A Finite Element Model to Predict the Influence of Asymmetries on Barrel Dynamics in Small Arms

Abstract

Appropriate boundary conditions, particularly asymmetries, are critical to modeling the dynamics of small arms barrels. Lateral barrel vibration, an important factor governing small arms accuracy, is primarily driven by the recoil couple created by the distance between the barrel-axis and the center of mass of the firearm. This paper presents a computational model which includes the action geometry in order to capture these physics. Solved using Abaqus/Explicit, this model features parameterization through Python scripting. Barrel parameters include length, contour, caliber, chambering, and rifling pattern. Action geometry and projectile are selectable from manually created model libraries. Model features include spatially and temporally varying pressure loading, gravity loading, projectile-bore interaction, projectile plasticity, and representative masses for geometry not explicitly included in the model. The long-term purpose of the model is to investigate the sensitivity of the muzzle exit condition to firing cycle initial conditions for barrels of variable geometry and composite construction.