Assessment of the Lifetime of Gun Barrels Under High-Speed Moving Loads

Abstract

The aim of this work is to assess the influence of the dynamic stresses (due to the projectile displacement and the gas pressure) on the lifetime of certain medium caliber (less than 40 mm) gun barrels. First, an experimental study of tube dynamics under high speed loads was made. The large number of experimental measurements made it possible for us to identify the forcing effect of the projectile. In parallel, experimental samples were submitted to periodic traction-compression forces in order to obtain the material parameters of the barrels used in the study. Second, a finite element (FE) model was elaborated which faithfully forecasts the experimental strain records. Three-dimensional modeling permitted us to correctly evaluate the response in the zones of stress concentration. Third, a lifetime calculation was performed. This shows that the lifetime of the barrel is determined by the most constrained zones during firing: in the present case by the stresses appearing at the bottom of the grooves.