Dynamics and vibrations of structures with bonded piezoelectric strips subjected to mechanical and unsteady aerodynamic loads

Abstract

This article presents an analysis of the dynamics of damaged structures with bonded piezoelectric strips executing flexural oscillations generated by mechanical loads, piezoelectric actuators or unsteady aerodynamic loads. These oscillations can be used to detect the presence of cracks for structural health monitoring. The proposed method of crack detection uses pairs of piezoelectric strip sensors bonded on the opposite sides of the structure and is based on the fact that the presence of a crack causes a difference between the strains measured by the two sensors of a pair. The structural analysis presented in this article uses a non-linear model for the cracks and a finite-element formulation for the piezoelectric strips coupled with the structure. A panel method is used to determine the unsteady aerodynamic loads acting on the oscillating wing structure. This study includes the dynamic analysis in the frequency domain of a cracked plate undergoing forced flexural vibrations in a range of frequencies generated by a pair of piezoelectric actuators. The dynamic analysis in the time domain is also performed for the oscillating structures with piezoelectric strips subjected to mechanical or unsteady aerodynamic loads. It was found that this method is quite effective in detecting cracks in the wing structures subjected to oscillatory aerodynamic loads.