Announcement

Collapse
No announcement yet.

Patran - Simulation of the instabiliy shape of an hyperelastic material

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Patran - Simulation of the instabiliy shape of an hyperelastic material

    Hi to everybody,

    I'm Andrea and I'm new to the forum. I graduated in Aerospace Engineering Bachelor Degree and this year I will graduate in the Master Degree in Aerospace Engineering.
    I have to simulate the instability of an elastic band, when you twist it and and it curls up on itself. I searched many informations on internet and I did a lot of tests but I'm very far to simulate a simil behavior. Starting from the beginning, the shape of the elastic band is a parallelepiped, so I simulate it in a 2-dimensional way. I have defined an hyperelastic material with C10 and C01 parameters with the theory of Mooney-Rivlin MATHE. Then, I have doubts on which property I can define to have displacements out of the plane, since I want to rotate the free end. Can someone give me some advices?

    Thank you very much,
    Andrea

  • #2
    I'm not quite sure I understand how you intend to rotate the free end. Can you provide a figure?
    It may be easier to simulate the problem using a 3D representation. That way you can apply any rotation that you like.

    -Jorgen
    Jorgen Bergstrom, Ph.D. PolymerFEM Administrator

    Comment


    • #3
      Hi Jorgen,

      Thanks for the reply. I will try to be as precise as possible. I'm trying to simulate the phenomenon of instability that occurs when an hyperelastic material band is twisted. For this reason, I want to create a surface (10x0.5 cm) as a geometry. One of its side (short one) will be constrained and the rotation will be applied to the opposite side until the instability shape will appear. I was able to define the material using the experimental fitting tool provided by Patran, but I have some problems in defining the property. I don't know what kind of property gives the possibility to apply an out of plane displacement for the hyperelastic materials. Could you give me some advice?

      I attached a picture of the warped shape of my model. I used a linear elastic material just for give you an idea.

      Thank you for your previous suggestion. The 3D geometry will be the next step, but at the moment I just want to try with a 2D model if it is possible.

      Andrea

      Comment


      • #4
        I am still unsure I follow your explanation. If you want to apply an out-of-plane displacement, can't you just apply it?
        Somehow I don't think I understand your question

        -Jorgen
        Jorgen Bergstrom, Ph.D. PolymerFEM Administrator

        Comment


        • #5
          Hi Jorgen,

          I apologize if I haven't replied so far, but I found the problem. There was an activated check that gave me an error. At first I thought it was a problem related to the property PSHELL, but the fact that you wasn't able to understand what I meant made me realize that the problem was different.
          However now I still need your help. As I told you in the previous messages, I would like to analyze the instability of a strip of hyperelastic material (rubber). My goal is therefore to find the critical load after which the material becomes unstable or, at least, a parameter that allows me to compare the instability between the various models of hyperelastic material.
          Could you suggest me a strategy to follow in Patran?

          Thank you

          Andrea



          Comment

          Working...
          X