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Experiment and computation on the initial contact force of the rails and C-shaped solid armature interface

The contact condition of the armature-rail interface (ARI) is analyzed by building a two-dimensional (2-D) model and a three-dimensional (3-D) model, and a small experimental electromagnetic launcher (EML) and a C-shaped solid armature are designed and used to verify the simulation results. Simulated by the finite element software ANSYS, the distributions of the contact pressure, contact area (or contact length) and the von mises stress (VMS) are shown in the 2-D and 3-D models, and the simulation results of two models are analyzed by processing the data. The simulation and experimental results are carefully compared by observing the distribution of the melted object remaining on the surface of rails at the initial position after launch, and the variation of contact condition with the sliding of the armature can also be found. The results show that the contact pressure and contact area distributions of the ARI are not only non-uniform along the armature arm length, but also non uniform along the thickness, and it is nearly impossible to make the armature arm completely contact with the rail. The results also tell us that the satisfactory contact force and contact area can be gotten by properly designing the armature structure.