Unconstrained model
Unconstrained model
(OP)
I am trying to compress a piece of bone between 2 stainless steel plates. I have fully constrained all dof's of the bottom plate and apply a constant surface load to my top plate. The plates are made of shell elements and the bone of bricks.
I have created contact elements between the faces of my bone and of the plates.
However when I solve, i keep getting an error that one of the nodes on the edge of the top plates has UZ = a massive number. Ie i haven't properly constrained my model. I'm not sure why this is happening. Can anyone help??
I have created contact elements between the faces of my bone and of the plates.
However when I solve, i keep getting an error that one of the nodes on the edge of the top plates has UZ = a massive number. Ie i haven't properly constrained my model. I'm not sure why this is happening. Can anyone help??





RE: Unconstrained model
To check if you have gaps or too much penetration use the contact tool (connections > contact tool).
If you have no initial gaps, there are three possibilities to avoid rigid body motions in this case (maybe there are more but these are the ones that I found out):
1. Reduce the initial substep size tremendously (can be increased for further substeps automatically)
2. Use higher Normal Stiffness Factors for the contacts
3. Sometimes most useful: Insert springs between the contacting bodies with an adequate low stiffness on your own. So that they act somehow like "weak springs"
Tell me if those suggestions help.
RE: Unconstrained model