Research On The Related Issues Of Residual Stress Relief By Electric Shock Method

The dissertation, which was sponsored by the Natural Science Fund of China "Research on Electric Shock Method for Residual Stress Relief and Its Application (No.50675200) ", targeted several issues in the techniques of residual stress relief by electric shock method.In chapter one, the research background and significance of the dissertation was presented first. Then the domestic and foreign research status was introduced, which included effect of electric pulse current on micro-structure of material, technique for measuring residual stress and the high-power electric pulse technology. Finally, the research content and research methods in the dissertation were addressed.In chapter two, the resistance and drive for the mobility of dislocation were presented, and the mechanism of residual stress relief by electric shock method was addressed where residual stress could be reduced by reducing amount of dislocation when the drive was greater than resistance.In chapter three, the principle of blind-hole method for measuring residual stress was first introduced; then, based on the principle for calibrating the strain release coefficients, the strain release coefficients by finite element analysis was simulatively calibrated, so the formulae for modifying the strain release coefficients of plastic material was proposed. Finally, the validity was verified.In chapter four, the several parts in the device for generating the electric pulse current was presented, which consisted of equipment for storing electrical energy, switches for electropulse current, electric-pulse-current-generated circuit, automatic switch-controlled circuit and measuring system for electric pulse current.In chapter five, the experiment of residual stress relief by electric shock method was presented which showed that the residual stress within the work pieces declined apparently after the electric pulse current's treatment. It proves that the residual stress relief by electric pulse method is distinctively effective.In chapter six, the achievements of the dissertation were summarized and the further research work that needed to be done in future was put forward.