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Showing posts from July, 2017

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

Ansys Workflow

Everyone has their own workflow in doing their analysis with different goals and preferences. Here's mine and a reasoning of why I do so. I would be eager to hear thoughts from other people on this subject. Geometry Cleanup in SpaceClaim The first step here is self explanatory. The litmus test is a crude mesh. Simplification of the model while maintaining objectives is next. Named Selection in SpaceClaim For a middle to large size model, every object I need in Mechanical gets a Named Selection. This is critical in organizing contacts and mesh properties. Modeling decisions gets clarity at this stage.  Rotating, hiding different parts and visualization is simply just easier in SpaceClaim compared to Mechanical.  If any geometry changes needs to be made, much of the model could be reused (e.g. contacts, boundary conditions).  First Pass Analysis The first analysis is usually very crude. The goal is to have a  minimum viable product  on hand that can be shared with the