Composite 5"/70 Caliber Barrel Componenet for MK-45 Gun Upgrade

The Naval Surface Fire support program is developing an upgrade to the Mk-45 gun which will require enhanced propellant charges to increase muzzle energy. The gun barrel needs to be lengthened from a 5"/54 to a 5"/70 caliber to allow sufficient in-bore volume for the complete combustion of the propellant while keeping the muzzle exit pressure within shipboard limits. The 5"/70 caliber barrel must. have a weight, moment and moment of inertia similar to the 5"/54 Caliber barrel, to eliminate modification costs to the gun train and elevation drives, and must be able to withstand high temperatures due to rapid firing and fatigue due to cyclic pressurization load. To achieve these goals it is proposed to design a lengthened barrel with a reduced steel wall thickness over a significant portion of the muzzle end, and use a graphite fiber filament wound composite overwrap, in a state-of-the-art high temperature thermally stable resin. a composite 5-/70I by performing a high temperature materials performing a gun barrel design study subscale test articles and performing testing on the test articles. The feasibility of developing will be demonstrated, during Phase survey and evaluation, fabricating filament wound thermal and pressurization testing on the test articles.