at the free-end.
Figure 10 shows that there are four further ‘free-ends’ within
this telescopic assembly where the bending stresses are
also zero. However, the surface bending stress in the
connecting tube is not zero at these positions. Here the
reinforcement of the section area from within the overlap
plays no part in the stress reduction, lying at the ends of the
linear regions for beams AB, CD and EF, as shown. The
reduction in stress across these regions is due entirely to
the manner in which the bending moment diminishes with
length. Within each overlap, away from its free-ends, the
area reinforcement becomes effective, serving to equalise
stress at the mid-position, as shown. It will be seen that
this bending stress distribution has its greatest variation
across the overlap compared to equivalent portion of the
continuous stepped-beam. The greatest bending stress
magnitude of 146 MPa in this figure shows that the structure
would remain elastic, given a yield stress for a medium
carbon steel of, say, 400 MPa. Their ratio, which provides
safety factor approaching 3, would be regarded as an
adequate figure for a practical design but a lower factor might
be applied to achieve a weight reduction. Here we should
note that the minimum safety factor is based upon the
greatest stress which applies to the fixed-end only. A fully
optimised cantilever design would employ tapered
contoured beams as a means of maintaining a uniform
safety factor throughout its length [5]. Figure 10 reveals that
a similar, optimal design criterion may be applied to
telescopic structure.
4.3 Shear Stress Distributions for a Telescopic Cantilever
Figure 11 shows the graphical comparison between the
shear stresses obtained analytically with those from FEA
(thin and thick lines respectively). Shear stress values apply
to the mid-wall position upon the neutral plane, where they
take their maximum value [2]. Analytical shear stress values
were obtained at 50 mm length intervals within the neutral
plane, as shown in Appendix A3. FEA values of shear stress
were obtained directly from the telescopic beam assembly
model (see Table 2). The overlay between the two shear
stress distributions in Figure 11 is self-validating. Both show
that the shear stress remains fairly uniform along with the
shear force across the unreinforced lengths. The tip
reactions enhance both this force and its stress within the
overlap where, again, the shear stress is fairly uniformly
distributed with the shear force (see Fig. 9). The reversal in
the tip reaction between beams AB and CD and again
between CD and EF is responsible for the alternation in
sign of the shear stress within Fig. 11. Nowhere does the
shear stress magnitude become zero despite it having a
relatively low magnitude compared to the accompanying
bending stress. As a design criterion, the application of a
limiting shear stress becomes important to shorter length
cantilever beams. This imposes a near uniform cross-
section when minimising weight [5], in marked contrast to
the taper imposed by an optimised bending design
mentioned above.
ENGINEERING INTEGRITY, VOLUME 31, SEPTEMBER 2011 pp.6-17.
11EIS 31 Inners v01.indd 11 22/9/11 15:47:14
Figure 10: Telescopic beam bending stresses from FEA
and tip reaction analysis
(Key: _______ Analytical; FEA)
Figure 11: Telescopic beam shear stresses from FEA and
tip reaction analysis
(Key: _______ Analytical; FEA)
5.0 Stress Analysis for the Continuous Beam
5.1 Force and Moment Diagrams
Appendix B1-B3 outlines the analysis of the single beam
model idealised, in Figure 12. The shear force and bending
moment diagrams, shown in Figure 13, have been
constructed from the S- and M-values given in B1. Section
B.2 gives a sample calculation for the bending and shear
stresses compared in Figures 14 and 15.
5.2 Bending Stress Distributions for a Single Stepped-
Beam
Bending stresses refer to the top surface of the single
stepped beam where they attain their maximum values [3].
Analytical stress values were obtained at 50mm intervals
along the beam, as shown in Appendix B.3. Numerical
values of bending stress were obtained directly from FEA.
Figure 14 compares the bending stresses obtained from
each method (thin and thick lines respectively). Here the
Figure 12: Single Beam Model
Figure 13: Shear force and bending moment diagram for
the continuous, stepped beam
stress distribution, are those for a continuous beam, but
due to its stepped changes in area, stress discontinuities
again appear. The corresponding stepped stress reductions
differ from those found within the overlaps in a telescopic
cantilever (see Fig. 10) despite the area having been
ENGINEERING INTEGRITY, VOLUME 31, SEPTEMBER 2011 pp.6-17.
12EIS 31 Inners v01.indd 12 22/9/11 15:47:15
increased by a similar amount. We have seen that in an
overlap one area bears far more stress than the other with
the greater showing here a two-fold increase over the
stepped beam value. This reveals an inherent feature of
telescoping: that each beam end within the overlap must be
stressed separately as they cannot be considered in terms
of an equivalent solid section.
It is instructive here to make a further comparison between
the overall bending stress distributions in Figs 10 and 14
when the overlaps are ignored. Thus, the maximum stress
in both beams decreases linearly from its greatest value at
the fixed-end to zero at the free-end, where the load acts.
The overall stress appears to be distributed linearly along
the entire length of the single beam when the thicker section
interruptions are ignored. In contrast, due to the tip reactions,
the overlap displaces the distribution to retain a similar
stress magnitude at its start and finish. Within the overlap
these each fall to zero at the ‘free-ends’ on either side as
shown. Comparing the overlap regions in the telescopic
beam with each region of increased area for the single
stepped beam, the stress reduction is less severe for the
former due to the effect of the reactions that exist either at
the tip positions (analytical) or the equivalent reactions
spread within the wear pad (FE). However, the stress
variation is greater across the overlap as it falls to zero at
each end. The greatest bending stress magnitude of 140
MPa in this figure shows that the structure remains elastic,
given a yield stress for a medium carbon steel of, say, 400
MPa. Their ratio, which provides safety factor of almost 3,
would be regarded as an adequate figure for a practical
design but a lower factor might be applied to achieve a weight
reduction.
5.3 Shear Stress Distributions for a Single-Stepped Beam
Shear stress values apply to the neutral planes of the beam
sections where their maximum values are attained [3].
Analytical shear stresses were found at 50mm intervals
along the neutral plane as shown in Appendix B3. Numerical
values of shear stress were obtained directly from the
telescopic beam assembly model using FEA. Comparing
Figs 13 and 15, the most significant difference between the
two shear distributions is the alternation to the sign of the
shear stress for the telescopic cantilever. This is a
consequence of the reversal in the tip reaction between
mating sections which, of course, is absent in a continuous
beam. For the latter, nowhere is the bending stress and the
shear stress zero despite their being lowered by the increase
in the section area at each step. The stress shear
magnitudes for telescopic and continuous beams are similar
at the fixed end and are fairly uniformly distributed within the
unreinforced lengths. The shear stress in the continuous
beam does not alternate between positive and negative
values but the stepped geometry provides a distribution that
is influenced by the changing cross-section. The greatest
shear stress occurs in the smallest cross-section for the
free-end length as shown. The greatest deviation between
the two predictions in Fig. 15 occurs at the step where there
appears an almost twofold increase in the peak value from
FE. Here the FE is likely to be more realistic given what is
known of the effect of sharp section changes upon stress
concentrations [6]. Everywhere the shear stress remains
positive albeit of small magnitude compared to the bending
stress values. This will always apply to long beams but for
shorter beams, where section dimensions are similar to
the length, shear can dominate. In fact, shear stress remains
an important design criterion for thin-walled sections whose
plates are at risk of local buckling in a shear mode [5].
Figure 14: Continuous beam bending stresses from FE
and Theory
(Key: _________ Analytical; FEA)
Figure 15: Continuous beam shear stresses from FE and
Theory
(Key: _________ Analytical; FEA)
ENGINEERING INTEGRITY, VOLUME 31, SEPTEMBER 2011 pp.6-17.
13EIS 31 Inners v01.indd 13 22/9/11 15:47:15
7.0 Conclusions
The graphs of the beam stresses provided by applying the
two methods as well as a Finite Element Analysis to each
structure respectively are presented for comparison. On
comparison, it can be seen that there is a definitive correlation
between them. As mentioned earlier these are self validating
in nature, in that the continuous beam theory provides a
check upon numerical stress levels from FEA and, in turn,
FEA provides a check upon the analytical stresses calculated
from tip reactions within a telescopic beam. Whereas the
paper preceding this outlined the Tip Reaction Model, as an
appropriate mechanism for telescopic beams, taking into
account their discontinuity, this paper takes it a step forward,
by obtaining beam stress values for the same and then
comparing it with the established classical theory.
Comparable stress values, confirms that the model
proposed is perfectly robust for application to a telescopic
cantilever, just as is the classical theory for continuous
beams. Given that telescopic cantilevers are finding
increasing applications in today’s world of material and
design optimisation, with the focus on weight saving in
engineering applications, this theory for discontinuous
beams counterbalances the need for a numerical solution
and can be adapted as is needed for any given purpose.
References
1. Abraham, J. Estimating deflection and stress in a
telescopic cantilever beam using the tip reaction model,
Ph.D. Interim Report, School of Engineering and Design,
Brunel University, November, 2010.
2. Rees, D. W. A. Mechanics of Solids and Structures, World
Scientific, 2000.
3. Gere, J. M. and Timoshenko, S. P. Mechanics of Materials,
Van Nostrand, 1984.
4. Benham, P. P. and Crawford, R. J. Mechanics of
Engineering Materials, English Language Book Society/
Longman Group Limited, Essex, England, 1987.
5. Rees, D.W.A. Mechanics of Optimal Structural Design –
Minimum Weight Structures, Wiley 2008.
6. Peterson, R. E. Stress Concentration Factors, Wiley 1974.
APPENDIX A
A1. Tip Reactions
Referring to Fig. 3a, the tip load is W = 10 N and the distributed
self-weights are 007536.01 =w N/mm,
006594.02 =w N/mm and 005652.03 =w N/mm.
Equations, derived in Part 1 [ ], provide the tip reactions RD,
RB and R
C in Fig. 3a-d:
+=
2
1 33
2
lwWRD
α
ENGINEERING INTEGRITY, VOLUME 31, SEPTEMBER 2011 pp.6-17.
Nlw
WRD 5648.1332
005652.0120030
25.0
1
2
1 33
2
=
×+=
+=
α
Similarly taking moments about D gives
−
+−×=2
)21()1(
1 2332
2
αα
α
lwWRE
N7824.962
)5.01(1200005652.0)25.01(30
25.0
1=
−×
+−×=
Similarly taking moments about C gives
)]1(2
[1
22
322
1
αα l
lR
lwRR EDB −×−×+=
)]1(2
1200006594.0[
12
1
αα
−×−×+= EDB RRR
From earlier calculations RD
= 133.5648N and RE= 96.7824N
NRB 8032.194)]1(7824.962
1200006594.05648.133[
12
1
=−×−×+=∴ αα
Balancing forces give
CDEB RRRR +×+=+ 1200006594.0
RC =194.8032 + 96.7824 - 133.5648 - 0.006594 x 1200 = 150.108N
Thus when 25.03
1,1200,1200,1000 21321 ===== αα andlll
the reactions are
NR
NR
NR
NR
E
D
C
B
7824.96
5648.133
108.150
8032.194
=
=
=
=
At the fixing A the reaction is:
RA
= 30 + 0.007536 x 1000 + 0.006594 x 1200 + 0.005652
x 1200 = 52.2312N
And the bending moment is
mmN
M A
4.108506)5001000007536.0(
)12001200006594.0()21001200005652.0()270030(
=××+
××+××+×=
14EIS 31 Inners v01.indd 14 22/9/11 15:47:16
ENGINEERING INTEGRITY, VOLUME 31, SEPTEMBER 2011 pp.6-17.
