Elastomer

mike

Hi All!
Just wondering which model and sim you'd use for modeling elastic behavior? Think a rubber band that I'm looking for reaction forces.
Thanks!

Sebastianmaklary

You need a model for hyperelastic behavior. I did a model some time ago of polyurethane bushings used in vehicle suspension. The material model was a Mooney Rivlin model and the solver used was CCX.

mike

Thanks, Sebastian! I didn't see that choice there. It's not giving me the reaction forces. Any insights? Everything converges and the deformation looks legit.

Victor

With the CCX solver, you have to use external force instead of reaction force.

mike

Victor, not sure what you mean by that. I am anchoring one end and displacing the other. Trying to get ballpark force to hold end in place while pulling.
Thanks!

Victor

Pick Solution -> Force and moment -> External force then solve again. CCX only outputs external force, which is reaction force and applied force together. At constrained nodes with no applied force, like your anchored end, it's the same as reaction force.

mike

Ah! understood, thank you!

disla

Hi,

I have always found the ccx output is kind of weird. Taking into consideration that looking at the reactions is part of any study's basic check , could you consider postprocessing that value internally subtracting the imposed forces to have only one output (reactions) for the overall solvers?

Regards

Victor

@disla I like that idea but I don't think it's safe or practical to predict all the node forces CCX might apply, including gravity, pressure, MPC forces, and their changes with large displacements.