LASER SPECKLE INSTRUMENT WITH HAND-HELD PROBING HEAD FOR NONCONTACTING INSPECTION OF ADVANCED MATERIALS

THE MATERIALS OF AEROSPACE COMPONENTS ARE SUBJECTED TO HIGH TEMPERATURES AND STRONG AERODYNAMIC FORCES DURING PROPULSION. THEREFORE, INNOVATIONS IN NON-INVASIVE SENSOR TECHNOLOGIES ARE REQUIRED FOR THE MEASUREMENT OF STRUCTURAL PHYSICAL PROPERTIES. FIBER OPTIC VIEWING PROBES AND OTHER OPTICAL MEASURING TECHNIQUES, ALTHOUGH PROMISING, FAIL TO COMBINE FLEXIBILITY WITH QUANTITATIVE ANALYSIS OF PHYSICAL MEASUREMENTS AT THE VERY HIGH TEMPERATURES (\ 400 DEG F) ENCOUNTERED IN NEW ADVANCED SYSTEMS SUCH AS SCRAMJET ENGINES AND AEROSPACE REENTRY VEHICLES. THE TARGET OF OPPORTUNITY IN THIS PROGRAM IS THE DEVELOPMENT OF A NONCONTACTING, HIGHLY SENSITIVE, OPTICAL STRAIN MEASUREMENT TECHNIQUE WHICH USES A LASER SPECKLE INTERFEROMETRIC SENSOR WITH ASSOCIATED DIGITAL OPTOELECTRONIC IMAGE PROCESSING EQUIPMENT. THE SYSTEM WILL PROVIDE A RAPID CORRELATION SIGNAL USED FOR THE MICROSTRUCTURAL CHARACTERIZATION OF MATERIALS SUBJECTED TO VERY HIGH TEMPERATURES. SPECIFIC PROGRAM OBJECTIVES INCLUDE THE EVALUATIONS OF TYPICAL AEROSPACE MATERIALS FOR THEIR SPECTRAL EMISSIVITY, THE ASSESSMENT OF CURRENTLY AVAILABLE HIGH-TEMPERATURE STRAIN MEASUREMENT TECHNIQUES, THE DESIGN AND DEVELOPMENT OF VERY HIGHTEMPERATURE AND HIGHLY SENSITIVE STRAIN SENSOR BASED ON A UNIQUE LASER SPECKLE INSTRUMENTATION AND DIGITAL OPTOELECTRONIC SIGNAL PROCESSING.