Prestressed Carbon Fiber Composite Overwrapped Gun Tube

Abstract

The emphasis on lightweight large caliber weapons systems has placed the focus on the use of advanced composite materials. Using composite materials not only directly removes weight from the gun tube but, by better balancing the tube, allows the use of smaller drive systems, thus further enhancing the system weight loss. Additionally the use of high stiffness composites helps with pointing accuracy and to alleviate the dynamic strain phenomenon encountered with high velocity projectiles.Traditionally there were two issues with composite jackets: the coefficient of thermal expansion mismatch between the steel substrate and the composite jacket causing a gap, and the lack of favorable prestress in the jacket. Dealing with these issues greatly complicated the manufacturing process to the point where mass-producing the barrels would have been problematic at best. By using a thermoplastic resin, a "cure on the fly" process and winding under tension the manufacturability of the barrels has been greatly improved, the gap has been eliminated, and a favorable prestress has been achieved. This paper will present the design, manufacture and testing of a 120mm barrel utilizing this process with IM7 carbon fibers in a polyetheretherketone (PEEK) matrix.