含气泡软媒质中的声传播特性研究

项目名称： 含气泡软媒质中的声传播特性研究

项目编号： No.10804050

项目类型： 青年科学基金项目

立项/批准年度： 2009

项目学科： 金属学与金属工艺

项目作者： 梁彬

作者单位： 南京大学

项目金额： 24万元

中文摘要： 软媒质作为一类特殊固体，含气泡后表现出极为独特的声学特性。含气泡软媒质在科研及应用中十分常见并具有重大应用背景，但其特有的声学特性尚未得到足够重视，例如非线性时变特性及局域化现象等均属全新研究领域。本项目以含随机分布气泡的软媒质为研究对象，目的是深化对此类媒质中声传播的物理机制的认识，并为含气泡软媒质的各种实际应用提供指导。 针对含气泡软媒质特有的强非线性等性质，本项目将利用自洽场方法以及解析方法进行研究，并部分结合其他数值方法，着重研究下列问题：1.建立并完善可正确描述含气泡软媒质非线性时变特性的等效媒质理论；2.研究声波在含气泡软媒质中发生局域化的物理机制及存在条件，并提出有效的鉴别方法；3.分析此类媒质组成的复合结构中的波动问题，设计特殊声学功能材料并提出优化材料性能的高效数值算法。

中文关键词： 气泡;软媒质;粘弹性;声传播

英文摘要： It is of both academic and practical significance to investigate the unique acoustic properties of soft media containing gas bubbles, a special kind of solid media that applies to a variety of important situations in scientific researches and practical applications. However relevant investigations still lack despite of their usefulness,such as the researches of the dynamical nonlinearity and the phenomenon of acoustic localization of bubbly soft media. The principal purposes of the present research are to study the propagation of acoustic waves in soft media containing randomly-distributed bubbles as well as to provide theoretical methodologies for the practical applications of such media. In this study we shall particularly accomplish three primary aspects of goals by employing the analytical and the numerical methods such as self-consistent approaches,as follows: 1. to develop and improve the effective-medium theory that accurately describes the dynamical nonlinearity of soft medium containing bubbles; 2. to study the physical mechanism and the existent condition for the phenomenon of acoustic localization in such media, and to present effective methods for identifying the existence of the localization phenomenon; 3. to design and fabricate the acoustic functional materials and to develop numerical algorithms that effectively improve their acoustic performance in an optimal manner, on the basis of proper analysis of the acoustic propagation in the composite structures consist of such media.

英文关键词： bubbles; soft medium; viscoelasticity; acoustic propagation