APPLICATION OF LOCALIZED VIBRATION AND SMART MATERIALS IN CONTROLLING THE DYNAMIC RESPONSE OF STRUCTURES

IN THE TREATMENT OF THE DYNAMIC PROBLEMS OF STRUCTURES, TWO ALTERNATE TESTING METHODS, BASED ON EXTERNAL AND EMBEDDED SENSORS, EXIST IN THE LITERATURE. IF THE SENSORS RESPOND TO THE CHANGES IN THE DYNAMIC CHARACTERISTICS OF THE STRUCTURE, AND/OR THE ENVIRONMENT, THEN THEY ARE REFERRED TO "SMART" STRUCTURES. SMART SENSORS AND SMART MATERIALS HAVE BEEN USED FOR DETECTING STRUCTURAL DAMAGES AND/OR CONTROLLING THE VIBRATION CHARACTERISTICS OF THE STRUCTURES. RECENT DEVELOPMENTS IN NEW MATERIALS, AND IN VIBRATION PHENOMENONS SUCH AS MODE LOCALIZATION AND TRANSITION HAVE MADE THE RESEARCHERS TO LOOK FOR WAYS OF COMBINING THE TWO IN ORDER TO MORE EFFECTIVELY ALTERING STRUCTURAL RESPONSE TO DYNAMIC LOADS. THE OBJECTIVE OF THIS PROPOSED RESEARCH IS TO INVESTIGATE THE FEASIBILITY OF DEVELOPING A MORE EFFICIENT AND PRECISE SMART STRUCTURES BASED ON SMART MATERIALS, SUCH AS SHAPE MEMORY ALLOYS, AND/OR EMBEDDING SENSORS, SUCH AS OPTICAL FIBERS, AND VIBRATIONAL PHENOMENONS SUCH AS LOCI CROSSING AND VEERING, AND MODE LOCALIZATION AND TRANSITION. IN PARTICULAR, SUCH PHENOMENONS WILL BE ENFORCED ON THE STRUCTURES SO THAT THE UNDESIRED VIBRATIONS ARE CONFINED TO A SMALLER REGION, AND THEREFORE EASIER TO DETECT AND CONTROL. SHAPE MEMORY MATERIALS AND OPTICAL FIBERS WILL BE USED TO DETECT AND CONTROL THE PARAMETERS THAT ARE MORE CRUCIAL IN VIBRATION RESPONSE OF THE STRUCTURE. SUCH COMBINATION WILL RESULT IN A HUGE REDUCTION IN THE NUMBER OF THE SENSORS, SIGNIFICANT GAIN IN COMPUTATIONAL SPEED, AND IMPROVING THE ACCURACY OF THE CONTROL SYSTEM. ANTICIPATED BENEFITS/POTENTIAL COMMERCIAL APPLICATIONS - THE OUTCOME OF THIS SBIR PROJECT WILL RESULT IN SIGNIFICANT ADVANCEMENT IN THE FIELD OF SMART STRUCTURES. IT WILL ENHANCE THE CAPABILITIES OF THE SYSTEMS USED BY DOD, NASA, AEROSPACE AND OTHER COMMERCIAL INDUSTRIES. THE COMMERCIAL APPLICATIONS OF SUCH DEVELOPMENT INCLUDE DAMAGE CONTROL, CONFINEMENT OF STRUCTURAL VIBRATIONS, AND VIBRATION CONTROL WHICH SIGNIFICANTLY IMPROVE THE PERFORMANCE AND RELIABILITY OF STRUCTURES.