The classic plastic constitutive relation, multi-yield surface constitutive relation and over-stress viscoplastic constitutive relation are a special example of this constitutive relation.

Giving an imitation of traditional plastic theory , a damage surface model on brittle rock about temperature in stress-space is introduced and the evolutionary law is discussed qualitatively.

Endochronic plasticity based on non-yield surface is deduced into the displacement-based finite element method and the plastic strain direct method is proposed for the plane stress problem.