Dynamic response of electromagnetic railgun under time-dependent electromagnetic moving loads

Abstract

The rail vibration of an electromagnetic railgun can affect the contact status between the armature and rails, even causing rail damage. To reveal the dynamic characteristics of a railgun, we investigated the rail vibration of an electromagnetic railgun under different armature motions. The rail is assumed to be a Euler–Bernoulli based beam, and the time-dependent electromagnetic moving loads applied on the rail are considered. By considering the reaction of the magnetic pressure to the rail deformation, a nonlinear finite element model is proposed to study the dynamic characteristics of the railgun rail. The model validation is presented through a comparison of the model predictions with the analytical solution of the rail deflection, and the experimental result of the rail strain. The differences between the dynamics of rail beam under different moving loads are then compared. Moreover, rail vibration features are discussed in detail. The results indicate that the probable fatigue areas of the rail are located where the pulse current reaches its maximum or where the armature approaches its critical speed. The results of these investigations will help improve the design of railguns.