Material properties 1

[dwarf12]

In Abaqus there is a way to define Material properties. For example a plastic material with specific yield point. This yield stress is from tensile tests (uniaxial).

My question is how does the program solve a triaxial stress state with this uniaxial parameter. I think it uses comparision stresses like 'von Mises' or 'Tresca' or something totally diefferent? Is there a way to choose which comparison stresses are used?

 

[mechfeeney]

Poisson's Ratio

 

[dwarf12]

In the elastic-case it uses Poisson ratio... My question was what is used when plastic deformation occurs.

 

[mrgoldthorpe]

Read Section 4, "Mechanical Constitutive Theories" of the ABAQUS Theory Manual, particularly the sub-section on metal plasticity.

 

[mechfeeney]

You can set custom parameters in tabular form to synthesize plastic deformation. I'll explain more tomorrow.

 

[mechfeeney]

In the Material Properties Module, you will see the Mechanical Tab. Here you can enter in values for things like:

1. Plasticity: Yield Stress and Plastic Strain
2. Elasticity

etc, etc

When I did a bumper analysis that entered plastic deformation, I actually used Mechanical-->Damage for Traction Seperation Laws. It's largely dependent on the data that you have available. If you don't enter in values for say anisotropic moduli of elasticity...it will only use the one you provided. Same with yield stress and other parameters. It's up to the user to enter in the tabular data in the Mechanical tab (in material properties) to best simulate the plastic deformation.

So the simple answer to your question would be: Mechanical Tab in Matetrial Properties. Use the Plastic option and you can enter in tabular data to get a nice curve. To add a row, right click and insert row above/below.