Testing the optimization setup (TEST_BEAD)

Testing the optimization setup without using simulation results is described.

Related Topics
In Other Guides
TEST_BEAD

The test run in bead optimization is controlled by the TEST_BEAD command. A test run is always based on a previously defined optimization job that is referenced in the OPTIMIZE command. The format information for post-processing is specified with the parameter FORMAT. The name of the file, which the postprocessing data is written into, is specified with the parameter FILE_NAME. The test displacement in a specified direction (DIRECTION) is applied in a number of increments (INCREMENT parameter) defined by the user until reaching a specified maximum displacement (DISPLACEMENT parameter).

A typical TEST_BEAD command appears as follows:

TEST_BEAD
 OPTIMIZE = <name_of_optimize>
 FORMAT = ONF
 FILE_NAME = <name_of_output_file>
 DIRECTION = GROW 
 DISPLACEMENT = <value_of_max_displacement>
 INCREMENT = <number_of_increments>
END_

  • If all information entered by the user is correct, the TEST_BEAD command is executed immediately after it is entered. The command does not have its own name with which it can be referenced, i.e. all command data is only temporarily active during the execution of the command.
  • Referencing a previously defined optimization task (OPTIMIZE command) is mandatory. The test displacements are applied to the design nodes of the optimization job.

Specifications

  • Specification of a format (FORMAT parameter) is mandatory. This can either be FORMAT=ONF for the SIMULIA Tosca Structure specific optimization neutral format to generate a vtfx sequence or FORMAT=VRML for vrml 2.0 output.
  • Specification of a file name (FILE_NAME parameter) is optional. By default the file name TEST_BEAD is used. An increment number is always attached to the file names (for example, 000, 001, 002 etc.) to enable identification of the results from the various increments.
  • Specification of a displacement direction (DIRECTION parameter) is optional. The default setting is GROW. Two possibilities can be selected to specify the displacement direction: uniform growth of all design nodes in the optimization group outwards (DIRECTION=GROW) or non-uniform ‘randomly controlled’ displacement of the design nodes in the optimization group (DIRECTION=RANDOM). For sensitivity-based algorithm DIRECTION=SHRINK does also make sense.
  • Specification of the maximum absolute displacement (DISPLACEMENT parameter) is optional. If no maximum absolute displacement is specified by the user then a maximum absolute displacement depending upon the FE mesh will automatically be determined.
  • Specification of a number of increments (INCREMENT parameter) is optional. The default value is INCREMENT=1. If the user specifies 5 increments, for example, 6 results files are generated, whereby the first result file has the file extension ‘000’ and represents the initial state.
  • If DIRECTION=RANDOM is selected, it is possible that the design node with the maximum displacement will have a smaller absolute displacement than specified in the DISPLACEMENT parameter. Here, the maximum specified displacement only represents an upper limit that does not need to be achieved due to the ‘randomly controlled’ distribution of the displacements.

Example

The optimization task named bead_optimization should be subjected to a test run. Optimization neutral file format is the selected output format. The file names have the name test_grow. In the growth direction five displacement increments should be applied with a maximum displacement of 1.5 length units, i.e. the displacements are applied in increments of 0.0, 0.3, 0.6, 0.9, 1.2 and 1.5.

TEST_BEAD
 OPTIMIZE = bead_optimization
 FORMAT = ONF
 FILE_NAME = test_grow
 DIRECTION = GROW 
 DISPLACEMENT = 1.5
 INCREMENT = 5
END_

Realization in Tosca ANSA® environment

Example TEST_BEAD with 5 steps to show the maximal displacement of 5.0:

  1. In SIMULIA Tosca Structure Task select CHECK_INPUTS > New > TEST_BEAD_CHECK.
  2. Select CHECK_INPUTS > TEST_BEAD_CHECK > New > TEST_BEAD.
  1. To view results directly afterwards select CHECK_INPUTS > New > VTF_VISUALIZATION.

Realization in Tosca Structure.gui

  1. As Module select Start SIMULIA Tosca Structure.
  2. As Type choose test1 and click Start Tosca.