General Mechanical

General Mechanical

transient analysis with pre-stress

    • Lenhart
      Subscriber

      Hello everyone, 


      I want to perform some dynamic analysis of rotating blade. But when I try to do the transient analysis after the static-mechanical analysis under the centrifugal stress field, an error occurs and reminds me that the transient analysis is not allowed. 


      Does anyone conduct the analysis in the same area, an agent guide is needed. 

    • peteroznewman
      Subscriber

      Please take a screen snapshot of the error message. For detailed help you could use File, Archive... in Workbench and attach the resulting .wbpz file to your reply.  Please reply with the version of ANSYS you are using (18.2, 19.0).


      Here is my pre-stressed, modal superposition, transient analysis. Is this how your are approaching the analysis?



      Attached is an ANSYS 19.0 archive if you want to see it in more detail.


      I can tell the rotational velocity pre-stress is working since Mode 1 is at 81 Hz and Mode 2 is at 83 Hz. Without the rotor velocity, they would be equal. The transient disturbance is a 100 ms duration, 10 G vertical acceleration.

    • Punnag Chatterjee
      Subscriber

      Hello,


      Is it possible to go from Static structural to Transient structural skipping Modal? If I am dealing with large deflection (geometric nonlinearity) pre-stressed anslysis then using Modal as an intermediate step blocks large deflection analysis. Any idea with that?


      So, with applied tension (Static structural), my mode shape changes for a clamped-clamped beam (with PZT patched at clamped ends). I want to use the information of the changed mode shape to run geometric nonlinear (large deflection) Transient analysis. I am not sure how I can achieve this, any thoughts/pointers?


       

    • peteroznewman
      Subscriber

      Hello,


      Use a two step Transient model. In step 1, you apply the load that prestresses the PZT patches, then in step 2, you apply the transient load.


      Regards, Peter

    • Autonewbie
      Subscriber

      Hi Peter,


      I have an assembly model where interference fit available between two parts. I run first load step without external load and Half Sine comes in second load step and 3rd step for stabilization purpose. However, I notice the displacement due to the interference fit is decreasing when the half sine load come in. Note it is non-linear contact with transient loading. Thank you so much!


       


    • peteroznewman
      Subscriber

      @Autonewbie,


      Let me check my understanding, Step 1 has no time integration but resolves an interference. Step 2 introduces time integration and a sinusoidal load and there is some displacement due to the load.  That is all fine.  If you have a concern, you have not provided enough context to convey it.


      When you add a post onto the end of someone else's discussion, you don't get notified of any replies posted. If you start a New Discussion, you do.  You can reference this discussion in the New Discussion by including a link.

    • Autonewbie
      Subscriber

      Thank you! I will create another new post!

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