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Serious issue when solving nonlinear static analyis with mixed solid and shell elements

Question asked by Jaspreet Hothi on Dec 23, 2013


I am trying to perform a nonlinear static analysis with large strain and large displacement option turned on and Von Mises plastic material model. The problem is that the solver does not run and fails in the first step with the following error for the iterative solver.


PCGLSS0102:Assembled Stiffness Matrix has a negative diagona 

Stiffness singularities have occurred, Automatic Reset:    



For the sparse solver it just fails without any error.

At the end I get the following recommendations from the solver:

1. Lack of adequate restraints for one or more parts.

2. Material properties may not be properly defined.

3. Load increment may be too large or too small.


I have tried all 3 recommendations and they do not work.



I have created a very simple model with two plates one meshed with solid and other with shells. Any ideas what could be wrong. I have attached the simple models created in Solidworks 2012.

Thanks in advance.


Jaspreet Hothi