SBIR Phase II: Validation of Remotely Powered and Interrogated Microwire Temperature Sensors for Composites Cure Monitoring and Control

This Small Business Innovation Research (SBIR) Phase II research project addresses an unfilled need in the composites manufacturing and repair industry. Current manufacturing and repair methods for curing Carbon Fiber Reinforced Plastic (CFRP) composite materials do not employ real time temperature feedback from the critical interior of parts or repair bond lines because no practical sensors can be permenantly embedded to report to a remote reader. This Phase II Project will lead to the commercialization of three complementary products designed to provide this capability so as to improve curing processes. Product 1 is an inexpensive microwire temperature sensor that is easy to use and does not negatively affect structural integrity. Product 2 is an autoclave/oven control system: modular antennas that reside inside the hot chamber and a reader with control software outside that combine to control the curing process via real-time temperature feedback from embedded sensors. Product 3 is a temperature-sensing accessory for all existing portable composite repair systems. This accessory allows existing repair systems, without modification, to monitor temperature from embedded Product 1 sensors. These complementary products will vastly improve legacy curing processes by cutting curing times, reducing labor, and reducing the number of rejected parts due to uncontrolled exotherm. The commercial aircraft industry's rapidly expanding use of CFRP composites is driving the marketplace demand for process enhancements that increase efficiency, yield and part quality. If successful the outcome of this project will address the needs of control system manufacturing companies, end-user companies and commercial aircraft manufacturers. The low cost of the microwire sensors and the anticipated improvements to the speed of legacy curing processes both for initial cure and repair may accelerate the use of CFRP composites within the automobile industry. This should result in reduced fuel/energy usage worldwide. Furthermore, the extremely low thermal mass of these microwire temperature sensors gives them such fast thermal response that they may allow for the development of unconventional and faster composite curing systems and processes that employ real time feedback, such as microwave ovens for initial cure and induction heating devices for repair cure, further speeding overall industry use of composites. Finally, microwire temperature sensing technology holds promise for remote measurement of internal temperatures of lithium ion batteries for electric and hybrid cars.