Innovative Sensing Fasteners for Aircraft Fatigue Monitoring

Modern aviation platforms and systems must be able to provide sustained operations in a wide variety of environments. These systems must be able to operate for extended periods in severe weather and marine environments, undergo large temperature extremes (desert to arctic conditions) and dust environments, and are subject to high vibration and shock environments. The systems are often required to perform well beyond normal maintenance and inspection cycles. These conditions lead to multiple forms of failure, including metal fatigue and cracking, particularly around mechanical fasteners and their corresponding holes. Existing condition based maintenance systems such as the HUMS are able to collect data critical to monitoring the physical condition of the aircraft or platform. This data is used to develop prognostics so that maintenance personnel can determine the useful life left for a platform and when repair services need to be initiated. Recent developments in eddy current sensors show that cracks as small as 50 mil can be reliably detected in and around aircraft fasteners. This research will explore and develop this capability for use with condition based maintenance and vehicle health monitoring systems such as the HUMS.