Guillermic R-M, Lanoy M, Strybulevych A, Page J H
Department of Physics & Astronomy, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada.
Department of Physics & Astronomy, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada.
Ultrasonics. 2019 Apr;94:152-157. doi: 10.1016/j.ultras.2018.10.002. Epub 2018 Oct 3.
Having a material that is matched in acoustic impedance with the surrounding medium is a considerable asset for many underwater acoustic applications. In this work, impedance matching is achieved by dispersing small, deeply subwavelength sized particles in a soft matrix, and the appropriate concentration is determined with the help of Coherent Potential Approximation and Waterman & Truell models. We show experimentally the validity of the models using mixtures of Polydimethylsiloxane (PDMS) and TiO particles. The optimized composite material has the same longitudinal acoustic impedance as water and therefore the acoustic reflection coefficient is essentially zero over a wide range of frequencies (0.5-6 MHz). PDMS-based materials can be cured in a mold to achieve desired sample shape, which makes them very easy to handle and to use. Various applications can be envisioned, such the use of impedance-matched PDMS in the design and fabrication of acoustically transparent cells for samples, perfectly matched layers for ultrasonic experiments, or superabsorbing metamaterials for water-borne acoustic waves.
对于许多水下声学应用而言，拥有一种声阻抗与周围介质相匹配的材料是一项相当大的优势。在这项工作中，通过将尺寸远小于亚波长的小颗粒分散在软质基体中来实现阻抗匹配，并借助相干势近似以及沃特曼和特鲁尔模型确定合适的浓度。我们通过实验证明了使用聚二甲基硅氧烷（PDMS）和TiO颗粒混合物时这些模型的有效性。优化后的复合材料具有与水相同的纵向声阻抗，因此在很宽的频率范围（0.5 - 6兆赫）内声反射系数基本为零。基于PDMS的材料可以在模具中固化以获得所需的样品形状，这使得它们非常易于处理和使用。可以设想各种应用，例如在设计和制造用于样品的声学透明单元、超声实验的完美匹配层或用于水中声波的超吸收超材料时使用阻抗匹配的PDMS。