15
Figure C.1: Section of the Beam above the Neutral Plane
The centroid of the section’s half-area above the neutral
plane is found from the square tube’s outer dimension d
and common thickness t = 1 mm:
)1(2
2422
1
2)2(
2
=−
××+
−−
==
d
dddd
A
yAy
i
ii
( ))1(8
462
)1(2(4
)1)(2(2222
−
++−=
−
+−−
d
ddd
d
ddd
)1(8
4632
−
+−=
d
dd
Area of cross section
=2
)1(21)2(12
12
mmdddd
−=×−+×+×
The maximum shear stress follows from Eq. 5 as follows
tId
dddSMax
2)1(8
)463()1(22
××−
+−×−×=τ
tI
ddS
24
)463(2
×
+−×=
Note: The b denominator in Ib
ySa=τ in this case is equal to
2t.
Within the overlap length CB for beam AB the bending
moment is
2
)()()( 1
111
xlxlwxlRM B
−×−×−−×−=
Once again the maximum bending stress applies to the top
surface where mmy 5.12max =
2max /9232
5.12mmN
M
I
yMMax
×−=
×−=σ
in which the sagging moment is positive.
The corresponding shear force expression is
A.2 Shear Force and Bending Moment Diagram for beam
ACB
Length AC
Shear force is = 52.2312 - 0.007536 × x where x is the
distance from A.
Bending moment
Therefore Shear force at
Bending moment at
Length CB
Shear force is = 52.2312 - 0.007536 × x + 150.108 where x
is the distance from A.
Bending moment
Therefore Shear Force at
Bending moment at
A.3 Calculation of Bending and Shear Stresses for Beam
ACB
Surface bending stress are maximum along the vertical
plane of symmetry. Within the length AC for the beam AB in
Figure 3, the bending moment at a distance from A is
The maximum bending stress applies to the top surface
where
−
−
mmNC
mmNA
2.78524
4.108506
))600(108.1502
007536.0232.52(4.108506 −×+××−×+−= xx
xx
B
C
−
0
2.78524
B
mmNC
x
2
)()()()( 1
11111
xlxlwxalRxlRM CB
−×−×−−−×+−×−=
)2
007356.02312.52(4.108506x
xx ××−×+−=
mmy 5.12max =
2max /9232
5.12mmN
M
I
yMMax
×−=
×−=σ
in which the sagging moment is positive.
The shear force in AC is given by
and the maximum shear stress lies at the mid-wall upon
neutral plane in Fig. C1.
xNS ×−= 007488.02312.52
EIS 31 Inners v01.indd 15 22/9/11 15:47:17
197.8176 N
194.8032 N
ENGINEERING INTEGRITY, VOLUME 31, SEPTEMBER 2011 pp.6-17.
NxS 108.150007536.02312.52 +×−=
The maximum shear stress follows from Eq. 5 as follows
tId
dddSMax
2)1(8
)463()1(22
××−
+−×−×=τ
tI
ddS
24
)463(2
×
+−×=
Note: The b denominator in Ib
ySa=τ in this case is equal to
2t where t=1mm, from Table1.
APPENDIX B Analysis of the Single beam Model
Referring to Table 1 and Fig. 15 it is appropriate here to
construct the S and M-diagrams for the full continuous,
stepped length ACBED. However, only a sample of the stress
calculations is given; namely those for length portions AC
and CB.
B1. S- and M- Calculations (Units: N and Nmm)
Length AC
Equating forces in the vertical direction and taking W = 30 N,
gives the reaction at A
[N
RA
2312.52
)500006908.0()400014444.0()600007536.0(
=
×+×+×=
]30)90000628.0()30001319.0() +×+×+ N2312.52=
The bending moment at A is
M A )1650300013188.0()225090000628.0()270030(
=××+××+
××+××+×=
)1250500006908.0( ××+ )800400014444.0( +××+
N108506)300600007536.0( =××+
The shear force in AC at a distance x from A is
S(x) x×−= 00753.03616.33
The bending moment in AC at a distance x from A is
M(x) )2
007536.02312.52(108506x
xx ××−×+−=
The linear and parabolic expressions give their extreme
values at A and C:
Shear force at
NC
NA
7096.47
2312.52
Bending moment at
−
−
NmmC
NmmA
2.78524
108506
Length CB
Shear force is )600(006594.0007536.02312.52 −×−×−= xx
where x is the distance from A.
Bending moment
006908.0)2
007536.02312.52(108506 ×−××−×+−=x
xx
)2
)600()600(
−×−×
xx
Therefore Shear force at
NB
NC
8032.194
8176.197
Bending moment at −
0
2.78524
B
NmmC
Length BE
Shear force is )600(006594.0108.150 −×−−= x where x is
the distance from A.
Bending moment
006594.0))500(488.72312.52(108506 ×−−×−×+−= xx
)2
)600()600(
−×−×
xx
Therefore Shear force at
NE
NB
7606.38
0576.42
Bending moment at
−
−
NmmE
NmmB
2.40366
7.60570
Length ED
Shear force is
7824.968032.194)600(006594.0108.150 ++−×−−= x
where x is the distance from A.
Bending moment
)600(006594.0))500(488.72312.52(108506 −×−−×−×+−= xxx
)2
)600()
−×
x
2
)1500()1500(005652.0
−×−×−
xx
Therefore Shear force at
−
−
ND
NE
478.98
7824.96
Bending moment at
− NmmD
E
1.29289
0
Length DF
Shear force is
)1500(005652.01200006594.0488.72312.52 −×−×−−= x
where x is the distance from A.
16EIS 31 Inners v01.indd 16 22/9/11 15:47:18
ENGINEERING INTEGRITY, VOLUME 31, SEPTEMBER 2011 pp.6-17.
Bending moment
1200006594.0)500(488.73616.33(4.56541
−
××−−×−×+−= xx
)1200( −× x )2
)1800()1800(005652.0
−×−×−
xx
Therefore Shear force at
NF
ND
30
0868.35
Bending moment at −
0
1.29289
F
NmmD
The shear force diagram and the bending moment diagram
for the continuous beam are shown in Figure 12.
B.2 Calculation of Bending and Shear Stresses
Consider the sectional view of the continuous stepped beam
shown in Figure 6. The maximum bending stress apply to
line A1C
1B
1E
1D
1F
1in Fig. 9. The shear stress will be maximum
along the line A2C
2B
2E
2D
2F
2. Note that the area properties
given in A3 again apply to each square tubular section of
outer dimension d and thickness 1 mm.
Length AB
Consider, firstly, the uniform section within the length portion
AC. The bending moment at the section at a distance x from
A
M )2
007536.03616.33(4.56541x
xx ××−×+−=
Taking sagging moments as positive, the maximum bending
stress follows from Eq. 4:
2max /9232
5.12mmN
M
I
yMMax
×−=
×−=σ
The shear force in AC is given by
xNS ×−= 007488.02312.52
The maximum shear stress follows from Eq. 5 as follows
tId
dddSMax
2)1(8
)463()1(22
××−
+−×−×=τ
tI
ddS
24
)463(2
×
+−×=
Note: The b denominator in Ib
ySa=τ in this case is equal to
2t where t=1mm and I = 9232 mm4 from Table1.
Length BC
For the stepped length CB, the bending moment is
M 006908.0)2
007536.03616.33(4.56541 ×−××−×+−=x
xx
)2
)600()600(006908
−×−×
xx
Taking sagging moments as positive, and referring to Table
1 for the corresponding second moment of area for the length
BC (Section 4), the maximum bending stress follows from
Eq. 4:
2max /16345
5.12mmN
M
I
yMMax
×−=
×−=σ
The accompanying shear force is
S )600(006594.0007536.03616.33 −×−×−= xx
The maximum shear stress follows from Eq. 5 as follows
tId
dddSMax
2)1(8
)463()1(22
××−
+−×−×=τ
tI
ddS
24
)463(2
×
+−×=
Note: The b denominator in Ib
ySa=τ in this case is equal to
2t where t=2mm and I =16345N/mm2 from Table1.
17EIS 31 Inners v01.indd 17 22/9/11 15:47:18
Mechanical Testing of Micro Specimens and Semi-finished Micro ProductsBernd Köhler*, Hubert Bomas*, Hans-Werner Zoch*, Bremen, and Jens Stalkopf°, Pfungstadt
*IWT Stiftung Institut für Werkstofftechnik, Bremen, Germany
° Instron Deutschland GmbH, Pfungstadt, Germany
Technical Article
Established in 2007, the Collaborative Research Centre
747 “Micro Cold Forming - Processes, Characterisation,
Optimisation” of the German Research Foundation
(Deutsche Forschungsgemeinschaft, DFG) focuses on the
provision of processes and methods for the manufacture of
metallic micro components through metal forming
technologies. The Project B4, Component Strength, deals
with the static and dynamic investigation of the mechanical
properties of micro specimens and semi-finished micro
products. Mechanical testing of such micro specimens
requires testing equipment specifically adapted to their
small dimensions. Within the context of this special
requirements profile, this paper discusses the comparative
advantages of different testing machine types available on
the market. To conduct the above-mentioned project, the
testing system considered to be most appropriate for the
task was procured, consisting of the Instron Electropuls™
E1000 electromechanical test machine equipped with the
non-contacting Advanced Video Extensometer AVE. This
article discusses some of the insights gained in the use of
this testing system.
The Collaborative Research Center 747 of the Deutsche
Forschungsgemeinschaft “Micro Cold Forming - Processes,
Characterisation, Optimisation” was established at Bremen
University in 2007. The central focus of this Collaborative
Research Centre is the investigation of processes and
methods for the manufacture of metallic micro components
by means of metal-forming technologies, i.e. of components
which are smaller than 1 millimetre in at least two
dimensions, and less than 5 mm in the third dimension [1].
These investigations encompass all relevant aspects of
the forming process, from the development of materials to
components testing.
In this context, the Project B4, in which three of the authors
work, deals with the determination of the mechanical
properties of thin metallic semi-finished products, and
components manufactured from these products, which, in
general, cannot be derived from those of semi-finished
products and components with significantly higher wall
thickness. This is due to the statistical and technological
effect of size, the dominant influence of surface, and
dimensions in the scale of the material’s microstructure.
Micro sheets with a sheet thickness in the order of the grain
size of the material, for example, exhibit mechanical
properties which are significantly different from those of
larger-thickness sheets.
For this reason the mechanical properties of the
manufactured semi-finished products and their post-forming
behaviour in the finished component have to be analysed
thoroughly, including their behaviour during failure, with a
view to validating calculation methods and transferability of
mechanical properties. Such analyses necessitate a testing
system capable of meeting the specific requirements for
static and cyclic testing of micro specimens. The system
has to allow low forces and strokes to be set and controlled
with sufficient accuracy, and provide for a method of strain
measurement which takes into account the mechanical
sensitivity of the test specimens. For the last two years, the
Collaborative Research Centre has had a materials testing
system of this type at its disposal. The following article will
discuss some of the experience gained with this system.
Test machine for micro specimens
Critical requirements for a testing system for micro
specimens and micro components, which is to permit both
static and cyclic investigations, fall into three areas:
1. Loads: Materials and specimen dimensions
determine the load range to be covered by
the test machine. Specifically with a view to
dynamic testing, the machine must allow for
precise control of low forces.
2. Dynamics: High dynamic performance of the machine
is desirable, i.e. for a specimen with given
material and geometry, the machine should
provide for an adequate displacement
amplitude at a maximum frequency of load
cycles, whilst maintaining the preset
waveform (e.g. a sine wave).
3. Stroke: To enable static tensile and compressive
tests to be performed, an adequate piston
stroke is required.
As resonant testing machines do not permit static testing,
and both, servo-pneumatic and spindle testing machines
do not meet the above requirements with regard to dynamic
performance and controllability, only electro-dynamic or
servo-hydraulic machines are, in principle, suited to the
application in hand.
