We study the interaction of highly nonlinear solitary waves propagating in granular crystals with an adjacent linear elastic medium. We investigate the effects of interface dynamics on the reflection of incident waves and on the formation of primary and secondary reflected waves. Experimental tests are performed to correlate the linear medium geometry, materials, and mass with the formation and...

Steady solitary and generalized solitary waves of a two-fluid problem where the upper layer is under a flexible elastic sheet are considered as a model for internal waves under an ice-covered ocean. The fluid consists of two layers of constant densities, separated by an interface. The elastic sheet resists bending forces and is mathematically described by a fully nonlinear thin shell model. Ful...

Microseismic events generate compressive waves and shear waves which can be recorded at receivers. We present a theory that shows how elastic P and S waves separately backpropagate to the original source location. These refocused P and S wavefields are free of singularities. We also demonstrate a technique that enhances the ability to image the spatial focus for each wave type using elastic wav...

In the present study normal plate-impact experiments are conducted to investigate the propagation of acceleration waves in 2-D layered material systems. The objective of these experiments is to understand the role of material architecture and material inelasticity in controlling precursor decay and late-time dispersion of acceleration waves in elastic-elastic and elasticviscoelastic laminates. ...

A method of calculating dispersion curves for guided waves in slight, azimuthally anisotropic formations is developed with perturbation theory. The fluid is assumed to be inviscid, the formation perfectly elastic and homogeneous, and the ·borehole wall cylindrical. The first step is calculating the elastic moduli for a transversely isotropic formation whose moduli are close to those for the azi...

In this paper we study the propagation of acoustic waves in two dimensional oceans with porous-elastic seabeds. First we outline our results developed for three dimensional ocean with rigid bottom and a depth dependent index of refraction. Then we extend this problem to an ocean bed consisting of porous, elastic sediment, lying over an elastic rock substrata.

Laser ultrasonics is based on the generation of elastic waves by transient surface heating or ablation with short laser pulses. These waves are traveling through the sample, are reflected and scattered at interfaces and the backside of the sample. To realize an ultrasound measurement device we have used either an interferometer coupled to a continuous wave laser (contact-free) or the sample was...

The amplitude of sound scattered from submerged elastic objects is dominated by resonance phenomena corresponding to the mechanical eigenvibrations of the object. It is often difficult to predict the resonance frequencies of bounded elastic targets using exact methods. It has been shown, however, that resonances arise due to phase matching of circumferential waves traveling over the object surf...

In this paper, we are concerned with the detection of point-like obstacles using elastic waves. We show that one type of waves, either the P or the S scattered waves, is enough for localizing the points. We also show how the use of S incident waves gives better resolution than the P waves. These affirmations are demonstrated by several numerical examples using a MUSIC type algorithm.

We consider elastic waves in materials with cylindrical orthotropy, this being a plausible model for wood. For time-harmonic motions, the problem is reduced to some coupled ordinary differential equations. Previously, these have been solved using the method of Frobenius (power-series expansions). We use Neumann series (expansions in Bessel functions of various orders), motivated by the known cl...