Experimental and theoretical analysis in impedance-based structural health monitoring with varying temperature

Abstract

In the recent years, the piezoelectric wafer active sensors (PWASs) are increasing as a measurement tool in structural health monitoring techniques. In impedance-based structural health monitoring (ISHM) method, the electrical impedance of a PWAS bonded to the structure is measured and served as a defect detection index of the structure. The principle of this method is based on the electromechanical coupling effect of PWAS materials. As any change in the structure will lead to a change in mechanical impedance of structure, the electrical impedance of PWAS could sense this change by the electromechanical coupling effect of PWAS. Since the physical and mechanical properties of PWAS materials are temperature-dependent, so the electrical impedance of PWAS will change with varying temperature. Consequently, the changes in environmental or service temperatures could be detected in ISHM method as a defect. In this article, in order to consider the temperature dependency of PWAS material properties, a temperature-dependent model is developed for a PWAS bonded to an Euler Bernoulli cantilever beam. An aluminum (alloy 2024) beam was examined experimentally by ISHM method in order to validate the proposed model. The comparison of theoretical and experimental results demonstrates a good improvement in ISHM modeling where temperature variation is present.

Low-cost simulation using model order reduction in structural health monitoring: Application of balanced proper orthogonal decomposition

“…For modeling of PWAS impedance, charge of PWAS Q(ω) could be calculated by integration of electrical displacement of piezoelectric over area of it . Electrical impedance is defined as …”

“…At high frequencies, the wavelength of the excitation is small, so this method becomes very sensitive and allows detecting minor changes in structure. Sepehry et al proposed and developed theoretical model for a cantilever Euler Bernoulli beam. Giurgiutiu calculated impedance of PWAS applying a continuous model of a beam and plate with PWAS .…”

A new model order reduction method based on global kernelk-means clustering: Application in health monitoring of plate using Lamb wave propagation and impedance method

“…At high frequencies, the wavelength of the excitation is small, so this method is sensitive to minor changes in structure. By considering temperature dependency of the PWAS and structure material properties, Sepehry et al proposed and developed a temperature‐dependent theoretical model for a cantilever Euler–Bernoulli beam. A model based on the mechanical impedances of a 2D structure and PWAS has been proposed by Bhalla and Soh .…”

Mechanical impedance measurement and damage detection using noncontact laser ultrasound

“…For example, the variability of the bonding condition between the piezoelectric transducer and the host structure can deteriorate the robustness and repeatability of EMI measurement [7]. Furthermore, the EMI waveform can be distorted by the cross talk between the excitation and sensing transducers or temperatureinduced variations of transducer capacitance [8].…”