An energy-based approach for analysis of dynamic plastic deformation of metals

An energy-based ordinary differential equation is derived for a plastic wave propagating through a Taylor impact test specimen. Using the definition of true strain, an analytical equation is presented to calculate the strain rate across the plastic wave front. Having considered a Johnson–Cook plasticity model for the projectile material, the derived energy equation accompanied by a governing kinematics relation and the strain rate equation is numerically integrated to obtain the final deformed profile of the specimen. The results of the energy based model are then compared with those of the commonly used momentum-based approach as well as the existing experimental data in literature for copper, aluminum and steel specimens. Moreover, the entire plastic profile of the specimens obtained from energy and momentum approach is compared with 3D finite element results. It can be concluded that the energy-based model exhibits a closer agreement with experiment and simulation.

► An energy approach is proposed for analysis of wave propagation within Taylor test specimen.
► An analytical equation is derived to calculate strain rate across the plastic wave front.
► The energy approach yields results closer to experiment and finite element simulation.