The use of numerical and phased array techniques to focus guided waves and perform inspection of plates and pipes has not been widely used; it represents an interesting solution for defect detection and localization. In addition, imaging of ultrasonic guided wave results using color coded B-Scans is also considered a highly valuable tool for data interpretation. While commercial ultrasonic phas...

Ultrasonic guided waves are used to detect the delamination between skin and honeycomb of a composite helicopter rotor blade. Theoretical work is carried out for guided waves in the trailing edge of a rotor blade, which is a multilayer composite skin/NOMEX half space structure. The dispersion relation is obtained with the global matrix method. Theoretically driven experiments are conducted on a...

In this paper, the reflection of ultrasonic guided waves from simple dent in pipes has been investigated using finite element method and the relationship between reflection coefficient of these waves and deformation rate has been determined. Also, the effect of the parameters of wave generation source on the generated wave field has been investigated using normal modes expansion method. At firs...

The nondestructive evaluation (NDE) of adhesively bonded structures is a complex process. Earlier work has confirmed that ultrasonic waves are influenced by the properties of the material in which they travel. Acousto-ultrasonic methods have been widely used by previous researchers to generate ultrasonic waves in plates and bonded structures for flaw detection, visualization, and measurements o...

Introduction Compared to ultrasonic bulk waves that travel in infinite media with no boundary influence, guided waves require a structural boundary for propagation. As an example, some guided wave possibilities are illustrated in Figure 1 for a Rayleigh surface wave, a Lamb wave, and a Stonely wave at an interface between two materials.

Guided waves have been the attractive ways for the nondestructive inspection of the large structure because of their many advantages. The characteristics of guided waves are presented; some consideration of guided waves in the large structure inspection is stated; excitation methods and their merits and shortcomings are introduced. Several typical applications of guided waves in the large struc...

Guided Waves Testing is a new technology of ultrasonic testing of NDT bloomed in recent years especially for pipes and boards inspection in industry. Different methods used in guided waves signal processing are analyzed. The contrast between Fourier and Wavelet analysis is presented to support the outstanding features of wavelet in the processing of signals with sudden changes, such as guided w...

Especially for ageing aircraft the development of fatigue cracks at fastener holes due to stress concentration and varying loading conditions constitutes a significant maintenance problem. High frequency guided waves offer a potential compromise between the capabilities of local bulk ultrasonic measurements with proven defect detection sensitivity and the large area coverage of lower frequency ...

Vibrothermography, is an established NDT method praised for its fullfield and defect-selective imaging. Especially for cracks and similar damage, defect signals are produced within seconds for a wide variety of materials. Usually high power sonotrodes that are applied with kN pressure are employed in order to maximize ultrasonic excitation of the specimens. An increase in excitation power is us...

Abstract It has been reported that in principle sludge and blockages in pipes can be detected and characterized by using ultrasonic guided waves. The model idealised the sludge to be an asymmetrically uniform layer that is well bonded to the internal surface of the pipe wall. However, in practice, sludge layers normally have a very irregular shape, an asymmetrical circumferential profile and al...