Smart Sounding System for Autonomous Evaluation of Concrete and Metallic Structures

Recent research by the proposers has shown that the sounding, such as chirp signal, can be generated by electronic speakers, and their magnitude and frequency can be controlled. Different from the mechanical impact hammers, the electronic sounding is consistent and can be designed with certain frequency characteristics to excite defects in concrete decks. The focus of this research is on development of “Smart Sounding System” that can be used to inspect underdeck and pier surfaces effectively and autonomously. Previous preliminary research has shown that common defects in concrete structures, such as shallow delamination, generally have a resonant response at a relatively low and narrow frequency band of 1 – 3 kHz, whereas solid areas can be excited at much higher frequency ranges. This observation implies that the sounding energy can be designed and focused on the “delamination frequency band” to increase the response of the delamination signal with respect to those from the solid areas. To further improve the efficiency of the detection, components of the sounding tool can be optimized such that sounding speakers and microphone have a similar resonant frequency close to the dominant frequency of the defect area so that the defect will have the “ringing” effect when excited by the sounding tool. For mapping of the inspection area, the “smart sounding system” can be integrated with advanced tracking camera and GPS device. By using the mapping device, no gridding process will be required, which is time-consuming and labor-intensive in the current practice of impact sounding. Preliminary research by the proposers has also shown that the proposed impact sounding tool can also detect hidden cracks and thickness loss in metallic components, such as girders. Outcome of this work will be a versatile electronic sounding tool that could be used to detect damages and delamination in concrete, metallic as well as composite surfaces. The tool will be designed to be incorporated into autonomous systems, such as crawlers