Inverse engineering coefficients Ogden model
 

Hello

I have a series of load and displacement values data from instron machine on a viscohyperelastic material (polyvinylchloride).

I am going to use the 1st order Ogden model to simulate this material in ANSYS Finite Element.

There is a way to use those data that I got from Instron Stress/Tensile machine (load,displacement) in order to inverse engineer the mu and alpha nonlinear coefficients of the ogden model (1st order) and predict the forces that cause the strain on the material along the width of its surfaces.

I don't know the procedure of how to do this in ANSYS. Any kind of help would be appreciated. Thank you very much.

Kind Regards

This process is called Curve Fitting.
https://www.youtube.com/watch?v=3bjCkvobbpY

No, it's not about curve fitting. My excel values are not stress strain. We don't know the stress caused the strain but we know the strain. So the excel data are X,Y where X is the length of the material and Y its thickness. In excel if plotted it looks a deformed rubber material. So by importing the strain in ANSYS the material should look deformed.

Hmm... Usualy stress is calculated from load, that you have. No one can measure stress directly in test sample.
Anyway you can try to use design optimisation module to run many cases with dufferent material coefficients and compare deformed shape. But I`m not sure that optimisation module can compare deformed shapes authomaticaly, so this process may be long.

I think there is a way to convert load-displacement curve to stress-strain. Our phd's have done so, but there were special experiments, one-dimensial and so on, than they have found constants for rubber and plastic materials considering hardening curve and plasticity theory.
Also curve fitting is used for such mat. constants generation.