Evaluation of fatigue damage using nonlinear guided waves
Evaluation of fatigue damage using nonlinear guided waves
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DOI：
10.1088/0964-1726/18/3/035003
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发表时间：
2009-03-01
影响因子：
4.1
通讯作者：
Jacobs, Laurence J.
中科院分区：
文献类型：
--
作者：
Pruell, Christoph;Kim, Jin-Yeon;Jacobs, Laurence J.
这项研究开发了一种使用非线性导波表征金属板疲劳损伤的实验程序。该工作首先考虑了非线性波在色散介质中的传播，并确定了导波中产生高次谐波的理论和实际考虑因素。通过使用非线性光学文献的结果，可以证明相位和群速度匹配对于非线性导弹性波的实际生成至关重要。接下来，用兰姆波测量低周疲劳损伤铝样本的归一化声学非线性。一对楔形换能器用于生成和检测基波和二次谐波兰姆波。结果表明，用兰姆波测量的归一化声学非线性与疲劳损伤直接相关，其方式类似于纵波和瑞利波的行为。然后将这种归一化的声学非线性与测量的累积塑性应变进行比较，以确认这两个参数是相关的，并强化兰姆波可用于使用已建立的高次谐波生成技术来定量评估塑性驱动的疲劳损伤的概念。
This research develops an experimental procedure for characterizing fatigue damage in metallic plates using nonlinear guided waves. The work first considers the propagation of nonlinear waves in a dispersive medium and determines the theoretical and practical considerations for the generation of higher order harmonics in guided waves. By using results from the nonlinear optics literature, it is possible to demonstrate that both phase and group velocity matching are essential for the practical generation of nonlinear guided elastic waves. Next, the normalized acoustic nonlinearity of low cycle fatigue damaged aluminum specimens is measured with Lamb waves. A pair of wedge transducers is used to generate and detect the fundamental and second harmonic Lamb waves. The results show that the normalized acoustic nonlinearity measured with Lamb waves is directly related to fatigue damage in a fashion that is similar to the behavior of longitudinal and Rayleigh waves. This normalized acoustic nonlinearity is then compared with the measured cumulative plastic strain to confirm that these two parameters are related, and to reinforce the notion that Lamb waves can be used to quantitatively assess plasticity driven fatigue damage using established higher harmonic generation techniques.