How to fit the stress-strain curve obtained from simulation with experimental data

Thang

Hello,
I have done a tensile test simulation using Law 36 and plotted it in the hypergraph. However, the simulation and test curve results have tolerances and I am having trouble adjusting the simulation curve to match the experimental curve.
I have followed the setup instructions for tensile simulation, however, I am not quite clear on the Fscale and Esp_dot setup step. Do these 2 parameters affect the results, and is there a way to find out the values ​​of these 2 parameters

Please can someone help me?

GTT Johan

Hi Thang
It looks like you trying to fit to several test that are performed at different strain rates!
eps_dot is the loading rate, and normally materials tend to increase in stiffness when loaded at higher rate!
//Johan

Thang

Hi Johan,

Actually, I got some experiment data of tensile tests, and I was asked to perform tensile tests with radioss. First, I followed the instruction of "RD-T: 3500 Tensile Test Setup" and this is my initial result.

and in my first job, eps_dot and fscale were set as described in the following image.

Second, I was asked to minimize the tolerance between the experiment and simulating curve. I considered setting up some of eps_dot and fscale factors and this is my result after setting these factors.

So, I would like to know that did I do it the right way?
And furthermore, I would like to know more about Fscale and Eps_dot. Is it true that fscale is the scaling factor of the x-axis (stress) and eps_dot is the value that determines the strain rate for that particular curve. And for each loading rate, the radioss will base on the eps_dot setting, the stress will be interpolated up or down proportional to fscale?