General Mechanical

General Mechanical

Smart crack Growth in ANSYS

    • dlee0041
      Subscriber

      Please help with this error message 


       *** ERROR ***                           CP =      43.484   TIME= 20:47:26
       For Cgrow Id 1 and Crack Id 1, the computed number of cycles is less   
       than 1.  Please check your model and fatigue parameters.  The crack    
       growth solve is aborted.                                               
              TOTAL ACCUMULATED MAX CRACK EXTENSION INC    0.0000   


       


       


       


       

    • Sandeep Medikonda
      Ansys Employee

      Please elaborate with details of your model, materials and how you are setting this up (include inline pictures).


      I would strongly recommend you do go over the tutorials first so that you can eliminate any mistakes in methodology/implementation.


    • dlee0041
      Subscriber

      Specimen geometry Force


      I am running Analysis on a specimen that has a rivet hole in the center and a small notch that Is cut into the right of the hole where the crack is suppose to start and propagate the material is Aluminum 7075-t6 .force is applied to the


      top and bottom faces of 5000N. I am basing this Analysis from experimentation. In the experiment the forces were applied over 30000 or so cycle and the crack length was monitored. I am trying to simulate this fatigue test in ANSYS. I also do not know if I am inputting the number of cycles that I need ran correctly. I turned on the weak springs feature to give the structure some type of constraints. 


       


    • David Weed
      Ansys Employee

      Hi,


      The message indicates that due to either 1) the magnitude of the applied load or 2) the Paris' Law constants, the analysis produces a solution that is not fatigue-driven (where crack growth evolution occurs over a large number of cycles), but rather sudden crack growth is occurring. Looking at your Paris' Law constants, I would check the literature or other sources to make sure that these are appropriate. Typically, for the material you're using, C is reported as being much smaller.

    • dlee0041
      Subscriber
      Now using a C value of
      2.5 e-9
      And 6.85 e-8
      But still receiving the same error messages
    • dlee0041
      Subscriber

      now receiving this error message 


      An unexpected error ( SIG$SEGV ) has occurred...  ANSYS internal data  
       has been corrupted.  ANSYS is unable to recover and will terminate.    
       Previously saved files are unaffected.  Please send the data leading   
       to this operation to your technical support provider, as this will     
       allow ANSYS, Inc to improve the program.                            


      I edited my engineering data and change my unit for the paris law constants but now a new error. What should I do?

    • David Weed
      Ansys Employee

      Hi,


      Are you able to run your model in the latest release (R19.2)? There may be a defect present in R19.0 which has since been fixed in a future release.

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