An Investigation of the Erosion Physics/Mechanisms of Current Army Systems (Point Studies)

Abstract : Future systems performance requirements have led to a heightened awareness of the erosion issue and to the development of erosion investigations in the U.S. Army and Navy. These investigations involve experimental and modeling efforts to understand the thermal, chemical, and mechanical contributions to erosion/wear. A description of the mechanistic erosion representation follows in this report. The calculation procedure is illustrated, including details of the mass transport scheme, gas surface interface, surface melt wipe model with dynamic gridding, and the equilibrium kinetics model, which utilizes the NASA Lewis thermochemical library. The following cartridges are investigated: the M829A2 APFSDS in the M256 12O-mm tank cannon and the M79l-APDS-T and 616W-APFS (the "original" M919), both in the 25-mm Bushmaster cannon. The resulting mass lost per round for these systems compares well qualitatively with the experimental data, providing some support to the assumptions in the code. The primary conclusion is that carburization leading to iron carbide formation is an important contributing factor for much of the material lost from the steel barrel once it is exposed through cracks or chips in the surface coating.