Projectile Driving Band Interactions With Gun Barrels

Abstract

This paper discusses results from a series of trials carried out to determine the effect of the projectile driving band on the stress applied to a 155mm gun barrel during firing. The interference between the driving band and gun barrel can apply significant loads to the barrel and, in extreme cases, lead to premature cracking and failure of the barrel. Strain gage data from firing trials has been used to characterize the external strain from firing different projectiles and charges to identify potential problems and provide information for fatigue analysis. Very high band strains were routinely measured under “oiled bore” conditions, i.e., after barrel cleaning and also during the first one to three rounds of a serial following a long pause in firing, such as at the start of a day’s firing. In general, the strain associated with the driving band was seen to decrease with increased charge zone, barrel wear, and, at higher charge zones, distance along the barrel. In the majority of tests fired at maximum charge, there was no strain peak associated with the driving band in the forward part of the barrel. In conjunction with these experimental observations, a laboratory study has been carried out on the effect of a narrow pressure band on the deformation of a thick-walled tube. An apparatus was constructed in order to pressurize a known length of a smooth-bore cylinder. Sealing width at the edges of the band was minimized to reduce edge effects, and an oversize pressurized “cap” was used to ensure that the bandwidth remained constant during the experiments. Spacer disks were used to vary the bandwidth and also to adjust the cylinder position relative to the band. Measured external strains on the tubes were compared to calculations based on analytical solutions for step pressure changes and are shown to be in good agreement.

Tribology of rotating band and gun barrel during engraving process under quasi-static and dynamic loading

“…Lisov investigated the wear mechanisms of 105-and 155-mm artillery projectiles' rotating bands theoretically and experimentally using variable parameters of internal ballistics [7]. Based on the measured strain of the barrel's exterior surface, Andrews [8] found that high charges generally degrade the rotating band by reducing the load the rotating band applies to the 155 mm gun barrel during firing. The influence of rotating band construction on gun tube loading was investigated experimentally and numerically by Toivola et al [9] and Keinänen et al [10].…”

Contributions to Dynamic Behaviour of Materials Professor John Edwin Field, FRS 1936–2020

“…During the course of Stephen's doctoral studies, he came to understand that the mechanical properties of polyethylene he was studying depended on how rapidly it is deformed. So, it made sense to accept a post-doctoral position that John Field offered him to investigate strain-rate effects in a number of different polymers that were being considered as replacement materials for the soft metals used in driving bands that spin up shells as they are accelerated up rifled gun-barrels [55][56][57]. Again, Stephen was very fortunate to be joined by two people John Field had attracted to the group (Peter Pope (Ph.D. 1984 [58]) and Nick Safford (Ph.D. 1988 [59])) who had taken over the miniaturised direct impact Hopkinson bar (3 mm diameter) previously developed by David Gorham [60].…”

A Riemann Problem Based Coupling Method for Predicting the Combustion of Propellant in a Gun Launching Process

“…In addition, methods dealing with moving boundaries for updating the fluid field in the expanding combustion chamber are also critical for an accurate simulation. Considered the complex nonlinear factors, such as nonlinear constitutive relation of materials, transient effects and contacts between the mechanical parts, the mechanical interactions between the projectile and the barrel, which affect the flow of the combustion products in the barrel, were investigated by using experimental methods [19][20][21] and numerical methods [22][23][24][25].…”