THERMOGRAPHIC NON-DESTRUCTIVE EVALUATION

THE PROPOSAL IS TO ESTABLISH QUANTITATIVE THERMOGRAPHIC NON-DESTRUCTIVE EVALUATION (QTNDE) FOR NONDESTRUCTIVE INSPECTION AND DEFECT EVALUATION OF FRACTURE-CRITICAL ADVANCED AIRCRAFT MATERIALS. THIS WILL BE BASED ON RECENT THEORETICAL AND EXPERIMENTAL ADVANCES CONCERNING THE ADIABATIC THERMOELASTIC EFFECT AND ADDITIONAL EXPERIMENTS ON TWO DEMONSTRATION MATERIALS. A SCREENING MATRIX WILL BE ESTABLISHED TO RATE QTNDE FOR SUITABILITY TO INVESTIGATE PARTICULAR MATERIALS AND COMPONENTS. THE SCHEME WILL ALLOW REALISTIC CONSIDERATION OF ARBITRARY MATERIALS (ISOTROPIC OR ANISOTROPIC), GEOMETRIES (NOTCHES; FLAWS; COMPLES TOPOLOGIES), AND SERVICE CONDITIONS (WITHOUT UPPER LIMIT IN TEMPERATURE). THE BEST SPECIAL TECHNIQUE OF QTNDE WILL BE USED FOR EACH MATERIAL TO ASSESS THE CRITICALITY OF FLAWS IN TERMS OF DAMAGE EVOLUTION RATES AND LIFE: A) EVOLUTION OF RANDOM STRESS RAISERS, B) MODULUS CHANGE, OR, C) DENSITY CHANGE. THE FULL-FIELD THERMOGRAPHIC DATA ARE ALWAYS COLLECTED AT NONDESTRUCTIVE LEVELS OF CYCLIC LOADS.