I want to use ABAQUS VUMAT to calculate a consitutive models.
The back stress will obtained from the eight-chain model B, in which the plastic strech tensor Vij will be used. But the strech tensor gave in ABAQUS is right strech tensor Uij.
I have saw some references about the Vij, they tell the deformation can be decomposed into stretch and rotation as Fij=Rik*Ukj=Vik*Rkj, but I do not know how to calculate the Vij, and is the right roation equal to the left rotation?
Thank you very much.