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Re: Abaqus bilinear material

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  • Re: Abaqus bilinear material

    At 10:17 AM 10/12/99 -0500, you wrote:
    >Would anyone have any information on how to implement a bilinear material
    >definition in Abaqus?
    >The only way I am aware of is through the use of a user-defined material
    >(UMAT). But, I am unsure of how to code the material definition. Could
    >someone who has coded something similar please offer some assistance? Or,
    >if there is alternative method.
    >The data I am working with is the value of the Young's modulus of
    >elasticity corresponding to a region of strain and an additional value of
    >the Young's modulus for the second region of strain through failure/maximum
    >Thanks in advance for any feedback
    >Brad Probst
    >Dept. of Biomedical Eng.
    >Tulane University


    I see a couple of replies advising using *ELASTIC and *PLASTIC but be
    careful there. Two questions: is your material elastic up to failure of
    does it actually go plastic? It won't matter if the loading is monotonic
    everywhere. If not, and some of it unloads, then *PLASTIC won't give the
    right response.

    I also see that you're in a biomedical department. If you're working with
    a nonlinear elastic biomaterial then *HYPERELASTIC may be your best bet up
    to the point of failure. If you want to allow it to damage and fail, you
    may need to use UMAT. However I find VUMAT, as found in Abaqus/Explicit,
    easier to code.



    PS I've also posted this to There are
    subscribers there who're at the interface between engineering and bio-stuff.

    Dr R D Thomson
    Ballistics, Impact + Sports Eng Group
    Mech Eng Dept, Glasgow Uni
    Glasgow G12 8QQ, Scotland

    tel UK (44) Gla (141) 330 4313
    fax UK (44) Gla (141) 330 4343

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