| 摘要: |
| 超声Lamb波被广泛用于薄板状结构的损伤检测，其频散特性为损伤信号特征参数的提取增加了难度，因此提出HHT方法对时域的Lamb波进行频域转换，以提取信号的能量和时间特征。首先，介绍了Lamb信号的特性及生成方式；其次，详细说明希尔伯特-黄变换(HHT)的实现方法及步骤，用Matlab进行了算法实现，获得Lamb波信号的Hilbert谱、瞬时能量密度谱和边际谱；最后，通过复合材料结构的损伤实验，分别对损伤前后的结构检测信号进行HHT变换，〖JP2〗提取信号的能量参数和时间参数，对比分析证明HHT能有效提取损伤前后信号的能量衰减和时间延迟信息，为下一步进行损伤程度和位置的识别提供了数据依据。 |
| 关键词: Lamb波 结构损伤检测 HHT 频域转换 能量衰减 |
| DOI： |
| 分类号: |
| 基金项目: |
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| Application of HHT for Extracting Characteristic Parameter of Lamb Wave |
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ZHANG Yan
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Jincheng College，Nanjing University of Aeronautics and Astronautics, Nanjing 211156，China
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| Abstract: |
| Lamb wave is widely used for damage detection of laminated structure.The dispersion characteristic of Lamb wave complicates the signal analysis procedure and this phenomena also brings difficulties in characteristic parameter extraction during damage detection.It is necessary to use a suitable time-frequency domain conversion method for the Lamb wave. Firstly， the propagation property and generation mode of Lamb are presented. Then Hilbert-Huang Transform (HHT) is introduced in detail in order to extract the Hilbert spectrum， instantaneous energy density spectrum and marginal spectrum of Lamb wave signal by Matlab. Finally， HHT is used to analyze the signals which are collected in the experiment before and after damage in order to extract characteristic parameter about energy and time. The experiment results and comparative analysis show that HHT is suitable to extract the energy attenuation and time delay information of the signal before and after the damage， which provides the data basis for the next step to identify the damage degree and location. |
| Key words: Lamb wave structural damage detection HHT frequency domain conversion energy attenuation |
