Abstract
Structural health monitoring (SHM) is emerging as an essential tool for constant monitoring of safety-critical engineering components. Ultrasonic guided waves stand out because of their ability to propagate over long distances and because they can offer good estimates of location, severity, and type of damage. The unique properties of the fundamental shear horizontal guided wave (SH0) mode have recently generated great interest among the SHM community. The aim of this paper is to demonstrate the feasibility of omnidirectional SH0 SHM in a thin aluminum plate using a three-transducer sparse array. Descriptions of the transducer, the finite element model, and the imaging algorithm are presented. The image localization maps show a good agreement between the simulations and experimental results. The SH0 SHM method proposed in this paper is shown to have a high resolution and to be able to locate defects within 5% of the true location. The short input signal as well the non-dispersive nature of SH0 leads to high resolution in the reconstructed images. The defect diameter estimated using the full width at half maximum was 10 mm or twice the size of the true diameter.
Highlights
Structural health monitoring (SHM) is rapidly emerging as an essential tool for continuous monitoring of safety-critical engineering components
This paper demonstrated the feasibility of an SH0 sparse array SHM system on a thin aluminum plate
The non-dispersive nature of SH0 combined with a broadband transducer enabled the use of a very short input signal. This resulted in high-resolution images and accurate defect localization
Summary
Structural health monitoring (SHM) is rapidly emerging as an essential tool for continuous monitoring of safety-critical engineering components. In a typical SHM system, transducers are permanently installed so as to enable periodic assessment of the structure. From a comparison of features in the signals acquired at different times, damages can be detected. The recent development of the SHM system will soon become the cornerstone in changing from scheduled maintenance to condition-based maintenance. SHM can be performed using a vast array of methods, e.g., acoustic emission and fiber Bragg grating [1]. Ultrasonic guided waves stand out because of their ability to propagate over long distances and because they can offer good estimates of location, severity, and type of damage [2,3]
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