Fiber Optic Acoustic Emission Monitoring System for Condition Based Maintenance Navy SBIR FY2009.1 Sol No.: Navy SBIR FY2009.1 Topic No.: N091-077 Topic Title: Fiber Optic Acoustic Emission Monitoring System for Condition Based Maintenance Proposal No.: N091-077-1244 Firm: Los Gatos Research 67 East Evelyn Ave. Suite 3 Mountain View, California 94041 Contact: An-Dien Nguyen Phone: (650) 965-7772 Web Site: www.lgrinc.com Abstract: Los Gatos Research proposes to develop a multi-channel, distributed fiber optic sensor instrumentation, capable of monitoring acoustic emission (AE) for rapid detection of impact damage and cracks in structural components. Our novel sensor technology offers a number of advantages including sensor compactness and lightweight with multiplexing capability for load, temperature, and AE for monitoring, characterizing, and locating damages in metal structures and components. We achieve this by employing Bragg grating sensor arrays and using a novel interrogation technique combined with state-of-the-art AE method to detect AE events from growing cracks in the presence of quasi-static background strain field. In Phase I, we will demonstrate the sensor's capability to monitor AE in a loaded (mechanical and thermal) aluminum panel using four FBG sensors and four piezoelectric sensors. The sensitivity of the system will be compared theoretically and experimentally to that of standard piezoelectric AE transducers. In Phase II, the grating sensors, interrogation system, and AE software will be integrated into a multi-channel, stand alone, dynamically reconfigurable, adaptive AE monitoring system with a small foot print. Benefits: The proposed fiber optic-based AE instrument may be applied to a wide range of applications including corrosion monitoring, strain/stress monitoring, and crack and corrosion induced acoustic emission detection in commercial aerospace, civil infrastructure, and automotive industry. Return