On the technique used to determine plasticity margin in high-speed deformation under high pressure

The work treats the determination of metal plasticity margin. Cylindrical Fe specimens were tensioned in a high-pressure machine. Constitutive equations and plasticity margin were determined from experiments, the specimen material being incompressible and isotropic. A new technique is proposed to determine plasticity margin by solving a boundary value problem modelling breaking tests. The stress–strain states until the moment of fracture were calculated with the application of the variable separation method based on the variational formulation of the boundary value problem. Plasticity margin calculated from the solution by the method is compared to the experimental one.