Page 197 - Using ANSYS for Finite Element Analysis Dynamic, Probabilistic, Design and Heat Transfer Analysis

184 • using ansys for finite eLement anaLysis
• To specify the file where optimization data is to be saved
(defaults to Jobname.OPT):
Command(s): OPDATA
GUI: Main Menu> Design Opt> Controls
• To determine whether information from the best design set is
saved (by default, the database and results files are saved only
for the last design set):
Command(s): OPKEEP
GUI: Main Menu> Design Opt> Controls
6. Initiate optimization analysis
After all appropriate controls have been specified, you can initiate
looping:
Command(s): OPEXE
GUI: Main Menu> Design Opt> Run
Upon execution of OPEXE, an optimization loop file (Job-
name.LOOP) is written from the analysis file. This loop file, which
is transparent to the user, is used by the optimizer to perform analy-
sis loops. Looping will continue until convergence, termination (not
converged, but maximum loop limit or maximum sequential infea-
sible solutions encountered), or completion (e.g., requested number
of loops for random design generation) has been reached.
The values of all optimization variables and other parameters at
the end of each iteration are stored on the optimization data file (Job-
name.OPT). Up to 130 such sets are stored. When the 130th set is
encountered, the data associated with the “worst” design are discarded.
7. Review design sets data
After optimization looping is complete, you can review the result-
ing design sets in a variety of ways using the commands described
in this section. These commands can be applied to the results from
any optimization method or tool.
To list the values of parameters for specified set numbers:
Command(s): OPLIST
GUI: Main Menu> Design Opt> Design Sets> List
To graph specified parameters versus set number so you can
track how a variable changed from iteration to iteration:
Command(s): PLVAROPT
GUI: Main Menu> Design Opt> Graphs/Tables
In addition to reviewing the optimization data, you may wish to
postprocess the analysis results using POST1 or POST26. By default,
results are saved for the last design set in file Jobname.RST (or .RTH,
etc., depending on the type of analysis). The results and the database