Liu Jiahe, Zheng Fangtong, Shen Wei, Li Dongsheng
School of Civil Engineering, Dalian University of Technology, Dalian 116024, China.
China Northeast Architectural Design & Research Institute Co., Ltd., Shenyang 110000, China.
Materials (Basel). 2024 Jun 7;17(12):2792. doi: 10.3390/ma17122792.
Orthotropic steel decks (OSDs) are commonly used in the construction of bridges due to their load-bearing capabilities. However, they are prone to fatigue damage over time due to the cyclic loads from vehicles. Therefore, the early structural health monitoring of fatigue damage in OSDs is crucial for ensuring bridge safety. Moreover, Lamb waves, as elastic waves propagating in OSD plate-like structures, are characterized by their long propagation distances and minimal attenuation. This paper introduces a method of emitting high-energy ultrasonic waves onto the OSD surface to capture the nonlinear Lamb waves formed, thereby calculating the nonlinear parameters. These parameters are then correlated with the fatigue damage endured, forming a damage index (DI) for monitoring the fatigue life of OSDs. Experimental results indicate that as fatigue damage increases, the nonlinear parameters exhibit a significant initial increase followed by a decrease. The behavior is distinct from the characteristic parameters of linear ultrasound (velocity and energy), which also exhibit changes but to a relatively smaller extent. The proposed DI and fatigue life based on nonlinear parameters can be fitted with a Gaussian curve, with the R-squared value of the fitting curve being close to 1. Additionally, this paper discusses the influence of rib welds within the OSDs on the DI, whereby as fatigue damage increases, it enlarges the value of the nonlinear parameters without altering their trend. The proposed method provides a more effective approach for monitoring early fatigue damage in OSDs.
正交异性钢桥面板（OSD）由于其承载能力，常用于桥梁建设。然而，由于车辆的循环荷载，随着时间的推移，它们容易出现疲劳损伤。因此，对OSD疲劳损伤进行早期结构健康监测对于确保桥梁安全至关重要。此外，兰姆波作为在OSD板状结构中传播的弹性波，具有传播距离长和衰减极小的特点。本文介绍了一种在OSD表面发射高能超声波以捕获形成的非线性兰姆波的方法，从而计算非线性参数。然后将这些参数与承受的疲劳损伤相关联，形成用于监测OSD疲劳寿命的损伤指数（DI）。实验结果表明，随着疲劳损伤的增加，非线性参数最初显著增加，随后下降。这种行为与线性超声的特征参数（速度和能量）不同，后者也会发生变化，但程度相对较小。基于非线性参数提出的DI和疲劳寿命可以用高斯曲线拟合，拟合曲线的决定系数（R平方）值接近1。此外，本文还讨论了OSD内的肋焊缝对DI的影响，即随着疲劳损伤的增加，它会增大非线性参数的值，但不改变其趋势。所提出的方法为监测OSD早期疲劳损伤提供了一种更有效的途径。
