On the decomposition of deformation into elastic-plastic parts

This paper analyzes the decomposition of finite deformation into elastic an d plastic parts. The analysis argues that Lee's multiplicative decompositio n of the deformation gradient is not the real separation of the total defor mation into elastic and plastic parts and that the Green strain cannot be d ecomposed into elastic and plastic parts. The paper also analyzes the decom position of the velocity gradient and presents an exact elastic-plastic dec omposition of deformation rate.