GENERALIZED FAILURE CRITERIA FOR LAMINATED CARBON-CARBON

THE WESTAR/PALAPA SATELITE LAUNCH EVENTS, IN WHICH TWO-DIMENSIONAL (2D) CARBON-CARBON (C-C) ROCKET NOZZLE EXIT CONES FAILED AND CAUSED A LOSS OF MISSION, POINTS GRAPHICALLY TO THE INADEQUACIES OF THE DESIGN -ANALYSIS- MANUFACTURING -TEST- AND INSPECTION PROCESS. WE BELIEVE THAT THE LACK OF UNDERSTANDING OF THE MECHANICAL BEHAVIOR OF 2D C-C IS THE LEADING CONTRIBUTOR TO THE PRESENTLY UNACCEPTABLE CONDITION. THE PROPOSED PROJECT IS PLANNED TO REMEDY THIS PROBLEM BY EVOLVING A PHYSICALLY BASED FAILURE CRITERION FOR 2D C-C TO BE USED IN DESIGN/ANALYSIS. THE KEYFACTOR IN THIS WORK IS ESTABLISHMENT OF A "PHYSICAL BASIS". THIS WILL ENABLE THE RESULTS TO ALSO BE USEFUL IN ALL FACETSOF THE MECHANICAL ENGINEERING OF 2D C-C INCLUDING IMPROVED PROCESSING, BETTER INSPECTION AND CLEARER TESTING GOALS. CURRENT AND PREVIOUSLY CONDUCTED PROGRAMS HAVE PROVIDED MUCH OF THE 2D C-C TEST DATA NEEDED FOR THIS PROJECT, BUT THESE PROGRAMS HAVE ONLY BEGUN TO ILLUMINATE THE PHYSICAL FACTORS INFLUENCING STRESS-STATE INTERACTIONS AND MATERIAL STRENGTH VARIABILITY. THIS PROJECT PROPOSES TO DIG DEEPER INTO EXISTING DATA AND RESULTS AND TO CONDUCT THE ADDITIONALWORK NECESSARY TO ACHIEVE A METHODOLOGY WHICH WILL LEAD TO THE DESIRED LEVEL OF CONFIDENCE IN SOLID ROCKET MOTOR RELIABILITY.