Impact physics model and influencing factors of gouging for electromagnetic rail launcher

Gouging is a damage mechanism that occurs on the surface of rails of electromagnetic railgun. The disadvantages of gouging include lowering efficiency of railgun system, decreasing life of rails and reducing direction accuracy of projectile. According to configuration and dimension of the experimental arrangement, analysis of rail vibration induced by hypervelocity sliding load and numerical solve of the dynamic response for rails have been accomplished. Based on numerical solve of the dynamic response for rails under hypervelocity sliding load, a gouging physics model of impact has been established in this paper, and gouging on the rail was successfully replicated in LS-DYNA. Through dynamic simulating, effect rule of influencing factors such as deflection bulge size on the formation of gouging and key phenomenon of gouge process were investigated. The results suggested that the obvious gouging would be avoided by lowering the maximal local deflection size in 0.5mm; the structure of smooth on the head of the armature and decrease of contact pressure between armature and rails can be utilized to alleviate the damage; during gouging process, maximal strain-rate of rail material could reach to 10⁷s^-1 while the contact area and velocity of armature would fell greatly. This work would be a foundation of future effort of avoiding rail gouging during the launch duration.