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UEXPAN together with UMAT

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Posts: 1
Topic starter
New Member
Joined: 9 years ago

Im working on a new material model in Abaqus, for which i use the Uexpan subroutine and the umat subroutine together. In the uxpan i define a thermal strain tensor (real,dimension(6), intent(out)::EXPAN=...) as output for Abaqus. In the UMAT i define the stress tensor and the jacobian as a function of the deformationgradient (DFGRD0 and DFGRD1). My Problem is, that the thermal strain tensor (EXPAN) has no influence of DFGRD0 and DFGRD1, although STRAN and DSTRAN are correct in UMAT (STRAN = -EXPAN). Has some an idea why the deformation gradient is not updated by the thermal strain tensor?

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Posts: 3998
Joined: 5 years ago

I believe that when you use a UMAT then you need to incorporate the thermal expansion directly into the UMAT code. You cannot combine a UMAT with basic thermal expansion.


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