LS Dyna

LS Dyna

Topics related to LS-DYNA, Autodyn, Explicit STR and more.

Need some insights into contacts

    • Fernando Torres
      Subscriber

      Hi Dear Community, 
      I want to 'TiE' these solid layers down (1,2,3 as shown in picture) and study their collective response to a low velocity impact. I have used Tie contact(s) option but I'm not sure if I have used the correct options as after solution there comes an abrupt decline in stress values (to almost zero), which doesn't make any sense.
      Thanks a lot!!

    • Aniket
      Forum Moderator
    • Fernando Torres
      Subscriber

      Well, partially yes. Only difference between both questions is that this one hs solid top and bottom layers, while other has top and bottom layers made of shells (with a proper space allocated for the thickness of the shells)...

    • Pedram Samadian
      Ansys Employee

      Hi,

      Did you use *CONTACT_TIED_SURFACE_TO_SURFACE?

      Thanks,

      Pedram

    • Fernando Torres
      Subscriber

      Hi Pedram, yeah actually I tried a bunch of options and they "worked" (worked in terms of taking the solution to termination time) but the stress behavior was strange as in a couple of time steps it suddenly decreases down to zero and I'm assuming here that there is something not right with the contacts as other provided data seems ok (material prop(s), bc(s), ic(s) etc) 

    • Fernando Torres
      Subscriber

      In order to further clarify...here is the graph. Yellow shows the "issue" where as the green line is "assumed" right...

    • Pedram Samadian
      Ansys Employee

       

       

      Hi,

      Thanks for providing more information. Which element has this stress history?Do you have any damage model or failure criteria in terms of the stress or strain level in your simulation? If the input hardening curves are accurate, the stress going to zero means the element deletion.

      Pedram

       

       

    • Dennis Chen
      Subscriber

      @Fernando Torres are you willing to share your k file with me?  

Viewing 7 reply threads
  • You must be logged in to reply to this topic.