Best way to load model until specified strain criteria?

I have a requirement to load my static structural model until a specific strain criteria is met. This is for use with non-linear plasticity data, so it is not a straight-forward calculation.

My current approach is to use a Direct Optimization. The input variable is displacement, the target is a strain criterion at a specific location (averaged over a very short path in the area of interest). The output variable is the reaction force at the displacement boundary.

However, Direct Optimization does not take an overly efficient approach; picking numerous random values within the boundaries I give it for displacement, and then doing various clever things (depending on algorithm picked) to find the displacement that results in the target strain value (within a tolerance). It occurs to me that actually the most efficient approach would be to increase the displacement until the strain target is met (since the relationship between displacement and strain is known to be positive).

The efficiency of this procedure is relevant since I am running this Direct Optimization iteratively using Python and an external dataset (not part of discussion). I could create my own Python script to perform what I am trying to achieve, but would like to know if Ansys has a suitable function built-in, that I am not aware of.

Answers

  • cscs Forum Coordinator

    I think increasing the displacement makes sense. You could ramp the displacement over time and let ANSYS do multiple solutions at various displacement levels. You could actually use commands to loop like below:

    • apply a displacement increment
    • solve
    • check if strain is exceeded your criterion
    • If not restart the analysis and apply another displacement increment.
    • If strain criterion is met stop


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