Electro-dynamically driven test machines are available on
the market in various sizes with maximum load capacities
ranging from ± 22 N up to ± 10 kN. By contrast, even the
smallest servo-hydraulic systems provide a load capacity of
18EIS 31 Inners v01.indd 18 22/9/11 15:47:19
5 kN. Depending on the strength and dimensions of the
specimens, the loads required for testing of micro
specimens can be found predominantly in the range below
1000 N, whilst thin sheets with thicknesses in the range of
10 µm require forces of less than 10 N.
Although electro-dynamic and servo-hydraulic systems
basically exhibit a comparable dynamic performance when
it comes to higher loads, even the smallest servo-hydraulic
testing machines have been shown to be hard to control
during cyclic tests with loads in the order of only a few
Newtons, due to the relatively high moving masses of the
machine. Besides, electro-dynamically driven machines
are superior to their servo-hydraulic counterparts in a number
of other ways which are shown in Figs 1 and 2 using the
example of two 10 kN machines.
Figure 1. Servohydraulic testing machine
Due to the absence of the hydraulic power pack, the electro-
dynamic testing system has a lower footprint. It does not
require a 3-phase power supply or a cooling water
connection and is less maintenance-intensive, as there are
no hydraulic hoses to replace, no oil filters or seals to change,
no oil to be replaced and properly disposed of, and no
maintenance of servo valves is required. In addition, the
testing system is characterised by low noise emission. The
electro-dynamic drive concept is therefore clearly superior
to the servo-hydraulic concept considering the requirements
profile for testing of micro specimens.
Apart from their maximum load capacity, electro-dynamic
testing machines available on the market also differ with
regard to their maximum stroke, which is particularly relevant
in the case of static tensile tests. Some of the test machines
have a maximum piston stroke of 25 mm or less. Some
electro-dynamical testing machines even require a costly
additional drive unit to apply the static load. Considering all
relevant requirements for static and cyclic mechanical
Figure 2. Electrodynamic testing machine
testing of micro specimens, an electro-dynamic testing
machine type Instron E1000 (see Fig. 3) was considered
the ideal solution.
Figure 3. Testing machine ElectropulsTM E1000
19EIS 31 Inners v01.indd 19 22/9/11 15:47:19
This test machine is driven by a brushless linear motor and
provides a maximum load capacity of ± 710 N for static tests
and ± 1000 N for cyclic tests. The machine’s test space has
a height of max. 610 mm, the maximum piston stroke is
60 mm, which is adequate for performing static tensile tests.
The piston position is measured by means of a Linear
Variable Differential Transformer (LVDT) in the setup mode,
and by means of a calibrated incremental transducer in the
displacement control mode. Two appendant Dynacell load
cells calibrated to ISO 7500-1 with measuring ranges of
± 2kN and ± 250 N, respectively, and automatic inertia
compensation are available for load measurement.
Special attention was given in the selection of the test system
to the accuracy of load control for small loads and in cyclic
operation. Figure 4 shows the variation of the load amplitude
for a cyclic tensile test under sinusoidal load at a stress
ratio R = 0.1 and a frequency f = 20 Hz. The specimen was a
micro rotary swaged wire made from steel grade 1.4301
with a diameter of 0.5 mm. The graph shows the feedback
load amplitude at a command value of Fa
= 40.5 N. The
average load feedback amplitude determined over 2000 load
cycles is Fa = 40.487 N with a standard deviation of
s = 0.055 N. The first 1000 cycles were not taken into account
in the calculation of the mean value, to ensure that the result
is not distorted by the process of stabilisation. Normalisation
of the standard deviation with respect to the measuring range
of the load cell used provides:
sn = s/250 N = 0.00022 = 0.022 %
Figure 4. Fluctuation of load amplitude during cyclic test
In contrast to mechanical testing with resonant testing
machines, the linear motor driven electro-dynamic system
enables the testing frequency to be varied within certain
limits. The dynamic performance of the testing system is
shown by way of example in Fig. 5 which illustrates the
relationship between the testing frequency and the
achievable displacement amplitude for three different
loading conditions. The curve plotted without a specimen
installed represents a limiting curve resulting from the
maximum achievable acceleration of the moving masses.
Looking at the plot with installed specimen at a static mean
load of 200 N and a load amplitude of 100 N, you will find
that a significant deviation from the limiting curve does not
occur until a frequency above 100 Hz has been reached.
When the mean load is increased to 500 N and the amplitude
to 500 N, the curve shifts towards lower frequencies, i.e. a
given displacement amplitude will not be achievable under
these conditions unless the test frequency is reduced.
Basically, the performance diagram shows that testing
frequencies of 100 Hz can be achieved with the testing
system in cyclic tests, provided that the stiffness of the
specimen is adequate.
Figure 5. Dynamic performance plot of the testing
machine ElectropulsTM E1000
No-contact strain measurement
In view of the micro dimensions of the test specimens (typical
sheet thickness ranges between 10 µm and 100 µm), strain
measurement using specimen-contacting methods such
as strain gauges or clip-on extensometers is not feasible.
On the one hand, such methods involve the danger of
damaging the specimens during the attachment of the
respective strain measurement device, on the other hand,
the impact of these measuring methods on the result can
no longer be neglected, as it can be with larger specimens.
For this reason, a non-contacting optical strain
measurement method was chosen.
The system supplier provides such a solution as part of the
ElectroPuls testing system in the form of the so called
Advanced Video Extensometer (AVE), see Fig. 6. Essentially,
20EIS 31 Inners v01.indd 20 22/9/11 15:47:19
the AVE consists of a high-resolution digital video camera
and an LED light source, which illuminates the specimen
with pulsed, monochromatic, red, polarised light with a
wavelength of 650 nm.
For the application in hand, the video camera is configured
with a lens system optimised for small specimens, which
has a focal length of 55 mm and permits a viewing field of
60 mm in the axial direction, and 8 mm in the transverse
direction. Strain measurement is achieved by tracing the
axial movement of markings applied on the specimen with
the video camera, and calculating strain by means of a real-
time image processing system.
Figure 6. Video extensometer AVE (a) with integral
illumination unit (b)
Measurement of the original gauge length, which is defined
by the markings on the specimen and which is essential for
strain measurement, is achieved prior to the test by the
calibrated AVE, with an absolute accuracy of ± 2.5 µm. The
markings take the form of two spots with a diameter between
0.5 and 3 mm (Fig. 7), or alternatively lines with a thickness
between 0.25 and 2.5 mm, which can be applied in different
ways, e.g. by means of a suitable marker pen or by means
of a template, or by means of adhesive spots.
A suitable choice of colour has to be made to ensure
adequate contrast between the marking and the background
colour. In addition, a second polarisation filter in front of the
camera lens works as analyser, suppressing undesirable
Figure 7. Gauge marks applied to a tensile specimen for
theAVE
reflections from the specimen surface and enabling
optimum boundary definition between the marking and the
specimen surface. In addition, an electronic bandpass filter
in the camera ensures that only light with the wavelength of
the mono-chromatic light source can pass, such that the
influence of ambient lighting is eliminated. During the
measurement, the centres of gravity of the markings are
computed in real time and the strain is determined from
their distance.
This eliminates potential errors due to a deformation of the
markings under the influence of high strains. The minimum
original gauge length, i.e. the distance between the markings
at the beginning of the test, is 5 mm in the case of the camera
lens used, maximum tracking speed for the markings is
150 mm/min. When the 55 mm lens is used, the resolution
for displacement measurement is 0.5 µm, absolute
accuracy is 2.5 µm or 0.5 % of gauge length, whichever is
greater.
Figure 8 shows the results of static tensile tests conducted
on flat specimens with the shape shown in Figure 9. The
test measured the yield strength Rp0.2
, tensile strength Rm
and elongation after fracture A of Al-99.5 micro sheets having
a sheet thickness of 100 µm at various test velocities. The
test system enabled the strain rate to be varied over more
than two orders of magnitude, and the AVE enabled strain to
be measured up to a nominal test velocity of 5 mm/s,
equivalent to a strain rate of more than 0.2 s-1
Apart from measuring axial strain, the AVE also permits
measurement in the transverse direction, meeting the
requirements of ASTM E 8, EN 10001-1 and ISO 6892 for
testing of metals.
21EIS 31 Inners v01.indd 21 22/9/11 15:47:20
Figure 8. Mechanical properties of micro-flat-specimen
of Al 99.5 (thickness 100 µm) in dependence
of the strain rate
Figure 9. Sketch of the tensile specimen
With the help of the ElectroPuls testing system it has been
possible, in cooperation with other Project Areas of the DFG
Collaborative Unit, to make contributions in various fields:
The further development of a PVD-based manufacturing
process for AlSc micro sheets was supported by extensive
studies of their physical properties [2]. In addition, the
mechanical variables determined were used for the
optimisation of micro cold forming processes such as deep
drawing [3] and applied in FEM simulations [4]. Last, but not
least, differences were observed in the mechanical
properties of micro specimens [5], which can be attributed
to typical size effects occurring on transition into the micro
range [6]. On the whole, the test system described here has
proven itself as a valuable and flexible tool for the DFG
Collaborative Research Centre 747 for meeting the wide
spectrum of requirements in the static and dynamic testing
of micro specimens and components.
Acknowledgements
The authors would like to thank Deutsche
Forschungsgemeinschaft (DFG) for their beneficial support
provided during these studies within the framework of the
Project B4 “Component strength” of the Collaborative
Research Centre 747 “Micro Cold Forming – Processes,
Characterisation, Optimisation”.
Literature references
1 F. Vollertsen: Size effects in manufacturing, F. Vollertsen,
F. Hollmann (Hrsg.): Strahltechnik vol. 24, BIAS Verlag
Bremen (2003), S. 1-9, ISBN 3-933762-14-6.
2 H.-R. Stock, B. Köhler, H. Bomas, H.-W. Zoch: Properties
of aluminium-scandium alloy thin sheets produced by
physical vapour deposition, Materials and Design, 31
(2010) 576-581.
3 F. Vollertsen, Z. Hu, H.-R. Stock, B. Koehler: On the limit
drawing ratio of magnetron sputtered aluminium-
scandium foils within micro dee drawing, Prod. Eng. Res.
Devel. 4, 5 (2010) 451-456.
4 P. Bobrov, J. Lütjens, J. Montalvo Urquizo, W. Wosniok, M.
Hunkel, A. Schmidt, J. Timm: Zu einer
verteilungsbasierten Modellierung von Mikrowerkstoffen,
F. Vollertsen, S. Büttgenbach, O. Kraft, W. Michaeli (Hrsg.):
4. Kolloquium Mikroproduktion, BIAS Verlag Bremen
(2009), S. 235-242, ISBN 978-3-933762-32-0.
5 B. Köhler, H. Bomas, J. Lütjens, M. Hunkel, H.-W. Zoch:
Yield strength behaviour of carbon steel microsheets
after cold forming and after annealing, Scripta Mat. 62
(2010) 548-555.
6 F. Vollertsen, D. Biermann, H. N. Hansen, I. S. Jawahir,
K. Kuzman: Size effects in manufacturing of metallic
components, CIRP Annals – Manufacturing Technology
58, 2 (2009) 566-587.
22EIS 31 Inners v01.indd 22 22/9/11 15:47:20
Report on EIS Forum “Seven posters - is that three too many?”The forum took place at the annual EIS instrumentation
exhibition at Silverstone on 8th March. It was chaired by Colin
Dodds with an invited panel of guest speakers: David Hamer
from Lotus Renault GP, David Purdy from Cranfield University,
Defence Academy, Bruce Oliver from Lola Cars and Bernard
Steeples ex Ford and now an engineering consultant.
Colin opened the proceedings with a short presentation
describing the 7-post application and how it differed from
the classic 4-post road simulator and then, each guest
speaker took it in turn to express his views on the subject
before opening up the topic to short presentations and
questions from the floor.
Since the F1 application was the main interest at Silverstone
the discussion focused more on the performance (ride and
handling, leading to lap time) side rather than structural
integrity. A consensus agreed that the 7-post was best suited
to refining dynamic response of a F1 car and had little
application elsewhere whereas the 4-post system has a
plethora of applications ranging from full vehicle durability,
ride, packaging studies and dynamic response.
