Synchronized wireless sensors for aircraft structural health monitoring

This paper presents the design and development of synchronized wireless sensors for monitoring impact events which may occur on composite airframe. Rare, random and transitory impact events, such as bird strike, runway debris or tool drops during maintenance, can introduce barely visible damage to airframes (especially composite structures) which may reduce its load bearing capacity. An innovative wireless sensing skins concept consisting of piezoelectric transducers and wireless transceivers based on Bluetooth Low Energy (BLE) is proposed to monitor the operational condition on-board continuously. An event-based mechanism is adopted for low-power operation while maintaining the sensing performance. The sampling frequency can be set up to 200 kHz while the overall idle state current can be as low as 41 µA. A synchronization method is proposed and implemented to share common time stamps among multiple wireless sensors. The performance is validated by the results from an oscilloscope. The proposed wireless sensors demonstrate a potential solution for the next generation aircraft structural health monitoring (SHM).