Contactless Characterization of Distributed Damage in Concrete Using Diffuse Surface Wave Scattering

提出了开发非接触式超声表面波传播传感系统，可以监测大型混凝土结构的结构健康，如安全壳结构在核电厂。非接触式系统具有很高的潜力，是有用的，在这种结构中的损伤的特征，因为许多数据可以有效地收集在一个大的区域。该项目的目标是传递和感知超声波的传播，可以检测混凝土内部的表面和内部裂缝损坏。其结果将使关键大型基础设施系统的快速测试、扫描和表征的新能力成为可能。研究工作将通过创建新的传感和测试能力，以及对此类材料中波的传播和散射的更完整的理解来进行。控制混凝土样品将在实验室进行测试，以表征和解释波散射特征。本研究的目的是提高表面波传播和散射在混凝土中的分布损伤的扩散波方法的基本理解，并提供一个新的能力，完全非接触式超声混凝土的审讯。这些目标将通过一系列协调一致的实验来实现。在这项工作的过程中，超声波表面波将部署在混凝土中使用非接触式扫描设置和结果将被解释使用一种新的“中频”漫散射方法，重点是开裂损伤和孔隙度。研究工作分为两项任务：（a）建立新的传感和测试能力，实施新的微机电机（MEMS）传感器，以检测泄漏表面波和（B）的特点和解释观察到的波散射功能，使用控制混凝土样品。与橡树岭国家实验室的合作将加强多学科的研究生和本科生教育。

It is proposed to develop contactless ultrasonic surface wave propagation sensing system that can monitor structural health of large concrete structures, such as containment structures in a nuclear power plant. Contactless systems have high potential of being useful in characterizing damage in such structures because many data can be collected efficiently over a large area. The goal of the project is to impart and sense propagation of ultrasonic waves that can detect surface and internal cracking damage inside the concrete. The results will enable new capabilities for rapid testing, scanning and characterization of critical large infrastructure systems. The research effort will be pursued by creating new sensing and testing capability, and a more complete understanding of wave propagation and scattering in such materials. Controlled concrete samples will be tested in the laboratory to characterize and interpret wave scattering features. The objectives of this research are to improve fundamental understanding of surface wave propagation and scattering in concrete with distributed damage using a diffuse wave approach and to provide a new capability for completely contactless ultrasonic interrogation of concrete. These objectives will be accomplished through a coordinated set of experiments. In the course of this effort, ultrasonic surface waves will be deployed in concrete using a contactless scanning set up and the results will be interpreted using a new 'mid-frequency' diffuse scattering approach with a focus on cracking damage and porosity. The research effort is divided into two tasks: (a) Create new sensing and testing capability implementing new micro-electro-mechanical machine (MEMS) sensors to detect leaky surface waves and (b) Characterize and interpret observed wave scattering features using controlled concrete samples. Collaboration with Oak Ridge National Laboratory will enhance multidisciplinary graduate and undergraduate education.