The session closed with a presentation by Chris Lamming
from the University of Bath who discussed control techniques
for aero-loaders.
The feedback was positive from a number of attendees and
this type of forum may become an annual event coupled
with the instrumentation exhibition. However, there was fear
that the forum detracted from attendance at the exhibition;
the exhibition attendance was small in the afternoon. This
should be resolved prior to introducing the forum as an
annual event. That said, the forum was a success.
ENGINEERING INTEGRITY SOCIETY
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training course and exhibitions and advance notice where booking is required. They receive FREE copies of the EIS
Journal and get priority booking in Exhibitions when space is limited.
We would like to join the EIS as a Corporate Sponsor.
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Please keep our representative informed of the activities of the:
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Engineering Integrity Society, 18 Oak Close, Bedworth, Warwickshire, CV12 9AJ.
23EIS 31 Inners v01.indd 23 22/9/11 15:47:21
Industry NewsWelcome to the Industry News
section of the journal. Thank you to
everyone for their submissions, of
which we received over 500 press
releases. The nominal limit for entry
is 200 words, which should be sent
to [email protected] or
posted to EIS, c/o Amber Instruments
Ltd, Dunston House, Dunston Road,
Chesterfield, S41 9QD. We would
appreciate you not sending entries
by fax.
Paul Armstrong
Exeter study brings brain-like
computing a step closer to reality
The development of ‘brain- l ike’
computers has taken a major step
forward with the publ icat ion of
research led by the University of
Exeter.
Published in the journal Advanced
Mater ials and funded by the
Engineering and Physical Sciences
Research Council, the study involved
the f i rst ever demonstrat ion of
simultaneous information
processing and storage using
phase-change materials. This new
technique could revolut ionise
computing by making computers
faster and more energy-efficient, as
well as making them more closely
resemble biological systems.
Computers current ly deal with
processing and memory separately,
resul t ing in a speed and power
‘bottleneck’ caused by the need to
continually move data around. This
is totally unlike anything in biology,
for example in human brains, where
no real distinction is made between
memory and computat ion. To
perform these two funct ions
simultaneously the University of
Exeter research team used phase-
change materials, a kind of semi-
conductor that exhibits remarkable
properties.
Their study demonstrates
conclusively that phase-change
materials can store and process
information simultaneously. It also
shows experimentally for the first
time that they can perform general-
purpose computing operations, such
as addit ion, subtract ion,
multiplication and division. More
str ik ingly perhaps i t shows that
phase-change mater ials can be
used to make artificial neurons and
synapses. This means that an
artificial system made entirely from
phase-change devices could
potent ial ly learn and process
information in a similar way to our
own brains.
CPT receives investment boost for
its ‘green’ car technology
The UK Low Carbon Innovation Fund
(LCIF), based at the University of
East Anglia (UEA), has invested
£400,000 in new automotive
technologies designed to improve
fuel efficiency and reduce carbon
emissions.
Control led Power Technologies
(CPT) has developed a range of
products to help car makers meet
t ightening legislat ion on CO2
emissions by making the car
signif icant ly more fuel eff ic ient,
through mild electric hybridisation,
without the need to redesign the car
or the car engine. The UK Essex-
based specialists have a range of
products currently in development.
CPT chief executive Nick Pascoe
said: “Although we are now working
on applications around the world, our
products and technologies have all
been developed by our experienced
and growing team of engineers in
the East of England and we are
proud of our roots here. LCIF joins
the list of our major shareholders at
an exciting stage as we work to bring
our more developed products to
market. We welcome and appreciate
LCIF’s support and its recognition of
the fruits of our work since the launch
of CPT in 2008.”
Launched in 2010, the Low Carbon
Innovation Fund is part of a £20
million venture capital investment
programme, including an £8m
contr ibut ion from the European
Regional Development Fund. The
fund, which is based at the University
of East Anglia, invests in SMEs
across the East of England – a region
which aspires to become a leading,
world class low carbon economy.
Companies interested in seeking
investment from the fund should
contact Kevin Murphy on 0207
2481506.
Further detai ls can be found at
www.lowcarbonfund.co.uk and
www.cpowert.com/
UK first as TfL installs eco-lighting
in a London road tunnel
In a UK-first, innovative, eco-friendly
lights have been installed in a central
London tunnel by Transport for
London (TfL) helping to improve
safety, reduce maintenance closures
as well as cut energy consumption
and costs.
The Upper Thames Street
westbound tunnel is now entirely lit
with low energy, long-life LED (Light
Emitting Diode) lights providing a
host of benefits for Londoners. The
design and colour of the lights is
designed to improve visibility for
24EIS 31 Inners v01.indd 24 22/9/11 15:47:21
cyclists and motorists to boost safety.
The l ights wi l l a lso cut CO2
emissions by more than 60 per cent
compared with convent ional
systems, helping to reduce TfL’s
energy bills. Projections show the
cost of lighting the tunnel could fall
from around £50,000 each year to
less than £10,000, del iver ing a
potential annual saving of at least
£40,000. The innovative lights are
also expected to last for 20 years as
opposed to the existing system’s two
year life span, significantly reducing
the need for maintenance closures.
Upgrading the lighting system in
Upper Thames Street tunnel is just
one way the Mayor of London and TfL
are working together to make the
Capital cleaner and greener. London
is already leading the way on the
introduction of hydrogen buses and
electric vehicles while the Capital’s
cycle revolution is increasing the
numbers of bikes on the streets and
improving cycling safety.
Subject to funding, it is hoped that
further schemes can be developed
across London, delivering further
benefits to road users across the
Capital.
‘Walking Chair’ could be step-up for
disabled access
A student inspired by moving
sculptures has designed a prototype
‘walking chair’ that he hopes could
go on to give people with mobility
problems greater freedom.
Martin Harris, 21 – who is about to
complete his BA (Hons) Product
Design degree at the University of
Derby – developed his battery-
powered chair, which uses metal
legs instead of wheels, after seeing
the ‘walking sculptures’ of Dutch
artist and engineer Theo Jansen.
Martin, originally from Birmingham,
said: “I first saw Theo Jansen’s work
many years ago, he calls the walking
sculptures Strandbeests. The
walking mechanism had so much
potential and I wanted to put it to a
practical purpose.”
Instead of wheels the chair moves
on a dozen legs, six on each side,
which are made up of 216 separate
pieces bolted together. The ‘one size
fits all’ seat is completely adjustable,
so it will comfortably accommodate
anybody.
The prototype can move at the
maximum wheelchair speed limit of
four miles per hour. It is powered by
standard wheelchair batteries and
motors, which gives it a range of
several miles on a single charge.
Mart in added: “Most motor ised
wheelchairs are optimised to work
indoors or outdoors, not both. The
walking chair is compact enough for
use indoors whilst also having the
all-terrain ability to cross soft surfaces,
such as sand or grass, which can prove
difficult for wheeled chairs.
“This design is a prototype, and I’d
be happy to see someone take up
the concept and develop it further, for
commercial use.”
Robotics Centre to pave the way for
robots of tomorrow
A groundbreaking new robot ics
centre set to make signi f icant
technological advances, including
developing assistive robots to help
chi ldren and adults with special
needs, has been launched by the
University of Sheffield and Sheffield
Hallam University.
The Sheffield Centre for Robotics
(SCentRo) wi l l combine the
expertise from both universities in a
bid to boost research into the
creation of animal-like robots, self-
driving cars, robots for the farms of
the future and robots that can
intelligently communicate with humans.
Devices on display at this year’s
Towards Automatic Robot ics
Systems (TAROS) conference
included:
• Shrewbot - a unique animal-like
robot that can seek out and identify
objects with its artificial whiskers
using a new technology that was
developed jointly by the Active
Touch Laboratory at the University
of Sheffield and Bristol Robotics
Laboratory. The technology will
enable the robot to function in
spaces where vision cannot be used.
• Guardians – firefighter assisting
robots developed by Sheff ield
Hallam University.
• Grail - a robotic arm designed for
use in domest ic and cater ing
scenarios developed by the
Universi ty of Sheff ie ld’s
Department of Automatic Control
and Systems Engineering.
• The Tact i le Helmet - a super-
sensing helmet being developed
by the University of Sheffield’s
Department of Psychology to help
firefighters find their way in smoke-
filled buildings. The helmet works
by detecting walls and obstacles
through an ul trasound sensor
which converts the signal to a
tactile stimulus such as a buzz on
the head when near a wall.
SCentRo, visit: www.scentro.ac.uk
25EIS 31 Inners v01.indd 25 22/9/11 15:47:21
Industry NewsThe Infrastructure Show
(NEC,Birmingham, 17-19 October)
The show will offer visitors a fresh
insight into major rail infrastructure
projects alongside the opportunity to
understand how these schemes are
managed to reduce environmental
impact and meet spending targets
plus the chance to learn about the
latest product and system
innovations in the sector.
A major highlight of the show will be
its sector-focused hubs and Keynote
Theatre, featuring expert speakers
from Network Rail, Crossrail, HS2,
London Underground and others in
a series of free-to-attend talks. The
Rail hub will also provide a forum for
vis i tors to meet with special ist
suppliers and manufacturers and
see major project updates from the
biggest clients.
A diverse range of leading sector
suppl iers and manufacturers
showcasing the latest product
innovations will also be attending
The Infrastructure Show. Among the
major exhibitors already confirmed
for the event are ACO Technologies,
Cleshar Contract Services, Costain,
CPM Group, CU Phosco Lighting,
JCB, Peri Ltd, Severn Trent Services,
Vinci Construction UK Korec Kosran,
RMD Kwikform, Tony Gee & Partners
and Topcon.
A full exhibitor list is available from
www.infrastructure-show.com
500,000 tonnes of vehicle CO2
emissions could be saved in London
with Start/Stop technology
Fol lowing the announcement by
Transport Secretary Phi l ip
Hammond of the creation of a ‘Clean
Air Fund’ to improve air quality in
London, including such measures as
a ‘no-idling zone’, Bosch believes
that the use of Start/Stop technology
for vehicles in London could reduce
CO2 emissions by over 500,000
tonnes annually.
”Bosch is at the forefront of
developing technologies to make
gasoline and diesel engines more
efficient and less polluting”, said
Peter Fouquet, President of Bosch in
the UK.
The system works by automatically
switching off a vehicle’s engine when
it comes to a stop, for example at
traff ic l ights. When the clutch is
depressed, or the foot is taken off the
brake pedal for an automatic
transmission, the engine restarts
seamlessly in a fraction of a second.
”A Start/Stop system can reduce a
vehicle’s CO2 emissions by 8
percent in average city driving, and
up to 15 percent in dense city traffic.
In addit ion, the technology also
reduces noise pollution”, Fouquet
said. “The benefit can be further
improved when a Bosch ul tra-
eff ic ient al ternator is added.”
See Bosch’s Start/Stop system in
action for vehicles with both manual
and automatic transmissions via the
following link:
w w w . y o u t u b e . c o m / u s e r /
boschautomotive
University doubts after ‘A’ level
results? - Current students
recommend a working gap year
despite the fee increases.
Students struggling with their options
in the light of their ‘A’ level results
have clear advice from a survey of
current university students who took
a working gap year with ‘The Year in
Industry’ programme (YINI). They are
overwhelmingly recommending that
‘A’ level students in relevant subjects
should in pr inciple go on the
programme, with 94% of those
surveyed saying they would
recommend the programme, and,
significantly, only one in six see the
2012 fee increase as presenting a
strong reason not to undertake this
career changing paid gap year in
2011/12.
‘The Year in Industry’ programme, run
by educat ional chari ty EDT,
specialises in placing students on a
paid working gap year with leading
engineering, technology or science
companies.
