对于地脚螺栓之类螺栓本体埋藏于结构中的螺栓联接装置,提出了一种将压电材料粘贴于螺母外侧面并通过测量压电阻抗峰值频率变化来反映螺栓联接状态的监测方法.结合有限元仿真,理论分析了该方法的基本原理.构建实验装置,实验以螺栓联接结构中螺母作为对象,采用万能材料拉伸试验机对螺栓联接结构进行加载,模拟螺母所受预紧力,并在不同预紧力下测量了粘贴在螺母侧面的压电材料的导纳信号,提取了其峰值频率,得到峰值频率随预紧力的变化规律.结果表明压电材料的导纳峰值频率随着螺栓预紧力增大而增大,且预紧力大小变化与频率变化成一定的线性关系,提出以峰值频率表征螺栓联接状态的方法,该方法具有较好的应用前景.%For bolt connection device such as anchor that the bolt is buried in the structure,a piezoelectric imped-ance frequency shift method with the piezoelectric patch on the outer side of the nut is proposed to monitor the bolt connection status. Combined with the finite element simulation,the basic principle of the method is analyzed theo-retically. The experimental device is established. The nut of the bolted joint is used as the object in the experiment. The piezoelectric patch is bonded on the outer side of the nut. The universal tensile testing machine is used to apply the required load on the bolted joint precisely to simulate the preload force on the nut precisely. The admittance sig-nals of the piezoelectric patch are measured under different preload and the peak frequency in the admittance signal is extracted as the feature parameter of bolt pre-tightening force. The experimental results show that the admittance peak frequency of piezoelectric patch increases with the increase of bolt preload,and the linear relationship between the preload and frequency changes shows that this method has a good application prospect.
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