Overcoming Singularities in FEA
EnDuraSim authored this pdf document several years ago, but it remains a definitive summary of resolving the common causes of singularities in FEA models. It was written with Femap and NX Nastran (USER FATAL MESSAGE 9137) in mind, but the principles are equally relevant to virtually any structural/mechanical FEA code such as Ansys, Abaqus, MSC.Nastran, Patran, Strand7, Microstran, Spacegass and more. If your FEA program uses terminology such as singularity, excessive pivot, FATAL 9137, SEKRRS, FATAL 9050, maxratio or bailout, then this linked pdf doc will help.
EnDuraSim-Overcome-Singularities.pdf
Vernon McKenzie