Dynamic Response of Electromagnetic Rail Launcher Due to Projectile Motion

Abstract

The dynamic response in the dynamic launching process of electromagnetic rail launcher (EMRL) is very important for the design of launchers and armatures. With the Bernoulli–Euler beam located on an elastic support as an object of the study, the analytical model of EMRL dynamic characteristics under the influence of EM repulsive force and contact force between the armature and the rail is obtained, and the corresponding 3-D finite-element simulation model [moving load–rail model (MR model)] is established. On this basis, the 3-D finite-element simulation model [projectile–rail model (PR model)] considering the projection vibration is established to obtain the dynamic response of EMRL due to projectile vibration. Studies show that the calculation results of the analytical model agree well with that of the MR model. When the moving load works at a critical speed and reaches the point of action, the rail will have an increased deformation and then a harmonic vibration, whose amplitude is five or six times than that under the noncritical operating condition. The analysis of the impact of projectile vibration on the rail deformation makes it known that the vibration amplitude of the PR model is four or five times than that of the MR model because of projectile vibration. The greater the gap between the rail and the armature is, the more violent is the projectile vibration and the greater is the vertical deformation of the rail, and the greater the density of the payload with the same volume is, the more intense is the projectile vibration and the greater is the vertical deformation of the rail. When launching reaches the critical speed, the rail deformation of the PR model is less than that of the MR model, which is mainly caused by the vibration of the projectile, but the vibration periods of those two models are the same.