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transversal isotropy for beam elements

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  • transversal isotropy for beam elements

    Hi all,
    I am doing some simulations for UD pultruded composite beams in Abaqus. In my case the considered profiles are symmetric and solid. I wrote the following simple VUMAT to specify the material behaviour ('1' being the fibre direction):

    e11 = props(1)
    g12 = props(2)
    v12 = props(3)

    do k = 1, nblock

    C Update stresses (direct & torsion shear)
    stressNew(k,1) = stressOld(k,1) + e11 * strainInc(k,1)
    stressNew(k,4) = stressOld(k,4) + g12 * strainInc(k,4)
    C Define transverse strain increments (direct)
    strainInc(k,2) = -v12 * strainInc(k,1)
    strainInc(k,3) = strainInc(k,2)

    end do


    This seems to work fine, but I still have two questions:
    1. The subroutine manual states that it is necessary to define the transverse strain increments. However, I notice the results are the same when this step is omitted. Does Abaqus actually use these strain increments, and how?
    2. Using a VUMAT, the transverse shear stiffness needs to be defined separately. When K12 = k G12 A; can we use the same shear correction factor k as for isotropic material? In some first checks against analytical calculation of a cantilever beam and simulation of a solid model this seems to hold fairly well, though there exists some error.

    Thank you.
    Last edited by Joren; 2018-10-09, 06:18.

  • #2

    Hello

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    Or
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    or from the ResearchGate discussion forum.

    For advice on mechanics in general, including modeling,
    you can consult
    http://imechanica.org/

    If you need subroutines: as an introduction get the file
    http://imechanica.org/files/Writing User Subroutines with ABAQUS.pdf

    Good luck

    Frank

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    • #3
      Hi Frank,

      Thanks for the links.
      There is also the Simulia Learning Community 3ds.com/slc (though it's not the most user-friendly interface)

      But in the past I have always found the most interesting information on this forum, which is why I post it here.

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