Natran In-Cad Incremental Loading

[travis.potier]

In the old Simulation Mechanical software, it was possible to set incremental loading steps based on time steps. I am trying to mimic the same thing in Nastarn In-Cad. You could both increase the load from step to step and decrease the load from step to step meaning you could check residual stresses once the part was unloaded. How can this same operation be performed in Nastran In-Cad?

[Anonymous]

Please have a look at the "Self-Paced Training" tutorial "Flexural Test Fixture Exercise".

Is this what you are searching for? You can do what you describe with a sequence of subcases in a non-linear static analysis. Instead of the enforced motion in the tutorial you can also use forces.

[travis.potier]

Michael,

It does appear that this is what I am looking for. Thanks for the assistance. However, I was hoping you could make one more confirmation for me. In the tutorial exercise, a forced displacement is used, and therefore to go back to the original state a negative displacement was used. When doing this task with pressures and/or forces, would the "unloading" force/pressure applied have a magnitude of 0, or would the negative of the applied force/pressure be required? I believe it would simply be 0, but would like your input on that.

Thanks,

Travis

[Anonymous · Accepted solution]

For the release state no load would be best. A negative load would end in a deformation to the other direction. Unfortunately (and of course) a subcase must have a load (to increment). Therefore a load of 0 magnitude or a very small dummy load should be OK.