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1
Content available remote Theoretical and experimental analysis of guided wave propagation in plate-like structures with sinusoidal thickness variations
Zima Beata, Moll Jochen
Archives of Civil and Mechanical Engineering
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2023
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Vol. 23, no. 1
art. no. e34, 2023
EN
Guided waves have attracted significant attention for non-destructive testing (NDT) and structural health monitoring (SHM) due to their ability to travel relatively long distances without significant energy loss combined with their sensitivity to even small defects. Therefore, they are commonly used in damage detection and localization applications. The main idea of incorporating guided waves in NDT and SHM is based on processing the received signals and appropriate interpretation of their characteristics. A great amount of research devoted to diagnostics of plate-like structures considers specimens with constant thickness, which significantly facilities the diagnostic process. In such a case the velocity is also assumed to be constant. However, the developed diagnostic methods should be applicable, especially for the structures exposed to an aggressive environment, excessive load, or unfavorable weather conditions, etc., when the probability of damage occurring is much higher. In such cases, the assumption about the uniform thickness alongside the propagation path cannot be applied in every case. Thus, the present study is focused on wave propagation in metallic plates with variable thickness. The results of theoretical, numerical and experimental investigations of antisymmetric Lamb mode propagation in aluminum plates with a sine-shaped surface are presented. In the first step, the influence of non-uniform thickness distribution on wave velocity has been described. Next, the inverse problem aimed at shape reconstruction based on time of flight (ToF) analysis and spatially varying wave velocity was solved and compared with the standard dispersion curve-fitting method.
2
Content available Obrazowanie wad w strukturach cienkościennych z wykorzystaniem ultradźwiękowych fal prowadzonych
Spytek Jakub, Dziedziech Kajetan, Ambroziński Łukasz, Pieczonka Łukasz
Badania Nieniszczące i Diagnostyka
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2022
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1-4
93--96
PL
W pracy przedstawiono nowatorską technikę badań nieniszczących struktur cienkościennych bazującą na estymacji lokalnej liczby falowej ultradźwiękowych fal prowadzonych. Technika bazuje na punktowym wzbudzeniu fal ultradźwiękowych i rejestracji odpowiedzi drganiowych na siatce punktów w obszarze zainteresowania z wykorzystaniem skanującego wibrometru laserowego. Wzbudzenie może być zrealizowane bezkontaktowo za pomocą impulsu lasera, bądź kontaktowo za pomocą przetwornika piezoelektrycznego. Praca omawia podstawy teoretyczne metody oraz jej zastosowania praktyczne. Skuteczność działania omawianej metody zilustrowano na przykładzie jednorodnej płyty aluminiowej oraz niejednorodnej warstwowej płyty kompozytowej.
EN
In this paper we present a novel nondestructive testing technique for platelike structures, using the local wavenumber estimation of ultrasonic guided waves. The technique is based on the excitation of ultrasonic waves and measuring the full-field response on a grid of points in the area of interest with a scanning laser vibrometer. The excitation can be realized using a non-contact laser pulse or a piezoelectric transducer. The paper discusses theoretical background of the technique and its practical applications. The efficacy of the proposed approach is demonstrated on a homogeneous aluminum plate and an inhomogeneous layered composite plate.
3
Content available A quadrature-free Legendre polynomial approach for the fast modelling guided circumferential wave in anisotropic fractional order viscoelastic hollow cylinders
Zhang X., Liang S., Shao S., Yu J.
Archives of Mechanics
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2021
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Vol. 73, nr 2
121--152
EN
Compared to the traditional integer order viscoelastic model, a fractional order derivative viscoelastic model is shown to be advantageous. The characteristics of guided circumferential waves in an anisotropic fractional order Kelvin–Voigt viscoelastic hollow cylinder are investigated by a quadrature-free Legendre polynomial approach combining the Weyl definition of fractional order derivatives. The presented approach can obtain dispersion solutions in a stable manner from an eigenvalue/eigenvector problem for the calculation of wavenumbers and displacement profiles of viscoelastic guided wave, which avoids a lot of numerical integration calculation in a traditional polynomial method and greatly improves the computational efficiency. Comparisons with the related studies are conducted to validate the correctness of the presented approach. The full three dimensional spectrum of an anisotropic fractional Kelvin–Voigt hollow cylinder is plotted. The influence of fractional order and material parameters on the phase velocity dispersion and attenuation curves of guided circumferential wave is discussed in detail. Moreover, the difference of the phase velocity dispersion and attenuation characteristics between the Kelvin–Voigt and hysteretic viscoelastic models is also illustrated. The presented approach along with the observed wave features should be particularly useful in non-destructive evaluations using waves in viscoelastic waveguides.
4
Content available Effect of Pipe Bends on the Low-Frequency Torsional Guided Wave Propagation
Wu Wenjun, Wang Junhua
Archives of Acoustics
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2020
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Vol. 45, No. 3
385--391
EN
Wave motion in pipe bends is much more complicated than that in straight pipes, thereby changing considerably the propagation characteristics of guided waves in pipes with bends. Therefore, a better understanding of how guided waves propagate in pipe bends is essential for inspecting pipelines with bends. The interaction between a pipe bend and the most used non-dispersive torsional mode at low frequency in a small-bore pipe is studied in this paper. Experiments are conducted on a magnetostrictive system, and it is observed that T(0,1) bend reflections and mode conversions from T(0,1) to F(1,1) and F(2,1) occur in the pipe bend. The magnitude of the T(0,1) bend reflections increases with increasing propagation distance and excitation frequency. The amplitude of the mode-converted signals also increases with increasing propagation distance, but it decreases with increasing excitation frequency. Because of their longer bent path, the test signals for a pipe bend with a bending angle of 180º are much more complicated than those for one with a bending angle of 90º. Therefore, it is even more difficult to scan a bent pipe with a large bending angle. The present findings provide some insights into how guided waves behave in pipe bends, and they generalize the application of guided-wave inspection in pipelines.
