IMPROVED TRANSDUCER PRODUCTION TESTING FOR RUBBER-TO-METAL BONDED JOINTS

THE OVERALL GOAL OF THIS RESEARCH IS TO DEVELOP AN INNOVATIVE NONDESTRUCTIVE (NONINVASIVE) INSPECTION TECHNIQUE FOR THE DETERMINATION OF THE INTEGRITY OF RUBBER-TO-METAL BONDS OF THE TYPE USED IN PRODUCTION SONAR TRANSDUCERS. THE PHASE I EFFORT WILL DEVELOP THE IMPEDANCE ANALYSIS TECHNIQUE THAT RELATES THE ELECTRICAL IMPEDANCE CHARACTERISTICS OF AN ULTRASONIC TRANSDUCER TO THE PROPERTIES OF A BONDED SAMPLE WITH WHICH IT IS IN CONTACT. PERFORMANCE OF THE TECHNIQUE WILL BE EVALUATED BY IT'S CAPABILITY TO DETECT AN UNBOND CONDITION IN WHICH THE RUBBER AND METAL ARE IN INTIMATE CONTACT. THEORETICAL WORK WILL CONSIDER THE ELECTRICAL EQUIVALENT CIRCUIT MODEL OF TRANSDUCER INCLUDING THE ACOUSTIC LOADING PRESENTED BY THE SAMPLE WITH WHICH IT IS IN CONTACT. EXPERIMENTAL WORK WILL INCLUDE DEVELOPMENT OF SUITABLE TRANSDUCERS AND ANALYSIS OF IMPEDANCE DATA USING INVERSE ACOUSTIC MODELING TECHNIQUES TO INFER MATERIAL CHARACTERISTICS RELATING TO THE BONDED AND UNBONDED CONDITION. A NUMBER OF CONTROLLED RUBBER-TO-METAL BONDED SAMPLES WILL BE MANUFACTURED AND INSPECTED TO DETERMINE THE SUITABILITY AND LIMITS OF PERFORMANCE OF THE PROPOSED METHOD.