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How to have Patran set up a basic SOL 200 optimization run for Nastran?
Here is the rough procedure based upon Patran V2001:
1) Once the model is set up, go to TOOLS -- Model Variables
2) Set action/object/method to: Create Variable Property (or beam dimension or material depending on what your design variables to be). You can create as many design variables as you like linked to various shell, beam or material properties.
3)Once all the design variables are defined, go to TOOLS -- DESIGN STUDY
4) On this form, select the design variables you want to use in this optimization, the design objective and design constraints. In Patran, you are limited to design objectives of weight or volume. However, from the bulk data deck, you can create objectives for almost anything. Patran is giving you access to the basics of SOL 200, but not the complete set. Also, avoid setting the upper or lower bounds of constraints to 0.0 since that can cause numerical difficulties for the optimizer. If you really have a constraint where you need 0.0 to be the lower or upper bound, there are ways of dealing with this in the bulk data, but not through Patran.
5) Once you have applied the design study, go to the ANALYSIS form. Then select: Optimize Entire Model. Under translation parameters, select OP2 and Print instead of the default of XDB and print. If you use OP2 output for post processing, you will automatically get plots for the design variable history and objective function history created in Patran when you import the OP2 results file.
6) Once the job is run, you can browse the .f06 file for your results. The end of the .f06 file will contain the design variable history. A page or two above that will be the objective function history. After the design variable history printout, pay attention to the user information messages. There will be a message telling you why the job finished...e.g. Converged to a feasible design, or converged to the best compromise infeasible design. |
