Coupled crack tip fields under the action of an electric current

Abstract

Coupled fields of crack tip under the action of electric current is studied by means of theoretical analysis, experimental investigation and numerical simulation. The distribution of electric field, temperature field and thermal stress field near the crack tip is analyzed theoretically when electric current is applied to a metal plate with an edge crack, and the theoretical calculation expression of thermal stress intensity factor is derived. The current treatment process of Al 5052-H32 alloy plate with fatigue crack is investigated by experiment and finite element simulation. The results show that current density and crack length have significant effects on temperature, thermal compressive stress and thermal stress intensity factor near the crack tip. Through the current treatment experiment of Al 5052-H32 alloy plate with fatigue crack, it is found that micro welding is occurred due to temperature concentration and thermal compressive stress around the crack tip. The simulation results also show that there is a high heat flux at the crack tip due to the concentration effect of current flow around. The annular thermal compressive stress caused by temperature gradient is formed around the crack tip to prevent crack propagation and help crack healing. The simulation results are in good agreement with the theoretical and experimental results.