Von Mises Strain in Tendon

Altair Forum User
Altair Forum User
Altair Employee
edited October 2020 in Community Q&A

Hi George, 

 

When I plot the Von Mises strain for a spring (/ANIM/SPRING/VONM) in a very simple setup (only two nodes connected with a spring and a fixed bc on one side an imposed disp. on the other side) I get zero Von Mises strain. Why is that? And is there an option to plot strain in different directions (e.g. EPSX, EPSY) analogue to SIGX, SIGY, ....

 

Thanks, Best

J

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Answers

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited April 2018

    Hi,

    We can't extract stress/strain results for spring elements. For extracting these a geometry is required, as an example stress is force/area, and since no geometry is there for spring elements it's not possible. Forces do exist for spring elements which you can extract using the time history (/TH/SPRING) file.

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited April 2018

    Hi George, 

     

    Hmm.. a 1D element has also strain (dL/L0) and von Mises strain should then be 2/3 * ( 3/2 * strain^2 )^(1/2), right? But there is no way to directly plot the strain of a tendon. I have to export the displacement, measure the L0 length and compute it myself?

     

    Thanks, Best

    J

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited April 2018

    Hi,

    Unfortunately there is no direct way to output strain results for spring elements. You may have to manually calculate this.

    From the /TH/SPRING you can get the elongation of each spring element in required direction.

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