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Assoc. Prof. Dr Nadras Othman

[email protected]

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Students Activity 1Students Activity 1

What is rubber

engineering??

EBP 420/2-Rubber Engineering

Brainstorm Brainstorm

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CourseCourse

Synopsis

Synopsis - The main focus of this course covers an application ofma

thematics in rubber elasticity including classical, statistical,and phenomenological theories.

- t also covers an e!ects of reinforcement on young, shear, andbul" elasticity moduli and concept and behaviour of force-deformation including compression, shear, combinedcompression and shear, tor#ue, bending and buc"ling.

- The course also covers the e!ects of structure and lamination$models of inclined rubber mounting and slender column andapplication in bridge bearing, doc" fender, and others.

- t also include dynamic mechanical behaviour %ith storageand loss modulus, tan δ, damping and hysterises, vibrateisolation and transmissibility.

- The course also covers about the strength and mechanicalfatigue of rubbers, tyre as a engineering product %hichinclude %et grip, rolling resistance and application of &niteelements analysis '()A* in prediction of rubber engineering

products.


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Contribution of AssessmentContribution of Assessment

Assessment MethodsAssessment Methods %%

TestTest 1010

QuizQuiz 1010

AssignmentsAssignments 2020

Final ExaminationFinal Examination 6060

TOTALTOTAL 100100

Notes:

1. Test will be on!ute! in wee" # $1 test & AP 'r A(ur)

2. *ui( in e+er, wee"s $4 *ui( & AP 'r A(ur)

. n!i+i!u)l sort )ssignent $1 grou )ssignent $1 &AP 'r N)!r)s


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Course Outcomes (CO)

At the end of the course, the students should be able to: Explain the fundamentals principles of rubber

engineering and understanding force-deformationbehaviour of rubber

Determine an appreciation of iDetermine an appreciation of intrinsic properties ofntrinsic

properties ofengineering with rubbersen

gineering with rubbers focusing on dynamicmechanical properties and fracture mechanicsbehaviour.

Differentiate and explain the basic principles of rubberengineering products (shear and compression bearings,vibrations and noise control, Raykin fenders, anti-vibrations mounting and vibration isolations!

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1. Introduction to rubber in engineering Application of mathematics in rubber elasticity: "lassical theory # $hermodynamic of rubber elasticity %tatistical theory &henomological theory

2. Dynamic force-deformation properties 'inear viscoelastic behaviour on-linear viscoelasticity behaviour Energy dissipation and heat build up in rubber unit

3. Analysis of the deformation of rubber units undereuilibrium loading conditions Applications of deformations theories %hear of rubber blocks "ompression of rubber blocks "ombined compression and shear

CourseCourse OutlineOutline


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!. Design of components %hear and compression bearings: &lanar sand)ich forms,

'aminate bearings, $ube form bearings and mountings andsample problems

*ibrations and noise control: *ibrations background andinformation, Design re+uirements and %ample problems

". #iers and $enders Raykin fenders &rinciple re+uirements

ritish engineering re+uirements

%. Introduction to rubber in dynamic applications *isco-elastic properties of rubber : "reep, %tress relaxation,

odel ax)ell and *oigt and olt.man superposition principle

Dynamic/static ratio

CourseCourse Outline (cont)Outline (cont)


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&. Dynamic mechanical properties Dynamic behaviour : Dynamic stiffness (storage and loss

modulus, 'oss angle (tan δ, damping and hysteresis $emperature and fre+uency dependence

Application of dynamic mechanical properties $ransmissibility, 0solation of mechanical vibrations, Anti-vibration mounting and 1actors for ideal /effective anti-vibration mounting

'. (trength of rubbers 1racture mechanics : $he tearing energy concept and

easurements of tearing energy "rack gro)th behaviour

). Mechanical fatigue Application of fracture mechanics to mechanical fatigue of

rubber 0nitiation and propagations of cracks



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1*. +ire ,ubber 1unctions of tire ain rubber parts of tire and their re+uired properties

11. $riction and sid resistance of rubber 2enerating mechanisms of skid resistance of tire 1rictional forces bet)een thread rubber and road!

12. $A applications in rubber engineering 0ntroduction to 1EA 3sed of 1EA in predicted rubber engineering products



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1. Engineering with Rubber: How to design rubber components,Alan +ent 'edited*, econd edition, anser Publishers, ///

2. Rubber Products Manufacturing Technoog!, Anil 0.1ho%mic",2alcolm 2.all and enry A.1enarey, 2arcel De""er, nc, 3445

". Engineering design with #atura Rubber, P.1.6indley, (ifth )dition, The 2alaysian 7ubber Producers8 7esearch Association, 344.

