Rubber Bumper Modeling

[ZhiMing]

Hi,

This is the first time I am posting on Eng-Tip, so I apologize if my question sounds stupid. I am trying to model the compression/crushing behavior of a D-shaped rubber bumper used for cargo loaders. I have defined the bumper as a hyperelastic material with a Mooney-Rivlin model. The coefficients that I have correlate well with my experimental data and produced a stable material for all strains. My model also has a fine mesh so that I don't notice any node inversions. However, I kept getting error messages like "Excessive distortion at a total of ___ integration points in solid (continuum) elements," and the program eventually exited. I am currently trying to switch to an adaptive mesh and see if it would run to completion. I am wondering if anyone can give me some pointers. Any help at all would be appreciated. Thank you.

Zhi

 

[rstupplebeen]

I would put the hyperelastic model on the shelf and try a linear elastic model and see if the model is set up appropriately. Once you have that working add the hyperelastic properties into the model.

Is the model deforming as you would expect up until the error?

I hope this helps.

Rob Stupplebeen

 

[ZhiMing]

Rob,

Thank you very much for your response.

Yes, I have tried the using linear elastic constants and usually ended with the same "excessive distortion" message.

The model does behave correctly with both hyperelastic and elastic properties up until the point the program exits.

Because both models exit at about the same time step when using the same mesh, I think it is really an issue with the mesh size.

Zhi

 

[ZhiMing]

Thank you, Rob. I think I'll try the elastic model with an adaptive mesh.

Zhi

 

[rstupplebeen]

Is there an element set of the excessively deformed elements? If so it may be a mesh size or quality issue. I hope this helps.

Rob Stupplebeen