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Design optimization • 175
File.DB
ANSYS
database
file
SAVE RESUME
ANSYS
Model
database
File.LOOP
OPEXE Loop file
Analysis file Optimization
(parametrically OPEXE database
defined model) OPEXE
File.OPO
Last loop
OPSAVE OPRESU output
File.OPT
optimization
data file
Figure 5.2. Optimization data flow.
5.2.2 oPTiMizATion MeThoDS
The ANSYS optimization procedure offers several methods and tools that
in various ways attempt to address the mathematical problem stated ear-
lier. ANSYS optimization methods perform actual minimization of the
objective function of Equation 5.3. It will be shown that they transform
the constrained problem into an unconstrained one that is eventually min-
imized. Design tools, on the other hand, do not directly perform minimi-
zation. Use of the tools offer alternate means for understanding design
space and the behavior of the dependent variables. Methods and tools are
discussed in the following sections.
The ANSYS program uses two optimization methods to accommo-
date a wide range of optimization problems:
• The subproblem approximation method is an advanced zero-order
method that can be efficiently applied to most engineering problems.
