Effective identification of rebar debonding is crucial for health monitoring of reinforced concrete (RC) structures. In this article, a method for detection, localization, and quantification of interfacial debonding based on nonlinear harmonic energy entropy and using a combined surface-bonded and rebar end-mounted smart piezoelectric module system is proposed. The distribution of complex stress wave scattering field and the contact acoustic nonlinear phenomenon in the rebar debonding region are investigated by combining the numerical finite element analysis and experimental test, which reveal the energy distribution characteristics of nonlinear harmonics. The rebar debonding in RC structures is for the first time identified using the energy entropy as the damage indicator. The changing law of nonlinear harmonic energy entropy at different debonding locations is utilized to perform the identification of interfacial debonding, and at the same time, it eliminates the interference in the traditional wavelet packet analysis caused by the location of sensors. The numerical and experimental verifications of four RC beam specimens with different interfacial debonding lengths demonstrate the effectiveness of the present rebar debonding identification method. The findings from the combined numerical and experimental study manifest the potential of proposed rebar debonding identification method for practical applications.
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