PHYSICALLY BASED FAILURE CRITERIA FOR CARBON-PHENOLIC

CARBON-PHENOLIC MATERIALS HAVE BEEN WIDELY USED IN SOLID ROCKET MOTORS (SRMS) FOR MANY YEARS, DESPITE THE FACT THAT THEIR THERMOSTRUCTURAL BEHAVIOR HAS NOT BEEN WELL UNDERSTOOD. THE APPLICATION OF CARBON-PHENOLIC TO THE MAN-RATED SPACE SHUTTLE SRMS, HOWEVER, HAS NECESSITATED THE CAPABILITY FOR ACCURATE ANALYSIS, INCLUDING FAILURE PREDICTION, OF THIS MATERIAL. THIS PROPOSAL SEEKS TO ADDRESS THIS PROBLEM THROUGH THE CREATION OF A PHYSICALLY BASED FAILURE CRITERION FOR CARBONPHENOLIC. BY "PHYSICALLY BASED" IT IS MEANT THAT THE FAILURE CRITERION MATHEMATICAL FORMULATION WILL BE BASED ON PHYSICAL MATERIAL PARAMETERS OBSERVED FROM TEST DATA. THIS IS OPPOSED TO A PURELY MATHEMATICAL "CURVE FIT" CRITERION WHICH MERELY SEEKS TO FIT TEST DATA. THIS CRITERION WILL SEPARATELY ADDRESS THREE DISTINCT PHASESOF CARBON-PHENOLIC BEHAVIOR THROUGHOUT ITS TEMPERATURE RANGE: THE LOW TEMPERATURE, PYROLYSIS AND HIGH TEMPERATURE PHASES. WITHIN EACH OF THESE PHASES MATERIAL FAILURE MODES,PROCESSING VARIABLES, STATISTICAL BEHAVIOR AND CRITICAL SIZE EFFECTS WILL BE CONSIDERED. THIS PROGRAM WILL MAKE USE OF MANY RECENT AND CONCURRENT PROGRAMS TO ACHIEVE ITS OBJECTIVES.