The Oretical And Numerical Analysis Of Stress And Temperature Fields Of The Composite Rail

There is a large amount of heat when the electromagnetic railgun is launched.The generation mechanism of thermal energy mainly includes joule heat of rail's resistance.Most of the thermal energy is absorbed by the rails,along with rail temperature increasing,and the high temperature causes part of the material of the rail to fall off,gasification,and even ionization.These aggravate the erosion of the rail surface.The heat exchange in rail is very complicated,and there are many kinds of phase transitions in the materials,which lead to the serious erosion of the rail surface.Although the copper rail has good electrical properties to ensure the speed of the armature,under the high temperature,the strength of copper is low and the wear resistance is poor.Therefore the service life of the track is reduced,and the repeated application of the technology in high power is limited.Copper based composite rails based on ensuring high conductivity improve the mechanical properties of the inner surface,not only ensure launch speed of the projectile,but also improve the rail's surface strength and erosion resistance ability.Therefore,the complex rail has been paid attention to in the design of modern railgun.In this paper,the contact stress of copper based composite electromagnetic trail is studied and the coupling state of multi physical field is analyzed by numerical simulation.The copper based composite rail is simplified as uniform load and concentrated half plane contact problem.The stress distribution of the composite layer is obtained by using the plane elasticity theory and the load expression of the local base of the track is given.The coupling analysis of multiple physical fields in the launch of the composite rail is presented by Comsol Multiphysics software to obtain distribution of magnetic field and current density in the rails and the armature.Furthermore,the temperature rise and the stress field of the rail and the armature are calculated.The influence of the geometrical dimensions of the rail,the physical parameters of the composite layer and the physical parameters of the armature on the electromagnetic field,temperature field and stress field distribution is analyzed.