HD79401: SINGULARITY ERROR WHILE COMPUTING A MODAL ANALYSIS, FREQUENCY C ASE.

APAR status

• Closed as Permanent restriction.

Error description

• Singularity error while computing a modal analysis,
  frequency case.
  .
  SCENARIO:
  .
  1 Open the attached CATAnalysis file.
  2 Make sure that the mesh type is Parabolic TET
  elements.
  3 Compute the FE model.
  4 RESULT: Singularity error is shown..
  .
  5 Change the mesh type to linear TET elements
  with same mesh size and sag size as before.
  6 The FE model is computed without any error.
  7 The singularity error is shown only when
  parabolic TET elements are used..
  .
  EXPECTED RESULT:
  .
  The computation should be successful.
  .
  .
  

Local fix

Problem summary

• ANALYSIS ( GSA ) / Singularity error while computing a modal an
  alysis, frequency case.
  Singularity error while computing a modal analysis,
  frequency case.
  .
  SCENARIO:
  .
  1 Open the attached CATAnalysis file.
  2 Make sure that the mesh type is Parabolic TET
  elements.
  3 Compute the FE model.
  4 RESULT: Singularity error is shown..
  .
  5 Change the mesh type to linear TET elements
  with same mesh size and sag size as before.
  6 The FE model is computed without any error.
  7 The singularity error is shown only when
  parabolic TET elements are used..
  .
  EXPECTED RESULT:
  .
  The computation should be successful.
  .
  .
  

Problem conclusion

• THIS PROBLEM IS PERMANENT RESTRICTION IN
  CATIA
  INCIDENT DIAGNOSIS:
  .
  Singularity detected while computing.
  .
  .
  RESTRICTION EXPLANATION:
  .
  2 independent structures are formed due to a
  geometry defect.
  .
  Due to this reason the model becomes ill-
  constrained and singularity is detected while
  computing.
  .
  BY-PASS:
  .
  To overcome this geometry defect, while
  generating the mesh, set the Geometry size limit
  marginally greater than the defect dimension.
  .
  Due to these settings the geometry defect is
  ignored while mesh generation and the FE model is
  correctly generated.
  .
  After such a mesh, the model is computed
  successfully and no singularity is detected.
  .
  .
  

Temporary fix

Comments

APAR Information

• APAR is sysrouted FROM one or more of the following:

• APAR is sysrouted TO one or more of the following:

Fix information

Applicable component levels