Constitutive Modelling

Question 1

What are the 4 non-linear elasticity models?

Answer 1

1. Bi-Linear model
2. K-G Model
3. Hyperbolic
4. Small strain stiffness

Question 2

Bi-linear

Answer 2

assumes that the bulk and shear stiffness are constant until the stress state reaches the failure condition. Needs 2 parameters, straight lines

Question 3

k-G model

Answer 3

Needs 5 parameters, results in stress strain curves, K and G are not constants, its more realistic

Question 4

Hyperbolic model

Answer 4

Its effective in representing the effects of confining pressure and deviator stress on stress-strain behaviour

Question 5

small strain stiffness model

Answer 5

curved lines, requires lots of parameters, not to be used for large strains as the soil approaches failure

Question 6

Elasto-plastic behaviour

Answer 6

1. perfectly plastic
2. softening/hardening

Question 7

What are the four models for perfectly plastic

Answer 7

1. Tresca
2. Von Mises
3. Drucker-Prager
4. Mohr-Colulmb

Question 8

Which of the perfectly plastic models are used for soils

Answer 8

Von Mises - circular, total stress
Mohr-colulmb-effective stress

Question 9

Which of the perfectly plastic models are used for metals?

Answer 9

Tresca and Drucker-Prager

Question 10

What are the softening/hardening models?

Answer 10

Modified Cam Clay
Modified Cap Model
Schofield model