General Mechanical

General Mechanical

Topics relate to Mechanical Enterprise, Motion, Additive Print and more

How to evaluate Random Vibe results taking into account the pre-stressed enviro

    • Casey Main


      Is it possible to estimate the total stress on an object undergoing random vibration by adding the random vibe stress to the analysis' pre-stress? For example if I have a cantilevered beam with 17,000 psi at the fixed support in a static structural analysis with standard gravity, and my random vibration 3sigma stress is 1,000 psi, can I say that the total 3sigma stress is 18,000 psi? If so, is this a conservative estimate or do I need to add any additional boundary conditions to make it more accurate?


    • Ashish Khemka
      Ansys Employee

      Hi Casey,

      The results of a random vibration analysis are statistical in nature and adding it to prestress result is not a correct approach. Please see the following two links that maybe of help to you.

      Why does the prestress from Static analysis does not add up to the stress in Random Vibration analys (

      How to Correctly Interpret PSD results| Ansys Courses


      Ashish Khemka

Viewing 1 reply thread
  • You must be logged in to reply to this topic.