Seven-wire strands are commonly used in civil-engineering structures such a cable-stayed bridges, pre-stressed concrete bridges or retaining walls structures. These civil engineering structures suffer from ageing and degradation due to corrosion and fatigue of structural steel members. Guided ultrasonic waves are potentially attractive tools for non destructive assessment of their integrity. Th...

The detection, location, and sizing of a fatigue crack emanating from a fastener hole in an aluminum plate is investigated. Two linear arrays of surface mounted piezoelectric disk transducers send and receive ultrasonic guided waves that are transmitted, reflected, and scattered by both the joint geometry and the fatigue crack. A tomography algorithm is used to detect and locate the crack. Ampl...

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)...

Guided wave focusing has been developed as a promising technique for defect detection in pipeworks, where non-axisymmetric flexural modes are tuned so that ultrasonic energy can be focused at a target point in a pipe. If a defect is located at the target point, large amplitude reflected waves can be observed. In this study, the focusing phenomenon is analyzed using a semi-analytical finite elem...

Abstract A model-based algorithm is presented that uses minimal a priori information and assumptions to adaptively estimate parameters associated with propagating waves in a homogeneous medium. These parameters include transmitter and receiver transfer functions, propagation distances, dispersion, and propagation loss. The algorithm is described in a general framework that accommodates direct a...

Using numerical simulations, we investigated the responses of the π-phase-shifted fiber Bragg gratings (πFBGs) impinged by pressure ultrasonic waves. The effect of the grating length, grating refractive index modification depth, and ultrasonic frequency on the wavelength sensitivity and intensity sensitivity of the πFBG ultrasonic sensor for ultrasonic waves of different wavelengths was analyze...

non-destructive ultrasonic testing is one of the methods utilized to evaluate quality of agricultural produce. transducers used in this method are made for basically industrial applications. since ultrasonic attenuation of waves in agricultural produce is very high, industrial transducers cannot be used in agriculture and needs to be modified. this is done with horns that concentrate energy on ...

al’s properties and acoustical characteristics have been studied for a long time and ultrasonic techniques have been used in non-destructive testing and imaging for decades. Ultrasound as an analytical tool has revolutionised diagnostics in medicine, but the application of ultrasound to material’s analyses has been held back by problems with ultrasonic design, electronics, sample handling, comp...

Compared with conventional linear ultrasonic inspection methods, which are sensitive only to severe defects, nonlinear ultrasonic inspection methods are better for revealing micro-cracks in thin plates. However, most nonlinear ultrasonic inspection methods have only been experimentally investigated using bulk or Rayleigh waves. Numerical studies, especially numerical simulations of Lamb ultraso...

The application of laser ultrasonic technique is developed for evaluation of friction stir spot welding (FSSW) quality. The features of laser-generated ultrasonic waves in good welding and incomplete fusion area are simulated by finite element method (FEM). The non-contact laser ultrasonic inspection system (LUIS) was established to verify the numerical results. The interaction of laser ultraso...