Hello all!
I am having some trouble formulating Jacobian for one of the martensitic phase transformation model in shape memory alloys. There is no problem when there is only austenite phase. It is elastic and elastic stiffness tensor is equal to Jacobian tensor. However, during phase transformation, according to the model there is a strain softening and I want to calculate the consistent Jacobian by using the finite difference method in UMAT but I couldn't. Derivative of the stress is partial not ordinary. What can I da about this problem. Can you give me suggestions?
Nazim Babacan
I am having some trouble formulating Jacobian for one of the martensitic phase transformation model in shape memory alloys. There is no problem when there is only austenite phase. It is elastic and elastic stiffness tensor is equal to Jacobian tensor. However, during phase transformation, according to the model there is a strain softening and I want to calculate the consistent Jacobian by using the finite difference method in UMAT but I couldn't. Derivative of the stress is partial not ordinary. What can I da about this problem. Can you give me suggestions?
Nazim Babacan