Mooney Rivlin with Von Mises Fiber Distribution does not seem to work

[sschwaner]

Hello,

I am trying to implement the Mooney Rivlin with Von Mises fibers material model. I've run several different models, but the fibers don't seem to be doing anything. The models are behaving as if they are isotropic. I've attached an FEBio file of a simple box. I'm trying to apply negative pressures on the positive X and Y faces and define fibers in the y direction using the MeshData section. However, the resulting displacement is the same in the X and Y directions. I'm using FEBio 2.8.0 .

Thanks,

Stephen

[maas]

Hi Stephen,

I checked the model and everything looks good to me. I double-checked that the material axes are read in correctly and I don't see a problem there either. What I suspect is that the fibers are not contributing much to the stress. Try playing with the material parameters, especially c3 and c4, and see if you can get the expected behavior.

Cheers,

Steve

[sschwaner]

Thanks for the response, Steve. You were right. Increasing c4 quite a bit caused the fibers to start contributing. Everything looks good, now. Stupid mistake on my part.

Cheers,

Stephen