General Mechanical

General Mechanical

cylic constant amplitude loading in APDL?

    • sohrab

      Hi everybody,

      I am developing an APDL code for crack growth analysis. I am confused with loading. my model would be 2D and method to analyse crack growth would be XFEM.

      I use  

      nsel,s,loc, Y, 100
      sf, all, pres, -10


      and also 

      time, 1.0
      deltim, 0.25, 0.25,0.25
      outres,all, all

      My question is:  how many cycles the loading would be continue? (above mentioned is  a 10 Mpa pressure with 0.25 frequency and also 0 stress ratio) and how can I control this loading until crack reaches a specific length?


      I in my analyses cycle of loading reaches to 10^8 orders


      I appreciate your helps and comments in this regard.

    • Sandeep Medikonda
      Ansys Employee


        Can you please refer to section 3.6 and 3.7 of the 19.0 Fracture Analysis Guide that cover XFEM based crack growth analysis?


    • sohrab

      Thank you Sandeep for your reply.

      I once more looke in detail section3.6 but my question is unsolved yet.

      the question is that how many cycles APDL runs the simulation? 

      when i plot the crack extension vs cycles only to specific amount of crack extension  the analysis continues (depends on element size of crack region) in my case 0,48 mm . but there is no control to continue simulation to an specific amount.

    • David Weed
      Ansys Employee

      Hi Sohrab,


      You can stop crack growth at a specified value using the CGROW,STOP command:


      Command Specification for Action = STOP

      CGROW, STOP, Par1Par2

        Par1 --

        CEMX -- Stops the analysis when the crack extension for any crack-front node reaches the maximum value (specified via Par2).

        Par2 --

        Value of maximum crack extension allowed.


        help link:

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