DETECTION AND QUANTIFICATION OF SUBSURFACE CORROSION USING IMPROVED MAGNETO-OPTIC/EDDY-CURRENT IMAGING AND IMAGE PROCESSING

NONDESTRUCTIVE INSPECTION FOR CORROSION IN ALUMINUM AIRCRAFT STRUCTURES OF AGING AIRPLANES HAS BEEN DEMONSTRATED RECENTLY USING MAGNETO-OPTIC/EDDY CURRENT IMAGING TECHNOLOGY. THIS TECHNOLOGY WAS DEVELOPED FOR RAPID INSPECTION OF SURFACE BREAKING CRACKS NEAR RIVETS IN ALUMINUM AIRCRAFT ALLOYS, BUT HAS BEEN SHOWN TO BE CAPABLE OF GENERATING IMAGES OF CORRODED REGIONS AS WELL. DEVELOPMENT OF A CORROSION DETECTION INSTRUMENT BASED ON THIS NEW AND INNOVATIVE TECHNIQUE IS PROPOSED HERE. THIS NEW NONDESTRUCTIVE INSPECTION TECHNOLOGY COUPLES LINEAR INDUCED EXCITATION WITH MAGNETO-OPTIC SENSING TO PRODUCE DIRECT, REAL-TIME IMAGES OF DEFECTS. ONCE DEVELOPED, THE PROPOSED INSTRUMENT WILL BE ABLE TO DETECT AND IMAGE SUBSURFACE CORROSION, QUANTIFY THE PERCENTAGE OF MATERIAL LOSS, AND PROVIDE COMPUTER GENERATED IMAGES OF CORRODED AREAS. DURING PHASE I OF THIS PROJECT, THE FEASIBILITY OF THIS PROPOSED INSTRUMENT WILL BE ESTABLISHED. AREAS OF FURTHER RESEARCH AND DEVELOPMENT FOR ENHANCED CORROSION DETECTION INCLUDE SENSOR PERFORMANCE IMPROVEMENT, DEVELOPMENT OF CONTINUOUSLY VARIABLE EXCITATION FREQUENCY CAPABILITY, DEVELOPMENT OF ROTATING FIELD EDDY CURRENT EXCITATION, AND IMAGE PROCESSING.