Mechanical behaviour of materials

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Define stress
The intensity of a force. σ=F/A
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Name the two types of stress
1)Direct Stress: perpendicular to the plane e.g. tensile or compressive; 2)Shear stress: parallel to plane (τ).
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Define strain
The fractional difference in displacement. ε =x/L
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What is shear strain?
Distortion via rotation, the lateral displacement relative to the length over which it occurs. γ= w/L_0 = tanθ ] where L_0 is the thickness of the material.
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How is elastic behaviour explained?
stress α strain ] Hooke's law
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Give the equation for young's modulus
σ =Εε ] where E is the constant of proportionality - Young's modulus for the material
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Give the equation for Shear modulus
G =τ/γ
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What are the moduli dependent on?(give the relationship and an equation)
Temperature; As the temperature increases the elastic modulus decreases. E =E_0 -ATe^(-T_0/T)
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What is the shear modulus of a liquid ?
zero
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Explain 'indentation dependence on temperature
Materials offer less resistance to deformation at higher temperatures so there is an increases in ductility.
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Are G and E dependent or independent of each other ?
They are not independent as they both depend on atomic bonding. E =2G(1+v) ] where v is Poisson's ratio
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What is Poisson's ratio?
v= lateral strain /tensile strain
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Other cards in this set

Card 2

Front

Name the two types of stress

Back

1)Direct Stress: perpendicular to the plane e.g. tensile or compressive; 2)Shear stress: parallel to plane (τ).

Card 3

Front

Define strain

Back

Preview of the front of card 3

Card 4

Front

What is shear strain?

Back

Preview of the front of card 4

Card 5

Front

How is elastic behaviour explained?

Back

Preview of the front of card 5
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