Research On Multi-physical Field Coupling Effect In Electromagnetic Launch Process

The electromagnetic railgun converts the electromagnetic energy into the instantaneous kinetic energy required to launch the projectile.Compared with the traditional gunpowder launching,the projectile has a greater speed and is currently a research hotspot around the world.The emission process is a transient dynamic process with coupling of multiple physical fields,including electric,magnetic,thermal and structural fields.At the same time,it is difficult to accurately measure various parameters and coupling relationships only through experiments.Therefore,the finite element method is used to study the launching process and coupling mechanism of the electromagnetic railgun,and the time and space distribution of ampere density,temperature,and structural stress of the armature,rail and projectile are analyzed.At the same time,the influence on the launch performance of railguns with different armature structures is analyzed.It provides a simulation modeling and analysis method for the design of electromagnetic railguns.The specific research contents are as follows:In the first place,a 3D simulation model of the EMRG is established based on the principle of electromagnetic railgun,and the changing rule of the ampere density,magnetic field strength and temperature rise of each component during the launching process are simulated and stated.The results display that the ampere density and magnetic field strength of the rail are concentrated on the inner surface and side of the rail.The ampere density and magnetic field strength of the armature are concentrated at the throat;the temperature of the armature and the rail increases sharply in the current rising section,and then slowly fluctuates to a stable level.The temperature field has a great influence on the rail and the armature,which may cause ablation,wear,etc.,and have little effect on the projectile.Then,a 3D dynamic model of the EMRG is set up based on the projectile dynamics equation and Marshall’s criterion,and the changing rule of the stress and strain of each component are stated.The results display that the changing rule of stress,strain and deflection in Y and Z directions of the projectile is similar to the current excitation curve,and the stress on the projectile does not exceed its strength limit.It shows that the projectile strength can meet the requirements under the coupling environment.The influence of railgun with different armature and rail structures on the launch performance is simulated.The concave armature structure which fitting its rail can make the rail and armature lower in temperature and the projectile stress and deformation are smaller during the launch process,which is more conducive to stable launch of the projectile and extend the service life of the rail.The research results of this paper can be applied to the simulation of electromagnetic force,dynamic process and launch intensity during the launching process of electromagnetic railgun,and the research method adopted in this paper has practical reference value for the simulation of multi-physical field coupling of electromagnetic railgun.