Research On The Electro-pulse Generator For Residual Stress Relief

Supported by the National Natural Science Foundation of China "Research on Electric Pulse Method for Residual Stress Relief and Its Application", an electric pulse generator for residual stress relief was designed in the dissertation, where the relative technologies were researched both theoretically and experimentally.In chapter one, the background and significance of the research were presented. First, the hazard and eliminating methods of residual stress and the pulsed power technology were introduced. Secondly, the present research status both on the effects by electric pulse on the metal properties and the pulsed power technology were reviewed. Thirdly, the electric pulse treatment for residual stress relief was analyzed. Finally, the main research content and the aim of the dissertation were addressed.In chapter two, the effect of electric pulse on residual stress was studied theoretically. First, the mechanism of the influence of electric pulse on residual stress was analyzed with the dislocation dynamic theory. Secondly, based on the electron-wind force theory, a simplified modal of influence of electric pulse on dislocation was established, which was simulated in Ansys. Thirdly, by means of theoretically analyzing the influence of the parameters of electric pulse on the result of residual stress relief, the design requirement of the electric pulse generator was proposed.In chapter three, the power electric pulse generator was designed. The design of the energy-storing unit and the pulse-forming unit of the generator was finished by means of theoretical analysis and software simulation. First, constant voltage charging was employed in the energy storing unit. In order to satisfy the requirements of target charging and increasing the charging frequency, a new charging method of high-voltage fixed-time charging was proposed. Secondly, two releasing modes, unidirectional low-current pulse and bidirectional high-current pulse, were designed in the pulse-forming unit. In order to increase the releasing frequency, the releasing method of group charging and in-group releasing was proposed.In chapter four, the control system of the generator was designed. First, the hardware of the control system was designed, which includes the switch driving unit, the interacting unit and the DA/AD conversing unit. Secondly, the software of the control system was designed, which includes the charging-releasing module, the high-voltage fixed-time charging module and the interacting module.In chapter five, the experiments on the electric pulse generator were carried out to test its performance. The experiments include the performance of the high-voltage fixed-time charging, the acquisition of the output electric pulse, and the residual stress relieving experiment by the generator. The results indicate that the performance of the generator and residual stress relieving result have well met the expectation.In chapter six, the achievements of the dissertation were summarized briefly and the further research work need to be done was advised.