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User Defined Hyperelastic Material Model

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Hello,

I want to define my own function for a hyperelastic material. I plotted my data as W_siso (Energy) vs strain and got myself a function. But when I plug this function and try to run the simulation I get an error saying

"Undefined value found. - Detail: NaN or Inf found when solving linear system using PARDISO."

I tried using a constant and a linear equation to keep it simple, but I'm still getting the same error. It seems I haven't defined a parameter but I don't know what. Any suggestions?

I filled the parameters mentioned in Hyperelastic material settings page, only W_siso in this case since I chose my material to be incompressible so there is no bulk modulus. Density is defined under Materials.

I'm also attaching the model to this thread (I'm using COMSOL 6.0).

Thank you for your time, Ece



1 Reply Last Post 2023年3月27日 GMT-4 11:27
Henrik Sönnerlind COMSOL Employee

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Posted: 1 year ago 2023年3月27日 GMT-4 11:27

You have made the strain energy density proportional to the parameter strainZ. That is a constant, no different from if you would just have written a number in the text field.

Check in the documentation for what variables you can use for describing a strain energy density function.

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Henrik Sönnerlind
COMSOL
You have made the strain energy density proportional to the parameter *strainZ*. That is a constant, no different from if you would just have written a number in the text field. Check in the documentation for what variables you can use for describing a strain energy density function.

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