In-flight structural health monitoring (SHM) of composite aerostructures can be a complex task requiring many types of sensors. Vibrational behaviour is a good global characteristic that offers the potential to significantly reduce the number of sensors. However, practical application of vibration-based SHM strategies requires many real-world training sessions for successful fault detection, identification and localisation. The EU-funded VIBRATION project replaced the majority of real-world tests with simulated training for substantial time and cost savings. Project partners developed an in situ SHM platform that can estimate the possibility of damage to a composite structure during flight from changes in its vibration characteristics. To achieve this, they first manufactured 40 small-scale composite booms. Their vibration response was studied to form a baseline for the healthy state of the structure. The tests helped to reveal all variability from materials, manufacturing processes and post-process machining. Some of the small-scale booms were damaged afterwards at specific locations and under particular conditions. These booms were also analysed for their vibration response and then compared to healthy states. The responses’ high variability led to the development of dedicated mathematical analysis tools for distinguishing the damaged parts from the healthy ones with very high probability. Researchers devised a damage detection methodology to ensure that the probability of a false positive detection is almost zero. They performed numerical modelling on the structure to extend the number of visual experiments on the boom and enhance the accuracy of damage prediction. The damage detection performance assessment measures the probability of damage to a composite boom structure and indicates the threshold between a healthy and damaged part. The in-flight SHM platform for aerospace composites based on vibrational signals should reduce the complexity of sensor networks and improve passenger and crew safety. It will also significantly decrease the time and cost of inspection and maintenance, thus boosting the competitive position of the aerospace industry.
Structural health monitoring, aerostructures, vibrational behavior, VIBRATION, damage detection