HIGH DAMPING GRAPHITE FIBER

AN ORDER OF MAGNITUDE INCREASE IN PASSIVE STRUCTURAL DAMPING IS NEEDEDTO GUARANTEE THE OPERATIONAL ROBUSTNESS OF RETARGETING STRATEGIC DEFENSE SPACECRAFT. FOR CONTINUOUSLY-JOINED PRECISION STRUCTURES OPERATING IN THE VACUUM OF SPACE, MATERIAL DAMPING WILL BE THE DOMINANT SOURCE OF STRUCTURAL DAMPING. ALTHOUGH HIGH DAMPING NON-STRUCTURAL MATERIALS EXIST, THEIR USE RESULTS IN UNDESIRABLE WEIGHT INCREASES. GRAPHITE-REINFORCED COMPOSITE MATERIALS ARE IDEAL FOR USE IN THESE STRUCTURES BECAUSE OF THEIR TAILORABLE ULTRAHIGH SPECIFIC STIFFNESS AND THERMAL DIMENSIONAL STABILITY. THE HIGH RELATIVE MODULUS OF GRAPHITE CAUSES MOST OF THE COMPOSITE STRAIN ENERGY TO BE FOUND IN THE GRAPHITE. BECAUSE CONSTITUENT CONTRIBUTIONSTO COMPOSITE DAMPING ARE WEIGHTED BY THEIR CONTRIBUTION TO STRAIN ENERGY, THIS LEVERAGE INDICATES THAT EFFORTS TO INCREASE COMPOSITE MATERIAL DAMPING SHOULD FOCUS ON THE GRAPHITE FIBERS IS BEING ESTABLISHED. THE FEASIBILITY OF DEVELOPING HIGH DAMPING GRAPHITE FIBERS. FIBER DAMPING TEST TECHNIQUES ARE BEING DEVELOPED AND EXISTING GRAPHITE FIBERS CHARACTERIZED. KNOWN FIBER CHARACTERISTICS ARE BEING CORRELATED WITH DAMPING RESULTS. MODELS THAT RELATE THE CONTROLLABLE ASPECTS OF GRAPHITE MICROSTRUCTURE AND COMPOSITION TO ITSBULK DESIGN PROPERTIES ARE BEING DEVELOPED. THESE MODELS ARE BEING USED TO ASSESS THE FEASIBILITY OF DEVELOPING HIGH DAMPING GRAPHITE REINFORCEMENT.