Glass fiber-reinforced polymer composite bolted structures, as an all-composite connection method, offer significant weight reduction advantages. However, the structural failure caused by preload attenuation has become a major safety hazard threatening engineering applications. To address this issue, this study proposes a novel method for structural health monitoring of composite bolted joints based on a washer-type buckypaper (BP) sensor. The feasibility and load variation synchronization of this new washer-type BP sensor for monitoring bolt preload changes were verified through multistage continuous loading–unloading comparative tests. Static tensile tests, vibration characteristic tests, vibration tests under different acceleration levels (20, 40, 60, and 80 g), vibration fatigue tests (58,000 cycles), and simulated loosening tests were conducted on composite bolted joint specimens equipped with this new washer-type BP sensor. The results demonstrate that the sensor exhibits excellent load response synchronization, high sensitivity, and outstanding stability. It enables in situ monitoring of preload force in composite bolted structures, providing real-time response to preload variations under both static and dynamic loading conditions. This offers a novel solution for full-life cycle loosening health monitoring of composite bolted joints.
AnQWangCMaT, et al. Aeronautical composite/metal bolted joint and its aeronautical composite/metal bolted joint and its mechanical properties: a review. J Intell Manuf Special Equip2024; 5(1): 70–91.
2.
McCarthyCTMcCarthyMA. Design and failure analysis of composite bolted joints for aerospace composites. Polym Compos Aerosp Ind2015; 11: 295–334.
3.
NikbaktSKamarianSShakeriM. A review on optimization of composite structures part I: laminated composites. Compos Struct2018; 195: 158–185.
4.
GalińskaA. Mechanical joining of fibre reinforced polymer composites to metals—a review. Part I: bolted joining. Polymers2020; 12(10): 2252.
5.
JadeeKJOthmanAR. Fiber reinforced composite structure with bolted joint – a review. Key Eng Mater2011; 471–472: 939–944.
6.
NikraveshSMYGoudarziM. A review paper on looseness detection methods in bolted structures. Lat Am J Solids Struct2017; 14(12): 2153–2176.
7.
SatasivamSBaiY. Mechanical performance of bolted modular GFRP composite sandwich structures using standard and blind bolts. Compos Struct2014; 117: 59–70.
8.
LiuQHuangGLiuX, et al. Optimized high energy vibration environmental for four-way joint lock nut of hydraulic pipeline in aircraft energy storage systems. In: 2023 3rd New energy and energy storage system control summit forum (NEESSC), Mianyang, China, 2023, pp. 17–20.
9.
SunLLiuSMuhammadU, et al. Study on bolt loosening mechanism under transverse load considering slip and adhesion status of contact surfaces. J Constr Steel Res2025; 224: 109149.
10.
ZhangLZhangBLuS, et al. Tensile and vibration fatigue monitoring of composite laminate bolted joints with local enhancement using buckypaper sensors. Struct Health Monit2025; 1–15.
11.
MožePBegD. A complete study of bearing stress in single bolt connections. J Constr Steel Res2014; 95: 126–140.
12.
CacceseVMewerRVelSS. Detection of bolt load loss in hybrid composite/metal bolted connections. Eng Struct2004; 26(7): 895–906.
13.
WangTSongGLiuS, et al. Review of bolted connection monitoring. Int J Distrib Sens Netw2013; 9(12): 871213.
14.
HuangJLiuJGongH, et al. A comprehensive review of loosening detection methods for threaded fasteners. Mech Syst Signal Process2022; 168: 108652.
15.
QinXPengCZhaoG, et al. Full life-cycle monitoring and earlier warning for bolt joint loosening using modified vibro-acoustic modulation. Mech Syst Signal Process2022; 162: 108054.
16.
ZhengZMiaoXHuangX, et al. Fastening reliability analysis of bolted joint anti-self-loosening, J Constr Steel Res2023; 202: 107776.
17.
GongHLiuJFengH. Review on anti-loosening methods for threaded fasteners. Chin J Aeronaut2022; 35(2): 47–61.
18.
LiuSLiuXCuiX, et al. 3D printed MXene/rGO hierarchical porous structure based on ultralow-concentration 2D nanomaterial inks for highly sensitive pressure sensing. Chem Eng J2024; 496: 154250.
