Look at key performance indicators in Optistruct analysis with a text file

Robert Hoglund
Robert Hoglund
Altair Employee
edited April 15 in Altair HyperWorks

OptiStruct can output a key performance indicator (KPI).  It is a fast way to understand the maximum stress, strain, plastic strain, and displacement for subcases using a text file.  This is useful for a quick summary of the results of a linear or nonlinear static analysis.

 

Prerequisite: Set up a linear or nonlinear static analysis for OptiStruct.

 

  1. Create an OUTPUT card for KPI in HyperWorks.  Click CTRL+F, type OUTPUT, and select OUTPUT to create the output request.  Under the KEYWORD field for the OUTPUT definition, select KPI (shown on left).  You could alternatively set the KPI request as an output type under GLOBAL_OUTPUT_REQUEST (on right).

 

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The card OUTPUT, KPI will be added to the .fem deck:

 

OUTPUT, KPI

 

  1. Run OptiStruct. Click the Run button on the Analysis icon and then the OptiStruct button in the panel.  A text file with the extension .kpi is created in the run directory with the .fem file.

 

  1. Review the contents of the .kpi file in a text editor.  For each result type, the maximum result is output for each subcase by property. An example of the output format is shown below.

 

$DISPLACEMENTS

$SUBCASE ID =           1

       PID          GID          MAG          GID            X          GID            Y          GID            Z

         2        86509  1.42556E+02        85952 -5.56632E+00        81295 -4.11947E+01        86506 -1.41372E+02

         3        97892  1.37000E+02        94860 -2.02766E+00        97896 -3.43035E+01        97913 -1.32917E+02

$ELEMENT STRESSES

$SUBCASE ID =           1

       PID          EID          VON      XX/XX_1      YY/XX_2      ZZ/YY_1      XY/YY_2      YZ/XY_1      XZ/XY_2

         2       283248  1.58787E+03  1.52330E+03 -1.65572E+03  7.92633E+02 -4.85530E+02  5.09915E+02 -1.22884E+02

         3       294264  7.89146E+02  1.83666E+02 -4.08931E+02  4.40135E+02 -7.87480E+02  5.34369E+01  2.29076E+02

$ELEMENT STRAINS

$SUBCASE ID =           1

       PID          EID          VON      XX/XX_1      YY/XX_2      ZZ/YY_1      XY/YY_2      YZ/XY_1      XZ/XY_2

         2       283248  5.16981E-03  6.12147E-03 -7.19075E-03  1.59830E-03  5.32597E-05  6.31323E-03 -1.52142E-03

         3       294264  2.50579E-03  2.45837E-04 -8.22320E-04  1.83350E-03 -3.16572E-03  6.61600E-04  2.83618E-03

 

In this KPI file, the results are written out by property for subcase 1.  In a nonlinear analysis with material nonlinearity, plastic strain data would be added as well.  For shell and solid elements, stress and strain will be output.

 

Next Steps:

For further reference, you can review OUTPUT options in the OptiStruct Reference Guide.

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