Getting post-processing results from History Output afterwards 1

[Lucifer12]

Hello friends,

I have got my results from Abaqus after nearly three days however I had only requested stress variables for a set and not strain one's before running the simulation. Now that the simulation is complete i realized i need more variables but does that mean I need to re-run Abaqus again for three more days just to get more variables for the same sets?

Regards

 

[FEA way]

Unfortunately there's no way to get more predefined history output variables without performing the analysis again. You can only use what you have (displacements and stresses in your case) and post-process it using 'Operate on XY Data" (various options such as integration) or in some data processing sotware (like Excel) after exporting the nodal values. However you don't have to repeat the whole simulation if you use restart capability of Abaqus. Then only one step needs to be calculated again.

 

[Lucifer12]

Can i use restart capability to redefine history output without losing the data for all the step?

Also, my analysis is too slow. My last analysis took 3-4 hours but this time is taking days? Any suggestions on this?

 

[FEA way]

You will need restart request to start the simulation with changed settings from selected point. When you have it you can add new history output variables to the selected step but you will have to run the analysis for this step again.

What to do to decrease the time required for the analysis to complete ? Well, it depends what you are simulating. There are different approaches for Standard and Explicit analyses but some general rules apply to all cases:
- reduce the number of elements - this one seems obvious but it's the best thing you can do - reduce the number of DOFs by making mesh coarser. Leave it dense only in locations where high gradients are expected.
- simplify your problem using shell/beam elements
- use paralel processing - can help a lot
- reduce the number of increments
- reduce the number of requested output variables or frequency of their computation - it may take a lot of memory for Abaqus to calculate and save results and often you don't need them all. For example energies calculated automatically (ALLAE, ALLIE and so on) are sometimes redundant.

Special rules:
- in Explicit use mass scaling or make sure that stable time increment required for the analysis is not lowered by single small element (Abaqus calculates this value for all elements and then uses the lowest one)
- in linear dynamics use modal superposition instead of direct integration analyses if you can
and so on ...

 

[Mustaine3]

You can use Post Output to extract additional output from restart data.

See documentation:
Abaqus | Output | About Output -> Recovering additional results output from restart data in Abaqus/Standard

 

[Lucifer12]

Thanks guys. That parallel processing has increased the speed significantly!