Page 210 - Using ANSYS for Finite Element Analysis Dynamic, Probabilistic, Design and Heat Transfer Analysis

Design optimization • 197

SOLVE
FINISH
!
! ********************************************
***** POST
PROCESSING
/POST1
FSUM
*GET,THEAT,FSUM,HEAT
*SET,TOTALHEAT,-THEAT
ObjFunct=10000-TOTALHEAT
ALLSEL
*GET,Tempend,NODE,607,TEMP,
FINISH

5.3.4 oPTiMizATion PRobLeM

Using a BATCH file for the analysis describes this example optimization
analysis as consisting of two passes. In the first you create an analysis file,
and in the second you create the optimization input. It is better to avoid
graphical picking operations when defining a parametric model. Thus,
the GUI method is not recommended for performing the first pass of the
example analysis and will not be presented here. However, it is acceptable
to perform the optimization pass of the cylindrical fin example using the
GUI method instead of the ANSYS commands shown earlier. The GUI
procedure for performing the optimization pass follows.

5.3.5 SUMMARy oF STePS

1. Enter the Design Optimization (Design Opt) and execute the file for
the deterministic model (Fin.txt).
2. Specify Fin.txt as the analysis file for the design optimization analysis.
3. Define the design variables, state variables, and objective function
for your design optimization analysis. For this problem, you define
the length and radius of the cylindrical fin as design variables, tem-
perature at the tip of the fin as state variable, and total heat dissi-
pated as the objective function.
4. Run the optimization. Select a suitable method for optimization.
5. Obtain solution.
6. Perform postprocessing to visualize and evaluate the design sets of
optimization results.