RESEARCH AND DEVELOPMENT OF TITANIUM ROCKET MOTOR CASE.

A program was undertaken to design, fabricate, and test a composite rocket motor case similar to the case used for the first stage of the solid-propellant Pershing missile. The case was to be fabricated from Ti-13V-11Cr-3Al alloy B-120 VCA and would consist of two end closures and a center section joined by two circumferential girth welds. The central cylindrical section of the case would be reinforced with circumferentially wound resin-bonded glass filaments. A complete case and an additional reinforced center section were to be fabricated. The case was to be burst tested, and the center section was to be subjected to a buckling stability test. The case was designed, end closures were fabricated, and a satisfactory welding technique was developed. However, it was not possible to develop a satisfactory flow-turning technique for fabricating the center sections from the available number of blanks with the equipment available. Since the primary intent of the program was to evaluate cylindrical sections reinforced with circumferentially wound glass filament, it was decided to reinforce an existing thin-walled titanium cylinder and subject the resulting part to a buckling stability test. The cylinder failed at an axial compressive load of 385,000 pounds, which compares with an analytically determined failure load of 431,000 pounds. The test demonstrated that the level of prestress produced in the titanium by the winding load must be carefully controlled since excessive prestress reduces the axial load-carrying capacity of the cylinder. Author