{"id":377516,"date":"2024-08-07T09:42:38","date_gmt":"2024-08-07T09:42:38","guid":{"rendered":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/geometry-nonlinear-fem-iteration-process-how-to-compute-internal-force\/"},"modified":"2024-08-08T08:43:12","modified_gmt":"2024-08-08T08:43:12","slug":"geometry-nonlinear-fem-iteration-process-how-to-compute-internal-force","status":"publish","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/geometry-nonlinear-fem-iteration-process-how-to-compute-internal-force\/","title":{"rendered":"Geometry nonlinear FEM iteration process ( How to compute internal force?)"},"content":{"rendered":"
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Hello everyone,<\/p>\n

I am working on implementing a nonlinear finite element analysis (FEA) code in MATLAB. I have verified that my linear analysis results are accurate and that the initial displacement values match perfectly with those from ANSYS. However, when I proceed to compute internal forces and perform iterations for the nonlinear analysis, I am encountering issues where the residuals do not decrease and the iteration process diverges.<\/p>\n

Here’s a summary of my approach and where I suspect the issue might be:<\/p>\n