CRYOGENIC STRETCH-FORMING OF SOLID PROPELLANT ROCKET CASES.
Quarterly rept. no. 9, 1 Jun-31 Aug 64,
ARDE-PORTLAND INC PARAMUS N J
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Three subscale high strength vaessel preforms were fabricated and two of these were stretched. Very high stress levels were successfully achieved with the high strength cases during the cryogenic stretch-forming operation. This indicates that high room temperature strength may be anticipated after aging. The first two full-scale preforms were completed and stretched. Several problems were encountered. The basic problem which manifested itself during the stretch of the first preform consisted of severe buckling at the forward end of the case. A leak at the weld joint at the large diameter of the dog-bone was attributed to the buckling. A second case was stretched to confirm the conclusion that the buckling was a cause for the weld cracking. A design analysis was performed which indicated that the compressive stresses at the forward end were high during the lower pressures of the stretchforming operation. Author