The survey results throw the benefits
of a working gap year through “The
Year in Industry” into sharp focus:
• 94% said YINI had helped them
decide their career preferences
• 97% said YINI had made them
more employable
• 75% said it had helped them in
their degree studies
Turing Bombe rebuild team leader
recognised with honorary doctorate
On the 4th June 2011, John Harper
was among over 200 students
receiving various qualifications from
the Open University at Ely cathedral
but what made John special was he
was the only one receiving an
honorary doctorate. The Open
University presented John with this
honour in recognition of his work,
leading a team of talented volunteers
to recreate the Turing Welchman
Bombe at Bletchley Park.
John Harper, a qualified chartered
engineer, is a key member of those
26EIS 31 Inners v01.indd 26 22/9/11 15:47:22
visionary enthusiasts who undertook
the long and complex process of
recreating the technology of World
War Two. He has been the driving
force in preserving much historical
material in danger of being lost,
persuasively obtaining funding,
industrial and governmental support,
of ten in an environment of
disinterest.
The World War Two Bombe Rebuild
is on public display at Bletchley Park,
and is normally demonstrated at
weekends.
www.bletchleypark.org.uk
Dedication of Bletchley Park
Memorial by HM The Queen
Her Majesty The Queen dedicated a
public memorial at Bletchley Park,
Milton Keynes, Buckinghamshire on
Friday 15 July, to commemorate all
those that provided vital service at
Bletchley Park and its ‘Outstations’
during World War II.
This was The Queen and Duke of
Edinburgh’s first visit to the home of
the wartime code breakers. They
were accompanied throughout the
visi t by Sir Francis Richards,
Chairman of the Bletchley Park Board
of Trustees and Simon Greenish,
Director of the Bletchley Park Trust.
The Royal Party was provided with a
short tour of the museum and shown
some of the restoration projects
which have taken place at Bletchley
Park to rebuild the machines which
assisted with the wartime decryption
of enemy codes. These included the
Turing Bombe, brainchi ld of
mathematical genius Alan Turing,
and Colossus, the world’s f i rst
electronic computer. The Queen was
also shown an Enigma machine and
given a demonstration of how it
worked.
Following the ceremony, The Queen
was shown the Roll of Honour which
lists the names of all of those who
served at Bletchley Park and its
‘Outstations’ during the War. This
has been compiled over a number of
years and includes nearly 11,000
names.
www.bletchleypark.org.uk
Engineers find leaky pipes with
Artificial Intelligence
University of Exeter engineers have
pioneered new methods for
detecting leaky pipes and identifying
f lood r isks with technologies
normally used for computer game
graphics and Artificial Intelligence.
These techniques could help to
identify water supply and flooding
problems more quickly than ever
before, potentially saving people from
the traumatic experience of flooding
or not having water on tap.
Existing methods for detecting leaks
often result in false, so-called ‘ghost’
alarms. Universi ty of Exeter
engineers have developed a new
approach, based on technology
originally developed in the field of
Art i f ic ial Intel l igence. The new
technology is implemented as a
piece of software located on a
computer in the control room of a
water company. The software
cont inuously receives and
processes data coming from the flow
and pressure sensors installed in
the water system. It then searches
for anomal ies indicat ing the
presence of the leak. When a
potential problem is identified, an
alarm is generated to noti fy the
control room operator. The operator
also receives information on the likely
location of the leak and suggestions
of immediate act ions to take to
isolate it.
F1 in Schools™ out and about at
Silverstone, London, Goodwood and
Grove.
F1 in Schools™ had a busy couple
of weeks in July with the initiative
flying the flag for young engineering
talent and showcasing winners of its
innovat ive Formula 1™ l inked
education programme at a number
of high profile events.
The Santander Formula 1 British
Grand Prix was the highlight of the
year for winners of F1 in Schools
2011 National Finals Awards, with
eight teams visiting this prestigious
event on the Bri t ish sport ing
calendar. Prior to the Grand Prix
weekend the reigning UK F1 in
Schools champions, ‘Dynamic’, from
St. John Payne Cathol ic
Comprehensive School in
Chelmsford, Essex, were guests of
Hilton Racing for a high profile media
event, the Hilton on Park Lane Pit Stop
Challenge. A group of UAE primary
school students flew in to the UK to
link with the Bloodhound SSC land
speed record project at the
Goodwood Festival of Speed earlier
this month and this week teams of
9-11 year old primary school students
competed at the T1 Primary Racing
Challenge 2011 finals, supported by
F1 in Schools, held at the Williams
F1 team HQ.
For further information about F1 in
Schools visit www.f1inschools.co.uk.
27EIS 31 Inners v01.indd 27 22/9/11 15:47:22
Product Newsand dry gas applications.
The fast response times, combined
with high pressure and flow
capabilities, make the E-Series
solenoid valves ideal for use in a wide
range of applications, including
medical and respiratory healthcare
instruments, printing machinery and
sorting equipment, automated
packaging and air monitoring systems.
Gems Sensors and Controls,
Basingstoke, Hampshire.
Tel: +44 (0)1256 320244.
Email: [email protected]
Electric motion control system for
Wimbledon Centre Court retractable
roof
Moog Industrial Group, a division of
Moog Inc. (NYSE: MOG.A and MOG.B)
has signed a new 5 year contract with
SCX Special Projects, Sheffield, UK to
continue its support of the motion
control system for the Wimbledon
Centre Court Retractable Roof, London
until August 2015. The new service and
support contract is managed by Moog’s
operation based in Tewkesbury, UK.
Since the installation of the retractable
roof in 2009, Moog’s motion control
system has helped ensure
uninterrupted play during all weather
for tennis fans worldwide throughout
the 2009 and 2010 Wimbledon
Championships. The new contract is
now set to continue this successful run
until 2015.
Easy to use modular test controller
from MOOG handles wide range of
tasks
Moog’s latest test controller is intended
for simple and complex tests on
components, materials and vehicles.
The new Modular Test Controller is the
latest addition to a family that already
includes larger units dedicated to
aerospace and automotive testing, as
well as the Portable Test Controller.
Based on input from customers at
leading material, automotive and
offering users the latest technologies
as part of the complete vibration test
solution from Brüel & Kjær.
Both of the new variants promise to save
time and simplify testing procedures
by virtually guaranteeing signal under-
ranges and overloads are eliminated.
This is thanks to dual, parallel A/Ds that
deliver an exceptionally wide 130 dB
dynamic range for the input channels,
without the need for programmable
voltage range circuitry.
Bruel & Kjaer, Royston, Herts.
Tel: 01763 255 780, www.bksv.com
Net shape steel and titanium castings
Over the years, Castings Technology
International (Cti) has perfected the
manufacture of castings from
precision-machined polystyrene
patterns. As in the Lost Wax process,
layers of ceramic are built up on the
pattern, which is removed on firing to
leave an inert ceramic shell mould.
These can be used to produce
prototype Replicast® castings and to
meet a market need for short lead-time,
one-off and low volume castings.
More recently the MEGAshell®
technology has enabled exceptionally
large ceramic shell moulds to be
produced to deliver the benefits of
Replicast® of a size and weight far
greater than most casting
manufacturers would have believed
possible.
Castings Technology Int., Rotherham,
South Yorks. Tel: 0114 2541166, Email:
New low energy solenoid valves from
Gems Sensors give fast response and
high flow
Gems Sensors & Controls, a global
market leader in fluid sensing and
control solutions, has introduced the
energy efficient E Series family of
pneumatic solenoid valves, specifically
engineered to give fast response and
high flow rates in a wide range of air
New release of computing software
The latest, substantial new release of
Maple™, the flagship technical
computing software for
mathematicians, engineers and
scientists from Maplesoft™ (Waterloo,
Canada), has over 270 new
mathematical functions and over a
thousand enhancements to existing
algorithms. Now available from Adept
Scientific (Letchworth, Herts), Maple
15’s record-breaking solvers for
differential equations is just one of
many new advances in Maple 15 which
enables customers to solve more
complex problems even faster.
Adept Scientific, Letchworth, Herts.
Tel: 01462 480055.
Email:[email protected]
10 MHz USB data acquisition module
with two isolated Analog inputs
Data Translation announces the
release of a cutting-edge data
acquisition module that sets new
standards in 16-bit high-speed data
acquisition via USB 2.0. With up to 10
MHz signal sampling and direct
streaming to the PC, the new DT9862
can provide twice the USB throughput
rates achievable with comparable
solutions currently available on the
market. All I/O channels are galvanically
isolated to ensure ultra-high
measurement accuracy and signal
integrity. In addition, the new module
also features flexible clock and trigger
functions (e.g. pre-, post- and about-
trigger modes).
Data Translation GmbH, Germany.
Tel: +49 (0)7142/95 31-0.
www.datatranslation.eu
Good vibrations
Sound and vibration leader, Brüel &
Kjær, has released its next-generation
vibration controller. Type 7541 and 7542
vibration controllers are designed to
meet the requirements of vibration
testing for production test applications,
28EIS 31 Inners v01.indd 28 22/9/11 15:47:23
aerospace test laboratories, it provides
for efficient operation in an array of
testing applications, including shock
absorber tests, single-axis test
systems, vibration and performance
evaluation tests.
Moog, Nieuw-Vennep, The
Netherlands. Tel: +31 (0)25 246 2034.
New motorized pendulum impact
testing system for increased
productivity and operator safety
Available in capacities from 300 via
450, 600 and 750, up to 900 J, Instron’s
newly developed MPX motorized
pendulum impact testers are ideally
designed for testing metals to Charpy
and Izod standards. Thanks to their
motor-driven raising of hammer with
auto-return after test, all MPX systems
are quick and easy to operate for
increased productivity and operator
safety. An electromagnetic brake/clutch
control allows the hammer to be safely
dropped, whilst its dual latch design
prevents accidental release and a
safety enclosure with interlocks
prevents the hammer from dropping
and stops movement when any door is
open. An adjustable latch height allows
for lower pendulum energy/velocity.
Instron Deutschland GmbH,
Pfungstadt, Germany.
Tel: +44 (0) 6157 4029 600.
LMS-InterAC partnership completes
the LMS Acoustic Simulation
solutions to cover the full frequency
range.
Recent distribution agreement brings
best-in-class Statistical Energy
Analysis (SEA) technology to the
world’s leading acoustic simulation
package.
LMS International and InterAC have
signed a strategic partnership to
distribute InterAC’s SEA+, SEAVirt and
related SEA modules to complement
the market-leading LMS Virtual.Lab
Acoustics package. In the world of
vibro-acoustic simulation, SEA is a
technology that provides a reliable
solution for high frequency problems
as well as full system vibro-acoustic
evaluation.
As acoustics takes more of a defining
role in product development, vibro-
acoustic engineers need better tools
to assess concepts and early stage
designs. Unlike other methods, SEA
does not require geometrical details,
but merely global system properties.
This is why SEA is ideal early in the
concept phase when design details,
like CAD or a FEM mesh, are not available.
www.lmsintl.com
PULS UK introduces life expectancy
data logging to QS/QT 40 power
supplies
Leading Din Rail power supply
manufacturer PULS UK has introduced
data logging to its single-phase QS40
and three-phase QT40 1 kW units. The
move will enable the company to
establish life expectancy figures based
on actual in service conditions.
PULS uses semi conductor technology
to collect data relating to operating
temperature, input voltages and other
vital information which can later be
downloaded to calculate the life
expectancy of the product. The company
is also developing a version that can
be downloaded externally allowing
customers to monitor the condition of
the power supply and schedule its
replacement during normal
maintenance programmes. PULS
expects its new technology to be
particularly effective in mission critical
applications, such as oil and gas
installations, where power failure could
result in serious consequences for
operators.
Power supply manufacturers use MTBF
(Mean Time Between Failure)
procedures to estimate the life
expectancy of their products using
accepted industry figures; but PULS is
the first to provide accurate information
based on real-life operating conditions.
