Multiset Animation does not see all frames after termination of impact analysis

[phill_scott]

As title really.

Spent 10 hours getting 130 steps in to an impact analysis and wanted to stop and inspect it to make sure the analysis is working as intended.

Pressed the stop run button

Now the multiset animation does not see all steps from the analysis - only the one I load.  Results node has caution warning that the results might not match the analysis.

How do I do multiset animations in this case?

[John_Holtz · Accepted solution]

Hi @phill_scott 

The multiset animation only sees one time step, just like the results only see one time step. That is because you have 130 different results files (.fno) with one time step in each. What you want is 1 result file with 130 time steps. (A transient and other multistep analyses write the results to separate files. Nastran combines the N result files when the analysis finishes, but it does not do that when you stop it.)

You can use FNO Reader to combine the 130 steps together to create the 1 result file. The multiset animation will then see all the steps.

[phill_scott]

Hi John,

Thanks for replying.

The interesting behaviour here is that if the impact analysis fails itself
(as it has done previously due to none convergence after reaching max number
of bisections for an iteration) the results are recorded and displayed
within the Inventor Nastran environment with all steps available in the
multistep animation settings form. Presumably if the impact analysis
succeeds then the program will also show the same behaviour.

So you can see, there is a difference with a user enacted run termination
versus a solver enacted termination. It seems to be that there is no final
FNO file created when the user terminates the run, if I'm interpreting your
post correctly.

Since impact runs can take days for large assemblies and fine meshes I would
think there are lots of people self-terminating Impact analyses. I feel a
change needs to be made to this behaviour. I feel the Nastran environment
should be able to pick up the files for all steps when loading results from
an impact analyses or similar run, or at least give the user the option to
select the required files from somewhere.

I'll go try that FNO reader now.

Cheers,

Phill

[phill_scott]

Can confirm the FNO reader is very useful.  John, if you wrote it, then thanks very much for your contribution!

Using the automatic impact analyis to Impact a wall in to the assembly of components appears to be working as intended but the timesteps were far too small so will do it via the Non-Linear Transient Analysis and can then impact the assembly in to the wall.

I would note for those searching via google, don't forget to use non-linear material properties when working in the non-linear large deflection domain.