PATRAN Pre-Post – NASTRAN Preference

Patran is a general-purpose pre & post-processor, it can post-process the results from many different solvers using their native output format.  For example, Patran can read in an Ansys .rst file to view the results from a particular Ansys solution.  Likewise, Patran can read in different output files created by a Nastran solution run (.xdb, & .op2 files).  Information and format written to output files is defined by the user in the input deck.

Request results to be written to.op2 output files

.xdb output files

Sample Nastran input deck (Martin.dat) is one I created a few minutes ago using Patran. It is basically a cantilever beam (composed of solid hex elements) fixed on one end and loaded vertically on the other end. If you examine the input deck, you can probably figure out what the input cards are doing. Near the top of the input deck, I’ve requested the output of displacements, stresses, and constraint forces for this statics analysis run (using the default .xdb
binary output format).

When you run this example deck, Nastran will generate a number of output files including the martin.xdb file. If you want to post-process the results in Patran, you will need to do the following:

1) Start up Patran
2) Open a new database with the “Nastran” preference
3) Go to the “Analysis” Form and use the following settings:
– Action: Attach XDB
– Object: Both (you’re reading in the model geometry and attaching the
– Method: Local
4) Click on the “Select Results File…” button and select the file
5) Click “Apply”
6) Go to the “Results” Form
7) Select “Fringe Result” = Stress Tensor
“Deformation Result” = Displacements
8) Click “Apply”

You should see the Von-Mises stresses mapped on the model with the deformation exaggerated.