Dynamic Response Of Electro Magnetic Rail Launch System Due To Armature Movement

In recent years, the technology of electromagnetic rail launch, which avoids inherent limitations and faults of traditional launch technology, caters to demands for high-speed launch to some extent. In the process of launch, we have many problems to study. There is a very important question, in order to guarantee the firing accuracy, is that electromagnetic orbit must ensure the rail has enough rigidity, namely the displacement should not to be largein in the process of launch. So the purpose of this paper is to study the dynamic response of rail.First, the paper reviews the present situation and course of development of technique of electromagnetic launching in aspects of domestic and abroad. The distribution of electromagnetic induction in electromagnetic launcher is obtained based on electromagnetic field theory. Then the thrust of armature and the repulsive force between two rails are calculated in different forms of current element. Also the extrusion pressure works on rails due to armature's expand is obtained based on fundamentals of heat transfer.The electromagnetic rail is modeled as a beam of finite length sitting on an elastic foundation. According to the theory of vibration, the dynamic response of the rail is governed by a fourth-order differential equation with an extra term of elastic support subjected to armature's thrust. Then the parameters, such as the current intensity, the elastic constant and damping of the elastic foundation, are analyzed. The theoretical basis of the design of rail is obtained from the analysis result.At last, according to kinetic equation the rail's critical speed is worked out. And it is simulated by the ANSYS software. So the launch speed range of the rail is put forward in this paper, which should be avoid.