Can anyone point me to how to do a restart?
I ran a SOL 601 that stopped halfway through and I would like to try and continue from that point using a SOL 701 explicit analysis.
Restart is a useful feature in Advanced Nonlinear Solution (SOL601). It can be used when the user wishes to continue an analysis beyond its previous end point, or change the analysis type, loads or boundary conditions or tolerances. A restart analysis is selected by setting MODEX = 1 in the NXSTRAT entry. Recovering results from a restart file without continuing the analysis can also be done setting MODEX = 2.
According the NX NASTRAN QRG the parameter MODEX of NXSTRAT card indicates the mode of execution:
0 – Normal analysis run, i.e. not a restart analysis
1 – Restart analysis
2 – Recover results from restart (.res) file without running analysis for any additional time steps. GPFORCE and SPCFORCES cannot be recovered. MODEX=2 is supported only for SOL 601 analysis.
The restart (.res) file from a previous run must exist to do a restart analysis or result recovery. The filename and location of the restart file is determined by the “dbs” keyword. By default, dbs points to the current working directory with the prefix of the current job name. The IDs of grids, elements, properties, materials, contact sets, contact pairs and contact regions should be the same in both the original and the restart model. Note that keyword scratch=no must be used when running a restart analysis or result recovery.
According the NX Advanced Nonlinear Manual the geometry, and most element data, cannot be changed in a restart analysis. However, the following changes are allowed:
Thanks Blas. A few more dumb questions:
1. Do I modify the current analysis or create a new one? Sorry, restarts are a new one for me.
2. Are there any simple examples or tutorials out there?
You can modify the current analysis or create a new one. The key is to use MODEX=1 and preserve the file with extension *.res to run the restart analysis, just created after the analysis was completed. If you create a new one you must copy the *.res file as well.
Here you are a workflow playing with the TSTEP card modified to achieve intended time steps:
Also remember: when changing from SOL 601 to SOL 701, all features used must be
supported by SOL 701, e.g., cannot have higher-order elements.