基于压电智能垫片的木结构螺栓松动监测方法探索OA

Quantification of bolt loosening in engineered timber structures is challenging,and existing structural damage identification methods based on piezoelectric ceramic sensors,which are directly bonded to the structural surface,are susceptible to environmental variations with degrading sensor performance.To address these issues,a piezoelectric ceramic smart washer was developed to replace conventional washers in bolted connections for evaluating the reliability of bolted joints.The working principle and fabrication method of the smart washer were introduced.Experimental results show that the smart washer exhibits stable performance,with the maximum mean absolute percentage error(MAPE)of its impedance curves under varying temperature and humidity conditions being less than 2％.Under experimental conditions,validation tests were conducted on timber members with both parallel-to-grain and perpendicular-to-grain connections.By analyzing the signal strength received by the smart washer under various bolt preload torques,a linear correlation was established between the preload torque and both the maximum amplitude and energy of the piezoelectric signal.For a single bolt,the preload torque and the degree of loosening can be assessed based on the maximum amplitude and energy of the signal received by the smart washer.Furthermore,finite element simulations using ABAQUS reveal that the dominant portion of signal energy in timber bolted joints propagates along the bolt shank.These results indicate that the piezoelectric ceramic smart washer can be embedded within timber bolted connections to acquire real-time piezoelectric signals,which can be directly converted to evaluate the interfacial tightness between connected timber members.