Chen Jian, Xu Yusen, Yuan Shenfang, Qin Zhen
Research Center of Structural Health Monitoring and Prognosis, State Key Laboratory of Mechanics and Control for Aerospace Structures, Nanjing University of Aeronautics and Astronautics, 29 Yudao Street, Nanjing 210016, China.
Sensors (Basel). 2023 Nov 16;23(22):9224. doi: 10.3390/s23229224.
Multi-layer and multi-rivet connection structures are critical components in the structural integrity of a commercial aircraft, in which elements like skin, splice plate, strengthen patch, and stringer are fastened together layer by layer with multiple rows of rivets for assembling the fuselage and wings. Their non-detachability and inaccessibility pose significant challenges for assessing their health states. Guided wave-based structural health monitoring (SHM) has shown great potential for on-line damage monitoring in hidden structural elements. However, the multi-layer and multi-rivet features introduce complex boundary conditions for guided wave propagation and sensor layouts. Few studies have discussed the guided wave characteristic and damage diagnosis in multi-layer and multi-rivet connection structures. This paper comprehensively researches guided wave propagation characteristics in the multi-layer stringer splice joint (MLSSJ) structure through experiments and numerical simulations for the first time, consequently developing sensor layout rules for such complex structures. Moreover, a Gaussian process (GP)-based probabilistic mining diagnosis method with path-wave band features is proposed. Experiments on a batch of MLSSJ specimens are performed for validation, in which increasing crack lengths are set in each specimen. The results indicate the effectiveness of the proposed probabilistic evaluation method. The maximum root mean squared error of the GP quantitative diagnosis is 1.5 mm.
多层多铆钉连接结构是商用飞机结构完整性的关键部件，其中蒙皮、拼接板、加强片和桁条等部件通过多排铆钉逐层固定在一起，用于组装机身和机翼。它们的不可拆卸性和难以接近性给评估其健康状态带来了重大挑战。基于导波的结构健康监测（SHM）在隐藏结构元件的在线损伤监测方面显示出巨大潜力。然而，多层多铆钉特征为导波传播和传感器布局引入了复杂的边界条件。很少有研究讨论多层多铆钉连接结构中的导波特性和损伤诊断。本文首次通过实验和数值模拟全面研究了多层桁条拼接接头（MLSSJ）结构中的导波传播特性，从而为这种复杂结构制定了传感器布局规则。此外，还提出了一种基于高斯过程（GP）的具有路径波带特征的概率挖掘诊断方法。对一批MLSSJ试件进行了实验验证，在每个试件中设置了不断增加的裂纹长度。结果表明了所提出的概率评估方法的有效性。GP定量诊断的最大均方根误差为1.5毫米。
