Non convergence of model with compression bars in Robot Structural Analysis

Autodesk Support

Oct 8, 2023

Products and versions covered

Issue:

No convergence after activation of bars working for compression only in Robot Structural Analysis.

Solution:

Neglect compression bars while dead load definition. Modify nonlinear load cases parameters.

To neglect compression bars while dead load  follow the steps:
  1. Open Loads >Load table.
  2. Select and delete load case record including dead load definition.
  1. Close Load table.
  2. Open Loads >Load definition.
  3. Go to Self-weight and mass tab.
  4. Select dead load case using Load case filter.
.
  1. Select Dead load on selected elements then Add.
  1. Activate Apply to in Load Definition dialog.
  2. Select All objects using Object filter.
  1. Open Advanced filter setting.
  2. Select Bar selection.
  3. Select Advanced in Attributes section
  4. Select Compressed only.
  5. Click Subtract option to remove Compressed bars from selection.
  1. Activate Load Definition dialog (selected objects numbers should appear in object list).
  2. Apply in Load Definition Dialog.
To modify non-linear load cases parameters follow the steps:
  1. Open Analysis >Analysis types.
  2. Type in list of simple load cases/combinations to be calculated in Case list field.
  3. Open Set parameters.
  4. Activate Set non-linear parameters.
  5. Open No- linear analysis parameters.
  6. Activate matrix update after each iteration.
  7. Increase values of Relative code tolerance for Residual forces and Displacements (0.001 recommended).
  8. OK  then OK.


 

Products:

Robot Structural Analysis Products;

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