Hu Chaojie, Yang Bin, Xuan Fu-Zhen, Yan Jianjun, Xiang Yanxun
School of Mechanical and Power Engineering, East China University of Science and Technology, No. 130 Meilong Road, Shanghai 200237, China.
Sensors (Basel). 2020 Feb 5;20(3):849. doi: 10.3390/s20030849.
s: In this paper, the guided wave propagation behavior in damaged 30CrMo steel curved plates was investigated experimentally and numerically. The effects of the notch orientation, depth in the curved plate, as well as its radius, on the wave propagation characteristics were mainly analyzed by the amplitude distribution curves and the directivity diagrams of A0/S0 (zero-th order of the symmetric/antisymmetric Lamb wave) modes. An ellipse-based algorithm was compiled to locate the notches in the curved plates. Results show that the normalized S0 wave amplitude in the circumferential orientation was the largest, and it increases as notch depth increases in the axial orientation. The A0 wave amplitude in axial orientation was the largest, while it decreases with the increasing of notch depth in the other orientations. The normalized A0 wave amplitude in axial orientation increases with the increasing of radius. With the increasing of radius, the other normalized A0/S0 amplitudes linearly decreased for the other paths. The ellipse-based algorithm has high notch localization accuracy, and the notch localization error increase from 0.005% to 1.47% with the notch depth decreasing from 5 mm to 1 mm in the curved plates. For the curved plates with different radius, the maximum notch localization error is 1.20%. These satisfactory results demonstrate the effectiveness of the developed algorithm in locating damages in the researched structure.
s：本文通过实验和数值模拟研究了损伤30CrMo钢弯板中的导波传播行为。主要通过A0/S0（对称/反对称兰姆波零阶模式）模式的幅度分布曲线和指向性图，分析了缺口方向、弯板深度及其半径对波传播特性的影响。编制了一种基于椭圆的算法来定位弯板中的缺口。结果表明，周向方向上归一化的S0波幅度最大，且在轴向方向上随着缺口深度的增加而增大。轴向方向上A0波幅度最大，而在其他方向上随着缺口深度的增加而减小。轴向方向上归一化的A0波幅度随半径的增加而增大。随着半径的增加，其他路径上归一化的A0/S0幅度呈线性下降。基于椭圆的算法具有较高的缺口定位精度，在弯板中，随着缺口深度从5mm减小到1mm，缺口定位误差从0.005%增加到1.47%。对于不同半径的弯板，最大缺口定位误差为1.20%。这些令人满意的结果证明了所开发算法在定位研究结构损伤方面的有效性。
