Scattering of a plane longitudinal elastic wave by a large convex rigid object with a statistically corrugated surface. I. Perturbation solutions

1974 ◽  
Vol 15 (6) ◽  
pp. 831-841 ◽  
Author(s):  
W. Fan ◽  
Y. M. Chen
Keyword(s):  
Elastic Wave ◽  
Rigid Object ◽  
Corrugated Surface ◽  
Longitudinal Elastic Wave ◽  
Perturbation Solutions

A Hypothesized Mechanistic Model of Longitudinal Wall Motion at the Common Carotid Artery

2019 ◽  
Author(s):  
Zhili Hao ◽  
Leryn Reynolds ◽  
John M. Herre
Keyword(s):  
Carotid Artery ◽  
Elastic Wave ◽  
Common Carotid Artery ◽  
Wall Motion ◽  
Mechanistic Model ◽  
External Source ◽  
Arterial Tree ◽  
Longitudinal Elastic Wave ◽  
Longitudinal Wall ◽  
The Common

Abstract In light of recently recognized independent clinical values of longitudinal wall motion ux(t) at the common carotid artery (CCA) and the struggle on appropriate arterial indices for interpreting ux(t), this paper hypothesizes a mechanistic model of ux(t) and explores clear implications of the antegrade amplitude ux0-ante and retrograde amplitude ux0-retro of ux(t) in systole to the cardiovascular (CV) system. By examining findings on ux(t) and other relevant findings through the lens of the engineering essence of ux(t), a mechanistic model of ux(t) is hypothesized: the left ventricle (LV) base rotation is the excitation source for initiating the longitudinal elastic wave propagating along the arterial tree; wall shear stress at an artery serves as a local external source for supplying energy to the longitudinal elastic wave; and longitudinal elasticity at the arterial wall dictates the wave propagation velocity. Integrating the mechanistic model with findings on ux(t) gives rise to interpretation of ux0-ante and ux0-retro for their clear implications: longitudinal elasticity Exx at the common carotid artery (CCA) is estimated from ux0-ante, and ux0-retro is an inverse indicator of the maximum base rotation of the LV and a positive indicator of longitudinal elasticity at the ascending aorta (AA). For the first time, this model reveals the mechanisms underlying those statistical-based findings on ux(t).

SEISMIC VELOCITY STUDY OF SYNTHETIC CORES

Geophysics ◽  
1957 ◽  
Vol 22 (4) ◽  
pp. 813-820 ◽  
Author(s):  
William O. Murphy ◽  
Joseph W. Berg ◽  
Kenneth L. Cook
Keyword(s):  
Elastic Wave ◽  
Elastic Waves ◽  
Atmospheric Pressure ◽  
Room Temperature ◽  
Seismic Velocity ◽  
Pore Filling ◽  
The Core ◽  
Wave Velocities ◽  
Longitudinal Elastic Wave ◽  
Alcohol Benzene

The velocity of a longitudinal elastic wave through rock at room temperature and at atmospheric pressure depends upon the nature of the rock frame, the porosity of the rock, and the nature of the pore‐filling fluid. In the present investigation longitudinal elastic wave velocities were measured for sixty synthetic cores. The rock frame consisted of sorted quartz sand grains and cement, the percentage of cement varying from ten to fifty percent. The core porosities varied from 8.8 percent to 22 percent. The velocities were measured for dry air‐filled cores and for cores saturated with various liquids. These pore‐filling liquids were distilled water, ethyl alcohol, benzene, carbon tetrachloride, and chloroform. The measured velocities ranged from 2,360 feet per second to 14,710 feet per second. The wave velocity in liquid‐filled cores of 10 percent porosity was approximately twice the velocity for cores of 20 percent porosity, the same type of cement being used in both instances. For any given core, flooded with fluids of wave velocities ranging from 3,000 to 5,000 feet per second, the maximum observed variation in core velocity was around 20 percent. The experimental data fitted the empirical linear equation [Formula: see text] where [Formula: see text] of longitudinal elastic waves passing through the flooded core; [Formula: see text] of longitudinal elastic waves in passing through the saturating fluid. The constant k depends upon the porosity of the rock and the type of cement used. The constant, C, depends upon the nature of the rock frame.

scholarly journals Longitudinal elastic wave control by pre-deforming semi-linear materials

2017 ◽  
Vol 142 (3) ◽  
pp. 1229-1235 ◽  
Author(s):  
Dengke Guo ◽  
Yi Chen ◽  
Zheng Chang ◽  
Gengkai Hu
Keyword(s):  
Elastic Wave ◽  
Longitudinal Elastic Wave ◽  
Wave Control

A Flexural and Longitudinal Elastic Wave Propagation Theory Applied to Ice Floe Impact With Sloping Structures

1987 ◽  
Vol 109 (1) ◽  
pp. 75-84
Author(s):  
C. H. Luk
Keyword(s):  
Wave Propagation ◽  
Elastic Wave ◽  
Beam Theory ◽  
Elastic Solid ◽  
Elastic Wave Propagation ◽  
Finite Difference Approximation ◽  
Difference Approximation ◽  
Propagation Theory ◽  
Longitudinal Elastic Wave ◽  
Impact Problems

This paper presents a one-dimensional flexural and longitudinal elastic wave propagation theory for analysis of ice floe impact with a rigid structure having a constant slope. In this paper, governing differential equations were derived following the Timoshenko beam theory which includes the rotary inertia and shear deformation of the ice beam, as well as the buoyancy effect of the water. The ice material was treated as a homogeneous, isotropic, and linearly elastic solid. Interactions between the longitudinal and flexural waves in the ice sheet, and the boundary conditions imposed by the rigid slope, have been considered. Solution procedures were developed based on the method of characteristics using a fixed grid finite difference approximation in both space and time. Computer solutions were obtained and plots were provided to show ice impact force-time histories and the wave propagation phenomenon for a range of floe impact problems of current interest. Comparisons were also made with other existing methods for calculating ice bending loads on sloping structures.

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