EVALUATION OF HIGH PERFORMANCE ROCKET MOTORS USING SUBSCALE PRECRACKED CASES.
Abstract
The Army Materiel Command recently completed a program directed toward developing improved techniques for the fabrication of high performance solid propellant rocket motors. As a result of this study, cases fabricated by ARDE-Portland Inc. and The Budd Company were available for test. The solid propellant rocket motors fabricated by ARDE-Portland Inc. were made by cryogenically stretch-forming 301 stainless steel; The Budd Company developed a helically wrapped and welded case using cold rolled and aged 250 grade maraging steel. Plane strain fracture toughness values were determined for the cryogenically stretch-formed 301 stainless steel and the cold rolled and aged 250 grade maraging steel. These values were used to calculate the size of the defect to be introduced in the case wall. A semicircular crack 0.030 in. long by 0.015 in. deep was recommended for the maraging steel case and a semicircular crack 0.050 in. long by 0.025 in. deep was recommended for the ARDE-Portland case. These cracks were introduced into the case wall and the cases were hydrotested at -65 F. The data show that, as predicted by fracture mechanics, the case strength was not degraded by the presence of these small defects. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 1967
- Accession Number
- AD0660335
Entities
People
- Carl M. Carman