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Problem with hyperelastic material: Time increment required is less than the minimum specified

Problem with hyperelastic material: Time increment required is less than the minimum specified

Problem with hyperelastic material: Time increment required is less than the minimum specified

(OP)
Hi All,

Am running simulation on silicone tubing (hyperelastic), applying inner pressure to 120 mmHg (~0.016 N/mm2). Getting error:Time increment required is less than the minimum specified

Analysis:
ANALYSIS SUMMARY:
TOTAL OF 3 INCREMENTS
1 CUTBACKS IN AUTOMATIC INCREMENTATION
26 ITERATIONS INCLUDING CONTACT ITERATIONS IF PRESENT
26 PASSES THROUGH THE EQUATION SOLVER OF WHICH
26 INVOLVE MATRIX DECOMPOSITION, INCLUDING
0 DECOMPOSITION(S) OF THE MASS MATRIX
1 REORDERING OF EQUATIONS TO MINIMIZE WAVEFRONT
0 ADDITIONAL RESIDUAL EVALUATIONS FOR LINE SEARCHES
0 ADDITIONAL OPERATOR EVALUATIONS FOR LINE SEARCHES
3 WARNING MESSAGES DURING USER INPUT PROCESSING
7 WARNING MESSAGES DURING ANALYSIS
0 ANALYSIS WARNINGS ARE NUMERICAL PROBLEM MESSAGES
6 ANALYSIS WARNINGS ARE NEGATIVE EIGENVALUE MESSAGES
1 ERROR MESSAGES



JOB TIME SUMMARY
USER TIME (SEC) = 103.90
SYSTEM TIME (SEC) = 0.90000
TOTAL CPU TIME (SEC) = 104.80
WALLCLOCK TIME (SEC) = 106


Any help?

RE: Problem with hyperelastic material: Time increment required is less than the minimum specified

Hi,

I would recommend the following steps.

  • First in Property Module->Material Manager->Evaluate, evaluate your hyperelastic material. There are possibilities instabilities in the material parameters/models used.
  • Second in Mesh Module->Verify Mesh->Size Metrics try to look for the Stable time increment.
  • Last(Not a very recommended idea) in the Step Module->Edit Step->Incrementation, try to reduce the Initial increment less the current Minimum value and observe first 2-3 increments. This will just make sure if your model is correct at the cost of time and computation.

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