Calculating Reaction Forces in a Spectrum Analysis in ANSYS Mechanical


Calculating the Reaction Force on an Ansys Mechanical structural or vibration model is an important step in not just verifying your model, but it may also be a key output of the simulation. However, with some physics, not all entity types are selectable for the Force Reaction Probe. Back in 2011, we did a blog post on how to use APDL commands in Ansys Mechanical to grab reaction forces for a Random Vibration Analysis. But, the math behind a Spectrum Analysis is different, so the “FSUM” command will not return the proper answer.

Calculating Reaction Forces in an Ansys Mechanical Spectrum Analysis

In this blog post, we will show the correct way to extract reaction forces from a Spectrum Analysis. There is also a script included to automate the repetitive steps needed to get the proper answers. Then, to make sure we did everything right, we do a Structural Transient Analysis that is equivalent to the Spectrum Analysis and show how close the calculated reaction forces are.

Presentation on Calculating Reaction Forces in an Ansys Mechanical Spectrum Analysis

The PowerPoint below steps you through everything, and you can find a zip file with sample files below that.

Here is a zip file of the model we used and the input APDL commands:

If you have any questions, need training, or would like to outsource this type or analysis or any other simulation, please contact us.

Calculating Reaction Forces in an Ansys Mechanical Spectrum Analysis

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