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A
Andrea_A7-Bedrock
7-Bedrock
July 8, 2026
Question

Cannot select or create measures for random vibration analysis in Creo Simulate

  • July 8, 2026
  • 2 replies
  • 80 views

Hi everyone,

I am setting up a Random Vibration analysis in Creo Simulate and I am running into an issue regarding Measures. It appears that none of the measures I create are available for selection or evaluation within this specific analysis type.

Specifically, I need to output the following two quantities:

  1. Failure Index: I need to track the failure index across the random vibration analysis, but it does not appear as an option.

  2. Stresses in a custom coordinate system: some standard stress components are available, but they are strictly tied to the global coordinate system. I need to evaluate direct stresses relative to a user-defined, local coordinate system.

Is there a specific workflow or workaround required to enable custom measures, or to evaluate failure indices and localized stresses, for a random vbration analysis?

Any insights or step-by-step guidance would be greatly appreciated.

Thanks in advance,

2 replies

Catalina
CatalinaCommunity Manager
Community Moderator
July 21, 2026

Hi ​@Andrea_A 
 
Thank you for your question.  
 
Your post appears well documented but has not yet received any response. I am replying to raise awareness. Hopefully, another community member will be able to help. 
 
Also, feel free to add any additional information you think might be relevant. It sometimes helps to have screenshots to better understand what you are trying to do. 

Thanks, 

Catalina | PTC Community Moderator
    MikeBennett
    MikeBennett16-Pearl
    16-Pearl
    July 21, 2026

    Hi ​@Andrea_A,

     

    I believe this topic is covered by CS57071 and the Creo Help Center:
    https://support.ptc.com/help/creo/creo_pma/r13/usascii/#page/simulate/simulate/meas_not_calc.html

    Failure Index is not calculated for Dynamic Random Analyses.

    Certain Stress measures are also not calculated regardless of WCS or custom CSYS but other stresses such as XX, YY, etc. can be set to custom CSYS

    A
    Andrea_A7-BedrockAuthor
    7-Bedrock
    July 23, 2026

    Hi,

    Yes, that's correct, the KB article and documentation are accurate: the Failure Index is not computed directly for Dynamic Random analyses, and stress tensors are provided relative to the WCS.

    The main issue with requesting stresses in a custom CSYS relates to laminate definition. For components modeled as multilayer shells (in my case, a tube represented by its midsurface), querying stress outputs at specific points returns a single stress value at the location. It does not specify which ply (or z-location through the thickness) that value belongs to.

    Since evaluating the Tsai-Wu Failure Index for each unidirectional ply requires stress components in the local material frame (XX, YY, XY: fiber direction, transverse, and shear), my guess is that the remaining viable approach is to:

    1. Extract the XX, YY, and XY stress components in the WCS.

    2. Apply coordinate transformation (in-plane stress rotation matrices) to rotate the stress state to the specific ply orientation angle for each layer.

    3. Analytically compute the Tsai-Wu failure criterion per individual ply.

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