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UMAT INP communication troubles

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Posts: 5
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Joined: 8 years ago

Hi all!
Ill be happy to post my UMAT and INP files to assist going forward, but what would be some reasons for a .INP for to not pass PROPS values or even NPROPS to the UMAT?

I have a print check and I get nothing, no values at all for PROPS! When I print out NPROPS, it gives me -143541113, which i know is a junk value. It all compiles and the job runs, but since there are no material parameters, there is no stress hence rapid convergence!

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Hi Frank,

Thanks for your reply! However the intro to subroutines doesnt answer my question on this particular issue and Id like to see if there might be any obvious solutions.

I checked again and all my PROPS values are E-300 type numbers, and NPROPS is -143541113. All other inputs from abaqus to the UMAT such as DFGR1 etc are all there and have correct values. Its only PROPS and NPROPS that is the issue. Here is an except of my .inp file where im calling the material

*Material, name=Material-1
*User Material, constants=11
0.078399999999999997, 0.011900000000000001, 0.0304, 0.0511, 0.011900000000000001, 0.078399999999999997, 0.032800000000000003, 0.0137
0.032800000000000003, 0.019400000000000001, 0.9

Really weird as to whats happening.


Posts: 3998
Joined: 5 years ago

Abaqus is picky about the length of the parameters that you provide. Can you input the parameters in shorter format, for example,
0.0784, 0.0119, etc.

If that does not work then I suspect that you have some issue with your UMAT code. For example, perhaps you missed a material parameter in the argument list.