Toyohashi Tech researchers (Japan)
develop magnonic crystal-based
ultra-high sensitive magnetic fields
sensors for monitoring heart and
brain activity and room temperature
High sensitivity magnetic sensors are
important in medical diagnostics for
applications such as monitoring heart
and brain activities, where mapping
distributions of localized extremely
weak magnetic fields arising from
these organs could provide early
warning of life threatening diseases
and malfunction.
Mitsuteru Inoue and colleagues at
Toyohashi University of Technology
(Toyohashi Tech) have developed high
sensitivity magnetic sensors using
magnonic crystals—artificial magnetic
crystal structures capable of controlling
the propagation of magnetostatic
waves. Magnonic crystals support the
propagation of magnetostatic waves
through the crystal spin system or
suppress the propagation of waves due
to the periodicity of the crystal structure.
Contact: Ms. Junko Sugaya and Mr.
Masashi Yamaguchi, International
Affairs Division Tel: (+81) 0532-44-
2042, E-mail:[email protected]
New Sidewinder(TM) reference
design can provide a complete base
station on a single PCB
Cambridge Consultants, a leading
design and development firm, has
launched Sidewinder(TM), the smallest
commercially available 2G and 3G
small-cell platform. Ideal for use in
mobile phone communications and
professional radio, Sidewinder is
software configurable between GSM/
GPRS/EDGE, WCDMA/HSPA+ and
other SDR applications, providing new
levels of adaptability for cellular base
stations. It offers a low cost of entry for
companies wishing to exploit these
standards and sets a new benchmark
in flexible, cost effective designs.
Contact: +44 (0)208 408 8000.
29EIS 31 Inners v01.indd 29 22/9/11 15:47:23
The Engineering Integrity Society is an independent charitable organisation, supported and sponsored by industry.The Society is committed to promoting events and publications, providing a forum for experienced engineersand new graduates to discuss current issues and new technologies. We aim for both company and personaldevelopment and to inspire newly qualified engineers to develop their chosen profession.
Events run provide an ideal opportunity for engineers to meet others who operate in similar fields of activity overcoffee and lunch. All of our events enable engineers to establish and renew an excellent ‘contact’ base whilekeeping up to date with new technology and developments in their field of interest.
We are involved in a wide range of Industrial sectors including Automotive, Aerospace, Civil, Petrochemical etcand continue to be interested in new members from all sectors.
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Act now and become an EIS Member today.
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Thank you for becoming a member of the Engineering Integrity Society.
Registered in England No. 1959979 Registered Office: 18 Oak Close, Bedworth, CV12 9AJ VAT No. GB 443 7696 18 Registered Charity No. 327121
EIS 31 Inners v01.indd 30 22/9/11 15:47:24
Profile of Company MembersAdept Scientific plc
Amor Way
Letchworth
Herts
SG6 1ZA
UK
Tel: +44(0)1462 480055
Fax: +44(0)1642 480213
Website: www.adeptscience.co.uk
Adept Scientific is one of the world’s leading suppliers of
software and hardware products for research, scientific,
engineering and technical applications on desktop
computers.
Adept’s customer base includes world-leading technology-
based manufacturing corporations, universities in the UK,
Ireland, Germany and Denmark, small and medium-sized
businesses, government departments, local authorities,
hospitals, charities and NGOs.
In the academic, business and technical world Adept
Scientific is known for its efficiency and expertise in supplying
solutions essential for customers’ business requirements,
offering the highest level of support and back-up.
Millbrook Proving Ground LtdStation Lane
Millbrook
Bedfordshire
MK45 2JQ
UK
Tel: +44 (0)1525 404242
Fax: +44 (0)1525 403420
Email:[email protected]
Website:www.millbrook.co.uk
Contact: Neil Fulton
Millbrook is one of Europe’s leading locations for the
development and demonstration of every type of land vehicle,
from motorcycles and passenger cars to heavy commercial,
military and off-road vehicles. Our custom-built facility
provides virtually every test, validation and Homologation
service necessary for today’s demanding programmes,
complemented by a worldwide reputation for confidentiality,
service and competitiveness.
We also engineer, develop and build low-volume service
vehicles, trial and evaluate vehicle capability, investigate in-
service failures and provide specialist Driver Training.
MIRA Limited
Watling Street
Nuneaton
Warwickshire
CV10 0TU
UK
Tel: +44 (0)247 635 5000
Fax: +44 (0)247 635 8000
Email: [email protected]
Website: www.mira.co.uk
Contact: Kristy Thompson, Marketing Manager
MIRA is a highly customer-focused, world-class,
independent vehicle engineering consultancy, shaping
everything we do around the partnerships we create. We
harness the skills, experience and knowledge of our talented
experts to provide our customers with intelligent solutions
to their challenging problems. MIRA offers full system design,
test and integration expertise to the global automotive,
defence, rail and transport industries. MIRA’s technical
facilities provide a truly global centre of excellence from which
to innovate, engineer, test and implement market changing
solutions.
31
Research by the Younger Engineer
Are you just starting out on an engineering career or
currently studying for a postgraduate degree. Would
you like to tell us about your research? What is the hot
topic at the moment?
We have many industrial readers who would be
extremely interested in hearing about your research,
both what it involves and its background. Articles of up
to 850 words (approx 1 A4 page) can be published
under our new ‘Research of the Younger Engineer’ in
the journal, presenting a great opportunity to make
industry aware of your work.
Send your articles to the Editor:
Dr Karen Perkins
Materials Research Centre
School of Engineering
Swansea University
SA2 8PP
EIS 31 Inners v01.indd 31 22/9/11 15:47:24
News on Smart Materials and StructuresWelcome to our
co lumn on Smar t
Materials, with the
usual mix between
technical news and
forthcoming evens
in the field.
The MEMS industry
relies heavily upon
rare -ear th meta ls
(Neodymium, Yttrium, Gadolinium
for example). It is now a well know
fact that 97 % of rare earth metals
wor ldw ide a re p roduced in PR
China, and this situation generates
some concern about any possibility
of monopolising the market (“Put all
the eggs in a basket, but watch that
baske t ” , as popu la r w isdom
enunc ia tes) . A recent paper
produced by a team f rom the
University of Tokyo and published
in Nature Geosc ience (h t tp : / /
www.nature.com/ngeo/journal/v4/
n8/ful l /ngeo1185.html) describes
up to 78 sites, between 3000 and
6500 m below the South and North
Pacific surface. These sites could
provide up to one fifth of the world’s
consumpt ion o f ra re ear th
elements, definitely not a negligible
percentage. There are some strong
env i ronmenta l concerns about
mining rare earth minerals, both
above and below the sea. However,
considering the extremely strategic
role that these metals invest in our
techno logy, I wanted to g ive a
particular mention to this discovery.
Someth ing e lse tha t may be a
future game-changer for systems
and architectures for active control,
embedded sys tems and mode l
simulation is the new Intel Tri-gate
chip (ht tp: / /newsroom.intel .com/
docs /DOC-2032) , wh ich shou ld
al low to cont inue the val idi ty of
Moore’s law beyond the 22 nm and
14 nm processors ( the la t te r
currently considered as the limit for
in tegra t ion due to quantum
mechanics effects). Although this
transistor appears to have been
designed essentially to cut a big
slice of the market for tablets and
smar t phones (cur ren t l y
monopolised by ARM, a truly British
success story), i t is foreseeable
that the use of the chip will have
more than an appl icat ion, f rom
sensor systems with high through-
put bus data rates to h igh-end
design and s imulat ion sof tware
tools.
In the field of Structural Integrity, I
would like to highlight the recent
development of an opt ical f ibre
corrosion sensor based on l ight
reflection principles, and produced
by a team from the University of
Texas at Arlington. The design of
the sensor is based on an optical
fibre reflection device coupled to a
tube/film sub-assembly, formed by
welding a sacrificial metallic fi lm
to a steel tube. One side of the
sacrificial metallic film is polished
and isolated from the environment,
while the opposite side is exposed
to the corrosive environment. The
corrosion pits erode the sacrificial
film, and reduced the reflectivity of
the polished surface, which is then
detected by the fibre optics. The full
descr ip t ion o f th is in te res t ing
sensor has been recent ly
published in Smart Materials and
Structures
(IoP, http://iopscience.iop.org/0964
1726/20/8/085003/pdf/0964
1726_20_8_085003.pdf).
Another recent in te res t ing
development generated by a team
f rom Fraunhofer Ins t i tu te and
University Technical Darmstadt is
the use o f ac t ive p iezoe lec t r ic
pa tches to reduce c rack
propagation in aluminium plates
(h t tp : / / i opsc ience . iop .o rg /0964
1726/20/8/085009/pdf/0964
1726_20_8_085009.pdf). The main
idea behind the concept is to lower
the cyclic stress intensity factor
near the tip of the crack using low
voltage piezo actuators, decreasing
therefore signif icant ly the crack
growth ra te . The paper a lso
descr ibes a s tat is t ica l analys is
made on several test layouts, and
showing an average 20 % reduction
of crack propagation in the various
cases. A promising start for this
concept, and a very good piece of
work from the German team.
We look now a t a se lec t ion o f
incoming conferences in the area
of smart materials and structures.
For the aud ience in teres ted in
Structural Heal th Moni tor ing an
important event this year will be
SHM 2011 in Krakow (Poland: http:/
/en.shm2011.pl/). Embedded within
the conference there will be a short
course on St ruc tu ra l Hea l th
Mon i to r ing w i th p res t ig ious
speakers of the field. Preparations
are already underway for CIMTEC
2012 (4th International Conference
of Smart Materials and Systems,
Monteca t in i ( I ta ly : h t tp : / /
www.c imtec-congress.org/2012/
genera l_ou t l ine .asp) . The
conference has several paral le l
sessions, and promises to be one
of the t rue happen ings o f the
season in the smar t mater ia ls
field. For people having the chance
of travelling through India at the
beginning of next year, the Indian
Ins t i tu te o f Techno logy o f
Bangalore organises the 6th ISSS
Conference ( ISSS – 12: h t tp : / /
isssonline.in/isss-2012), which is
anticipated to be one of the major
events in Asia next year. Closer to
home is the ECCOMAS SMART’11
organised by Fraunhofer IZFP in
Saarbrücken (Germany – URL at
h t t p : / / w w w. i z f p . f r a u n h o f e r. d e /
smart11/).
Best wishes for a fruitful activity in
the months to come.
Fabrizio Scarpa
Professor of Smart Materials and
Structures, Bristol University
32EIS 31 Inners v01.indd 32 22/9/11 15:47:25
News from Formula Student
33
Institution to
host Ai r
C a p t u r e
Week to
demonstrate
key c l imate
c h a n g e
solution
T h e
Ins t i tu t ion o f Mechan ica l
Eng ineers w i l l be hos t ing “A i r
Capture Week” in October to raise
awareness amongst the publ ic,
pol icy makers and engineers of
one o f the most innova t ive
emerging technologies in the fight
against climate change.
The week long series of events,
which will start on 24 October, will
feature an international summit of
experts, workshops, discussions
and debates, as wel l as a l ive
public demonstration of air capture
technology. The latter will be given
by Professor Klaus Lackner from
Columbia University in front of a
London audience on the evening
of 26th October.
By using air capture machines to
remove CO2 from the air and then
storing it underground, it creates
negat ive emiss ions which help
reduce the concent ra t ion o f
g reenhouse gases in the
atmosphere.
CO2 captured by the devices could
also be used for carbon recycling,
where industries that require CO2
as a chemica l feeds tock fo r
mak ing p roduc ts such as
substitute fuels, source their CO2
from the atmosphere and thereby
es tab l i sh ‘ c losed ’ loops fo r
carbon.
