This Small Business Innovation Research (SBIR) Phase I project will develop Micro-Electro-Mechanical Systems (MEMS) based acoustic emission (AE) sensors for structural health monitoring. AE is a well-established nondestructive testing technique commonly used to monitor for active fatigue cracks in metals, leaks in pressurized lines and tanks, impact damage, and matrix and fiber damage in composites. The project team will develop novel MEMS AE sensors to be applied generically to concrete, steel, and composite structures and rotating machinery in structural health monitoring applications. The primary goal is to design and implement an array of high quality factor MEMS resonant-type capacitive transducers in the frequency range between 100kHz and 1MHz, corresponding to the frequency spectrum of the ultrasonic wave generated when elastic energy is released in a structure during permanent and irreversible crack formation. Secondly, the sensor packaging issues will be addressed in parallel with the performance to ensure the development of a robust sensor for commercial applications. The proposed research is an innovative and transformative effort with anticipated performance enhancement particularly with regard to both the mechanical resonant characteristics and sensor packaging aspects of the AE sensor. The broader impact/commercial potential of this project related to the safe and economical operation of publically and privately held assets (bridges, railroads, pressure vessels, etc.) around the world. This infrastructure is aging and significant investment must be monitored continuously. The proposed technology will be low-cost and high volume solution to this massive aging infrastructure issue. Economically speaking, the objective of the proposed technology is to monitor two orders of magnitude (100X) more structures inspection budget levels. The technology, therefore, will have a significant impact in bridge, pressure vessel, commercial and military aircraft, vibrating machinery, etc. Non-proprietary information about the technology shall be disseminated through journal and conference publications. Since there is a large market for this technology a significant number of technical jobs will be created by the successful development of the technology via engineering student interns, post-docs, and professional engineers. Successful development of the technology will also create significant amount of field technician employment opportunities
