Autodesk Simulation Mechanical and Multiphysics

[#1]

When Autodesk Algor Simulation 2011 reads a model from an XXX.igs files it correctly models small diameter holes and archs.  When same model is read from an XXX.stp file it models small diameter holes and archs as hexagonal or octagonal surfaces, depending on the diameter or radius.  This causes extremely high stress concentrations and stresses in the analysis of models loaded from XXX.stp files.

MSC NASTRAN correctly models these entities whether loaded from XXX.igs or XXX.stp files.

[#2]

A lot of this is quite often graphical only, when you mesh (with 2nd order elements) this usually disappears. They have however improved how they handle importing surfaces since the 2011 release. I used to find quite a big difference between, step, iges, dwg and inventor files when importing the same model. Although most of this did not affect hole circle approximation per se, was more curved surfaces, particularly cylinders.

[#3]

The visualization in the results interface is based on the mesh size used in the pre-processor. If you mesh the model finer in FEA Editor, you will see a better representation in the Results environment. You can add local or global mesh refinement using the built in mesh refinement tools.

Best Regards

Sualp Ozel, PE

Product Manager

Digital Simulation
Autodesk, Inc.