Typically, lambwave patterns can be observed when there is a highvelocity stiff layer at the top of a nearsurface section. Rayleighlamb wave definition of rayleighlamb wave by the. Lamb waves and nearlylongitudinal waves in thick plates david w. They are elastic waves whose particle motion lies in the plane that contains the direction of wave propagation and the plane normal the direction perpendicular to the plate. From source to detector sound from an instrument to ear cell phone to cell tower and vice versa em waves water waves a disturbance in the water moves outward. Rayleigh and lamb waves transport in random waveguides. Theory lamb waves are twodimensional vibrations propagating in plates with free boundary conditions. Apr 05, 20 this animation shows the separation of an a0 and s0 lamb wave, whose group speeds differ slightly. A partial solution to this complexity is the use of. Numerical simulation of lamb wave scattering in semi. However, for most of the lamb wave modes there is a low attenuation. The nondestructive testing of materials can be conducted by various techniques. Timefrequency representation of lamb waves using the reassigned spectrogram marc niethammer, laurence j.
Sometimes they are referred to as free or normal modes, because. Therein lies my problem as it seems to be one of the rarest books out there. Rayleigh and lamb waves basic principles worden 2008. Lamb waves can be used for nondestructive testing of aluminum aircraft panels, composite panels, and other plateshaped objects. Rayleigh waves occur on the earths surface during earthquakes. Rayleigh and lamb waves physical theory and applications.
Typically, lambwave patterns can be observed when there is a high velocity stiff layer at the top of your section. An analytical approach compared with fem banibrata poddara and victor giurgiutiua adepartment of mechanical engineering, university of south carolina, usa abstract. Here a link to our paper about modeling lamb waves using higher order methods. Firestone and ling inaugurated lamb wavebased damage detection in the 19401950s 6, 7, after which lamb waves found. Lamb wave inspection of large structures using permanently attached transducers by paul david wilcox a thesis submitted to the university of london for the degree of doctor of philosophy department of mechanical engineering imperial college of science, technology and medicine london sw7 2bx march 1998. One of the main problems in lamb wave testing is the dispersive nature of lamb waves. Tunable focusing and mimicking phase conjugation, the journal of the acoustical society of america, 140, 1, 591, 2016. Lamb waves are guided waves that propagate in thin plate or shell structures. Damage in materialsstructures can be detected by analyzing the difference between the phasegroup velocity and the loss of amplitude of lamb waves on damaged and undamaged. Your print orders will be fulfilled, even in these challenging times. Description of lamb waves lamb waves are a form of elastic perturbation that can propagate in a solid plate with free boundaries, first escribed in theory by horace lamb in 1917 16d 18.
Experimental and theoretical study of rayleighlamb waves in a plate containing a surfacebreaking crack article pdf available in research in nondestructive evaluation 14. These waves were excited by an 11sec pulse, projected onto the cylindrical surface at an excitation angle given by sin 1 c o c s, where c o is the velocity of sound in water and c s is the velocity of the surface wave. Notes on wave propagation in anisotropic elastic solids. By matching theoretical multimodal lamb wave dispersion curves with experimental ones, shear wave velocity vs, poissons ratio, and thickness of the tested plate structure can be evaluated. Timeefficient simulation of surfaceexcited guided lamb wave. It has been demonstrated that geometrical acoustics approximation for rayleigh waves and for lamb waves of the lowest order, especially flexural waves, is a powerful tool. The thickness of the layer where the waves are localized is 12. Simulation and testing of transducers for lamb wave generation.
Rayleighlamb wave from eric weissteins world of physics. Optimization of lamb wave methods for damage detection in. There has been a clear increase of interest in using lamb waves for identifying structural damage, entailing intensive research and development in this field over the past two decades. Fundamentals and analysis of lamb waves springerlink. Rayleigh waves involve interaction between p and 5 waves at a free surface.
A free surface requires the tractions to vanish at x 3 0. Lamb waves lamb, 1917 are guided dispersive waves propagating in free plate structures. If you dont want to wait have a look at our ebook offers and start reading immediately. Rayleigh waves have a speed slightly less than shear waves by a factor dependent on the elastic constants of the material. Lamb waves are ultrasonic guided waves that propagate between two parallel free surfaces and their use for damage detection has been widely explored and demonstrated. This paper investigates the interaction of different shear and rayleighlambguided waves in plates with a discontinuity such as a. The calculation includes stoneley waves along a solidsolid interface of two bonded halfspaces, rayleigh lamb type waves in a layered halfspace, and guided waves in a general multilayered plate. Guided lamb waves based structural health monitoring. This animation shows the separation of an a0 and s0 lamb wave, whose group speeds differ slightly. Modelling of attenuation of lamb waves using rayleigh damping. Also, in the past decade, there has been increasing interest in the. A study of lamb waves in anisotropic plates northwestern. Interaction of lamb wave modes with weak material nonlinearity.
