板坯电磁成形载荷计算方法及分布特性

用平面螺旋和多叠式线圈加工平板毛坯是电磁成形的一种基本方式，其理论研究包括电路分析和动态变形分析两个方面，其中电路分析的目的是确定作用在工件上的脉冲电磁力，并用于变形分析。通过分析板坯电磁成形中工作线圈在强脉冲电流激励下的动态响应过程，建立了线圈磁场、工件表面感应涡流及磁场的计算公式，给出了成形载荷的计算方法。通过数值分析讨论了载荷的分布特性，数值求解结果与相关实验研究结论一致。将成形载荷数值求解结果用于变形分析时，成功地预测了铝板毛坯的自由胀形过程。

CALCULATION AND DISTRIBUTION OF FORMING LOAD FOR SHEET METAL MAGNETIC FORMING

To form flat workpiece by the flat spiral coil or conical coil is a typical method of magnetic forming. The analysis of the forming processes consists of the analysis of the electric circuit and the dynamic deformation of the workpiece. The purpose of the electric circuit analysis is to calculate the impulsive magnetic pressure and to apply it to the deformation analysis. By analysing the dynamic response of the coil workpiece system while the working coil being stimulated by intentive impulsive current, the formulas calculating magnetic intensity induced by coil, whirling current on workpiece and its magnetic intensity have been established. And the method for determination of forming load has been given. Then, some characteristic curves of forming load have been obtained to describe its distribution. The computation results are consistent with the conclusion obtained from some relative experiments. Finally, by applying the calculating results of forming load to the deformation analysis, the free magnetic bulging process of sheet aluminium have been predicted successfully.