Research into ultrasonic NDE techniques for the inspection of multilayered structures relies strongly on use modeling tools which calculate dispersion curves and reflection transmission spectra. These predictions are essential to enable best strategies be identified their sensitivities evaluated. General purpose multilayer may developed from a number matrix formulations have evolved in latter half this century there is now formidable publications subject. This paper presents review main...

The reflection of the L(0, 2), axially symmetric guided elastic wave from notches in pipes is examined, using laboratory experiments and finite element simulations. results show that coefficient this mode very close to a linear function circumferential extent notch, stronger through thickness depth notch. motivation for work was development technique inspecting chemical plant pipework, but study addresses nature has general applicability.

A quantitative study of the reflection T(0,1) mode from defects in pipes frequency range 10-300 kHz has been carried out, finite element predictions being validated by experiments on selected cases. Both cracklike with zero axial extent and notches varying extents have considered. The results show that coefficient axisymmetric cracks increases monotonically depth at all frequencies any given depth. In interest there is no conversion defects. With nonaxisymmetric cracks, a roughly linear...

Lamb waves can propagate many metres along plate and shell structures, so have great potential in 'smart structure' applications where it is important for a transducer to interrogate significant area of the surrounding structure. However, there are different types wave order obtain simple signals that be reliably interpreted, excite single mode well controlled direction. The choice which use particular application depends on numerous factors, including resolution required, type defects or...

An analysis of the reflection fundamental Lamb mode s0 from surface-breaking rectangular notches in isotropic plates is presented. The results are obtained finite element time domain simulations together with experimental measurements. Very good agreement found between and Results shown for a range notch widths depths, including special case crack, defined as zero-width notch. interference phenomenon identified which explains periodic nature coefficient when plotted function width. Finally,...

An analysis of the reflection fundamental Lamb mode a0 from surface-breaking rectangular notches in isotropic plates is presented. The results are obtained finite element time domain simulations together with experimental measurements. Good agreement found between and Results shown for a range notch widths depths, including special case crack, defined as zero-width notch. coefficient, when plotted function width, exhibits cosinusoidal periodic shape, this explained by interference separate...

A study of the reflection mode-converted guided waves from notches in pipes has been carried out. Measurements were made on a 76-mm bore diameter (nominal 3-inch), 5.5-mm wall thickness pipe with circumferentially oriented through-thickness various lengths. In parallel, finite element model was used to simulate experiments. The axially symmetric L(0, 2) mode incident and 2), F(1, 3), F(2, 3) modes received reflection. results showed excellent agreement between measurements predictions for...

The Semi-Analytical Finite Element (SAFE) method is becoming established as a convenient to calculate the properties of waves which may propagate in waveguide has arbitrary cross-sectional shape but invariant propagation direction. A number researchers have reported work relating lossless elastic waves, and recently solutions for nonpropagating guides complex viscoelastic been presented. This paper presents further development, addressing problem attenuating attenuation caused by leakage...

Long-range guided wave testing is a well-established method for detection of corrosion defects in pipelines. The currently used routinely above ground pipelines variety industries, e.g. petrochemical and energy. When the applied to pipes buried soil, test ranges tend be significantly compromised unpredictable due attenuation resulting from energy leakage into embedding soil. characteristics propagation an 8 in. pipe sand are investigated using laboratory full-scale experimental rig model...

A study of the interaction S0 Lamb wave with a circular through-thickness hole in plate is presented. The limited to nondispersive frequency range this wave, which distributions stress and displacement are simple. This allows Finite Element analysis be undertaken using two-dimensional membrane discretization. Predictions direct reflection mode lateral scattering SH0 made for diameters hole. At same time, an analytical solution based on modal superposition developed, also used predict...

There is currently a need to improve the nondestructive testing techniques that are used inspect grouted steel reinforcing tendons, anchors, and rock bolts for corrosion fracture. A method of inspection using guided ultrasonic waves has been proposed, which uses pulse-echo technique carried out from free end structure. The maximum range determined by amount attenuation wave experiences as result leakage into embedding material losses. However, previous work identified high frequency modes...

This paper presents a study of the velocity propagation energy in guided waves plates. The motivation work comes from practical observation that conventional approach to predicting velocities pulses or wave packets, is, simple group calculation, breaks down when are attenuative. is therefore not valid for absorbing materials leaky waves. theoretical derivation an expression predict isotropic plate, based on integration Poynting vectors. When applied modes with no attenuation, it shown...

The transmission of Lamb waves across adhesively bonded lap joints is investigated using finite element analysis. studies consider three modes for excitation and reception, s0, a0, a1, applied to consisting parallel aluminum sheets with an epoxy adhesive. Transmission coefficient results a two-dimensional range bond thicknesses overlap lengths are presented all modes. coefficients calculated from the spectra received transmitted signals approach which insensitive presence multimode...

The prototype of a guided ultrasonic wave array for the structural integrity monitoring large, plate-like structures has been designed, built, and tested. development suitably small transducers excitation measurement first antisymmetric Lamb mode Ao is described. design consists ring 32 transducers, permanently bonded to structure with protective membrane, in compact housing necessary multiplexing electronics. Using phased addition algorithm dispersion compensation deconvolution wavenumber...