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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

### Tension Only LINK180

Figure 1: Von Mises Stress Animation

LINK180 is a very interesting element which allows tension but not compression. A snippet in a Beam element does the trick of configuring beams in Workbench into tension only beams.

et, matid, 180
*get, area, secp, matid, prop, area
sectype, matid, link
secdata, area
seccontrol,, 1 ! Tension only

The example problem has a thin plate that has a Revolute joint in the middle that rotates $\pm3^o$. The two chain LINK180 on each sides of the plate will thus take turns being in tension and be relaxed.

Figure 2: Displacement Animation

The forces plotted using SMISC1 shows forces in tension.

Figure 3: Force Animation

V18.2 Archived Workbench File: Link

### Comments

1. Hello. Ive imported my beam design from autodesk and am now trying to use APDL to change the elements to LINK180. From googling i think i need to change my model and use line bodys ? Is this the correct way to go about this