Nikolaev Dmitry A, Tsysar Sergey A, Khokhlova Vera A, Kreider Wayne, Sapozhnikov Oleg A
Physics Faculty, Moscow State University, Leninskie Gory, Moscow 119991, Russia.
Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, University of Washington, 1013 Northeast 40th Street, Seattle, Washington 98105, USA.
J Acoust Soc Am. 2021 Jan;149(1):386. doi: 10.1121/10.0003212.
For the acoustic characterization of materials, a method is proposed for interpreting experiments with finite-sized transducers and test samples in terms of the idealized situation in which plane waves are transmitted through an infinite plane-parallel layer. The method uses acoustic holography, which experimentally provides complete knowledge of the wave field by recording pressure waveforms at points on a surface intersected by the acoustic beam. The measured hologram makes it possible to calculate the angular spectrum of the beam to decompose the field into a superposition of plane waves propagating in different directions. Because these waves cancel one another outside the beam, the idealized geometry of an infinite layer can be represented by a sample of finite size if its lateral dimensions exceed the width of the acoustic beam. The proposed method relies on holograms that represent the acoustic beam with and without the test sample in the transmission path. The method is described theoretically, and its capabilities are demonstrated experimentally for silicone rubber samples by measuring their frequency-dependent phase velocities and absorption coefficients in the megahertz frequency range.
为了对材料进行声学表征，提出了一种方法，用于根据平面波透过无限平面平行层的理想化情况来解释使用有限尺寸换能器和测试样品的实验。该方法采用声学全息术，通过记录与声束相交的表面上各点的压力波形，实验上可提供波场的完整信息。测得的全息图使得能够计算声束的角谱，从而将场分解为沿不同方向传播的平面波的叠加。由于这些波在声束外相互抵消，如果有限尺寸样品的横向尺寸超过声束宽度，则无限层的理想化几何形状可用该有限尺寸样品来表示。所提出的方法依赖于在传输路径中有和没有测试样品时表示声束的全息图。从理论上描述了该方法，并通过测量硅橡胶样品在兆赫兹频率范围内与频率相关的相速度和吸收系数，对其实验能力进行了验证。
