Piezoelectricity in Structural Adhesives and Application for Monitoring Joint Integrity via Guided Ultrasonic Waves.

In an adhesively bonded structure, utilizing the adhesive itself for monitoring the joint integrity can be beneficial in reduction of labor, time, and potential human errors while avoiding problems associated with introduction of a foreign sensor component. This work started from the examination of effective piezoelectricity of commercial structural adhesives/sealants, and five of them were found to possess effective piezoelectric property, with effective piezoelectric coefficient d from -0.11 to -1.

In situ disbond detection in adhesive bonded multi-layer metallic joint using time-of-flight variation of guided wave.

Adhesive bonded joints are frequently adopted in structural applications. The adhesive aging, low quality of surface preparation, as well as the exposure to external harsh environment and loading, may degrade the quality of adhesive, leading to disbond and decrease of the interfacial strength of the bonded joints. This study addresses both numerical and experimental investigations of ultrasonic guided wave (UGW) propagating in adhesive bonded metallic waveguide, whereby disbond detection is realized based on variation of the wave arrival time of UGW.

High-frequency ultrasonic methods for determining corrosion layer thickness of hollow metallic components.

Corrosion in internal cavity is one of the most common problems occurs in many hollow metallic components, such as pipes containing corrosive fluids and high temperature turbines in aircraft. It is highly demanded to non-destructively detect the corrosion inside hollow components and determine the corrosion extent from the external side. In this work, we present two high-frequency ultrasonic non-destructive testing (NDT) technologies, including piezoelectric pulse-echo and laser-ultrasonic methods, for detecting corrosion of Ni superalloy from the opposite side.

Trapping of vesicles on patterned surfaces by physisorption for potential biosensing applications.

The pre-defined selective positioning of a controlled number of vesicles on a rigid substrate is crucial in many potential applications such as diagnostics, biosensors, lab-on-a chip, microanalyses and reaction chambers. In this paper, the vesicles made up of block copolymer using Poly [-(2-methyloxazoline) -poly- (dimethylsiloxane)-poly- (2-methyloxazoline)] (ABA) with dimensions of 100-200 nm are trapped by physisorption on hydrophilic surfaces. We discuss the protocols established for vesicle trapping.