Simulation of railgun gouging

Gouging in railgun rails involves the formation of teardrop-shaped depressions in the rails by a moving armature. Gouging is deleterious to rail performance and is a critical life-limiting defect. The precise cause of gouging is difficult to ascertain due to the highly dynamic nature of its formation and the complex electromechanical environment in which gouges form. A prevalent hypothesis is that gouging is the result of mechanical interaction of protrusions or local asperities with the armature/rail assemblage. Understanding of the gouging process would be appreciably advanced by accurate predictive mechanical modeling of the process. The majority of approaches to mechanical modeling do not embody the necessary features unique to gouging: high velocity/strain rate; elastic-plastic deformation; multiple materials interfaces; fracture capability; and extension to three dimensions. The goal of this research was to computer model the railgun under various conditions of firing, including the effects of armature/rail material pairs and armature velocity. Results of a series of simulations of materials damage are presented.