scholarly journals Exponentially Decaying Pressure Pulse Moving With Constant Velocity on the Surface of a Layered Elastic Material (Superseismic Layer, Subseismic Half Space)

1970 ◽  
Vol 37 (1) ◽  
pp. 141-152 ◽  
Author(s):  
J. P. Wright ◽  
M. L. Baron
Keyword(s):  
Half Space ◽  
Constant Velocity ◽  
Moving Load ◽  
Elastic Half Space ◽  
Normal Surface ◽  
Entire Plane ◽  
Normal Loading ◽  
Wave Speeds ◽  
S Waves ◽  
Typical Configuration

The response of a layered elastic half space to a progressing exponentially decaying normal surface pressure is evaluated for a case in which the constant velocity V of the moving pressure is greater than that of the P and S waves, respectively, in the upper layer (superseismic) and smaller than these wave speeds in the underlying half space (subseismic). It is assumed that a steady state exists with respect to coordinate axis attached to the moving load. The superseismic-subseismic geometry results in a stress field that extends over the entire plane, with sharp shocks possible only in that portion of the layer that lies behind the front of the progressing normal loading. A computer program for evaluating stresses and velocities at points in the medium was developed and results are presented for a typical configuration of interest.

Transient Green’s Function Behavior for a Prestressed Highly Elastic Half-Space

2000 ◽  
Vol 68 (2) ◽  
pp. 162-168 ◽  
Author(s):  
L. M. Brock
Keyword(s):  
Half Space ◽  
Rayleigh Waves ◽  
Arbitrary Constant ◽  
Elastic Half Space ◽  
Normal Surface ◽  
Poisson Effect ◽  
Wave Speeds ◽  
Wave Patterns ◽  
Infinitesimal Deformations ◽  
Surface Loads

A plane-strain study of a prestressed isotropic compressible neo-Hookean half-space subjected to shear and normal surface loads is performed. The loads are either stationary and applied for an instant, or travel at an arbitrary constant speed. The transient process is viewed as the superposition of infinitesimal deformations upon large, and exact expressions for the displacements, within and upon, the half-space are obtained. These, and the associated wave patterns, demonstrate the anisotropy induced by prestress. The wave speeds themselves are sensitive to prestress; in particular, Rayleigh waves disappear beyond a critical compressive prestress. A critical tensile prestress also exists, beyond which a negative Poisson effect occurs.

scholarly journals Dynamics of inhomogeneous elastic half-space under moving load

2019 ◽  
Vol 97 ◽  
pp. 05048
Author(s):  
Bakhtiyor Yuldashev ◽  
Sagdulla Abdukadirov
Keyword(s):  
Half Space ◽  
Numerical Solutions ◽  
Moving Load ◽  
Elastic Base ◽  
Elastic Half Space ◽  
Thin Elastic Plate ◽  
Wave Processes ◽  
Load Effect ◽  
Time Period ◽  
Resonant Processes

Wave processes in an elastic half-space covered with an elastic layer and (or) a thin elastic plate are considered in the paper. External load moves along the free surface. In the stationary statement, the waveguide properties of the system are determined. The multiple roots of the dispersion equations are revealed and the critical load velocities, leading to the initiation of resonant processes, are determined. In the case when the load moves with the velocity of the Rayleigh wave, additional resonances determined by the structure can be realized in the structure under consideration. It is revealed that Rayleigh resonance exists for long waves only. Numerical solutions are obtained that make it possible to trace the development of resonant excitations. The models of simple structures that have dispersive properties in the medium wave zone are analyzed, such as a thin plate on an elastic base; a model with an attached inertial medium. Analytical solutions have been obtained for these models. Computer simulations conducted simultaneously allow us to analyze the quantitative features of process throughout the entire time period of the load effect. The numerical and asymptotic solutions are compared.

scholarly journals Application of low-order potential solutions to higher-order vertical traction boundary problems in an elastic half-space

2018 ◽  
Vol 5 (5) ◽  
pp. 180203 ◽  
Author(s):  
Adam G. Taylor ◽  
Jae H. Chung
Keyword(s):  
Boundary Condition ◽  
Half Space ◽  
Granular Media ◽  
Elastic Half Space ◽  
Higher Order ◽  
Classical Solutions ◽  
Internal Stresses ◽  
Normal Surface ◽  
Soil Medium ◽  
Traction Distribution

New solutions of potential functions for the bilinear vertical traction boundary condition are derived and presented. The discretization and interpolation of higher-order tractions and the superposition of the bilinear solutions provide a method of forming approximate and continuous solutions for the equilibrium state of a homogeneous and isotropic elastic half-space subjected to arbitrary normal surface tractions. Past experimental measurements of contact pressure distributions in granular media are reviewed in conjunction with the application of the proposed solution method to analysis of elastic settlement in shallow foundations. A numerical example is presented for an empirical ‘saddle-shaped’ traction distribution at the contact interface between a rigid square footing and a supporting soil medium. Non-dimensional soil resistance is computed as the reciprocal of normalized surface displacements under this empirical traction boundary condition, and the resulting internal stresses are compared to classical solutions to uniform traction boundary conditions.

