With an increasing use of adhesively bonded joints in the industry, there is a correspondingly growing need for the inspection of adhered joints. It is necessary to detect defects in the adhesively bonded materials such as voids inclusions, chemical miscure of the adhesive, or delaminations of the bonded layers. In order to use an ultrasonic technique to detect these defects, a thorough underst...

Modal control and spatial filtering technologies for vibration and/or structural acoustics radiation mitigation may be implemented through the use of distributed modal piezoelectric transducers with properly shaped electrodes which, in order to increase the robustness and stability of the controlled structural system, turn undesirable mode’s contributions unobservable and uncontrollable over th...

The thermoelectroelastic GreenÕs functions are presented for an in®nite piezoelectric plate with an elliptic inclusion of dissimilar material induced by a thermal load located inside or on the boundary of the elliptic inclusion. The load may be a point heat source and the thermal analog of a line dislocation with temperature discontinuity. The derivation is based on the Stroh formalism, conform...

The problem of matching a thick piezoelectric transducer to an air medium is considered and it is concluded that a suitable matching device can be designed and built in the form of a rigid plate, a few millimetres thick and pierced by a closely packed array of horn-shaped channels, the wide mouths of the horns facing the external world and the narrow throats facing the transducer. Design parame...

Surface acoustic wave (SAW) devices based on Rayleigh wave, shear wave, love wave, acoustic plate mode (APM) wave and flexural plate wave have been explored for sensors, actuators and telecommunication applications. An interdigital transducer (IDT) is a metallic comb-like structure fabricated over piezoelectric substrate. SAWs are generated over the substrate by applying electrical signal to th...

We study transient ®nite deformations of a neoHookean beam or plate with piezoelectric (PZT) patches bonded to its upper and lower surfaces. The constitutive relations for the PZTs are taken to be linear in the Green-Lagrange strain tensor but quadratic in the driving voltage. A ®nite element code using 8-noded brick elements has been developed and validated by comparing computed results with e...

We investigate the possibility of designing phononic crystal-based devices for telecommunication applications using materials commonly employed in microfabrication. We focus our attention on a phononic crystal made of a square array of cylindrical holes drilled in an active piezoelectric PZT5A matrix. Two different structures are considered, namely, a freestanding phononic crystal plate and a p...

In the paper a feasibility study on the use of surface acoustic wave (SAW) vibration sensors for electronic warning systems is presented. The system is assembled from concatenated SAW vibration sensors based on a SAW delay line manufactured on a surface of a piezoelectric plate. Vibrations of the plate are transformed into electric signals that allow identification of the sensor and localizatio...

This paper presented development work of an in situ method for damage detection in thin-wall structures using embedded two-dimensional ultrasonic phased arrays. Piezoelectric wafer active sensors were used to generate and receive guided Lamb waves propagating in the plate-like structure. The development of a generic beamforming algorithm that does not require parallel ray assumption through usi...