Question

What is a yield criterion? What are the assumptions that we normally make when applying a yield criterion?

Answer 1

Yield criteria is a hypothetical criteria which defines the elastic limit in a material and the starting of permanent or plastic deformation under different stress combinations.

or

We can say that relationship among different combinations of stress provides an idea of the yield of any material can be termed as yield criteria.

Assumptions while applying yield criteria:

• The material to be used is incompressible
• The material is isotropic in nature
• Incompressible materials can include porous materials with
  `v < 0.5`
• Incompsressible stress is not responsible for yielding of material.