Magnetic-Structural Coupling Analysis of Armature in Induction Coilgun

Armature is a key component in induction coilgun (ICG) which can easily be destroyed by enormous electromagnetic forces during the launching process. In order to design high-strength armature and guarantee the success of ICG launchings, a mathematical model of magnetic-structural coupling of the armature is built. Distribution of eddy currents, magnetic forces, deformation, and stress is obtained through simulation. How stresses in the armature vary resulting from changes of the radial thickness is analyzed in this article. Simulation results reveal that the magnetic flux density, eddy, magnetic forces, and deformation in armature display nonuniform distribution and reach the maximal value in the tail of the armature. The maximal stress appears at the inner side of the tail of the cylinder-shaped armature and decreases with the increase of the radial thickness. Methods for increasing the strength of the armature are given. Strain measurement of the heating-treated armature is carried out. The maximal deformation of the armature occurs at 0.5 ms in the tail, and the strain distribution around the periphery of the armature is nonuniform. Therefore, in the engineering project, high mechanical strength armature should be designed to improve the performance of ICG.