Damage indices evaluation for one-dimensional guided wave-based structural health monitoring

Abstract Damage detection in structures and systems is essential for monitoring parameters that can affect their integrity. This paper evaluates the efficiency of four damage indices (DIs) commonly used with temporal wave signals. The root mean square deviation, mean absolute percentage deviation, covariance, and correlation coefficient deviation DIs are presented, and a normalization is then proposed. An Euler-Bernoulli beam is used as a guided wave modelled with the spectral element method and excited by a toneburst signal. It includes the theoretical background of the throw-off beam, undamaged and cracked beam spectral elements. The DIs for a single crack position and a map varying crack depth and positions are calculated with deterministic and random temporal signal responses derived from noise addition. Results showed that DIs could identify and quantify the damage conditioned to the pulse location point and the influence of noise in the estimation, which leads in an analysis comparable to practical applications.结构与系统的损伤检测，是保障其结构完整性的关键监测环节。本文评估了四类常用于时序波信号的损伤指标（Damage Indices，DIs）的检测效能，所涉指标包括均方根偏差（root mean square deviation）、平均绝对百分比偏差（mean absolute percentage deviation）、协方差（covariance）以及相关系数偏差（correlation coefficient deviation），并提出了一种归一化处理方案。本文采用欧拉-伯努利梁（Euler-Bernoulli beam）作为研究对象，利用光谱元法（Spectral Element Method）对导波（guided wave）进行建模，并通过音猝发信号（toneburst signal）进行激励。本文涵盖了自由梁、无损梁与带裂纹梁的光谱单元的理论背景。本文通过向时序信号中添加噪声得到确定性与随机性信号响应，据此计算了单裂纹位置下的损伤指标，以及裂纹深度与位置均变化的损伤指标分布图。研究结果表明，损伤指标可基于脉冲激励位置点实现损伤的识别与量化，但需考虑噪声对评估结果的影响，该分析结果可与实际应用场景相媲美。