Correcting the Error: FE Model of the Next Iteration Is Not Calculated

The first iteration was successfully completed. However, the program aborts before the stop condition has been reached.

Error Message on screen

Error message in TOSCA_OUT

Error message using the solver log file (MSC Nastran® in this example)

Cause:

  • Strongly distorted elements can appear in shape optimization if the displacements are too large or the mesh modification caused by the displacements of the design nodes is done in an unfavorable manner. It causes the solver to fail during FE analysis.

This task shows you how to:

Locate the Error

  1. First read the error file of the solver to see if any information concerning the distorted elements is available.
  2. Confirm the mesh in the FE preprocessor, find the place where it became distorted. Usually, more information can be found from the analysis of the incorrectly calculated iterations. It should be checked if the optimization boundary conditions have been set correctly (care should be taken with the AUTO_FIX function, as all surface nodes that do not have DOF restrictions will be fixed).

Correct the Error

  1. Reduce the limits for displacements.
  2. If none of these methods help: mesh the model in such a way that the surface changes only lead to a slight distortion of the mesh.