Nonlinear ultrasonic phased array with fixed-voltage fundamental wave amplitude difference for high-selectivity imaging of closed cracks.
Nonlinear ultrasonic phased array with fixed-voltage fundamental wave amplitude difference for high-selectivity imaging of closed cracks.
复制标题
具有固定电压基波幅度差的非线性超声相控阵用于闭合裂纹的高选择性成像。
DOI：
10.1121/1.5116017
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
T. Mihara
中科院分区：
文献类型：
--
作者：
Y. Ohara;Hiromichi Nakajima;S. Haupert;T. Tsuji;T. Mihara
闭合裂纹的无损检测是超声检测中一个具有挑战性的课题。最近，具有固定电压基波幅度差的非线性超声相控阵（固定电压FAD）已被提出作为一种实用的方法。在这项研究中，最大入射波振幅，这是一个最关键的参数在闭合裂纹成像，进行了研究。首先，建立了一个理论模型，明确地说明了FAD的基本原理和固定电压FAD相对于不同电压FAD的优势。在实验中，作者成像一个封闭的疲劳裂纹使用非线性超声相控阵与固定电压FAD，而不同的入射波振幅。结果表明，当入射波幅值足够大时，非线性图像显示出闭合的裂纹尖端，而线性图像不能显示。此外，入射波振幅依赖的非线性响应进行了量化。结果表明，疲劳裂纹的不同部位表现出不同的非线性行为。这表明，固定电压FAD是有用的，不仅在实际应用中的闭合裂纹成像，但也用于检查在不同部分的闭合裂纹的非线性动力学与高的空间分辨率。
The nondestructive evaluation of closed cracks is a challenging subject in ultrasonic testing. Recently, nonlinear ultrasonic phased array with fixed-voltage fundamental wave amplitude difference (fixed-voltage FAD) has been proposed as a practical approach. In this study, the maximum incident wave amplitude, which is one of the most critical parameters in closed-crack imaging, was investigated. First, a theoretical model was formulated to explicitly show the essence of the fundamental principle of FAD and the advantage of fixed-voltage FAD over different-voltage FAD. In experiments, the authors imaged a closed fatigue crack using a nonlinear ultrasonic phased array with fixed-voltage FAD while varying the incident wave amplitude. It was found that when the incident wave amplitude was sufficiently high, the nonlinear image visualized the closed crack tip, which could not be visualized in linear images. In addition, the incident-wave-amplitude dependence of the nonlinear responses was quantified. It was found that different parts within a single fatigue crack showed different nonlinear behaviors. This suggests that fixed-voltage FAD is useful not only for practical application of closed crack imaging but also for examining the nonlinear dynamics at various parts of closed cracks with a high spatial resolution.