Abstract
Acoustic emission (AE) has been used extensively for structural health monitoring based on the stress waves generated due to evolution of cracks in concrete structures. A major concern while using AE features is that each of them responds differently to the fractures in concrete structures. To tackle this problem, Mahalanobis—Taguchi system (MTS) is utilized, which fuses the AE feature space to provide comprehensive and reliable degradation indicator with a feature selection method to determine useful features. Further, majority of the existing investigations gave little attention to naturally occurring cracks, which are actually more difficult to detect. In this study, a novel degradation indicator (DI) based on AE features and MTS is proposed to indicate the performance degradation in reinforced concrete beams. The experimental results confirm that the MTS can successfully distinguish between healthy and faulty conditions. To alleviate the noise from the DI obtained through MTS, a noise-removal strategy based on Chebyshev inequality is suggested. The results show that the proposed DI based on AE features and MTS is capable of detecting early stage cracks as well as development of damage in concrete beams.
Highlights
Concrete beams are widely used in construction of buildings, dams, and bridges
The proposed method leverages the difference in Acoustic emission (AE) from shear connectors before and after they engage in shear transfer
The AE signals were collected in real time from the experimental setup designed for implementing three-point bending tests on the reinforced concrete beam
Summary
Concrete beams are widely used in construction of buildings, dams, and bridges. Heavy load, aging, disasters like earthquake can cause severe damage to beam in concrete structures. During the fracture process in concrete beams, materials release energy and generate mechanical waves that propagate through the solid These mechanical waves can be detected by mounting AE transducers on surface of the concrete specimen [1,3,4,7,8,9,10,13] and the present condition of the concrete structures can be determined. A lot of previous works have considered AE features extracted through the flexural test conducted on concrete beams Most of these works focus on fault classification (minor/intermediate/severe), crack classification (tensile/shear), fracture identification, analyzing load against AE history, etc. Existing literature lacks in building a solid DI for the degradation assessment of the concrete beams over time To fill this gap and tackle the above challenges, in this paper, Mahalanobis–Taguchi system (MTS) is utilized to fuse the useful AE features and develop the DI [24].
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