5
Content available remote Barely visible impact damage identificationin a 3D core sandwich structure
Sikdar S., Ostachowicz W., Kudela P., Radzieński M.
Computer Assisted Methods in Engineering and Science
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2017
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Vol. 24, no. 4
259--268
EN
3D core sandwich structure (3DCSS) is a popular lightweightconstruction material in the automotive,aerospace and marine industries. However, barely visible low-speed impact-damage (BVLID) may occurin the 3DCSS due to foreign-object-impact that can significantly reduce the load-bearing capacity of thestructure. This paper presents a guided wave (GW) propagation based BVLID identification technique forthe 3DCSS. A global-matrix formulation based semi-analytical model is applied to generate the dispersioncurve for the GW propagation in the 3DCSS. It is observed thatthe GW propagation in the 3DCSS ismulti-modal in nature. Finite-element numerical simulation of GW propagation in the 3DCSS is carriedout in Abaqus. A significant increment in the primary antisymmetric mode is noticed due to the presenceof BVLID region in the structure. Experiments are then conducted on a 3DCSS sample to validate thesimulation results. There is a good agreement between the simulation and experimental results in allthe cases.
6
Content available Wave propagation in piezoelectric rings with rectangular cross-sections
Zhang X., Wang Y., Chen H.
Journal of Theoretical and Applied Mechanics
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2015
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Vol. 53 nr 3
673--682
EN
The ring ultrasonic transducers are widely used in the ocean engineering and medical fields. This paper employs an extended orthogonal polynomial approach to solve the guided wave propagation in two-dimensional structures, i.e. piezoelectric rings with rectangular cross- -sections. The extended polynomial approach can overcome the drawbacks of the conven- tional orthogonal polynomial approach which can be used to solve wave propagation in one-dimensional structures. Through numerical comparison with the available results for a rectangular aluminum bar, the validity of the present approach is illustrated. The dispersion curves and displacement and electric potential distributions of various rectangular piezo- electric rings are calculated, and the effects of different radius to thickness ratios, width to height ratios and polarizing directions on the dispersion curves are illustrated.
7
Analiza możliwości oceny stanu technicznego kotew gruntowych za pomocą propagacji fal prowadzonych
Zima B., Rucka M.
Inżynieria i Budownictwo
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2015
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R. 71, nr 11
614--616
PL
Przedstawiono identyfikację długości swobodnej cięgna kotew gruntowych z wykorzystaniem metody propagacji fal prowadzonych. Badano propagację fal w modelach kotew w skali laboratoryjnej z różnymi długościami buławy.
EN
The paper presents the identification of the free length of the tendon in ground anchors using guided wave propagation technique. Experimental investigations of wave propagation were carried out on laboratory scale anchors with different bonding lengths.
8
Content available Aplication of guided wave propagation in diagnostics of steel bridge components
Rucka M., Zima B., Kędra R.
Archives of Civil Engineering
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2014
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Vol. 60, nr 4
493--515
EN
Early detection of potential defects and identification of their location are necessary to ensure safe, reliable and long-term use of engineering structures. Non-destructive diagnostic tests based on guided wave propagation are becoming more popular because of the possibility to inspect large areas during a single measurement with a small number of sensors. The aim of this study is the application of guided wave propagation in non-destructive diagnostics of steel bridges. The paper contains results of numerical analyses for a typical railway bridge. The ability of damage detection using guided Lamb waves was demonstrated on the example of a part of a plate girder as well as a bolted connection. In addition, laboratory tests were performed to investigate the practical application of wave propagation for a steel plate and a prestressed bolted joint.
9
Content available remote Field experience of using guided waves for corrosion monitoring of piping
Niederhauser S., Ernst R.
Przegląd Spawalnictwa
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2013
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R. 85, nr 12
114--116
EN
DEKRA Industrial AB has used Guided Waves Ultrasonic Technique (hereafter called GWUT) for some years now. During time, DEKRA has acquired a lot of field experience with this technique and together with customers tried to find the limits of the technique. This article gives an overview on the technique and shows some results from field testing. Nonetheless of the experience acquired, DEKRA and its customers are still trying to find new possibilities for using the technique and find new areas to employ it.
PL
DEKRA Industrial AB już od kilku lat stosuje technikę ultradźwiękową fal kierowanych (dalej nazywaną GWUT). Podczas tego okresu DEKRA zdobyła wiele praktycznych doświadczeń w stosowaniu tej techniki oraz wraz z klientami próbuje znaleźć jej graniczenia. Niniejszy artykuł stanowi zwięzły opis podstaw techniki GWUT i prezentację wybranych wyników badań w terenie. Niezależnie od zdobytych już doświadczeń DEKRA wspólnie z klientami wciąż próbuje znaleźć nowe możliwości i obszary zastosowania tej techniki.
10
Content available remote Effects of initial stresses on guided waves in unidirectional plates
Zhang X. M., Yu J. G.
Archives of Mechanics
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2013
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Vol. 65, nr 1
3-26
EN
The guided wave propagation in unidirectional plates under gravity, homogeneous initial stress in the thickness direction and inhomogeneous initial stress in the wave propagating direction is investigated in this paper based on the theory of mechanics of incremental deformations. The Legendre orthogonal polynomial series expansion method is used to solve the coupled wave equation. Two different wave propagating directions, the fiber orientation and the vertical fiber orientation, are discussed respectively. The effects of the initial stresses on the Lamb-like wave and shear-horizontal (SH) wave are respectively investigated. The effects of the initial stresses on the dispersion curves and on the displacement and stress distributions are discussed.
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