intro dscm
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DESIGN, SELECTION & CHARACTERISATION OF
ENGINEERING MATERIALS (MY-407)FALL TERM: 2014
BOOKS TO BE CONSULT:
ASM Handbook volume 20: Materials Selection and Design.
ASM Handbook volume 10: Materials Characterisation
EVALUATION:
1. Popup Quizzes (approx. 4):10 Marks
2. Test & VIVA: 10 Marks
3. Assignment: 10 Marks
SYNOPSIS OF COURSE:
The specific objectives for the course are:
1. Describe, both conceptually and analytically, how system components work using
scientific engineering principles.
2. To gain experience in the selection of materials and optimization of behavior by
using a systematic methodology which combines materials properties with the
engineering function of the process or product design.
3. To acquire knowledge about different Characterization techniques.
REMEMBER!!!!
Thetrue art of memory is the art of attention
Samuel Johnson!
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WHAT QUALITIES IN A GOOD ENGINEER?
A sharp mind.
Refined knowledge
Superb observational
capabilities Great listening power
Reflexivity
Attitude
Communication Skills
MINIMUM COMPUTER SKILLS?
BASIC COMPUTER OPERATIONS
MS OFFICE
WORD
POWER POINT
EXCEL
PUBLISHER
AUTOCAD, PRO-E
PREZI
FEA, SOLID CAST etc.MS PROJECT , MATLAB
C++ Language
JOB TITLE(s):
Design Engineer (Metallurgy),
Trainee Design Engineer.
The ENGINEERis the key figure in the material progress of the world.
It is his engineering that makes a reality of the potential value of science
by translating scientific knowledge into tools, resources, energy and labor
to bring them into the service of man ... To make contributions of this kind
the engineer requires the IMAGINATIONto visualize the needs of society
and to appreciate what is possible as well as the technological and broad
social age understanding to bring his vision to reality
Sir Eric Ashby!
Positive point
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Formaldefinition
of
design:
Design
establishesand
definessolutionstoand
pertinentstructuresfor
problems
not
solved
before,ornewsolutions
toproblemswhichhave
previouslybeensolved
inadifferentway.
Adesignmayormay
notinvolveinvention.
The
professional
practiceofengineering
is
largely
concerned
withdesign;itisoften
saidthatdesignisthe
essenceofengineering.
Theactionorfactof
carefullychoosingsomeo
ne
orsomethingasbeingthe
bestormostSuitable.
Theselectionofmaterials
isacriticalstageinprodu
ct
developmentand
manufacturingofEngg.
Component.Vastmateria
ls
processesavailableand
enormousvarietiesofdes
ign
requirementshavebeen
identifiedastherootofth
e
problemsinmaterials
selectionthatchallenges
engineer.
Fromthemanufacturing
perspective,thesequence
throughwhichthe
componentismanufactur
ed
isconsideredmorecritica
l
thandesignrequirement.
Therefore,
theselection
processisnotonly
determinedbyitsfunction
andshape,butalsobythe
manufacturingprocess
MaterialsChara
cterization
referstotheuseof
externaltechniqu
esto
probeintotheinternal
structure&Propertiesofa
material.
Basedonthe
informationrequ
ired,
the
characterizationof
materialsmaybe
divided
intothefollowin
ggroups:
Microscopi
cAnalysis
ChemicalA
nalysis
ThermalAnalysis
MechanicalAnalysis
NDTAnaly
sis
DESIGN,SELE
CTION&CHARACTERISATIONOF
ENGINEERINGM
ATERIALS
Thetangiblesubstance
thatgoesintothemakeupof
aphysicalo
bject.
Eng
ineer
ing
Ma
teria
ls:
Materialsfo
rEngineering
applications
.
Metals
Polym
ers
Composites
Ceram
ics
Glass
esetc.
SELECTION
DESIGN
CHARACTERISATION
ENGINEERINGMATERIALS
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THE FOUR CsOF DESIGN
1.CREATIVITY Requires creation of something that has not existed before or has not existed in
the designers mind before
2.
COMPLEXITY
Requires decisions on many variables and parameters3.CHOICE
Requires making choices between many possible solutions at all levels, from
basic concepts to the smallest detail of shape
4.COMPROMISE Requires balancing multiple and sometimes conflicting requirements
COMPARISON BETWEEN THE SCIENTIFIC METHOD
AND THE DESIGN METHOD
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WAYS TO THINK ABOUT THE ENGINEERING DESIGN PROCESS:
1-A SIMPLIFIED ITERATION MODEL
2-A PROBLEM-SOLVING METHODOLOGY
1-A SIMPLIFIED ITERATION MODEL
ITERATIONis the process of doing something again and again, usually to improve it. OR Anamount that you get when you use a mathematical rule several times.
