Elastic waves guided by a welded joint in a plate

Abstract

The inspection of large areas of complex structures is a growing interest for industry. An experimental observation on a large welded plate found that the weld can concentrate and guide the energy of a guided wave travelling along the direction of the weld. This is attractive for non-destructive evaluation (NDE) since it offers the potential to quickly inspect for defects such as cracking or corrosion along long lengths of welds. In this paper, a twodimensional semi-analytical finite-element (SAFE) method is applied to provide a modal study of the elastic waves that are guided by the welded joint in a plate. This brings understanding to the compression wave that was previously observed in the experiment. However, during the study, a shear weld-guided mode, which is non-leaky and almost non-dispersive, has also been discovered. Its characteristics are particularly attractive for NDE, so this is a significant new finding. The properties for both the compression and the shear mode are discussed and compared, and the physical reason for the energy trapping phenomena is then explained. Experiments have been undertaken to validate the existence of the shear weld-guided mode and the accuracy of the FE model, showing very good results.

Feature-guided waves for monitoring adhesive shear modulus in bonded stiffeners

“…This was found first by observation of a compression-like mode [13], which is dispersive, partially-trapped at low frequencies, and perfectly-trapped at high frequencies. This geometry was then investigated by model and further experiments, showing the existence of both the compression-like mode and a perfectly-trapped shear-like mode with very little dispersion [14,15]. The shear-like mode is slower than any other mode at all frequencies, and so does not leak any energy into the adjacent plates.…”

Ultrasonic guided waves in elliptical annular cylinders

“…Such an effect is closely related to feature-guided wave phenomena noted in the literature in recent years. 3,7,8 Also an interesting observation is that pipe eccentricity does not seem to affect the T(0,1) mode as strongly, and its modal structure and nondispersive nature are very similar to the circular pipe even in cases of high ovalness. This paper is organized as follows.…”

“…3,7,8 Recent analytical studies (Postnova and Craster 11,12 ) have shown that curvature effects in waveguides are mathematically equivalent to local thinning. Again drawing upon the work of Postnova and Craster, 11,12 we find that for longitudinal modes, trapping is only possible for local thinning for Poisson ratio in the range of metals.…”

Guided waves' dispersion curves in anisotropic viscoelastic single- and multi-layered media

“…The SAFE method is popular for studying properties of guided waves along waveguides with arbitrary cross-section, such as railway lines [48], beams [49,50], welded [51] or stiffened plates [52], etc. It uses FEs to represent the cross-section of the waveguide, plus a harmonic description along the propagation direction, thus limiting the FE model to two dimensions.…”