19.
MiaoRShenRZhangS, et al. A review of bolt tightening force measurement and loosening detection. Sensors2020; 20(11): 3165.
20.
ChelimillaNChinthapentaVKaliN, et al. Review on recent advances in structural health monitoring paradigm for looseness detection in bolted assemblies. Struct Health Monit2023; 22(6): 4264–4304.
21.
HuoLChenDLiangY, et al. Impedance based bolt pre-load monitoring using piezoceramic smart washer. Smart Mater Struct2017; 26(5): 057004.
22.
HuMSalmani Pour AvvalSHeJ, et al. Explainable artificial intelligence study on bolt loosening detection using Lamb waves. Mech Syst Signal Process2025; 225: 112285.
23.
PhamHCTaQ-BKimJ-T, et al. Bolt-loosening monitoring framework using an image-based deep learning and graphical model. Sensors2020; 20(12): 3382.
24.
ZhangYSunXLohKJ, et al. Autonomous bolt loosening detection using deep learning. Struct Health Monit2019; 19(1): 105–122.
25.
HuynhT-CParkJ-HJungH-J, et al. Quasi-autonomous bolt-loosening detection method using vision-based deep learning and image processing. Autom Constr2019; 105: 102844.
26.
LuoJLiKXieC, et al. A novel anti-loosening bolt looseness diagnosis of bolt connections using a vision-based technique. Sci Rep2024; 14(1): 11441.
27.
AiDMoFChengJ, et al. Deep learning of electromechanical impedance for concrete structural damage identification using 1-D convolutional neural networks. Constr Build Mater2023; 385: 131423.
28.
PanXYangTY. Image-based monitoring of bolt loosening through deep-learning-based integrated detection and tracking. Comput Aided Civil Infrastruct Eng2021; 37(10): 1207–1222.
29.
HuynhT-C. Vision-based autonomous bolt-looseness detection method for splice connections: design, lab-scale evaluation, and field application. Autom Constr2021; 124:103591.
30.
PanXYangTY. 3D vision-based bolt loosening assessment using photogrammetry, deep neural networks, and 3D point-cloud processing. J Build Eng2023; 70: 106326.
31.
WangXYueQLiuX. Bolted lap joint loosening monitoring and damage identification based on acoustic emission and machine learning. Mech Syst Signal Process2024; 220: 111690.
32.
MarshallMBLewisRHowardT, et al. Ultrasonic measurement of self-loosening in bolted joints. Proc IMechE, Part C: J Mechanical Engineering Science2011; 226(7): 1869–1884.
33.
DengSWangTTanB, et al. Theoretical and experimental study on FBG bending sensor for quantitative monitoring of bolt looseness. Measurement2023; 216: 113002.
34.
NayakMMGunasekaranNRajannaK, et al. The strain gauge pressure transducers—an overview. IETE Tech Rev2015; 9(2): 170–177.
35.
WangTTanBLuG, et al. Bolt pretightening force measurement based on strain distribution of bolt head surface. J Aerosp Eng2020; 33(4): 04020034.
36.
LiDNieJ-HWangH, et al. Loading condition monitoring of high-strength bolt connections based on physics-guided deep learning of acoustic emission data. Mech Syst Signal Process2024; 206: 110908.
37.
AmeriniFMeoM. Structural health monitoring of bolted joints using linear and nonlinear acoustic/ultrasound methods. Struct Health Monit2011; 10(6): 659–672.
38.
ShinH-JLeeJ-Rand Park C-Y, A novel fiber optic bolt loosening monitoring sensor system for aircraft bolt joints. J Intell Mater Syst Struct2013; 25(5): 647–653.
39.
ChavezJFlindtRGamitM, et al. Testing of strain-based sensorized bolts for loosening detection and condition monitoring. Forschung im Ingenieurwesen2025; 89(1): 27.
40.
YinHWangTYangD, et al. A smart washer for bolt looseness monitoring based on piezoelectric active sensing method. Appl Sci2016; 6(11): 320.
41.
LuHLiangFGouJ. Nanopaper enabled shape-memory nanocomposite with vertically aligned nickel nanostrand: controlled synthesis and electrical actuation. Soft Matter2011; 7(16): 7416–7423.
