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When I run forming simulation, I had such message as “Error: slaves nodes may cross the surface, please check your model, job continues.” I’ve checked my input deck and didn’t find any obvious mistake for the mesh. How can I fix this problem?

This problem results from bad mesh of the rigid tools. If one of the parts is not connected, LS-DYNA will try to connect the unconnected sections. If the gap is large or the mesh is complicated, LS-DYNA might not be able to connect the gap properly. Then it will generate this above-mentioned message. Under this condition, it is better to specify each unconnected section as one part, and then the problem can be avoided.

Sometimes, even though there is no disconnected section for one part, it is still possible to have such error message. For example, if the element for the rigid body overlaps each other, you will find this message. Under this condition, you have to check your model to see: if there is overlapping element or not.

When the normal of the element in one rigid part is not uniform, LSDYNA will try to fix this problem. However, it might cause problem and out such problem.

In summary, try to have a clean model, i.e. without overlapping of the mesh, the mesh normal should be uniform for one part, no initial penetrations.