弹性楔波理论及其光学测试研究

项目名称： 弹性楔波理论及其光学测试研究

项目编号： No.11274175

项目类型： 面上项目

立项/批准年度： 2013

项目学科： 数理科学和化学

项目作者： 沈中华

作者单位： 南京理工大学

项目金额： 88万元

中文摘要： 楔形体弹性导波是一种沿楔形体顶端传播的导波,其低相速，能量集中等特征使其在信号处理器件、生物化学传感器、无损检测与评价等方面具有很好的潜在应用价值。本项目拟从实验和理论两个方面研究激光在楔体激发产生的楔波的特性。理论上，拟建立沿平行于楔顶线方向传播的导波模型。通过系统的理论分析，研究楔波、楔顶区附近导波的模态分布、能量分布及模态转换等问题，以及它们与楔顶角、楔顶距离等参量之间的关系，并澄清McKenna的薄板近似解的适用范围及与楔顶角的关系。实验方面，利用激光激发和光学探测的方法，研究楔波的色散、模态转化、能量分布及衰减等特征。同时，对沿非直线楔顶传播的楔波进行研究，通过综合考虑曲率与非理想楔顶带来的色散的影响，控制楔波的色散，进而设计可以传播无色散楔波的非直线型楔体结构。本项目的研究成果可以为实现楔波模态、色散等的有效利用和控制提供理论指导和实验依据。

中文关键词： 楔波；色散；截断；曲率；激光剪切干涉

英文摘要： Wedge waves are guided waves propagating along wedge tips, which have much lower velocity than Rayleigh wave, and their energy is tightly confined near the apex about one or two wavelength. On the base of these special characteristics, they can be possibly well applied in signal processing devices, biochemistry sensors, and nondestructive detection. In this project, we aim at investigating the characteristics of wedge waves generated by laser ultrasound technology both theoretically and experimentally. Firstly, wedge waveguide model in which wedge waves propagating parallel to the wedge tip will be built and the mode distribution, energy attenuation and mode transformation near wedge tip will be researched theoretically. Meanwhile, we will study the effect of the angle of wedge tip and the distance from the wedge tip on the mode and energy and determine the limitation of McKenna's thin plate theory. Then pulsed laser excitation and optical deflection beam method will be used to investigate the characteristics of dispersion, mode transformation, energy distribution and attenuation in experiment. By considering the dispersion brought by curvature and non-perfect wedge tip, then we will control the dispersion and design non-linear wedge on which wedge waves propagate with non-dispersion. The results of the project

英文关键词： wedge waves；dispersion；truncation；curvature；laser shearing interferometry