Investigation of Contact Characteristic in an Augmented Quadrupole Electromagnetic Launcher

In order to overcome ablation on the rail-armature contact region and increase electromagnetic thrust force, a structure of armature arm with interference fit is designed in augmented quadrupole electromagnetic launcher (EML). Good contact characteristic between the armature and rails plays an important role in the success of EML. The electromagnetic-structure coupling model based on the finite element analysis is presented to investigate the contact characteristic, the distribution of current density, and the electromagnetic force (EMF) and the contact pressure is given, which indicates the EMF needs to be loaded unevenly on the armature arm. Finally, based on electromagnetic-structure coupling model, some important parameters including the contact area, the contact efficiency, the contact counterforce, and maximal contact pressure are analyzed with the different interference, different length, and different thickness of armature arm after the pulse current is loaded. The dependences of nonuniform contact parameters on the nonuniform EMF are obtained.