Restart option's effect on results

k.anagnostopoulos

Hello,

 

I am running a simulation with Acusolve and I try to investigate the effect of the Restart option at the final results. So I run the simulations in 3 different ways:

1) Using the job launcher of Hypermesh and letting Acusolve solve until it reaches convergence at the 31th time step.

2) I make an initial run through job launcher of Hypermesh, I stop the solver at the 20th time step and then I use AcuConsole's Restart tab to continue solving, initializing from the first run. The convergence is achieved at the 30th time step.

3) I utilize AcuConsole's Project tool in order to project the results of the initial (stopped) solution of the 20th step and then continue solving until the convergence is achieved at the 30th step.

 

The resultant force as shown at AcuProbe is the same for cases 2 and 3 (175N) while for the first case it stops at (207) N. This difference seems strange to me since the models for all the simulations have the same mesh and solver settings. I would expect that the calculated forces by AcuProbe would be the same for all of the 3 cases. Is something that I am missing? Any ideas why does it happen?

 

Thank you in advance.

 

Ntinos 

acupro

There could be some 'path dependence' on the results, but I would also not expect such a large difference in the result, about 15%.  Do you also get similar results differences if you reduce the convergence tolerance from 0.001 (assuming you're using the default) to 0.0001?  Are you able/willing to share the model files (.inp, MESH.DIR) here?  If not, you should contact the local Altair Greece support team.