Guided Wave Structural Health Monitoring for Impact Damage Detection and Characterization


Laminated composite structures are susceptible to impact damage mechanisms such as disbonds and delaminations that significantly weaken the structure. Due to the unpredictable and sudden nature of impacts, traditional scheduled maintenances might fail to detect such damage in a timely fashion. Guided wave structural health monitoring (GWSHM) uses a network of sensors that are permanently surface-mounted or embedded in the structure, allowing for continuous monitoring, and potentially make it possible to detect an impact damage the moment it happens. In order for a GWSHM system to be reliable, it is important to investigate the ability of guided waves to detect impact damage with high probability and with a low false alarm rate. In this work, a glass fiber composite coupon with plain-weave S-glass/SC-15 epoxy is instrumented with lead-zirconate-titanate (PZT) piezoelectric thin films that are used for the generation and detection of guided waves. Baseline data is then recorded for each transducer path in the bonded GWSHM transducer network. The composite coupon is then hit by drop weight impactor with varying energies. The correlation between impact energy, observed structural damage, and the change in the guided wave signals is investigated. Based on those observations, multiple signal features based on baseline comparison are then investigated, including time domain and frequency domain signal features.

American Society of Composites 30th Technical Conference