The problem of shape control and correction of small displacements in composite structures using piezoelectric actuators glued or embedded was addressed. A finite element model based on Mindlin plate theory was used to characterize the behaviour of the structure and the one of the actuators. Emphasis was put on the development of an efficient and general methodology, based on genetic algorithms...

The main objective of this article is to describe the development of a fully-integrated disposable lab-on-achip for point of care testing and monitoring of biochemical parameters in biological fluids. The lab-on-achip is composed mainly by two dies: the fluid and the detection. The fluid die, fabricated in SU-8, comprises three microfluidic cuvettes, containing the fluids into analysis, and a β...

This paper focuses on the design, fabrication and characterization of unimorph actuators for a microaerial flapping mechanism. PZT-5H and PZN-PT are investigated as piezoelectric layers in the unimorph actuators. Design issues for microaerial flapping actuators are discussed, and criteria for the optimal dimensions of actuators are determined. For low power consumption actuation, a square wave ...

The performance of smart structures depends on the electromechanical behaviour of piezoelectric actuators and the bonding condition along the interface, which connects the actuators and the host structures. This paper provides a theoretical study of the effect of partially debonded adhesive layers on the coupled electromechanical behaviour of piezoelectric actuators subjected to high-frequency ...

Piezoelectric bimorph actuation has been successfully used in numerous types of microdevices, most notably micropumps. However, even for the simple case of circular geometry, analytical treatments are severely limited. This study utilized the finite-element method to optimize the deflection of a circular bimorph consisting of a single piezoelectric actuator, bonding material and elastic plate o...

We present a microfabricated grating whose period can be tuned in analog fashion to within a fraction of a nanometer. The tunable angular range is more than 400 microrad in the first diffracted order. The design concept consists of a diffractive grating defined onto a 400-nm membrane, with the membrane subsequently strained in the direction perpendicular to the grating grooves by thin-film piez...

This paper describes a lab-on-a-chip device with acoustic thermoagitation based on a piezoelectric β-PVDF polymer. The device is used for testing and monitoring biochemical parameters in biological fluids using optical absorption spectrophotometry. Experimental results regarding the influence of the electrical signal amplitude and frequency applied for the generation of acoustic thermoagitation...

This paper presents a piezoelectric tube scanner with a novel electrode pattern and describes how it may be used for simultaneous sensing and actuation. The electrodes are arranged such that the tube is driven in an antisymmetrical manner, resulting in a collocated system suitable for positive position feedback (PPF). A PPF controller is designed to damp the scanner's resonance. Piezoelectric s...

This study presents numerical simulations and experimental verification of a vibration-based damage detection technique. Health monitoring of a submerged pipe's girth-weld against an advancing notch is attempted. Piezoelectric transducers are bonded on the pipe for sensing or actuation purposes. Vibration of the pipe is excited by two means: (i) an impulsive force; (ii) using one of the piezoel...