Apply 0D springs to only some of the load steps

Alfonso_20743
Alfonso_20743 Altair Community Member
edited May 7 in Community Q&A

Hi All!

I want to create and simulate two cases at the same time - one case has springs attached to the part + forces, while the other one has only forces and inertia relief. I model the springs as 0D springs with a PBUSH property. However, I don't select the springs in the load collectors (they seem to be applied nevertheless) and thus cannot create one load step with springs attached and one load step with forces only + inertia relief. Is it possible to do to create the two load steps? I want to use the two different load steps for a topology optimization.

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Answers

  • harte
    harte
    Altair Employee
    edited May 6

    Hi Alfonso,

    I see two options for you here:

    1. Use the SUBMODEL subcase information entry to select a set of elements for analysis for a given subcase.

    2. Use a combination of MPCs and SPCs to set up 2 subcases; one where the 0D CBUSH elements are connected to the structure and one where they are disconnected with both ends constrained.

    I hope these suggestions help.

    Greg.

  • Alfonso_20743
    Alfonso_20743 Altair Community Member
    edited May 7

    Hi Greg,

    thanks a lot for the suggestion. I went with the first approach and it seems to work.

    However, I was assuming that inertia relief would apply only to the unconstrained subcase - the one that doesn't have the 0D springs (one of the springs has all the K line factors as rigid, just to verify that the model should be constrained). But the part deformation with inertia relief switched ON and OFF for the case with the 0D springs is different. How can I apply the use of inertia relief for the second subcase only?

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