Chirp excitation of ultrasonic guided waves
Chirp excitation of ultrasonic guided waves
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DOI：
10.1016/j.ultras.2012.06.010
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发表时间：
2013-01-01
期刊：
影响因子：
4.2
通讯作者：
Wilcox, Paul D.
中科院分区：
文献类型：
--
作者：
Michaels, Jennifer E.;Lee, Sang Jun;Wilcox, Paul D.
大多数超声导波方法需要音调突发激励以在保持时间分辨率的同时获得一定程度的模式纯度。此外，通常希望使用多个频率来获取数据，特别是在方法开发期间，当特定应用的最佳频率未知时。然而，这一过程是不方便和耗时的，特别是当需要在每个激励频率进行广泛的信号平均以获得令人满意的信噪比时。如果测量到来自许多窄带音调突发激励的响应，则获取时间和数据存储要求都可能是令人望而却步的。这里利用线性调频激励来满足在多个频率下进行测试并实现高信噪比以最小化采集时间的需要。利用宽带线性调频进行宽频段数据采集，采用反卷积技术提取多个窄带响应。在对期望的短音激励的频率和持续时间进行优化后，使用长时间的窄带线性调频作为实际激励，并在后处理过程中类似地提取期望的短音响应。结果表明，宽带和窄带啁啾激励都是有效的。(C)2012爱思唯尔B.V.保留所有权利。
Most ultrasonic guided wave methods require tone burst excitations to achieve some degree of mode purity while maintaining temporal resolution. In addition, it is often desirable to acquire data using multiple frequencies, particularly during method development when the best frequency for a specific application is not known. However, this process is inconvenient and time-consuming, particularly if extensive signal averaging at each excitation frequency is required to achieve a satisfactory signal-to-noise ratio. Both acquisition time and data storage requirements may be prohibitive if responses from many narrowband tone burst excitations are measured. Here chirp excitations are utilized to address the need to both test at multiple frequencies and achieve a high signal-to-noise ratio to minimize acquisition time. A broadband chirp is used to acquire data at a wide range of frequencies, and deconvolution is applied to extract multiple narrowband responses. After optimizing the frequency and duration of the desired tone burst excitation, a long-time narrowband chirp is used as the actual excitation, and the desired tone burst response is similarly extracted during post-processing. Results are shown that demonstrate the efficacy of both broadband and narrowband chirp excitations. (C) 2012 Elsevier B. V. All rights reserved.