Han Cong, Yang Guoan, Wang Jianye, Guo Xiaoshuai
College of Mechanical and Electrical Engineering, Beijing University of Chemical Technology, Beijing 100029, China.
Ultrasonics. 2020 Dec;108:106177. doi: 10.1016/j.ultras.2020.106177. Epub 2020 May 22.
Mechanical equipment with the stiffener has a strong interference with the propagation of acoustic emission (AE) signals from faults, reducing the accuracy of fault detection. This paper conducts an in-depth study of the interaction between AE signals and the stiffener. The installation constraints, that can separate the direct signal, signals scattered from the stiffener and signals reflected from the boundary in the time domain, for sensors are deduced based on the multipath propagation model of AE signals in the stiffened plate. On this basis, the scattering characteristics of AE signals with different frequencies in different height stiffened plates are predicted by simulations. Moreover, the reflection and transmission coefficients are calculated to quantify the scattering characteristics. The results show that the signal, undergoing a "T-shaped" transformation at the stiffener, generates various modes, among which the transmission signal accounted for the largest proportion. In addition, experiments are performed to verify the numerical simulations, and the results are in good agreement with the numerical simulations. This work clarifies the propagation characteristics of AE signals in stiffened plates, and the research can optimize the spatial arrangement for sensors.
带有加强筋的机械设备对故障声发射（AE）信号的传播有很强的干扰，降低了故障检测的准确性。本文对AE信号与加强筋之间的相互作用进行了深入研究。基于AE信号在加筋板中的多径传播模型，推导了能在时域中分离直接信号、从加强筋散射的信号和从边界反射的信号的传感器安装约束条件。在此基础上，通过仿真预测了不同频率的AE信号在不同高度加筋板中的散射特性。此外，计算了反射系数和透射系数以量化散射特性。结果表明，信号在加强筋处经历“T形”变换，产生多种模式，其中透射信号占比最大。此外，进行了实验以验证数值模拟，结果与数值模拟吻合良好。这项工作阐明了AE信号在加筋板中的传播特性，该研究可为传感器的空间布置优化提供依据。
