student's blog

Does anyone know how can the plastic strain be greater than unity? Such as in the benchmark manual 3.2.10 Indentation of a crushable foam plate:

*CRUSHABLE FOAM HARDENING

0.2000E6, 0.0000

0.2577E6, 0.0094

0.2760E6, 0.0258

0.3053E6, 0.0452

0.3267E6, 0.0655

0.3623E6, 0.1084

0.3891E6, 0.1540

0.4250 e6, 0.2405

0.4568E6, 0.3812

0.4738E6, 0.4600

0.5170E6, 0.6391

0.5862E6, 0.8570

0.6503E6, 0.9857

0.7470 e6, 1。1324

0.9820E6, 1.2965

1.4702E6, 1.4808

Hi,

I am trying to extract logrithmic strains from Abaqus and then trying to compare with the experimental ones but I am getting different results. I found out the in Abaqus it uses slightly different formula then what I use theoretically.

In abaqus it computes LE from the following formula:

LE = plastic strain - true stress/E

But what I believe is that it should be like:

LE = plastic strain - yield stress/E

Can any one highlight why abaqus is using the first formula for LE calculation?

Hi,

I am currently facing difficulties in calibrating abaqus crushable foam model with my experimental results.
I think I am bit confused about what values needs to be input in the model.
Right now my elastic properties are: E=400 MPa, v=0 (because its crushing)
In plastic under crushable foam I use compression yield stress ratio =1
and hydrostatic yield stress ratio =0.1.