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Integrating ANSA

Integrating ANSA in the Optimization process.

ANSA Setup

 

Create Morphing-Boxes and -Parameters

  • With the Morphing Tool you can reshape surface or volume mesh for optimization studies.
  • Define morphing parameters to control the shape change.
  • Save the file for example as model.ansa.
   

Set Up the Optimization Task

Define the pre-processing sequence that will be connected to LS-OPT. This sequence of actions will be invoked in every optimization loop and every action of it will be executed in the defined order modifying the shape and parameters of the model. All these actions take place before the run of the solver. When the sequence runs the following tasks are executed:

  • Reading Design Variable values from ASCII file
  • Modify the model according to the values of the ASCII file
  • Output the model in LS-DYNA format

Save the Design Variable file for example as model.txt.

This file contains the Design Variable names and upper and lower bounds needed for the optimization.

 

 

 

LS-OPT Setup

The ANSA preprocessor can be interfaced with LS-OPT allowing for shape changes to be specified. 

example2.png

Several files must be specified:

  1. ANSA executable, typically named ansa.sh. Do not use an alias.
  2. ANSA design parameter file, typically with the extension .txt or .dat. This file is generated using ANSA and LS-OPT will read the ANSA design parameter names and values from this file. If LS-OPT already has a design variable with the same name then this variable will be used to drive the value of the ANSA parameter.
  3. ANSA binary database, typically with the extension .ansa.
  4. LS-DYNA executable.
  5. ANSA executed by LS-OPT outputs a file called "ansaout" regardless of the specification in the ANSA-Optimization-Task. "ansaout" can be used as include file, input file or appended file.
  6. Optionally a file can be appended to the LS-DYNA input file. This file typically includes input that is not specified in ANSA; for example, output requests.

 

Example of the com-file:

$
$ DEFINITION OF SOLVER "1"
$ SOLVER "1" uses ANSA
solver dyna '1'
$
prepro ANSA
prepro command "/home/usr/bin/ansa.sh"
prepro input file "model.txt"
prepro database file "model.ansa"
$
solver command "lsdyna"
solver input file "ansaout"
$