LS Dyna

LS Dyna

Constrained_Tired_Nodes_Failure in model fracture mechanics problem

    • longt8
      Currently, I am working on using *CONSTRAT_TIED_NODE_FAILURE to model fracture mechanics problems.  The crack surfaces seem to fail in the y-direction first(see fig.1 attached) and then in the x-direction (the direction of crack propagation).  In reality, this mode 1 crack should just fail at x-direction.  I think this unphysical result is caused by the *CONSTAINT_TIED_NODE_FAILURE release the nodes with the plastic strain reached the threshold.  It really should be when the plastic strain of any nodes in the tied node group reached the threshold, the node on the maximum v-m direction was released.  
          Please let me know whether there is any existing keyword that can solve this issue, or if there is any user-defined option.
      Fig1. Effective Plastic Strain of a crack with *CONSTRAT_TIED_NODE_FAILUR
      Fig2. Von-Misses Stress of a crack with *CONSTRAT_TIED_NODE_FAILURE
    • Ashish Khemka
      Ansys Employee



      Please see if the following link is of any help to you:


      ">LS-DYNA TUTORIAL 14: Delamination Test and Cohesive Elements - YouTube



      Ashish Khemka

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