Numerical study on the magnetic sawing effect in the rail of an electromagnetic launcher

Magnetic sawing phenomenon, induced by the crack in the rail of the electromagnetic launcher, can severely restrict the life of the launcher. To analyze this phenomenon, we built the magnetic field diffusion equation and heat conduction equation. Combined with the solid mechanics model in the finite element software COMSOL Multiphysics, we simulated the electromagnetic, thermal and mechanical behaviors of the crack. The results show that the current-crowding as the current path turns around the crack tip is a key factor for the formation of magnetic sawing phenomenon. Moreover, we found that, the smaller the aperture angle, the higher the current density, the faster temperature rises.