The Dynamic Response of an Elastic Half Space With an Overlying Acoustic Fluid

1976 ◽  
Vol 43 (1) ◽  
pp. 39-42 ◽  
Author(s):  
B. E. Bennett ◽  
G. Herrmann
Keyword(s):  
Dynamic Response ◽  
Half Space ◽  
Elastic Solid ◽  
Elastic Half Space ◽  
Plane Interface ◽  
Dynamic Problems ◽  
Normal Loading ◽  
The Past ◽  
Method Of Solution ◽  
Acoustic Fluid

A class of dynamic problems involving a semi-infinite elastic solid with an overlying semi-infinite acoustic fluid, subjected at the plane interface to arbitrary normal loading is investigated. A method of solution is proposed which reduces the class of problems under study to that in which the fluid is absent. This latter class has received considerable consideration in the past. A specific example is presented for an expanding disk-shaped load including numerical results for the subseismic range.

scholarly journals Surface Displacements due to a Steadily Moving Point Force

1996 ◽  
Vol 63 (2) ◽  
pp. 245-251 ◽  
Author(s):  
J. R. Barber
Keyword(s):  
Closed Form ◽  
Half Space ◽  
Elastic Half Space ◽  
Point Force ◽  
Two Dimensional ◽  
Normal Surface ◽  
Displacement Fields ◽  
Linear Superposition ◽  
Surface Displacements ◽  
Stress And Displacement Fields

Closed-form expressions are obtained for the normal surface displacements due to a normal point force moving at constant speed over the surface of an elastic half-space. The Smirnov-Sobolev technique is used to reduce the problem to a linear superposition of two-dimensional stress and displacement fields.

Moving Load on a Plate Resting on an Elastic Half Space

1967 ◽  
Vol 34 (4) ◽  
pp. 910-914 ◽  
Author(s):  
J. D. Achenbach ◽  
S. P. Keshava ◽  
G. Herrmann
Keyword(s):  
Half Space ◽  
Moving Load ◽  
Elastic Half Space ◽  
Winkler Foundation ◽  
Bending Moments ◽  
Line Load ◽  
Resonance Effects ◽  
Small Load ◽  
Smooth Contact ◽  
Time Invariant

An elastic plate supported by a semi-infinite elastic continuum is subjected to a moving line load. Both welded and smooth contact between plate and foundation are considered. Dynamic solutions for the bending moments in the plate are presented that are time-invariant relative to a coordinate system moving with the load. Resonance effects at certain critical velocities are discussed. The response of the system depends significantly on the relative stiffness of plate and half space and on the type of contact. For the relatively stiff plate certain resonances occur for smooth contact but not for welded contact. For subcritical load velocities the bending moments are calculated and compared with corresponding bending moments for a plate on a Winkler foundation. The Winkler foundation is adequate for smooth contact and small load velocities.

scholarly journals Near-Resonant Regimes of a Moving Load on a Pre-Stressed Incompressible Elastic Half-Space

2021 ◽  
Vol 15 (1) ◽  
pp. 30-36
Author(s):  
Askar Kudaibergenov ◽  
Askat Kudaibergenov ◽  
Danila Prikazchikov
Keyword(s):  
Surface Wave ◽  
Half Space ◽  
Moving Load ◽  
Elastic Half Space ◽  
Elementary Functions ◽  
Material Models ◽  
Line Load ◽  
Transient Regimes ◽  
Surface Wave Field ◽  
Asymptotic Formulation

Abstract The article is concerned with the analysis of the problem for a concentrated line load moving at a constant speed along the surface of a pre-stressed, incompressible, isotropic elastic half-space, within the framework of the plane-strain assumption. The focus is on the near-critical regimes, when the speed of the load is close to that of the surface wave. Both steady-state and transient regimes are considered. Implementation of the hyperbolic–elliptic asymptotic formulation for the surface wave field allows explicit approximate solution for displacement components expressed in terms of the elementary functions, highlighting the resonant nature of the surface wave. Numerical illustrations of the solutions are presented for several material models.

scholarly journals Reduced model for the surface dynamics of a generally anisotropic elastic half-space

2020 ◽  
Vol 476 (2234) ◽  
pp. 20190590 ◽  
Author(s):  
Yibin Fu ◽  
Julius Kaplunov ◽  
Danila Prikazchikov
Keyword(s):  
Surface Wave ◽  
Half Space ◽  
Travelling Waves ◽  
Moving Load ◽  
Multiple Scale ◽  
Elastic Half Space ◽  
Surface Dynamics ◽  
Near Surface ◽  
Surface Resonance ◽  
Anisotropic Elastic

Near-surface resonance phenomena often arise in semi-infinite solids. For instance, when a moving load with a speed v close to the surface wave speed v R is applied to the surface of an elastic half-space, it will give rise to a large-amplitude disturbance inversely proportional to v  −  v R . The latter can be determined by a multiple-scale approach using an extra slow time variable. It has also been shown for isotropic elastic half-spaces that the reduced governing equation thus derived is capable of describing the surface wave contribution even for arbitrary dynamic loading. In this paper, we first derive the analogous evolution equation for a generally anisotropic elastic half-space, and then assess its applicability in the study of travelling waves in a half-space that is coated with a continuous array of spring-like vertical resonators or bonded to an elastic layer of different properties. Our results are validated by comparison with previously known results, and illustrative calculations are carried out for a fibre-reinforced half-space and a coated half-space that is subjected to a finite deformation.

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