LOVELY PROFESSIONAL UNIVERSITY

Applied Elasticity and Plasticity (MEC-538)

Section-M1E12, M1E50

Duration - 50 minutes Test-3.1

Date – 26/11/2014 MM-30

1) A material is to be loaded to a stress state as given bellow

[40 −40 0−40 80 00 0 0

]

What should be the minimum uniaxial yield stress of the material so that it does not fail,

according to the (a) Tresca criterian (b) Von Mises criterion. What do the theories predict when

the yield stress of the material is 80MPa?

2) a) Define yield surface. Write two assumption for yield surface. Draw yield surface in 3-D

principal stress space.

b) Write atleast four assumption in plasticity theory.

3) a) Write the theory of Haigh-Westergaard Stress Space. Write two significance of Haigh-

Westergaard Stress Space.

b) Write a short note on anisotropic plasticity.

Note- Each question of 10 marks.

LOVELY PROFESSIONAL UNIVERSITY

Applied Elasticity and Plasticity (MEC-538)

Duration - 50 minutes Test-3.2

Date – 26/11/2014 MM-30

1. Explain Haigh-Westergaard Stress Space.

2. a) Define tangent modulus and plastic modulus using stress-strain curve

b) Write prandtl reuss equation and how it is different from levy mises equation.

3. a) How Drucker-Prager criterion is modified from Von Mises criterion. Draw Drucker-Prager

criterion surface in 3-D Principal Stress Space.

b) Draw Tresca and Von Mises Yield creteria in the π-plane and explain it.

Note- Each question of 10 marks.