1

Fracture Mechanics of PolymersB&R Ch. 16.1-16.3, Fried 4.4

Testing methods of mechanical properties

• Static

• Transient

• Impact

• Cyclical

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Static tensile testing

FixedClamp

MovingClamp

Extensometer

3

Stress-strain tensile testing

stress-strain curves of typical polymeric materials.

properties of common polymers

Viscoelasticity

4

Craze and Shear Banding

5

F

F

F

Shearbanding

F

Poisson’s ratio

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Cold drawing of semi-crystallinepolymers

7

Brittle vs. ductile failure

8

Factors affecting failure

-

-

-

-

-

-

• Compression

• Shear

9

Static tensile testing

Material subjected to uniform hydrostatic pressure

Material subjected to shear stress

Transient Test: Creep

• e1

• e2

• e3

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Transient Test: Stress relaxation

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eot

s

eo

e

Impact & fatigue testing

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Charpy Test