Yoo Jiung, Song Dong-Gi, Jhang Kyung-Young
Department of Mechanical Convergence Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 04763, Republic of Korea.
Advanced Reactor Technology Development Division, Korea Atomic Energy Research Institute, 111 Daedeok-daero 989beon-gil, Yuseong-gu, Daejeon 34057, Republic of Korea.
Ultrasonics. 2025 Jan;145:107484. doi: 10.1016/j.ultras.2024.107484. Epub 2024 Sep 30.
The acoustic nonlinearity parameter is determined from the amplitudes of the fundamental and second harmonic component of the acoustic wave propagating through the material. However, the generally used through-transmission based measurements with PZT transducers contain high system nonlinearity, so that the received second harmonic component includes an extra component caused by the transducer, which significantly decrease the reliability of measurements. In this study, we proposed a novel method to reduce the system nonlinearity in the conventional through-transmission based measurements by adding a simple process in which the transmitting and receiving transducers are in direct contact without a specimen. The proposed method was experimentally validated for two materials, Al6061-T6 and Fused Silica. For both materials, several specimens with different thickness were prepared, and the measurement results showed that the magnitude of the second harmonic was proportional to the thickness, but there was an offset due to system nonlinearity. On the other hand, after applying the proposed technique, the offsets were greatly reduced, and furthermore, this performance was maintained even when the transducer setup was changed, and the ratio of nonlinearity parameters measured for the two materials was in good agreement with the known literature value.
声学非线性参数是由在材料中传播的声波的基波和二次谐波分量的振幅确定的。然而，通常使用基于PZT换能器的穿透传输测量包含高系统非线性，使得接收到的二次谐波分量包括由换能器引起的额外分量，这显著降低了测量的可靠性。在本研究中，我们提出了一种新方法，通过添加一个简单的过程来降低传统穿透传输测量中的系统非线性，在该过程中，发射和接收换能器直接接触而不放置样品。所提出的方法在Al6061-T6和熔融石英两种材料上进行了实验验证。对于这两种材料，制备了几种不同厚度的样品，测量结果表明二次谐波的幅度与厚度成正比，但由于系统非线性存在偏移。另一方面，应用所提出的技术后，偏移量大大减小，而且，即使换能器设置改变，这种性能仍能保持，并且两种材料测量的非线性参数比值与已知文献值吻合良好。
