shape memory alloy model including thermal coupling

[shazar]

Hi to all,
I have a working sma model using return mapping algorithm for non linear behaviour. I need to add thermal coupling part to it. Anyone of you have some information about thermal coupling of SMA models ? I would be glad to collobrate with you. At least I need a guidence to show me the way to model it .

[Jorgen]

I have performed FE simulations of shape memory polymers, including the thermal coupling.

What material are you interested in (metals or polymers)?
What material model are you using?

-Jorgen

[shazar]

Hei Jorgen,
My material model includes latent heat matrix and so i Have to modify heat transfer equations so heat equation will be different. It is a special model for SMA metal. My material is metal. Is it possible to modify heat equations by using Umat ? that i do not know

[Jorgen]

Do you need to capture the heat transfer effects? If not, it might be possible to capture the latent heat as part of the UMAT state variables.
Also, a UMAT returns the energy loss quantity that can be converted to heat by Abaqus.

-Jorgen

[shazar]

In my constitutive equation I have Temperature coupling to the phase transformation (volume fraction of the phase transformation). I only need to see the temperature distribution on the specimen when you apply tension load. And in the constitutive model I have to solve discrete heat equation and in this energy equation i need to update conductivity matrix latent heat matrix convection matrix and heat capacity matrix. And my heat equation depends on phase change also.

[Frank]

The UMAT variable RPL can take care of thermal coupling.
Note that it is defined as
"Volumetric heat generation per unit time at the end of the increment caused by mechanical working of the material."

So, if using SI units in your simulation you have to define this term in unit Watt/m^3.

Look up RPL in the section on metal plasticity. I guess the term was coined as "rate of plastic work".