Iterative calculation in Abaqus by updating the plastic strain components ? 1

[Lemine]

Hello all,

I want to perform several analyses successively in Abaqus, in each analysis - except the initial one - I should update the plastic strain components from the results calculated in the previous analysis (extracted from .odb files).
I Know how to initialize plastic strain components in the .inp file using the keyword : *Initial Conditions, type=PLASTIC STRAIN, for a simple analysis but I want to automate the process using python scripting.
Any ideas or help are highly appreciated.

Thanks,
Best regards,

 

[FEA way]

The hardest part will be to extract plastic strain components from odb and save them to an include file in proper format to be used in *Initial conditions, type=plastic strain keyword in the next analysis:
element_number, section_point_number, first_plastic_strain_component, second_plastic_strain_component, third_plastic_strain_component

You can find some examples of accessing the output database (and extracting field output results) with Python scripting in the documentation.

The script will also have to submit the analysis, wait until it completes and extract the results again for another simulation but it shouldn't be very difficult to create such a loop.

 

[Lemine]

Thanks a lot, Dear FEA WAY, for your response,
I know how to extract all the plastic components from the .odb file, but the problem is how to update them in *Initial conditions (in the .inp file) at each iteration?
Thanks again,

 

[FEA way]

If you extract them and save to the include file in proper format (as mentioned above) then you can reference it in the input file:
*Include, input=...

Next step is to submit the analysis, extract results again, save them to another include file (or overwrite the previous one so that the *Include keyword remains unchanged) and run another simulation.

So the whole process will look like this:
1) Run the initial analysis
2) Extract plastic strains from it and use them as initial conditions for the next simulation
3) Run second analysis
...

Is that what you would like to achieve ?

 

[Lemine]

Thanks a lot, If the .inp file can read information from the appropriate file at each iteration, That exactly what I would achieve. If you have a link to an example would be very helpful.
Thanks a lot again

 

[FEA way]

*Initial conditions are applied only at the beginning of the analysis and then they are overwritten with new values computed in each increment.

 

[oldNail]

It's not completely clear what you are trying to do but it sounds like this would be much simpler if you just write restart data on the first analysis and read it on the following analysis. The plastic strain and everything else will continue as if the steps of the second analysis were a continuation of the first one.

Check out Restarting an Analysis in the manual.