Debond Detection for Critical Active Rotor Components Using Guided Wave Based Active Sensing

The application of a guide wave based active sensing approach to detect debond at critical active rotor components is presented. The proposed approach was developed based on the use of piezoelectric sensors, and a sensor layup is proposed to increase wave interaction with debond. A flex-beam test article was fabricated in order to validate the effectiveness of the technique. Flex-beam tests were designed to simulate rotor environments by creating strain responses close to real blade conditions at bonded interfaces. Signals from flex-beam tests confirmed that signal changes such as sudden arrival time changes were caused by the presence of debond. Sensor position and arrival time information were used to estimate the amount of debond. Finally, the effect of dynamic loading on the sensing system performance was investigated by introducing 4 Hz excitation to the flex-beam. The sensing performance was minimally affected by the low frequency excitation. Simulated G-load, additional dynamic testing, and fatigue testing of the flex-beam is planned in the near future.