Conventional contact sensors used for Lamb wave-based ultrasonic inspection, such as piezo-electric transducers, measure omnidirectional strain and do not allow distinguishing between fundamental symmetric and anti-symmetric modes. In this paper, we show that the use of a single fibre Bragg grating created in a dedicated microstructured optical fibre allows one to directly make the distinction ...

In this paper we present a cost effective method to fabricate flexible, high density piezoelectric tape, and expl'ore its potential application as a new type of Lamb wave phased array for Structural Health Monitoring (SHM) through simulating the Lamb wave propagation generated from single element and multielement arrays. The piezoelectric tape consists of many patterned and densely packed PZT (...

This paper describes a Lamb-wave scanning method for the detection of notches simulating cracks at rivet holes in thin plates. The approach requires the generation of an ultrasonic So-Mode Lamb wave using an incident transmitter excited with a tone burst centered at a near non-dispersive frequency. Area scans are performed on a plate with a hole with a notch to generate times series information...

In this paper we review the state of the art in an emerging new technology: embedded ultrasonic non-destructive evaluation (NDE). Embedded ultrasonic NDE permits active structural health monitoring, i.e. the on-demand interrogation of the structure to determine its current state of structural health. The enabling element of embedded ultrasonic NDE is the piezoelectric wafer active sensor (PWAS)...

background: both increased arterial stiffness and hyperuricaemia are associated with elevated cardiovascular risks. little is known about the relations of serum uric acid (ua) level to regional arterial stiffness and wave reflection. the aim of the study was to investigate the gender-specific association of serum ua and indices of arterial function in a community-based investigation in china. m...

Lamb modes are widely used for non-destructive evaluation of plate-like structures and simple interpretation procedures for the analysis of the monitored structures are needed. In this study we apply the orthogonality relation based method for post-processing Finite Element (FE) predictions in order to separate Lamb modes at a plate edge. The reflected wave field from the free edge is a superpo...

Shear and Compressional Wave Velocities along with other Petrophysical Logs, are considered as upmost important data for Hydrocarbon reservoirs characterization. Shear Wave Velocity (Vs) in Well Logging is commonly measured by some sort of Dipole Logging Tools, which are able to acquire Shear Waves as well as Compressional Waves such as Sonic Scanner, DSI (Dipole Shear Sonic imager) by Schlumbe...

in this paper the propagation of harmonic plane waves in a homogeneous anisotropic magneto-piezothermoelastic diffusive body with fractional order derivative is studied. the governing equations for a homogeneous transversely isotropic body in the context of the theory of thermoelasticity with diffusion given by sherief et al. [1] are considered as a special case. it is found that three types of...

A damage detection technique, which does not rely on any past baseline signals, is proposed to assess damage in composite plates by using an enhanced time reversal method. A time reversal concept of modern acoustics has been adapted to guided-wave propagation to improve the delectability of local defects in composite structures. In particular, wavelet-based signal processing techniques have bee...

In inspecting steel-rubber multi-layered structure, shielding of steel layer and intense attenuation of rubber layer result in ultrasonic echo from the interfaces of the deep layers being very weak. In order to overcome the difficulty, the double mode testing method is put forward. This method synthesizes the characteristics of transverse wave and Lamb wave testing. In the double modetesting tr...