Simcenter 3D Solutions Different time steps and bisections for solving same subcase of a problem

2024-07-22T10:10:35.000-0400
Simcenter Nastran Simcenter Samcef Simcenter 3D

Summary

In certain cases, users may encounter varying time steps and bisections when solving the same subcase in Simcenter 3D Non-linear Nastran Simulation. This variation can cast doubt on the results' accuracy. However, there is no need for suspicion as the results are indeed accurate. Such discrepancies can arise from machine precision differences when comparisons are made across two distinct machines. #Simcenter 3D #Non-linear #Nastran #SOL 401 #SOL 402

Details

In certain cases, users may encounter varying time steps and bisections when solving the same subcase of a problem. This variation can lead to doubts about the accuracy of the results. However, there is no cause for suspicion, as the results are indeed accurate.

Some reasons are:

  • It has been seen with some cases that solver in first inspection do not shows any indication of badly conditioned matrices. But solving a matrix sometimes led to ill-conditioned tangent matrices in resolution phase.
  • Numerical simulation results turn out to be unstable, since they depend on the machine precision.
  • This may happen due to machine precision if we are comparing in two different machines.
  • Presence of friction contact in simulation have also reported such instances, but actually friction presence required a non-symmetric solver

 

KB Article ID# KB000133832_EN_US

Contents

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Associated Components

Other SOL101 SOL103 SOL105 SOL106 SOL107 SOL108 SOL109 SOL110 SOL111-SOL112 SOL144 SOL145 SOL146 SOL153 SOL159 SOL200 SOL401 SOL402 SOL414 SOL601-SOL701 Superelement