General Mechanical

General Mechanical

Explicit Dynamics of a tube

    • zjuv9021
      Subscriber

      Hi all,


      I'm new to explicit and am trying to emulate some buckling behavior by pushing this tubing past the fixed support an having it create a sharp/occluded bend at or near the fixed support.


      In one of the examples, I've tried to insert layers to the surface with the 4 separate materials involved, in the other it's pure solids and contacts.


      I'm having difficulties even getting this to start up. For one, I don't care about "how fast" this thing moves, merely only the end buckling/deformed behaviors that this tubing exhibits one displaced a certain amount.


      Any help is greatly appreciated to get me on the right path.


      Regards,


      Zach

    • zjuv9021
      Subscriber

      Note: This is what I'm attempting to physically emulate.


    • peteroznewman
      Subscriber

      Hi Zach,


      I ran your 4 layer shell model in Explicit Dynamics and saw the error. You have to RMB on Solution and select Open Solver Files Directory. In that directory you will see admodel.log. In that file you will see...



      Checking model setup.....Please wait                                                                                                                                                                                                                            


      Error ! Invalid Material Data for Rubber. Incompressibility Parameter D1 must be non-zero.                                                                                                                                                                      


      Error ! Invalid Material Data for Elasthane 80A. Incompressibility Parameter D1 must be non-zero.                                                                                                                                                               


      Error ! Invalid Material Data for Elasthane 55D. Incompressibility Parameter D1 must be non-zero.     



      In Engineering Data, put a non-zero value for D1 for these three materials and the solver should at least start.


      Regards,
      Peter

    • peteroznewman
      Subscriber

      This post explains where to get a D1 parameter for a Yeoh hyperelastic material model.

    • Sandeep Medikonda
      Ansys Employee

      For a little background on determining this parameter, please see this article.


      Regards,


      Sandeep

    • zjuv9021
      Subscriber

      Do I have enough information to calculate D1, D2, D3 for a Polynomial 3rd Order? Similarly D1 for a Mooney-Rivlin 2 parameter? Can I use 2/K for this as well?


      Regards,


      Zach

    • Sandeep Medikonda
      Ansys Employee

      Yes, please see this section from the manual that gives insight into how this parameter is calculated for different hyper elastic material models.

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