A type of seismic surface wave that moves with a rolling motion, causing rock particles to vibrate in directions both perpendicular and parallel to the. Traveling waves waves propagate from one place to another. Acoustic waves propagating on the surface of solid and hollow elastic cylinders immersed in water were observed and their characteristics shown to be consistent with theory. Their displacements may be symmetric or antisymmetric with respect to the middle plane of the plate. Lamb waves are reflected in material properties and geometric discontinuities, such as damages. Interaction of lamb waves with geometric discontinuities. In such instances some parts of the dispersion curves may exhibit features that resemble lamb wave plate wave patterns and not rayleigh wave, free rayleigh waves. I have been told to get myself a copy of rayleigh and lamb waves.
Guided lamb waves for identification of damage in composite. The optimization of lamb and rayleigh wave generation. Scattering characteristics of lamb waves from debondings at structural features in composite laminates chingtai nga school of civil, environmental and mining engineering, the university of. Lamb waves are formed by interference of multiple reflections and mode conversion of longitudinal waves p waves and shear waves s waves at the free surfaces of the plate viktorov, 1967.
Lecture 11 chapter 16 waves i university of virginia. Rayleigh waves have horizontal displacement and the motion of a point in the medium is an ellipse. They are elastic waves whose particle motion lies in the plane that contains the direction of wave propagation. Rayleigh lamb wave synonyms, rayleigh lamb wave pronunciation, rayleigh lamb wave translation, english dictionary definition of rayleigh lamb wave. A comprehensive solution to lamb waves was completed by mindlin in 1950, followed by considerable detail provided by gazis in 1958 4 and viktorov in 1967 5 who also first evaluated the dispersive properties of lamb waves. There are two groups of waves, symmetric and antisymmetric as seen in figure, that satisfies the wave equation for this problem. Woodruff school of mechanical engineering, georgia institute of technology, atlanta, georgia 303320405. If you are a society or association member and require assistance with obtaining online access instructions please contact our journal customer services team. Structural health monitoring using lamb wave testing polytec. Pdf solutions of rayleigh waves and lamb waves generated. Types of mechanical waves waves that have compressions and rarefactions parallelwaves that have compressions and rarefactions parallel to the direction of wave propagation are longitudinal. Physical theory and applications ultrasonic technology on free shipping on qualified orders. Rayleigh waves are distinct from other types of surface or guided acoustic waves such as love waves or lamb waves, both being types of guided waves supported by a layer, or longitudinal and shear waves, that travel in the bulk.
The guided lamb wave is widely acknowledged as one of the most encouraging tools for quantitative identification of damage in composite structures, and relevant research has been conducted intensively since the 1980s. Krylov and others published geometrical acoustics approximation for rayleigh and lamb waves find, read and cite all the research you need on researchgate. N2 this paper is concerned with the lamb wave spectra for layered orthotropic elastic media. Experimental results are presented for the application of lamb wave techniques to quasi. Researcharticle numerical timedomain modeling of lamb wave propagation using elastodynamic finite integration technique husseinrappel,1 aghilyousefikoma,1 jaliljamali,2 andakobahari3. Numerical timedomain modeling of lamb wave propagation using. Identification of damage using lamb waves from fundamentals. Pdf experimental and theoretical study of rayleighlamb. Lamb waves and dispersion curves in plates and its. For many applications, lamb waves are of primary concern because they are able to give the best indication of wave propagation from a source whose distance from the sensor is larger than the thickness of the material. Complications that are encountered in applying lamb waves include the existence of multiple modes and the dispersive character of the modes.
Barsauskas ultrasound institute, kaunas university of technology abstract interpretation of the ultrasonic signals measured in guided waves applications usually are more complicated comparing to. Costeffective and reliable damage detection is critical for the utilization of composite materials. I have just started to look into this subject area which i am completely unfamiliar with. Lamb waves with particle displacement in both the x and ydirection actually represents a group. This paper presents part of an experimental and analytical survey of candidate methods for insitu damage detection of composite materials. Traveling perpendicular to the plate thickness, being guided. Viktorov and a great selection of related books, art and collectibles available now at. Rayleighlamb wave article about rayleighlamb wave by the. Ultrasonic waves used to check the surface layer of various device components and specimens are another example of rayleigh waves. For signal processing applications, lamb waves are. Scattering characteristics of lamb waves from debondings. Benoit gerardin, jerome laurent, claire prada and alexandre aubry, negative reflection of lamb waves at a free edge.
Jacobsa school of civil and environmental engineering, georgia institute of technology, atlanta, georgia 303320355 jianmin qu and jacek jarzynski g. Attenuation of lamb waves, both fundamental symmetric and antisymmetric modes, propagating through viscoelastic media crossply glassepoxy laminate was modelled using the finite element method. When the excitation of a particular mode is made by a broadband pulse. Waves that have compressions and rarefactions perpendicular to the direction of propagationperpendicular to the direction of propagation.
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