Evaluation of Closed Cracks by Model Analysis of Subharmonic Ultrasound
Evaluation of Closed Cracks by Model Analysis of Subharmonic Ultrasound
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DOI：
10.1143/jjap.43.3082
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发表时间：
2004-05
影响因子：
1.5
通讯作者：
K. Yamanaka;T. Mihara;T. Tsuji
中科院分区：
文献类型：
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作者：
K. Yamanaka;T. Mihara;T. Tsuji
如果固体中的裂纹是开放的，则可以通过超声波检测到。然而，当它们在闭合应力下闭合时，它们的检测是不容易的，因此这是超声检测中的基本问题。与输入频率的一半的次谐波是潜在的有用的检测和评估这种裂纹，虽然尚未建立定量分析。在这项工作中，我们开发的分析和数值理论占裂纹参数，如闭合应力和裂纹表面条件，为第一次。我们证明了他们的有效性与实验比较，在铝合金中定义的疲劳裂纹，找到合理的协议。在此基础上，通过将实测波形与理论预测值进行拟合，可以估计出部分闭合裂纹的重要参数，解决了裂纹超声检测中的根本问题。
Cracks in solids can be detected by ultrasound if they are open. However, their detection is not easy when they are closed with a closure stress, and thus it is a fundamental problem in ultrasonic testing. Subharmonics with half the input frequency is potentially useful in the detection and evaluation of such cracks, although quantitative analysis has not been established. In this work, we develop analytical and numerical theories accounting for the crack parameters, such as closure stress and crack surface conditions, for the first time. We proved their validity by comparison with experiments on a well-defined fatigue crack in aluminum alloy, finding reasonable agreements. Based on these theories, it will be possible to estimate important parameters of partially closed cracks by fitting measured waveforms to theoretical predictions, which solves the fundamental problem in ultrasonic testing of cracks.