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

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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.