Thermal Shock Waves Induced by a Moving Crack

The near-tip behavior of the thermal field around a moving crack is investigated analytically in this work. The thermal field is characterized by a thermal Mach number defined as the ratio between the linear speed v of the moving crack and the heat propagation speed C in the solid. Mathematically, M= v/C. In the subsonic range with M < 1, a detailed comparison with the thermal diffusion model is made. In the transonic and the supersonic ranges with M ≥ 1, thermal shock waves, which separate the heat affected zone from the thermally undisturbed zone, are shown to exist in the physical domain. A swinging phenomenon for the temperature variation as a function of the thermal Mach number is found in transition from the subsonic to the supersonic ranges. Also, the r dependency of the near-tip temperature is found to be the same as that of the near-tip heat flux vector. It transits from r^1/2, r, to r² as the thermal Mach number transits from the subsonic, transonic, to the supersonic ranges.