连续电磁发射过程中轨道受力分析

获取电磁轨道发射器轨道受力特性是分析轨道材料失效机理及极限安全连续发射边界的前提。通过建立电磁-温度-应力多物理场耦合计算模型，得到了动态发射过程中包括电磁力、温度应力和预紧力的多成分轨道应力载荷时空分布特性。分析结果表明：轨道受到的电磁力载荷在脉冲电流平顶沿电枢经过位置基本上均为峰值；轨道热量主要集中于电枢运动起始段，且热量密度在脉冲电流上升段结束时刻附近电枢经过位置达到最大值；轨道在脉冲电流上升段结束时刻附近电枢经过位置受力最为严酷；喷淋冷却可有效降低轨道中的温度应力；最优的预紧力大小以恰好满足动态发射时轨道与绝缘支撑体不分离使身管保持整体式稳定结构为判据。

Analysis of Force Load on the Rail in Rapid-fire Mode of Electromagnetic Rail Launcher

Acquisition of force load distribution of rail in electromagnetic rail launcher is the precondition for analyzing the material failure mechanism and rapid firing application boundary.A field coupling model of electromagnetic force,temperature and stress is established to obtain the temporal and spatial distribution characteristics of force load on the rail under the action of electromagnetic force,temperature stress and preload.Analysis results show that the electromagnetic force load on the rail is nearly always a peak value in the flat period of pulse current;the thermal energy is mainly distributed in the initial period of armature motion,and the thermal energy density reaches to the maximum value in armature position at the end of the pulse current rising;rails bear the most severe force load in armature's position at the end of the pulse current rising;spray cooling can effectively reduce the temperature stress in the rail;optimal pretightening load is to keep the rails not separating from the insulation supports during dynamic launching.