Air capture technologies currently
provide a viable solution to historic
emissions produced in the last
century and di f f icul t to manage
emiss ions l i ke those f rom
aviat ion,shipping and dispersed
industries.
Fur thermore as in te rna t iona l
climate change negotiations stall
these technologies buy the world
t ime to get to grips with cutt ing
emissions produced.
Efforts to combat climate change
have largely and rightly focused on
mitigation – so cutting the amount
of greenhouse gas emiss ions,
particularly the CO2, we produce.
While work must continue to reach
a global agreement with ambitious
cuts to emissions, there is also a
real need for governments and
industry to look at creat ive and
ingen ious ways o f p revent ing
climate change by tackling difficult
emissions sources and taking out
the greenhouse gases we have
already put in the atmosphere –
essentially cleaning up air.
As will be demonstrated during the
Institution’s”Air Capture Week”, the
technology to make these CO2
absorb ing mach ines a l ready
ex is ts , bu t government and
bus inesses need to p r io r i t i se
funding in these technologies to
make them happen quickly and on
a b ig enough sca le to make a
difference.
The Ins t i tu t ion o f Mechan ica l
Eng ineers i s ca l l i ng on UK
Government to:
• support more detai led work to
establish the cost of air capture
technology and demonstrate i ts
feasibility;
• develop policy frameworks that
enable the adoption of negative
emissions and carbon recycl ing
approaches to mitigation; and
• provide international leadership
on negative emissions and carbon
recycling.
Wi th the lack o f in te rna t iona l
p rogress in the mi t iga t ion o f
climate change, there is an urgent
need fo r governments and
bus inesses to fund techno logy
development and to accept that air
capture is a key part of the solution
to the b igger c l imate change
problem.
Dr Tim Fox
Head of Energy and Environment
at the Institution of Mechanical
Engineers
Instrumentation, Analysis and Testing Exhibition
Tuesday, 6 March 2012
10:00 - 16:00
Silverstone Race Track
International Exhibition Centre
Diary of Events
EIS 31 Inners v01.indd 33 22/9/11 15:47:25
Challenge to Improve the Process from design to productThis article is intended
to stimulate a debate on
a subject frequently
discussed but rarely
addressed. Within
organisations each
technology section is
driven by its own
objectives but the
c o m m u n i c a t i o n
between sections is
generally nobodies responsibility.
Our process from design through
prediction test and production needs
to improve if we are to realise the
demands of product improvement in
shorter time and lower cost whilst
ensuring product life and warranty.
The challenge is to achieve the
following targets and for Managements
to accept the need for the required
organisation to:-
1. Improve and validate predictive
models.
2. Use simpler materials with lower
manufacturing sensitivity.
3. Reduce test time and power
consumed by 50%.
4. Maintain or increase product fatigue
life.
5. Optimise and monitor
manufacturing effects on fatigue.
6. Reduce time to market.
Technologies used in the complete
process appear to have become
increasingly isolated and whilst they
have improved their own process the
transfer of data between has remained
historic and limited.
1. Improve and validate predictive
models
Predictions often use inappropriate
material data. Materials are now offered
that suggest improved life but frequently
suffer from the difficulty of maintaining
their advantageous properties through
the manufacturing process. The quality
control material inspection generally
only provides information based on
static values of a sample which has
not been stabilised and has unknown
residuals. Testing has shown that
material from different suppliers all to
the same specification and passed
goods inward inspection had a
difference in fatigue results of 5 to 1.
2. Use simpler materials with lower
manufacturing sensitivity
The manufacturing process is
significant in creating the final material
condition in the component and yet few
if any measurements are made to
identify manufacturing changes which
control and improve component life.
When components are formed and
welded significant changes to these
properties almost always take place.
The degree of work done in the forming
process and the distributed thermal
changes in the welding process can
result in significant residual strain
variations.
A 3 to 1 life variation caused by an
uncontrolled cooling process after
welding creating residual strain from
thermal gradients.
3. Reduce test time and power
consumed by 50%
Frequently information provided for a
test is a load profile to be applied. The
anticipated deflections at the loading
points should be provided but often are
not. These deflections fix the flow,
response and power requirements of
the servo hydraulic actuators of the test
rig. Often the limitations of the rig are
not identified until the rig is built. With a
complete set of initial information the
rig limitations can be identified and
addressed. Modifications to reduce test
time and power and give a repeatable
test with the available equipment can
be proposed. Slowing down the fewer
high velocity amplitudes and speeding
up the many lower velocity amplitudes
can significantly reduce test time whilst
applying the same profiles. Test times
are frequently reduced by a factor of 4
and in many cases a factor of 8. The
test takes 12% to 25% of the original
time and uses less power.
4. Maintain or increase product life
Difference in residual strain in received
material can be significant. Flat steel
sheet is bent straight to meet flatness
specifications. This has the potential
to create wide variation within the sheet
of residual strain.
When components are formed and
welded significant changes to these
properties almost always take place.
The degree of work done in the forming
process and the distributed thermal
changes in the welding process can
result in significant residual strain
variations. Control and manipulation of
induced residuals has shown 3 to 1
life improvement.
5. Optimise and reduce
manufacturing effects of fatigue
Test reports generally give arrangement
definitions and life as a cycle count with
details of failure location if appropriate.
If no failure occurs little or no information
is provided as to how much life was
still in the component. It is generally an
assumption that the test carried out did
have the load distribution of the
predictive model. Techniques are
available which give 3 D strain
distributions of the component under
test providing overlay files for model
validation. These show actual load path
and real deflections.
Huge differences between the
predicted and achieved are apparent
when unlike data is compared.
Incorrect changes in design can result
from this non validated process.
6. Reduce time to market
By applying these techniques and
continually updating and validating
each stage of the process with real
information significant changes can be
made in time to market for a new
product. It is important to develop the
complete product process based on
measured and improved data instead
of a comparative evaluation based on
previous units.
Discussion
The communication between
technologies needs to be improved
and techniques, which are available
34EIS 31 Inners v01.indd 34 22/9/11 15:47:25
BS 8888:2011
Later this year, a new
revision of BS 8888 will
appear, which will be the
most significant update
since the standard was
first published in 2000.
The year 2000 was
when the British Standards Institution
(BSI) withdrew BS 308, the UK’s
national standard for engineering
drawing, and adopted instead the
international system for technical
specifications which is defined in ISO
standards.
This international system for technical
product specification is known as
Geometrical Product Specification (ISO
GPS). It is defined in a range of
interlinked ISO standards, and has
been adopted throughout Europe, and
also by many other countries across
the globe. In fact, the only alternative in
widespread use is the American system
of geometric dimensioning and
tolerancing which is defined in the
ASME Y14.5 standard.
When the UK adopted the ISO GPS
system, BSI also published a new
standard, BS 8888, which was intended
to ease and simplify the transition from
BS 308 to the ISO GPS system.
BS 8888 has since been revised and
up-dated several times, to keep
abreast of developments and changes
within the ISO GPS system.
News from British StandardsBS 8888 was always conceived of as a
‘signpost’ document, which would
guide people through the ISO system,
and provide some explanation about
how to work with it. In large part it is an
index, which is essential if users are to
find information amongst the large
number of ISO standards that
constitute the ISO GPS system.
Despite this, it is still often difficult to
work with a system which is dispersed
across a wide range of different
standards, and although there is some
structure to the way in which these
documents are organised and inter-
relate, it is still somewhat haphazard
in many areas.
When this is coupled with the fact that
the ISO GPS system is continuing to
expand, with the development of many
new capabilities for the definition of
technical requirements, in ever
increasing detail, there are clearly going
to be challenges for anyone attempting
to work with it.
In an attempt to address these
challenges, the next revision of BS
8888, due for publication towards the
end of 2011, is going to incorporate a
substantial amount of technical content
which has been brought across from
some of the key ISO standards. The
aim is to provide the basic elements of
technical product specification, and ISO
GPS, in a single document. This will
not replace the ISO standards, which
will still be referenced from within the
British Standard, and will provide more
extensive and more detailed content,
but it should mean that the most
fundamental elements of the system
will be gathered together in a more
accessible format.
The document will be split into two
sections, the first for Technical Product
Documentation, and the second for
Geometrical Product Specification. The
first section will cover the manner in
which information is presented, such
as the layout of drawing sheets,
projections, format of dimensions and
tolerances, representation of features,
etc. The second section will deal with
how products are specified, with the
use of datums, geometrical tolerances,
surface texture requirements etc.
At the time of writing this, an early draft
is being published by BSI for public
comment and feedback, although there
is still further detail to be added, and
some further changes to be made,
before final publication. If you read this
in time, you will be able to have a look
at the draft document, and pass on any
comments or feedback (BSI publishes
draft standards for comment at http://
drafts.bsigroup.com/).
Iain Macleod
Iain Macleod Associates
and Chair of BSI technical committee
TDW/4/8 which is responsible for the
maintenance and development of BS
8888.
employed to control and validate each
stage of the process.
The global market demands less
sophisticated and more economic
controlled materials which are less
vulnerable to the manufacturing
process.
Cost and time of each step of the
process has to be reduced and our
predictive modelling capability
improved by validation that include
controlled production processes.
The technologies are available and
mature.
The problem is that there is no
organisational responsibility for the
improvement of information between
technologies. Techniques are not seen
within one technology area as being
their responsibility.
I look forward to your comments.
Norman Thornton
Engineering Consultant
Continued from previous page
35EIS 31 Inners v01.indd 35 22/9/11 15:47:26
In the last issue of the Journal I
contributed a column on Open Access
technical information. I also promised
a short series about large-scale
changes which are taking place in
publishing practices. Here is the
second.
The first article was about institution
repositories, and how this has made a
difference to accessing research
information. Alongside these changes
similar ones have been occurring in
availability of teaching material. A
development which was initially called
Open Courseware (OCW), and is now
usually called Open Educational
Resources (OER), has made much
teaching material freely available in all
subjects. Downloading is immediate
and copyright is usually a Creative
Commons License. If you want to know
more about this sort of License look
up my article in this journal (reference
below). Briefly it means that you can do
what you like with the information as
long as you say where it came from
and don’t use it to earn money.
You may not be involved in education,
but some OER material may still be
useful to you. For example, the UK
Open University have released many
of their courses under Creative
Commons Licences, using the
heading OpenLearn. They list 36
courses under Engineering and
Technology, 29 under Computing and
ICT, and 38 under Business and
Management. I have known for some
time that there was an OpenLearn
course called “Finding Information in
Engineering and Technology”. Recently
I needed to read another one called
“Finding Information in Business and
Management”. As I started this article I
had a closer look and discovered
‘Finding Information in’ Computing and
ICT, Arts and History, Education, Health
and Lifestyle, Modern Languages,
Mathematics, Science and Nature, and
Society. Many us spend time searching
for information these days. Perhaps these
free courses might be worth a look.
All ten of the courses have the same
framework, with bolted-on bits to suit
each subject. You will probably be able
to skip the starting questionnaire about
how competent you are already. You will
also know how to use keywords, but
the section about how to systematically
build a keyword list for a serious search
may sharpen your performance. You
probably use a general search engine
like Google, but the courses list many
more sources under various headings.
Taking the Engineering and Technology
one, the list is:
Search engines; Google, Yahoo!,
AltaVista, Ask.com, Google Scholar.
Subject gateways (Directories)
BUBL, Intute, TechExtra,
Books and electronic books
WorldCat.
Databases ROUTES, Recent
Advances in Manufacturing, TRIS
Online.
Images Arts and Humanities Data
Service, British Library Picture
Library.
Journals Directory of Open Access
Journals (plus some advice on
general journal searching).
Encyclopedias Wikipedia, Encarta.
Patents Esp@cenet, UK Patents
Office, World Intellectual Property
Organisation.
News sources EureaAlert, Abyz
News Links
A description is given of the
characteristics of each source. At the
end of the list is a section giving five
questions to help you decide whether
a particular source is right for your task.
