Finite element modelling of flux concentrators for coilguns

The use of flux concentrators in coilguns is an attractive proposition since they combine the strength and durability of a single turn coil with the versatility of a multiturn winding. The primary winding can be of large radius when compared to the bore size of the gun, enabling stresses to be reduced. Unfortunately, efficiency is rather poor, and so Finite Element models are used to investigate the various loss mechanisms and their relative significance. By comparing with full 3D models, 2D approximations are shown to be reasonable. This provides fast solutions for the purpose of design optimisation.