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Defining Ansys Superelement SUB File Manually

Photo by  James Owen  on  Unsplash A surprisingly popular blog-post written here is Exporting Stiffness Matrix from Ansys . A sensible follow up question is what can one do with the exported stiffness matrix? In a recent Xansys Forum post, a question was raised on how we can edit the stiffness matrix of a superelement and use it for our model.  An approach presented below is to first create a superelement that has the same number of DOF and nodal location that will serve as a template. An APDL script can then be written to edit the stiffness matrix entries as desired before exporting to a new superelement *.SUB file for use in future models. The self-contained script below demonstrates this.  /prep7 et ,1, 185 mp , ex, 1, 200e3 mp , prxy, 1, 0.33 w = 0.1 ! single element (note nodal locations) n , 1, w, -w, -w n , 2, w, w, -w n , 3, -w, w, -w n , 4, -w, -w, -w n , 5, w, -w, w n , 6, w, w, w n , 7, -w, w, w n , 8, -w, -w, w e , 1, 2, 3, 4, 5, 6, 7, 8 /solu antype , substr     ! analy

Increasing Number of Iteration per Substep

Recently I came across a problem where the large deflection solution that has Body-to-Body beam connection that wouldn't converge. Ansys bisected at the maximum number of  iterations (26) and then halved the load step again... and again...

The trick was to add a command snippet in the solve section:

...with the following text containing NEQIT to increase the maximum number of iterations per substep :
    neqit, 75

and VOILA! It Solves!

Comments

  1. Hi there, was looking for solution of similar kind of problem. I am working on frictional contact problem, structural analysis of overhanging components.
    Just as force criteria is about to converge, Ansys pops up a message ( in solution section) about substep unable to converge in 26 iterations and starts AGAIN.
    Will this command work in my case?
    Many thanks in advance.
    Regards

    ReplyDelete

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