Skip to main content

Posts

Showing posts from December, 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

Happy Holidays!

Happy Holidays! Hope everyone has a Merry Christmas and a Happy New Year! PS:  Way cooler animation by EpsilonFEA: http://www.epsilonfea.com/happy-holidays-17/ PPS: Archived V18.2 file: Link

Weld Analysis with Ansys

Figure 1: Equivalent Stress of White Paper Model There are many software out there now that does weld analysis. Among others... For fatigue type analysis, there are: FE-Safe  (Verity Method) &  Ncode  (Volvo Method) For static type analysis, there are: FEWeld & EDRMedeso A good reference classic book is Blodgett's  Design of Welded Structures . This book is a real gem. Here are two links to a short write-up by the same author et al: Welded Connections . White Paper Figure 2: Weaver's White Paper Comparing  FEA to Hand Calculations I came across this really good white paper by Weaver Engineering that had a worked example comparing both hand calculation to their software along with in depth discussions. The example was detailed enough to be replicated. This is a great stepping stone when following the  crawl-walk-run philosophy. Model and Snippet Comments A critical step in setting up the model is highlighted in Figure 3. Nodal Forces has to be computed f