Effects of Deformed Gun Tubes on Projectile Launch Dynamics

Abstract

Gun barrel centerline variations have been known to impact projectile in-bore behaviors. A deterministic analysis on a 60-mm projectile fired with a gun barrel having characteristic centerline variations was performed. Certain in-bore dynamic responses were obtained and compared with those for a perfectly straight gun tube. To gain a better understating of the projectile in-bore dynamics due to the flexure of gun tubes, the technique of design of experiments was adopted to simulate an array of gun barrels. The barrel centerline variations were modeled with four independent shape variables, i.e. four factors to be considered in the design. The values of each factor were assigned a certain number of levels that were determined by the pattern discovered from a large number of existing gun barrel data. The combination of the levels of the factors constituted a good representation of the barrel centerline variations profile. The focus of this study falls on how the shape variables influence the muzzle responses of the projectile. Analysis of variance method was utilized to identify the sources of variability and to determine the significance of each shape variable. The main effects of each controlled factor were studied and their interactions contributing to the muzzle responses were also discussed.