Structural mechanics of railguns with open barrels and elastic supports: The influence of multishot operation

The dynamic behavior of the railgun housing including the rails is of great importance for the system performance. The transient loading (magnetic pressure) may have a negative influence on the sliding electrical contact required for this acceleration technology. Therefore, the analysis of the displacement of the inner rail surfaces due to elastic waves is of great importance. The French-German Research Institute of Saint Louis is operating several railguns with housings characterized by an open barrel design allowing for innovative diagnostic techniques. The repelling forces between the rails are countered using discrete steel bolts. The rails are mounted to bars made from composite material. In the past, we presented experimental and numerical findings concerning the dynamic behavior of such railguns in single shot mode. In this work we present for the first time 3D Finite Element calculations concerning the dynamical behavior of the ISL rapid fire railgun RAFIRA operating in multishot mode. Multishot scenarios with fire rates of 50 Hz are considered and particular attention is paid to the question if the dynamical behavior of the railgun is influenced by preceding shots.