How Do I Investigate My RISA-3D Model Using the Deflected Shape?
When your RISA-3D model is not behaving as you anticipated, one of the best tools you have is viewing the deflected shape. Displaying the...
Do you get an instabilities warning when you’re trying to do a simple 2D model in RISA-3D?
Below is the easiest way to test and fix the instability:
- Open the Node Reactions spreadsheet, and see which joint is unstable.
- In the Boundary Conditions spreadsheet, apply a Reaction to the joint in the degree of freedom that was LOCKED.
- Re-run the model and examine the Node Reactions.
If the reaction that is restraining the instability is showing a ZERO force or moment, then the instability is inconsequential to the results. Also, if the reaction that is restraining the instability is showing a non-zero force or moment, then you have a problem with the model that must be corrected for you to get valid results.
DECEMBER 16, 2010
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How Should I Model Boundary Conditions for a Truss in RISA-3D?
When it comes to trusses in RISA-3D, boundary condition definitions (pin vs. roller) can make a huge difference. Let’s take an example of a...
JUNE 13, 2011
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How Do I Avoid Instability Warnings in a RISA-3D Model?
Have you ever received an instability warning when running a three dimensional RISA-3D model? This is because RISA-3D cannot build the stiffness...