Mechanical Systems and Signal Processing ( IF 8.4 ) Pub Date : 2021-05-30 , DOI: 10.1016/j.ymssp.2021.108054 Xiaoshu Qin , Chang Peng , Gaozheng Zhao , Zengye Ju , Shanshan Lv , Mingshun Jiang , Qingmei Sui , Lei Jia
Structural health monitoring (SHM) has played a crucial role in continuously assuring adequate integrity across equipment, especially early loosening estimation of bolt joints. Recently, the vibro-acoustic modulation (VAM) technique for bolt early loosening monitoring has received much attention due to its high sensitivity to contact-type defects. However, the current early loosening monitoring mostly focuses on the bolt head and interconnecting component loosening while ignoring the earlier loosening stage. The central contribution of this work is to develop full life-cycle monitoring for bolt loosening and consequently achieve even earlier warning in the stage of thread loosening. Firstly, regarding the bolt joints in the sand spreading device of high-speed trains, a modified VAM method, in which the designed sensor layout is more applicable for engineering and a swept signal is applied as a probing wave to overcome the dependence of detection accuracy on the exact resonance frequency excitation, is conducted for the full life-cycle monitoring. Secondly, the mechanisms, performances and dependency on the applied torques of the loosening-induced nonlinearity are explored with the proposed nonlinear indexes, theoretically and experimentally. The results demonstrate that both the nonlinear elastic mechanism and the amplitude-dependent dissipation effect contribute to such nonlinearity. Further analysis suggests two valuable and not yet mentioned findings: 1) there is a thread loosening stage that exhibits sufficiently sensitive nonlinear modulation index variations to predict bolt early looseness before the bolt head and interconnecting component loosening; 2) such nonlinear indexes are non–monotonically related to the torque levels in both the above two loosening stages, consistent with theory. Further, such full life-cycle monitoring is achieved by associating such nonlinear indexes and a linear transmitted energy index. All of the obtained results will aid in understanding the nonlinear symptoms under various bolt tightening levels and further improving the reliability of the VAM-based bolt early loosening monitoring.
中文翻译:
使用改进的振动声学调制对螺栓接头松动进行全生命周期监测和预警
结构健康监测 (SHM) 在持续确保整个设备的完整性方面发挥了至关重要的作用,尤其是螺栓接头的早期松动估计。近年来,用于螺栓早期松动监测的振动声调制(VAM)技术由于对接触型缺陷的敏感性高而受到了广泛的关注。然而,目前 早期的松动监测多 集中在 螺栓头和连接件 松动上, 而忽视了螺栓头和连接件松动。 较早的松动阶段。这项工作的核心贡献是开发螺栓松动的全生命周期监控,从而在螺纹松动阶段实现更早的预警。首先,针对高速列车喷砂装置中的螺栓接头,提出了一种改进的VAM方法,该方法设计的传感器布局更适合工程应用,并且将扫频信号用作探测波,从而克服了检测精度的依赖性。在精确的共振频率激励下,进行全生命周期监测。其次,利用所提出的非线性指标,从理论上和实验上探讨了松动引起的非线性的机制、性能和对施加扭矩的依赖性。结果表明,非线性弹性机制和振幅相关耗散效应都有助于这种非线性。进一步的分析提出了两个有价值但尚未提及的发现:1)存在一个螺纹松动阶段,表现出足够敏感的非线性调制指数变化,以预测螺栓头和互连部件之前的螺栓早期松动 松动;2) 这种非线性指标与上述两个松动阶段的扭矩水平非单调相关,与理论一致。此外,通过关联这样的非线性指标和线性传输能量指标来实现这种全生命周期监测。所有获得的结果将有助于了解各种螺栓拧紧水平下的非线性症状,并进一步提高基于 VAM 的螺栓早期松动监测的可靠性。