Different writers or designers have outlined the design process in as few as five steps or as
many as 25. One of the first to write about design was Morris Asimow.
He viewed the heart of
the design process as consisting of the elements shown in Fig.
As portrayed in fig, design is a sequential process consisting of many design operations.
Examples of the operations might be
(1) Exploring the alternative concepts that could satisfy the specified need.
(2) Formulating a mathematical model of the best system concept.
(3) Specifying specific parts to construct a subsystem. And
(4) Selecting a material from which to manufacture a part.
Each operation requires information (General, technical and business information
expected from the trained professional).
Acquisition of information is a vital and often very difficult step in the design process,
but fortunately it is a step that usually becomes easier with time. (We call this process
EXPERIENCE.)
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2-A PROBLEM-SOLVING METHODOLOGY
Designing can be approached as a problem to be solved. A problem-solving methodology that is
useful in design consists of the following steps.
Definition of the problem
Gathering of informationGeneration of alternative solutions
Evaluation of alternatives & decision making
Fig: Note how the design depends on the viewpoint of the individual who defines the
problem, illustrates how the final design can differ greatly depending upon how the
problem is defined.
Problem definition often
called needs analysis.
It is the nature of t
design process that ne
needs are established
the design proce
proceeds because ne
problems arise as t
design evolves
Design is proble
solving only when needs and potential issu
with alternatives a
known.
If these additional nee
require reworking tho
parts of the design th
have been completed, thpenalties are incurred
terms of cost and proje
schedule.
Experience is one of t
best remedies for th
aspect of designing, b
modern computer-basdesign tools he
ameliorate the effects
inexperience.
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While many consider that the engineering design process ends with detail design, there are
many issues that must be resolved before a product can be shipped to the customer. These
additional phases of design are often folded into what is called the product development
process.
Phase IV:Planning for manufacturedesign of tooling and fixtures, designing the process
sheet and the production line, planning the work schedules, the quality assurance system, and
the system of information flow.
Phase V:Planning for distributionplanning for packaging, shipping, warehousing, and
distribution of the product to the customer.
Phase VI:Planning for useThe decisions made in phases I through III will determine such
important factors as ease of use, ease of maintenance, reliability, product safety, aesthetic
appeal, economy of operation, and product durability.
Phase VII:Planning for product retirementAgain, decisions made in phases I through III
must provide for safe disposal of the product when it reaches its useful life, or recycling of its
materials or reuse or remanufacture.
(Phase I)
(Phase III)(Phase II)
STEPS IN THE DESIGN PROCESS
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Fig. The design paradox between design knowledge and design freedom.
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The goal of design:
To create products that perform their function effectively, safely, at
acceptable cost.. What do we need to know about materials to do this?
More than just test data.
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INTERACTION B/W MATERIAL, ITS FUNCTION, SHAPE,
AND PROCESS
The selection of material is tied in with process and shape.
To make a shape, the material is subjected to processes that, collectively,are called manufacture: these include primary forming processes (e.g.,
casting and forging), material removal processes (machining, drilling),
joining processes (e.g., welding) and finishing processes (e.g., painting or
electroplating).
Function influences material choice.
Material choice influences processes through the materials ability to becast or molded or welded or heat-treated.
Process determines shape, size, precision and cost.
These interactions are two-way: specification of shape restricts the
choice of material and process; but equally the specification of process
limits the material choice and the accessible shapes. The more
sophisticated the design, the tighter the specifications and the greater the
interactions.
The interaction between function, material, shape, and process lies at the
heart of the MATERIAL SELECTION PROCESS
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MATERIALS SELECTION METHODOLOGY
Translate the design
requirements into materials
specifications. It should takeinto consideration the design
objectives, constraints and
free variables.
Screening out of materials
that fail the design
constraints.
Ranking the materials by
their ability to meet the
objectives. (Material
Indices).
Search for supporting
information for the material
candidates.
MATERIAL ATTRIBUTES
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CHOOSING A MATERIAL:Design requirements are first expressed as constraints and
objectives. The constraints are used for screening. The survivors are ranked by the
objective, expressed as a material index.
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DEFINING THE DESIGN REQUIREMENTS
Free variables: What is the designer free to change?* It is sometimes useful to distinguish between hard and soft constraints. Stiffness and
strength might be absolute requirements (hard constraints); cost might be negotiable (soft
constraint).
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