Modelling of the electrical-magnetic-thermal-mechanical coupling behavior for the coil-structure electromagnetic launch

The electromagnetic energy can be efficiently converted into kinetic energy by using the coil-structure electromagnetic launcher. However, the design of such a device is hampered by the limited understanding of the extreme multi-physical coupling fields involved. In this paper, the mathematical modelling of the electrical-magnetic-thermal-mechanical coupling behavior is firstly proposed by solving the problems of current conduction, transient magnetic diffusion, transient heat transfer and structural dynamics based on finite element method for the coil-structure electromagnetic launcher. The proposed model is verified by comparison with the analytical solution for magnetic induction intensity and the model feasibility is further revealed by comparison with the experimental results of the final armature speed. It is found that the structural and muti-field characteristics of the coil-structure launcher will be affected by the initial armature position and armature length, and the optimal energy conversion efficiency can be achieved by adjusting the initial armature position. More importantly, the front material of the armature is completely under the yielding stress state, therefore, the structure design with outer layer of the copper alloy and the inner layer of titanium alloy is suggested to suppress the plastic deformation for armature component. These results will be significant to understand the engineering structure modelling and design with multi-field coupling behavior.