$. Theor! and practice of engineering with rubber, P.0.(rea"ley andA.7.Payne, Applied cience Publisher 6TD, 3499

%. Rubber technoog! and manufacture , :.2. 1lo% and :.epburn, nd ed, butter%orth, ///

&. Rubber Technoog! handboo' , ofman.;, anser ///

(. Po!mer s!nthesis: theor! and practice: fundamentas) method)

e*periments, 1raun, Dietrich,

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Rubber in Engineering??

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How to understand rubberHow to understand rubber

engineering?engineering?

2aterials properties )lastic moduli

) '>oung 2odulus* + 'hear 2odulus* 1 '1ul" 2odulus*

?nderstands Predicting the load

deformation behaviour Design and &tting

)nvironmental factor or conditions

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)cellent resistance to fatigue, cutgro%th and tearing

igh resilience 6o% heat build up Bery eCcient bonding to both metals

and other reinforcing materials

6o% cost and ease of manufacture A %ider range of operating temperatures

than most other rubber

Natural rubber as a spring materialNatural rubber as a spring material

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re#uire no maintenance

have a high energy storage capacity

can easily be designed to give di!erentsti!ness in di!erent directions, or non-linear load-deection characteristics

can accommodate a certain amount ofmisalignment and are easier to install

Metal springs vs NR springsMetal springs vs NR springs

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Earth quake rubber

bearing

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Tyres

eals )ngine 2ount 1ridge bearing )arth#ua"es bearing Bibration solators Doc" fenders +as"et

Example ofExample of

Rubber engineering productsRubber engineering products

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Definition of rubberDefinition of rubber

A uni#ue group of materials %hich may beidenti&ed by their ability, under certain

conditions to undergo large deformations andrecover almost completely and instantaneouslyon release of the deforming force.

•The property of high elasticity derives from aparticular kind of molecular structure

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3. The molecules must be very long and be able torotate freely about the Eoining neighbouring

molecular units

. The molecules must be Eoined at a number of sites toform a three dimensional net%or", either by chemicalbonds or mechanical entanglements 'crosslin"*

=. Apart from this crosslin"s the molecules must be ableto move readily past one another intermolecularattractions ' secondary or van der ;alls8 force* mustbe small

The propert! of rubber easticit! ma! be e*pained +uantitati,e!b! reference to the -rst aw of thermod!namics.

Requirements for material to beRequirements for material to be

an elastomer or rubberan elastomer or rubber

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f large elastic deformations results from#uite small stresses. This happens ifF

t is above its glass transition temperature

t is in an amorphous rather than crystalline state

The molecules are lin"ed together in a fe% placesto form a continuous net%or" %hich prevents thepolymer behaving li"e viscous uid achievede!ectively %ith chemical crosslin"ing.

Polmer ex!ibits rubber be!aviourPolmer ex!ibits rubber be!aviour

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+eneral stress-strain concept.

= common models of deformation ofrubber vulcanisates F

3. Tension

. :ompression

=. hear

"tiffness Modulus"tiffness Modulus

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# common models of deformation# common models of deformation

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n order to formulate an analyticalapproach elastomer can be consideredto be3. )lastic

. sotropic in their underformed state 'theproperties at direction is the same*

Therefore can be described by Eust t%ofundamental elastic constantF

3. 1ul" 2odulus, 1

. hear 2odulus, +

Rubber li$e elasticit at small strainsRubber li$e elasticit at small strains

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1. u' moduus

ratio of the applied pressure to the volumetricstrain

Deals %ith the materials resistance to

compression under a hydrostatic pressure

o

o

V

V V

P

volumeoriginal of volumeinchanges

pressurec Hydrostati B

−

==

2. Shear Modulus G,

Ratio of the applied shear stress required toproduce shear strain G

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Other commonly encountered small

strain elastic constants Tensile 2odulus, )

Poison8s ratio, v

GG related to the bul" and shear modulus

( )v E G+

=

12( )v E B213 −

=

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)lastomer are uni#ue class ofengineering materials as

both shear + and tensile 2oduli ) are verylo% 'in region of /.H-3/ 2Pa*

%hile 1ul" modulus is very large '3.H-./ +Pa*

Balue of Poison8s ratio is close /.H

Tensile 2odulus ) is almost eactly e#ualto =+

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In most engineering

applications elastomers can be considered as being incompressible.

the elastic behaviour at small strain can be describedby Eust a single elastic constant +.

The signi&cantly larger modulus is a maEor asset %hendesigning elastomeric component because of if agiven volume of the elastomer is constraint in shape,the part can be made to have high compression

sti!ness %ith a lo% shear sti!ness.

This phenomenon is eploited in the design ofvibration isolation compression mounts earth#ua"ebearing or mounting systems in automotive

applications.

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/n 2 0 " minutes in pair ist as

man! as the! can about an!conceptissueprincipeformuathat has been earned toda!

Students Activity Students Activity Focused listingFocused listing

ebp 420 - nota 1

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