Plasticity theory must satisfy the thermodynamic restriction conditions

of which Second Law of Thermodynamics is the most important. Yield /failure function is the original concept of plasticity theory

and it concerns the dissipation process described with Second Law nearly. Entropy or dissipation potential is a key state variable defined from Second Law of Thermodynamics to describe this irreversible process. So yield /failure function must have a close relation with the dissipation potential. In this research

dissipation potential corresponding to class of yield /failure functions in plasticity theory is deduced through solving the dissipation differential equation transformed from the yield /failure functions. Especially

the methodology of getting the dissipation potential is applicable for both the linear and nonlinear yield /failure functions. Thus the thermodynamic consistency of these yield /failure functions can be verified from this dissipation potential expediently. Moreover

the thermodynamic restriction conditions on the yield /failure function are deduced using the dissipation potential corresponding to a class of yield /failure functions and second law.