OPTIMAL DESIGN AND LIFETIME ESTIMATION OF FBG ACCELEROMETER FOR STRUCTURAL HEALTH MONITORING

Abstract

An FBG (fiber Bragg grating) accelerometer was developed for buildings and civil infrastructures. The accelerometer has a high sensitivity in low frequency range to cover the most important frequency components of the structural response, typically below 50Hz. The optimum design procedure to realize the maximum sensitivity under given constraints was developed considering two mechanisms. The proposed FBG accelerometer takes the advantage of an L-shaped angle element with its leverage effects. The lifetime of the developed sensor was also evaluated based on the crack theory. The lifetime of a sensor system consisting of ten FBG accelerometers was shown to be more than fifty years.