Irreversible thermodynamics of ideal plastic deformation

Abstract Thermodynamics for ideal plastic deformation causing no disorganization of the structure in the deformed body, which was discussed by P. W. Bridgman studied (1950), revealed that the concept of entropy was still applicable to its irreversible process. Noting that the structural invariability in an ideal plastic body is physically equivalent to the prerequisite of thermodynamics, namely, thermodynamic quantities must be independent of the macroscopic body shape, the generalized concept of entropy can be extended to the other thermodynamic potentials such as internal energy, free energies and so on. Here the extended generalization for ideal plastic deformation is theoretically justified on the basis of the irreversible thermodynamics constructed by Prigogine and his discipline. Thermodynamic state of the ideally deformed body is found to be specified both by the generalized thermodynamic potential (S, U, F, H or G) and by the irreversible potential energy J which drives the plastic deformation.