Thermo-mechanical coupling shock waves propagation with phase transition under impact loading

Abstract In the present study, a thermo-mechanical coupling model including constitutive relation and kinetics for phase transformation is developed to study stress wave propagation in shape memory TiNi rods. The front tracking/capturing method is adopted for numerical analysis and impact experiments are performed to verify theoretical model. It is demonstrated that, a phase transition shock wave will be induced during loading due to the mixed phase hardening effect originating from the temperature dependence of transformation stress, and for unloading, double wave profile (an elastic wave and a shock wave with reverse phase transition) will be excited since the change of unloading path caused by the transient temperature rise during loading. Furthermore, shock wave propagation speeds are increased with loading stress, while driving force acting on the shock wave is supplied by shock dissipation energy, in which the temperature gradient across the shock front plays an important role. SHPB experiments show that the phase change wave front is also a moving temperature interface, which will have an important influence on the stress wave structure. Taylor impact experiments show that the proposed kinetic relation in this paper is in good agreement with the experimental results, which reflects the intrinsic characteristic of materials with strong nonlinear thermo-mechanical coupling behavior.