| E5004 | FATAL ERROR: E5004 | STIFFNESS MATRIX SINGULAR OR NON-POSITIVE DEFINITE |
| Cause: | A singularity or non-positive definite has been detected in the stiffness matrix during the preconditioning phase of the iterative solver. | |
| Action: | Investigate the model for a lack of constraint. If using shell elements, either set the K6ROT model parameter to a value between 1.0 and 100.0, or set the SHELLRNODE model parameter to ON. Also, check for elements with bending stiffness (line and shell elements) improperly connected to elements without (solids). If you are unable to locate the source of the singularity, consider using the sparse direct solver. | |
| Remarks: | See Autodesk Nastran Reference Guide, Section 5, Parameters, for more information on the K6ROT and SHELLRNODE parameters. |