iMechanica - Calibration of rate independent phenomenological plasticity models - Comments

In my understanding,If the

Xu Zhang — Tue, 23 Jun 2009 22:28:33 -0400

In my understanding,If the material is rate-independent , in the material experiment, it's elas-plasticity behavior will not be affected by the strain rate, just like the elastic behavior

Yes, using a compaction simulator

tuhinsinha.25 — Mon, 22 Jun 2009 16:45:14 -0400

I have got access to a compaction simulator that can be used to perform compaction experiments at very low strain rates

Can you perform your

Yixiang Gan — Fri, 19 Jun 2009 04:37:18 -0400

Can you perform your experiments in relatively slow strain rate?

Basically, we encountered the similar problem to determine the model paramters. In our case, this material is even sensitive to the temperature field, in terms of qusi-static and rate-dependent behaviours.

Calibration of rate independent phenomenological plasticity models

tuhinsinha.25 — Thu, 18 Jun 2009 11:20:55 -0400

I have a question regarding the experimental determination of rate independent phenomenological elaso plastic constitutive model.

Since the models are rate independent, does the strain rate in the experiments used to calibrate the model parametes have any influence on the model. I am talking about this in context to the Cap plasticity model used in Abaqus. One has to run a certain number of powder compaction experiments to calibrate the model.

I know that at different strain rates (or compaction speeds), different values of the model parameters will be obtained. But, can those different values still be used in a quasi static model? It makes sense to me as those particular parameter values will correspond to the range of strain rates used during calibration and the model will predict the macroscopic field variables appropriate at that constant strain rate only. Since there is no "variation" in the strain rate either during experiments or in the FEM model, the results should seem OK.

But I am not sure about this and I need some opinion in this matter.

Thanks