Abstract: 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. Key

Key words: electromagneticlaunch, rapid-fire, multi-physicsfield, temporalandspatialdistribution, spraycooling, optimalpretighteningload