COST EFFECTIVE NONDESTRUCTIVE EVALUATION OF COMPOSITE PARTS WITH LASER SHEAROGRAPHY

THE AIM OF THIS PROJECT IS TO DEVELOP A LOW COST LASER DIODE SHEAROGRAPHY SYSTEM FOR USE IN THE INSPECTION OF ADVANCED COMPOSITE AIRCRAFT COMPONENTS AND STRUCTURES. LASER SHEAROGRAPHY IS A RELATIVELY NEW NONDESTRUCTIVE EVALUATION TECHNIQUES THAT IS USED WITH EXCITATION METHODS TO MEASURE DIFFERENTIAL DISPLACEMENTS AND SUBSEQUENT STRAINS IN A MATERIAL. SHEAROGRAPHY HAS PROVEN SUCCESSFUL IN LOCATING FLAWS SUCH AS PLY-PLY AND BONDLINE DELAMINATIONS. THE INTENT IS TO OPTIMIZE THE OPERATING EFFICIENCY AND DESIGN OF THE SYSTEM. THIS MEANS INCREASING INSPECTION THROUGHOUT WHILE REDUCING THE AMOUNT OF HUMAN INTERACTION NECESSARY TO INSPECT COMPOSITE PARTS. SAMPLE COMPOSITE AIRCRAFT PARTS WILL BE OBTAINED WITH KNOWN DEFECTS AND TESTED USING SEVERAL SHEAROGRAPHY EXCITATION TECHNIQUES. A LASER SHEAROGRAPHY CAMERA WILL BE USED TO RECORD AND EVALUATE THE SHEAROGRAMS IN REAL TIME. LASER DIODES WILL BE STUDIES AS A COMPACT, HIGH POWERED ALTERNATIVE TO HENE AND ARGON LASERS IN USE TODAY. THE OUTCOME OF THE PHASE I RESEARCH EFFORT WILL BE: 1) PROOF OF CONCEPT; 2) WELL DOCUMENTED TEST PROCEDURES; 3) RECOMMENDATIONS FOR THE DEVELOPMENT IN PHASE II OF FIELD-DEPLOYABLE, PORTABLE INSTRUMENT FOR MILITARY AND COMMERCIAL APPLICATIONS; 4) RECOMMENDATIONS FOR THE DEVELOPMENT OF AN AUTOMATED TEST SYSTEM FOR THE PRODUCTION LINE ENVIRONMENT. ANTICIPATED BENEFITS: SOME POTENTIAL MARKETS FOR USING LASER DIODE SHEAROGRAPHY AS AN NDE TOOL ARE: ON AIRCRAFT INSPECTION, AGING AIRCRAFT, PROCESS CONTROL, QUALITY CONTROL, BRIDGE INSPECTION, AND NDT SERVICE COMPANIES. NDE INSPECTORS WOULD USE LS TO COMPLEMENT ULTRASONICS, X-RAY, ETC. THIS ALONE PRESENTS A LARGE EXISTING MARKET. A PORTABLE SYSTEM COULD BE USED ON THE PRODUCTION LINE FOR PROCESS CONTROL, IN THE INSPECTION AREA FOR QUALITY CONTROL, AND WOULD BE USEFUL FOR IN-SITU INSPECTION.