3D NUMERICAL SIMULATION AND ANALYSIS OF RAILGUN GOUGING MECHANISM

A gouging phenomenon with a hypervelocity sliding electrical contact in railgun not only shortens the rail lifetime, it but also affects the interior ballistic performance. In this paper, a 3-D numerical model was introduced to simulate and analyze the generation mechanism and evolution of the railgun gouging phenomenon. Johnson-Cook failure material model and Mie-Gruneisen equation of state were adopted for the simulations. The results show that a rail surface bulge is an important factor to induce gouging. High density and high pressure material flow on the contact surface obliquely extruding into the rail when accelerating the armature to a high velocity can produce gouging. The formation of gouging is suppressed by controlling the bulge size to a certain range and selecting suitable materials for rail surface coating. The numerical simulation result is in a good agreement with the experimental result, which shows that the proposed computing model and methodology are reliable.