It is this property of the surface waves that leads to the resonance phenomena that accompany the motion of the perturbation sources like surface loads with velocities close to the Rayleigh one; see e. In this contribution we present some results related to sounding of layered structures and to ultrasonic detection of arbitrarily shaped and oriented cracks. It is associated with natural resonance poles lying close to the real axis in the complex frequency plane. The construction of source field asymptotics and the calculations of both energy dissipation coefficient and generalized electromechanical connection Auld coefficient are described. The first objective is the modeling of a reasonably general type of ultrasonic probe.
Versión del inglés de Cayetano Enriquez de Salamanca. General electromechanical reciprocity relations are applied to the calculation of elastic wave scattering coefficients observed at the electrical terminals of the transducer used in performing an experiment. Este libro es de segunda mano y tiene o puede tener marcas y señales de su anterior propietario. On the role of anisotropy in crystalloacoustics; V. The purpose of the paper is to verify the supposition that the energy flux along an elastic waveguide with an obstacle is blocked completely at the stop frequencies by the vortices. The model is based on the use of the integral equation technique and asymptotics derived from the oscillate integrals.
The normal-made diffraction by a surface punch on an elastic layer is taken as an example. Los libros de la misma proporcionan una variedad de bases posibles para los cursos de introducción, desde aquellas que destacan fundamentalmente la Física clásica hasta aquellas que incluyen una cantidad considerable de Física atómica y cuántica. A mathematical model of the main stages of the process of ultrasonic detection of deep three-dimensional cracks of arbitrary orientation in a uniform medium and of horizontal interfacial cracks is developed using a single boundary-integral approach. Illustrations are also given of the extensive validation which the model has undergone through comparison with experiment. This method of analysis is applicable to both the Born and quasistatic approximations and is valid for bulk, Rayleigh and plate wave transducers using any single transduction mechanism. An approach is developed to solve mixed boundary problems of elastodynamics which describe the diffraction of normal modes on horizontal and vertical obstacles in layered waveguides.
A mathematical model is developed on the basis of a unified boundary-integral approach for the main stages of the ultrasonic process of deepened three-dimensional crack detection with arbitrary orientation in a homogeneous medium and horizontal interface cracks detection. The semianalytic methods developed for solving the problems of elastodynamic diffraction by a horizontal strip-like crack are used to analyze the transmission and reflection of Rayleigh waves in a half-plane and normal modes in a layer with the aim to determine the parameters of blocking and study the blocking mechanism. Title Mecánica clásica Product Description Madrid. Guided waves in anisotropic media: applications; R. Exquisito en los detalles y al mismo tiempo totalmente accesible para el estudiante moderno, el presente texto será un valioso tesoro para toda persona interesada en vivir conscientemente y en la realización de su libertad interior. The second objective of the paper is to include the presented probe model into a complete model of the ultrasonic testing situation.
To this end the probe field is, via a series of transformations, expressed in spherical vector waves centered at the defect. High efficiency and accuracy of the method is due to a special stable truncation of the infinite algebraic system by taking into account the edge singularities. A general purpose computer model for calculating elastic waveguide properties, with application to Non-Destructive Testing; M. Resonant waves in a structured elastic halfspace; M. For a defect that is a penny-shaped crack or a spherical cavity some numerical examples are given showing the received signal as a function of position on the scanning surface. Note that the aforementioned resonance phenomena are related to the nature of the surface waves as homogeneous solutions eigenfunctions of the dynamic elasticity equations for a half-space i. The non-uniqueness of constant velocity crack propagation; K.
The present paper is aimed to give an insight into such phenomena using an analytically based computer model which strictly takes into account all wave interactions in a cracked structure. Predicted by Rayleigh in 1885, surface waves represent waves localized in the vicinity ofextendedboundaries surfaces of? Mathematical modelling of wave phenomena in layered solids is of increasing interest because it has various applications to seismic and physical acoustics and to non-destructive evaluation. It is hoped that this work will draw attention to the analogy between energy and fluid flows which is potentially fruitful for understanding Various wave phenomena. The influence of the initial stresses on the dynamic instability of an anisotropic cone; Y. Intheidealcase of an isotropic elastic half-space while the Rayleigh waves propagate along the surface, the wave amplitude displacement in the transverse direction exponentially decays with increasing distance away from the surface.
A relation between elastic wave energy vortices appearing near the obstacles and certain resonance phenomena is studied. The implementation of the method is illustrated by numerical examples. It is essential to note that resonance phenomena are also inherent to the elastic medium in the case where initially there are no free unloaded surfaces. Encuadernación en tapa blanda de editorial. The defect is situated in one of the half-spaces perpendicularly to the interface of materials. We have considered the three-dimensional problem of harmonic loading of a circular crack in an elastic composite consisting of two dissimilar half-spaces under sliding contact on the surface of their bonding.
The traction is either constant across the probe piston-type source or it may taper off toward the edges. The general formulation is applicable to anisotropic media, but is applied as an example to Rayleigh wave scattering from a surface-breaking crack on an isotropic substrate. Colección 'Colección Ciencia y Técnica : sección física'. Both direct backscatter and two transducer geometries are considered. We deal with low-cost computer implementation of the integral equation method in application to wave phenomena in solids. The paper describes the principles of the model and gives examples of its application to power plant problems.
Rayleigh waves and resonance phenomena in elastic bodies. I: Theoretical problems concerning propagation of surface wave in elastic anisotropic media. Surface waves of non-Rayleigh type; S. The mathematical modeling of a typical situation in ultrasonic nondestructive testing for defects is considered. Product Description Esta serie de Introducción a la Física del M. The effective probe area may be rectangular or elliptic and the traction may or may not include the tangential part glued or fluid-coupled probe, respectively.