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

提出了开发非接触式超声波表面波传播传感系统，用于监测核电站安全壳等大型混凝土结构的结构健康状况。非接触式系统在表征这类结构的损伤方面具有很高的潜力，因为可以在大范围内高效地收集许多数据。该项目的目标是传递和检测超声波的传播，以检测混凝土表面和内部的裂缝损伤。结果将使关键大型基础设施系统的快速测试、扫描和表征具有新的能力。研究工作将通过创造新的传感和测试能力，以及更全面地了解波在这种材料中的传播和散射来进行。受控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。这项研究的目的是利用扩散波方法提高对表面波在混凝土中的传播和散射的基本认识，并为混凝土的完全非接触式超声波检测提供新的能力。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，超声波表面波将使用非接触式扫描装置部署在混凝土中，结果将使用新的“中频”扩散散射方法进行解释，重点是裂缝损伤和孔洞。研究工作分为两项任务：(A)创造新的传感和测试能力，实施新的微电子机械(MEMS)传感器来检测泄漏表面波；(B)使用受控混凝土样品来表征和解释观测到的波散射特征。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.