Evaluation of Fatigue Specimens Using EMATs for Nonlinear Ultrasonic Wave Detection
Evaluation of Fatigue Specimens Using EMATs for Nonlinear Ultrasonic Wave Detection
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DOI：
10.1007/s10921-007-0026-9
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发表时间：
2007-10
影响因子：
2.8
通讯作者：
R. Murayama;K. Ayaka
中科院分区：
文献类型：
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作者：
R. Murayama;K. Ayaka
近年来，人们研究了使用非线性超声波方法检测闭合裂纹。该技术基于这样的事实，即当超声波的位移和裂纹的开口宽度几乎相同时，接收到的超声波的波形与入射超声波的波形略有不同。因此，对于入射超声波，其谐波频率分量随着其穿透裂纹而改变。然而，与使用具有高非线性效率的液体介质作为耦合介质时相比，固体材料的非线性非常小。然后，我们试图应用电磁声换能器（EMAT），这不需要耦合介质。此外，我们还尝试开发了一种可以交替驱动S0兰姆波和SH 0板波的电磁超声换能器，以检测不同超声波模式下的非线性。实际上，我们使用我们制造的疲劳试样测试了性能。因此，我们观察到，当我们使用具有特定加载条件和特定超声模式的试样时，谐波分量发生了变化。这说明，这个试验系统也能检测出任何结构、任何材料的损伤程度。
Detection of a closed crack using a nonlinear ultrasonic wave method has been studied in recent years. This technique is based on the fact that the waveform of the received ultrasonic wave is slightly different from that of the incident ultrasonic wave, when the displacement of the ultrasonic wave and the opening width of a crack are almost the same. Therefore, regarding the incident ultrasonic wave, its harmonic frequency components change as it penetrates the crack. However, the nonlinearity of a solid material is very small compared to that when a liquid medium with a high nonlinear efficiency is to be used as the coupling medium. We then attempted to apply an electromagnetic acoustic transducer (EMAT), which does not require a coupling medium. In addition, we tried to develop the EMAT that could alternately drive the S0-Lamb wave and SH0-plate wave to detect any nonlinearity in the different ultrasonic wave modes. We actually tested the performance using fatigue specimens we had fabricated. As a result, we observed that the harmonic components changed when we used the specimen with a specific loading condition and a specific ultrasonic mode. This indicated that the trial system could also detect the degree of damage to any structures or any materials.