Accession Number : AD0810924

Title :   DETERMINATION OF OPTIMUM LENGTH OF END RELEASE FOR CASE BONDED SOLID PROPELLANT ROCKET MOTORS.

Descriptive Note : Final rept. 1 Apr 66-15 Mar 67,

Corporate Author : ROCKETDYNE MCGREGOR TX SOLID ROCKET DIV

Personal Author(s) : Webb, L. Dale

Report Date : MAR 1967

Pagination or Media Count : 155

Abstract : The problem of predicting crack-type failures in composite solid rocket propellant grains has been a continuing one. The usual practice has been to use one of the classical failure theories to extrapolate the failure data collected from laboratory tests to the motor grain. Just which theory to use generally depends upon the stress state at the point being considered and the previous experience of the analyst. A new unifying approach based upon fracture mechanics is considered and evaluated both analytically and experimentally. The analytics illustrate the use of the numerical stiffness programs to compute the total strain energy in various grain-like configurations with different crack lengths and locations. The experiments were conducted to confirm the existence of a characteristic strain energy release rate for cracks propagating through propellants. Taken together, the growth of both cohesive cracks in the propellant grain and adhesive cracks along a grain-case interface can be predicted. The results reported indicate that the method may prove to be quite sensitive both for predicting the onset of grain cracking and for adjusting the design parameters to minimize the tendency for fracturing to begin. (Author)

Descriptors :   *CRACK PROPAGATION), *ROCKET ENGINE CASES), (*ROCKET PROPELLANT GRAINS, (*SOLID ROCKET PROPELLANT BINDERS, NUMERICAL METHODS AND PROCEDURES, COMPUTER PROGRAMS, SURFACE PROPERTIES, ENERGY, FRACTURE(MECHANICS), STRESSES, MATHEMATICAL PREDICTION.

Subject Categories : Solid Propellant Rocket Engines
      Solid Rocket Propellants

Distribution Statement : APPROVED FOR PUBLIC RELEASE