The core of structural health monitoring is to provide a real-time monitoring, inspection, and damage detection of structures. As one of the most promising technology to structural health monitoring, the Lamb wave method has attracted interest because it is sensitive to small-scale damage with a long detection range. However, in many real-world structural health monitoring applications, the nature of the problem implies structures work under normal condition in most of its operating phases; therefore, classes of data collected are not equally represented. The predictive capability of damage detection algorithms may significantly be impaired by class imbalance. This article presents a damage detection method using imbalanced inspection data which is collected through Lamb wave detection. Aiming at maximizing detection accuracy, an improved synthetic minority over-sampling technique using three-point triangle (triangle synthetic minority over-sampling technique) is proposed to conduct the over-sampling procedure and increase the number of minority samples. The iterative-partitioning filter is employed to remove the noisy examples which may be introduced by triangle synthetic minority over-sampling technique. Three conventional classification methods, namely, support vector machine, decision tree, and k-nearest neighbor, are used to perform the damage detection. A fatigue crack detection test using Lamb wave is performed to demonstrate the overall procedure of the proposed method. Three damage sensitive features, namely, normalized amplitude, correlation coefficient, and normalized energy, are extracted from signals as datasets. A cross-validation is performed to verify the performance of the proposed method for crack size identification.

结构健康监控的核心是提供对结构的实时监控，检查和损坏检测。作为结构健康监测的最有前景的技术之一，兰姆波法引起了人们的兴趣，因为它对检测范围长的小规模损伤敏感。但是，在许多实际的结构健康监视应用程序中，问题的性质意味着结构在大多数操作阶段都在正常条件下工作。因此，收集的数据类别不能平等地代表。类别不平衡可能会严重损害损坏检测算法的预测能力。本文提出了一种使用不平衡检验数据的损坏检测方法，该检验数据是通过Lamb波检测收集的。为了最大程度地提高检测精度，提出了一种改进的利用三点三角形的合成少数采样技术（三角合成少数采样技术）来进行过采样程序，并增加少数采样的数量。迭代分配滤波器用于去除可能由三角合成少数过采样技术引入的噪声示例。三种传统的分类方法，即支持向量机，决策树和k最近邻法，用于执行损伤检测。进行了使用兰姆波的疲劳裂纹检测测试，以证明所提出方法的总体过程。从信号中提取三个损伤敏感特征，即归一化幅度，相关系数和归一化能量作为数据集。