COHERENT LASER REMOTE STRUCTURAL ANALYSIS

LARGE STRUCTURES REQUIRE PERIODIC ROUTINE INSPECTION TO DETECT MECHANICAL FLAWS BEFORE THEY LEAD TO SIGNIFICANT DAMAGE AND DANGEROUS CONDITIONS. CONVENTIONAL INSPECTIONS ARE TIME CONSUMING, EXPENSIVE, AND LABOR INTENSIVE. INEXPENSIVE, REMOTE INSPECTION OF LARGE STRUCTURES WOULD THUS BE ECONOMICALLY BENEFICIAL AND WOULD FREE RESOURCES TO BE APPLIED TO IMPROVED MAINTENANCE AND REPAIR. WORK CONDUCTED RECENTLY ON MODAL ANALYSIS HAS SHOWN THAT STRUCTURAL CHANGES MAY BE IDENTIFIED BY ANALYZING CHANGES INTHE VIBRATION SPECTRUM OF A STRUCTURE. WE PROPOSE TO USE COHERENT LASER DETECTION, A TECHNIQUE ON WHICH THE LASER VIBROMETER IS BASED, TO COMPLEMENT MODAL ANALYSIS, THEREBY ALLOWING THE REMOTE INSPECTION OF LARGE STRUCTURES FOR FLAWS. A MAJOR ADVANTAGE OF THE LASER TECHNIQUE IS THE ABILITY TO PINPOINT STRUCTURAL ELEMENTS BY AIMING THE LASER AT EACH INDIVIDUALLY. THIS APPLICATION OF COHERENT DETECTION WILL STIMULATE DEVELOPMENT OF STATE-OF-THE-ART LASER-BASED SYSTEMS WITH NEW, SIGNIFICANT COMMERCIAL APPLICATIONS WHICH WILL BENEFIT THE US ECONOMY.