Global Modes - Load
After loading an OptiStruct or Nastran modal file, the subcase and modal frequencies from the result file are loaded. The Global Modes utility attempts to automatically identify the global modes based on the criteria and advanced options.
- File selection
- Select a result file containing normal modes results and click Load.
- Result selection
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- Subcase
- The drop-down menu contains the subcases from the normal mode result file.
- Criterion (1-100%)
- Enter a criteria value within the range 1-100. Identify the percent of structural grids participating in the mode shape. 100% means that all the grids are participating and the mode is considered a global mode. The recommended default value is 85-95%.
- Advanced Selections
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- Start and End Frequency
- Select the frequency range to identify the global/local modes.
- Mode Type
- Select the type of modes to be identified: global or local.
- Divider
- The divider is the value that is used to get the threshold by diving the top magnitude of displacement. This threshold is used to identify global/local modes.
- Top Magnitude
- The maximum displacement value used to calculate the
threshold for the identification of global/local modes.
- By node count
- The maximum displacement value is taken as an average of the displacements for the selected number of nodes.
- By percent of nodes
- The maximum displacement value is taken as an average of the displacements for the selected top percent of nodes.