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UMAT subroutine in ABAQUS for elasto-plastic cyclic loadings

I want to implement the elasto-plastic model for cyclic loadings (I suppose
something like chaboche) into the UMAT subroutine in my ABAQUS  model ,
but I haven't enough knowldge for do this. I read some book like mechanichs of solid materials but i don't understand how to implement my constitutive law into the subroutine. until the load is static i don't have many problems, but when i work with cyclic load I'm non able to generate a cyclic increments of plastic behaviou.

Can anyone kindly help me or
post me an example of the subroutine?

I hope my english was sufficient.
Thank you very much
Best regards
Bojan Huljev


Dear Bojan Huljev,

I have your same problem since I would implement in the UMAT or VMAt subroutine the Chaboche elasto-viscoplastic model. Did you received any help pr subroutine example that you can send me?

Thank you


Dear Bojan and Barbara,

I am also working on developing such a subroutine which I can use in ABAQUS. I see that the two of you have faced the same difficulty. Would you consider sharing your UMAT subroutine with me?



Sourabh Shekhar

hii sir i also need help about chabuche viscoplastic model



hii sir i also need help about chabuche viscoplastic model



you should just relate the number of cycles and increment in cyclic loading to determine life and fatigue damage. you can use both usdfld and umat subroutines. 

 Dear all

I´m working in a simple umat damage model to implemented with xfem. In this moment i can simulate the elastic material porperties, but no damage acumulation. Could anyone send me a umat with a simple damage model.



If you are trying to model crack initiation and growth using XFEM, you will probably need to use a UEL subroutine to add this functionality or use the built-in XFEM capabilities of Abaqus 6.9+.

A UMAT subroutine is suitable to implementing damage using material laws, such as through continuum damage mechanics. This is probably not the right subroutine for you if you need a simple XFEM implementation.

Can you provide more details about your problem?   

Thanks for your answer Mike.

 Yes i work with 6.9+. I can realise a crack gronw with xfem in a simple monotonic loading, but, i want to introduce a uniaxial cyclic loading conditions(sine curve load, for example) and introduce a simple UMAT or USDFLD subroutine model to obtain a cyclic loading crack gronw. The UMAT is required to realise a fatigue damage model (Pari´s, chaboche, etc) in XFEM.

  I would like to start with a simple damage model, but i do not know which model could be more appropiate. I have a UMAT that simule a isotropic material and i would like to improve it with a damage model for cyclic loading conditions.


Best Regards

Frank Richter's picture

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Good luck


ciprian.zub's picture


Did u find any UMAT/VUMAT for combined iso-kin hardening (for metal plsticity)?

What about UMAT for steel with yield plateau?

Thanks a lot! 


Dear Bojan,

I am also working on a damage model and if you get this UMAT, I'd really appreciate it if you share it with me as well.


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