Electromechanical impedance for SHM of aircraft bolted joints

Abstract

Some problems of the electromechanical impedance (EMI), especially its applications for structural health monitoring of aircraft bolt-joints and innovated approach of EMI prediction at loosening of bolt-joints are objectives of research. The full-scale test was performed using the Mi-8 helicopter tail beam. Effect of bolt-joint loosening was investigated by electromechanical impedance (EMI) method. It was shown that loosening of bolt-joint affects significant and stable changes of EMI parameters. It was assumed that both as the weak shift of resonance frequencies or EMI magnitude and resistance change is caused mainly by damping variation. The developed 2D model of constrained PZT based on modal decomposition approach can be used for analysis of influence of the elastic properties and geometrical parameters to properties of constrained piezoelectric transducer. This model has some advantages and can also be useful for structural health monitoring of aircraft components with different possible damages including bolt-joint loosening. .

Piezoelectric Transducers Assessed by the Pencil Lead Break for Impedance-Based Structural Health Monitoring

“…These characteristics allow for the installation of multiple transducers and for the monitoring of a wide area without significantly changing the mechanical properties of the structure. These features make the EMI method especially attractive for detecting damage in aircraft structures [15], [16], where size and weight are major considerations in the development of SHM systems.…”

Application of the Fatigue Crack Opening/Closing Effect for SHM Using Electromechanical Impedance Technology

“…A large number of EMI models have been developed [20][21][22][23][24][25][26][27]. New type of the EMI model and its application for aircraft structural health monitoring (SHM) was developed in articles [28,29]. There was obtained an expression of the electromechanical impedance common to any dimension of models (1D, 2D, 3D), and directly independent from imposed constraints.…”