Damage Evaluation Method of Smart Composite Joints Based on Acoustic Emission Technology

The bondded/bolted compistes joint is the most prone to failure area in the structure of aircraft, and it is necessary to monitor the status and damage assessment to ensure the reliability of aircraft. Acoustic emission is currently the most suitable dynamic monitoring method for full-size structures, but the propagation mechanism of acoustic emission signals in bonded/bolted composites joint and the characteristics information contained therein are still unclear, which is the main obstacle to the application of acoustic emission technology in composite structures. Guided by the demand to ensure the reliability of screw connection structures, this project uses embedded intelligent fasteners to explore the propagation evolution law of acoustic emission response in connection structures, clarifies the mapping relationship between structural damage types and acoustic emission response modes, and reveals the inherent propagation mechanism of acoustic emission signals. On this basis, by using spectral separation filtering methods to separate and identify different acoustic emission signals, and establish a multi-domain damage feature index database for data fusion technology for damage state assessment, further, based on the acoustic emission data feature fusion damage assessment method, the mapping relationship between feature information and damage types, degrees and remaining life is established, and then the damage assessment of screw hybrid connection structure is realised.