material models for hard plastics

[spears]

I have seen alot of inforamtion on the material models for elastomers, but what about hard plastics.

I think I can use actual true stress - strain data from a tensile test, but how does it behave in unloading in the plastic region? Is it similar to metals?

Are there certain hardening rules to follow for plastics?

Thanks in advance

Karl

[Jorgen]

With "hard plastics" do you refer to thermoplastics (which can be remelted and reformed) or thermosets (which are permanently crosslinked and cannot be reformed)?

The behavior of polymers can often be divided into three groups:
:arrow: elastomers or elastomer-like behavior (polymers above the glass transition temp.)
:arrow: thermoplastics (polymers below the glass transition temp.)
:arrow: thermosets (highly crosslinked polymers below the glass transition temp.)

The behavior of each of these groups is quite different and typically require different finite element approaches. The response of polymer is typically quite different than for metals, and metal plasticity is rarely the best solution approach.

What material(s) are you studying? What type of simulations are you planning to perform?

- Jorgen