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Umat for crystallizable shape memory polymers

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Posts: 1
Topic starter
New Member
Joined: 8 years ago

Hello Friends,

I am a new user of UMAT with ABAQUS simulating the shape memory effect of SMP. Now Im trying to do the one element uniaxial tension testing of the subroutine that I have.

Initially I apply 100% constant strain on my specimen at the temperature higher than transition temperature

Then cooling it to the temperature much lower than transition temperature (438K)

Then unloading

Finally reheat it up to the temperature about transition temperature.

As I expected shape memory behavior can be observed during this simulation, but seems like its not working at all. And I found all the stresses in unloading step are zeros, Im sure there much be something wrong in the UMAT, but couldnt debug it till now, how can i solve this problem? Does anyone and help me check the UMAT and please help me resolve this issue. Thanks in advance.

All my best regards.

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Posts: 10
Active Member
Joined: 12 years ago

dear liq0001:
I am trying to model shape memory alloy but I am facing a problem. The loading (forward transformation) and unloading (elastic) are correct. However, the reverse transformation is not converging. I tried to adapt the code of Lagoudas, but it looks so complicated. Can you share that one you said is working.

Thank you in advance

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