The modules I have used then go on to
a section about checking whether the
information found is of good quality.
Most of us know that much of the
information on the internet is unreliable.
If reliability is important an approach
called PROMPT is recommended. This
suggests checking six qualities. These
are:
• Presentation (is it easy and
pleasant to read)
• Relevance (whether it is what you
want)
• Objectivity (it should be objective,
that is not biased)
• Method (how was the information
obtained)
• Provenance (who published it, how
qualified are they)
• Timeliness (is it old or recent)
There are about 200 words of text for
each of the six points, giving guidance
about what to look for.
Information produced by searches will
normally be stored on a hard disk. Your
space on this disk will have your files,
usually separated into folders or other
divisions. Organising these so that you
can get the one you want when you want
it can be a problem. If you are using
Microsoft Windows this has a ‘Find’
command, but this can be slow. The
courses point out that a faster
alternative is a desktop search tool
such as:
• Ask
• Copernic
• Google Desktop
• Windows Live Toolbar
• Yahoo! Desktop Search
These also offer more ways of
organising the files.
Many other facilities are provided on a
computer equipped for office use. Alerts
can be set to give regular notice of new
information, groups can be joined, RSS
feeds can be used and so on. These
are all described in the courses.
Reference Sherratt, Frank “Free
teaching information: what does it
mean for companies?” Engineering
Integrity, Vol. 21, March 2007, pp 26-30
Frank Sherratt, Engineering
Consultant
“Open Access”, another instalment
36EIS 31 Inners v01.indd 36 22/9/11 15:47:26
Group News
Simulation, Test
& Measurement
Group
The Instrumentation
Analysis and Testing
Exhibition held at
Silverstone in March
this year drew an all time record high
of exhibitors, attendees and income for
the EIS. Against a backdrop of
shrinking and cancelled exhibitions
across the UK and across Europe, the
EIS is clearly growing well and
providing what the many other events
lack.
We are building on our success this
year and, just as we outgrow the Jimmy
Brown Centre at Silverstone, they kindly
built us a massive new Exhibition area,
which opened a few months ago. It will
provide us far more space and
maintains our now familiar view over
the start-finish line – which was also
moved.
The Open Forum we held during the
exhibition on 4 & 7 Poster testing
attracted a guest panel covering
production, military and motorsport
speakers and attendees from wider
industries still. Our particular thanks
to Colin Dodds for chairing with his
contagious humour, mixed perfectly
with his own experience and
knowledge. The single forum event will
be increased and cover : KERS, Vision
and Lasers, CAE Testing, Electric
Actuation, Data Protocols, Acoustic
Emission and Vehicle Simulators. If
you have some sound experience and
would like to be on the guest panel for
any of these or even ask questions for
the floor, we would love to hear from
you. The whole exhibition will again be
in early March (6th) and include a wide
range of exhibitors, presentations,
workshops and the forums, so it’s a
useful day away from your PC’s and
meetings. As always you are
guaranteed EIS hospitality,
refreshments and will invariably meet
up with many people you haven’t seen
for a while.
The STMG would like to thank Peter
Blackmore for chairing the EIS for so
many years. The EIS was recently
described to me as the who’s-who in
the world of Fatigue and Testing. To
everyone who’s met him Peter clearly
epitomises the uniqueness and quality
of characters in the EIS.
Conway Young
Chairman
Sound &
Vibration
Product
Perception
Group
The last event that the SVPP held was
a one-day seminar on 29th March 2011
entitled ‘Low Carbon Transportation in
New Sound Environments’. As with the
previous event in Dec 2009, it was a
joint event with Warwick Innovative
Research Centre, held at their Digital
Suite within the University of Warwick
campus.
Thanks to an outstanding effort by the
committee, a very interesting
programme was organised, including
three presenters from Germany.
Despite the challenging economic
situation a total of 44 delegates
attended, which met our expectation.
One welcome addition was the
attendance of two Warwick University
student groups who show-cased their
projects in the exhibition area, and
attended some of the presentations.
One of these groups showed their
research on which type of sounds could
be emitted from EVs as pedestrian
warnings, having developed their own
sound synthesis software and
hardware, which they demonstrated at
the event using mobility scooters. The
other group showed their work on an
ultra light-weight speaker system using
a foil laminate which can be formed to
a shape suitable for mounting in a
vehicle facia area. We were very
pleased to have the student
participation as it satisfies one of the
key EIS objectives - to get young
engineers engaged with EIS and its
events. We will plan to do this again at
the next event.
The seminar finished with an expert
panel session, where most of the
presenters were joined by other experts
to answer questions from the audience
in the style of BBC ‘Question Time’. A
very wide range of questions were put
to the panel, ranging from emerging
technology to new environmental
legislation, and each member of the
panel in turn gave their views. This has
now become a regular feature of the
SVPP events as it is not only highly
informative (and entertaining!), but also
seems to hold most of the delegates
until a much later time of day (due to
the quantity of good questions and
comprehensive answers we actually
finished at 5.00 even though timetabled
for 4.30!). At some past events, people
have started slipping away from mid-
afternoon, which can leave a rather
sparse lecture theatre for the
concluding address!
The committee is now in the early
stages of planning the next one-day
event to be held in early May 2012, once
again a joint event with WIMRC at the
their venue, and we expect soon to be
publishing a call for papers on a topical
sound and vibration product perception
subject.
John Wilkinson
Chairman
37EIS 31 Inners v01.indd 37 22/9/11 15:47:27
President: Peter Watson O.B.E.
Committee members
Acting Chairman
Trevor Margereson, Engineering Consultant ............................................................................................... 07881 802410
Vice Chairman
Robert Cawte, HBM United Kingdom .......................................................................................................... 0121 733 1837
Treasurer
Khaled Owais, TRaC Environmental & Analysis .......................................................................................... 01926 478614
Company Secretary
Robert Cawte, HBM United Kingdom .......................................................................................................... 0121 733 1837
EIS Secretariat
Lisa Mansfield ............................................................................................................................................... 02476 730126
Communications Sub Committee – ‘Engineering Integrity’ Journal of the EIS
Honorary Editor
Karen Perkins, Swansea University ............................................................................................................. 01792 295666
Managing Editor
Catherine Pinder ........................................................................................................................................... 07979 270998
Durability & Fatigue GroupChairman
Robert Cawte, HBM United Kingdom .......................................................................................................... 0121 733 1837
Secretary
Khaled Owais, TRaC Environmental & Analysis .......................................................................................... 01926 478614
Members
John Atkinson, Sheffield Hallam University .................................................................................................. 0114 2252014
Martin Bache, Swansea University ................................................................................................................ 01792 295287
Peter Blackmore, Jaguar Land Rover ........................................................................................................... 01926 646757
Feargal Brennan, Cranfield University .......................................................................................................... 01234 758249
Emanuele Cannizzaro, Atkins Aerospace ..................................................................................................... 01454 284242
Amirebrahim Chahardehi, Cranfield University ............................................................................................ 01234 754631
John Draper, Safe Technology ..................................................................................................................... 0114 255 5919
Steve Hughes, Bodycote ............................................................................................................................... 01524 841070
Karl Johnson, Zwick Roell Group ................................................................................................................. 0777957 8913
Davood Sarchamy, British Aerospace Airbus ................................................................................................. 0117 936 861
Giora Shatil, Darwind ........................................................................................................................... +31 (0)30 6623987Frank Sherratt, Engineering Consultant ....................................................................................................... 01788 832059
James Trainor, TRW Conekt Engineering Services ................................................................................... 0121 627 4244
John Yates, University of Sheffield ............................................................................................................... 0114 222 7748
Sound & Vibration Product Perception Group
Acting Chairman
John Wilkinson, Millbrook Proving Ground ................................................................................................... 01525 408239
Members
Marco Ajovalasit, Brunel University ............................................................................................................... 01895 267 134
Alan Bennetts, Bay Systems ......................................................................................................................... 01458 860393
Dave Boast, Avon Rubber .............................................................................................................................. 01373 863064
Mark Burnett, MIRA ......................................................................................................................................... 02476 355329
Peter Clark, Proscon Environmental ............................................................................................................. 01489 891853
Gary Dunne, Jaguar Land Rover ...................................................................................................................02476 206573
38EIS 31 Inners v01.indd 38 22/9/11 15:47:27
Henrietta Howarth, Southampton University ................................................................................... 023 8059 4963/2277
Paul Jennings, Warwick University ..............................................................................................................02476 523646
Rick Johnson, Sound & Vibration Technology .............................................................................................01525 408502
Chris Knowles, JCB .................................................................................................................................... 01889 59 3900
Colin Mercer, Prosig ...................................................................................................................................... 01329 239925
Jon Richards, Honda UK ..............................................................................................................................01793 417238
Nick Pattie, Ford ....................................................................................................................................................................
Simulation, Test & Measurement Group
Chairman
Conway Young, Tiab .....................................................................................................................................01295 714046
Members
Paul Armstrong, Amber Instruments ............................................................................................................. 01246 260250
Ian Bell, National Instruments ......................................................................................................................01635 572409
Steve Coe, Data Physics (UK) .......................................................................................................................01323 846464
Colin Dodds, Dodds & Associates ............................................................................................................... 07880 554590
Dave Ensor, MIRA .......................................................................................................................................... 02476 355295
Graham Hemmings, Engineering Consultant ............................................................................................ 0121 520 3838
Neil Hay, Napier University ........................................................................................................................... 0131 455 2200
Richard Hobson, Serco Technical & Assurance Services ............................................................................ 01332 263534
Trevor Margereson, Engineering Consultant ............................................................................................... 07881 802410
Ray Pountney, Engineering Consultant ........................................................................................................ 01245 320751
Tim Powell, MTS Systems ............................................................................................................................ 01285 648800
Mike Reeves, Engineering Consultant ......................................................................................................... 01189 691870
Gordon Reid, Engineering Consultant .........................................................................................................01634 230400
Nick Richardson, Servotest ...........................................................................................................................01784 274428
Paul Roberts, HBM United Kingdom ............................................................................................................0785 2945988
Jarek Rosinski, Transmission Dynamics .................................................................................................... 0191 5800058
Geoff Rowlands, Product Life Associates ....................................................................................................01543 304233
Frank Sherratt, Engineering Consultant ....................................................................................................... 01788 832059
Bernard Steeples, Engineering Consultant .................................................................................................. 01621 828312
Marcus Teague, LDS Test & Measurement ................................................................................................. 01763 255 255
Norman Thornton, Engineering Consultant ................................................................................................. 07866 815200
Jeremy Yarnall, Consultant Engineer ........................................................................................................... 01332 875450
SponsorsThe following companies are SPONSORS of the Engineering Integrity Society. We thank them for their continued support
which helps the Society to run its wide-ranging events throughout the year.
Adept Scientific
AWE Aldermaston
Bruel & Kjaer
Datron Technology
Doosan Babcock
HBM United Kingdom
Instron
Kemo
Kistler Instrumemts
LMS UK
Millbrook Proving Ground
MIRA
MOOG
National Instruments
Polytec
Rutherford Appleton Laboratory
ServoTest
Techni Measure
TRaC Environmental & Analysis
Transmissions Dynamics
39EIS 31 Inners v01.indd 39 22/9/11 15:47:28
Intensive short courses for engineers working inenvironmental testing and those concerned withdesign assurance, reliability and type approvaltesting, product development and screening.
VIBRATION TESTING18 – 19 January 2012
CLIMATIC TESTING15 – 16 February 2012
PRACTICAL SIGNAL PROCESSING21 – 22 March 2012
MECHANICAL SHOCK TESTING19 April 2012
Further information from:Andy Tomlinson, CPD Dynamics Ltd.
CPDdynamics
2012 SHORT COURSES
EIS 31 Inners v01.indd 40 22/9/11 15:47:30
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