The Use of Piezoelectric Thin Film Sensors for Structural Integrity Monitoring

Abstract

This is a review of the work performed at the Defense Science and Technology Organisation, Aeronautical Research Laboratory, Melbourne, Australia and the Department of Mechanical Engineering, Monash University to develop "active" sensor technology using piezoelectric thin films. The initial part of this review outlines a theoretical and experimental investigation on the characterisation of KYNAR piezoelectric thin film sensors. An experimental and theoretical study was then undertaken demonstrating the feasibility of using piezoelectric sensors to detect and monitor crack growth in a cracked aluminium specimen. The work was then extended to include a numerical investigation into the use of piezoelectric sensors to monitor crack growth, in an aluminium structure, beneath a boron/epoxy patch. Finally, the last section describes the use of piezoelectric sensors for detecting impact damage in composite structures. latter takes the form of thin sheets that can be attached to most surfaces. These materials exhibit excellent mechanical strength, low acoustic impedance and possess a flat response over a wide frequency range. Due to their low mechanical impedance a number of piezoelectric films can be distributed along the structure without drastically affecting its mechanical properties. These films can be readily cut and shaped to conform to the structure under consideration.

New trends in non-destructive evaluation in relation to the smart materials concept

“…More simply, due to their sensitivity to the local static strains, thin ® lms of polymeric piezosensors can be used in order to detect and monitor cracks growth on repaired and unrepaired metallic plates as well as in composite structures (Chiu et al 1994). A novel type of piezoelectric sensor has also been developed by sputtering a piezoelectric ® lm on a conductive ® bre.…”

The Process Optimization of Smart Nanostructured AlN Thin Films Sputtered by Pulsed DC

“…The feasibility of using piezoelectric thin film sensors for structural integrity monitoring has been demonstrated for both metallic and composite structures used in MEMS and aeronautical structural systems. [5][6][7][8][9] An engineered 'smart' thin film sensor has been designed to be incorporated within the tribological coating system to further improve the coating performance and multifunctionality of the coating. The piezoelectric layer is embedded to monitor the stress variation within the overall coating system and thus avoid catastrophic failure of the coating.…”

Response of impedance measured by polyvinylidene fluoride film sensors to damage propagation for wind turbine blade

“…Actually, in order to build a better plan for maintenance and avoid further damage, the need for damage detection and health monitoring techniques has been recognized for the engineering structures including the WT blade and the related several techniques, and nondestructive evaluation (NDE) sensors were developed (Chiu et al, 1994;Ciang et al, 2008;Gu et al, 2005;Park and Inman, 2007). Impedance-based structural health monitoring (SHM) technique is a method that has shown a possibility for various structures (Park and Inman, 2007).…”