scholarly journals Effect of compressible liquid on the contact between an elastic body and a rigid base with a periodic array of quasielliptic grooves

2017 ◽  
pp. 72-81
Author(s):  
Oleg Kozachok
Keyword(s):  
Elastic Body ◽  
Elastic Half Space ◽  
Transcendental Equation ◽  
Compressible Liquid ◽  
Normal Displacement ◽  
Rigid Base ◽  
Cauchy Kernel ◽  
Hilbert Kernel ◽  
Contact Compliance ◽  
Interface Gaps

The frictionless contact between an elastic body and a rigid base in the presence of a periodically arranged quasielliptic grooves with in interface gaps in the presence of a compressible liquid is modeled. The contact problem formulated for the elastic half-space is reduced to a singular integral equation (SIE) with Hilbert kernel for a derivative of a height of the interface gaps, which is transformed to a SIE with Cauchy kernel that is solved analytically, and a transcendental equation for liquid’s pressure, which has been obtained from the equation of compressible barotropic liquid state. The dependences of the pressure of the liquid, shape of the gaps, average normal displacement and contact compliance of the bodies on the applied load and bulk modulus of the liquid are analysed.

scholarly journals Contact interaction between bodies with wavy relief taking into account interstitial compressible liquid

2017 ◽  
pp. 45-54 ◽  
Author(s):  
Oleg Kozachok
Keyword(s):  
Frictional Contact ◽  
Compressible Liquid ◽  
Normal Displacement ◽  
Cauchy Kernel ◽  
Hilbert Kernel ◽  
Integration Interval ◽  
Elastic Bodies ◽  
Contact Compliance ◽  
Interface Gaps ◽  
Barotropic Liquid

The non-frictional contact between two semi-infinite elastic bodies, one of which has a wavy surface, is considered for the case of interface gaps filled with a compressible barotropic liquid. The contact problem formulated is reduced to a singular integral equation (SIE) with the Hilbert kernel, which is transformed into a SIE with the Cauchy kernel for a derivative of a height of the gaps. A system of transcendental equations for a width of the gaps and a pressure of the liquid is obtained from the condition of boundedness of the SIE solution at the integration interval ends and the equation of state of a compressible barotropic liquid, and then it is solved numerically. The dependences of the width and shape of the gaps, the pressure of the liquid, the average normal displacement and contact compliance of the bodies on the applied load and bulk modulus of the liquid are analyzed.

Contact problem for wavy surfaces in the presence of an incompressible liquid and a gas in interface gaps

2018 ◽  
Vol 24 (11) ◽  
pp. 3381-3393 ◽  
Author(s):  
Oleh Kozachok ◽  
Rostyslav Martynyak
Keyword(s):  
Surface Tension ◽  
Contact Problem ◽  
Incompressible Liquid ◽  
Constant Pressure ◽  
Cauchy Kernel ◽  
Hilbert Kernel ◽  
Elastic Bodies ◽  
Laplace Formula ◽  
Interface Gaps ◽  
Wavy Surfaces

This paper presents a study on smooth elastic contact between two semi-infinite elastic bodies, one of which has a wavy surface, for the case when there are an incompressible liquid, not wetting the surfaces of the bodies, at the central region of each interface gap and a gas under constant pressure at the edges of each gap. Due to the surface tension of the liquid, a pressure drop occurs in the liquid and the gas, which is described by the Laplace formula. The formulated contact problem is reduced to a singular integral equation (SIE) with the Hilbert kernel, which is transformed into a SIE with the Cauchy kernel for a derivative of a height of the gaps. A system of transcendental equations for a width of each gap and a width of the gap region filled with the liquid is obtained from the condition of boundedness of the contact stresses at the gap ends and the condition of liquid amount conservation. It is solved numerically, and the dependences of the width and shape of the gaps, the width of the gap regions filled with the liquid and the contact approach of the bodies on the applied load and the surface tension of the liquid are analyzed.

Guided Surface Waves on an Elastic Half Space

1971 ◽  
Vol 38 (4) ◽  
pp. 899-905 ◽  
Author(s):  
L. B. Freund
Keyword(s):  
Wave Propagation ◽  
Surface Wave ◽  
Surface Waves ◽  
Half Space ◽  
Body Wave ◽  
Three Dimensional ◽  
Elastic Half Space ◽  
Normal Displacement ◽  
Rigid Barrier ◽  
Wave Disturbances

Three-dimensional wave propagation in an elastic half space is considered. The half space is traction free on half its boundary, while the remaining part of the boundary is free of shear traction and is constrained against normal displacement by a smooth, rigid barrier. A time-harmonic surface wave, traveling on the traction free part of the surface, is obliquely incident on the edge of the barrier. The amplitude and the phase of the resulting reflected surface wave are determined by means of Laplace transform methods and the Wiener-Hopf technique. Wave propagation in an elastic half space in contact with two rigid, smooth barriers is then considered. The barriers are arranged so that a strip on the surface of uniform width is traction free, which forms a wave guide for surface waves. Results of the surface wave reflection problem are then used to geometrically construct dispersion relations for the propagation of unattenuated guided surface waves in the guiding structure. The rate of decay of body wave disturbances, localized near the edges of the guide, is discussed.

The impact of a rigid circular cylinder on an elastic solid

1962 ◽  
Vol 255 (1053) ◽  
pp. 153-191 ◽  
Keyword(s):  
Laplace Transform ◽  
Elastic Body ◽  
Contact Area ◽  
Elastic Solid ◽  
Coupled System ◽  
Poisson's Ratio ◽  
Normal Displacement ◽  
Plane Boundary ◽  
The Laplace Transform ◽  
Perfect Adherence

A method is described for approximating to any degree of accuracy the solution of the following problem: An elastic body which is bounded by a plane on one side, but extends to infinity otherwise, is hit by a circular disk of given mass, radius, and initial speed perpendicular to the plane boundary. The whole surface of the disk enters into contact with the elastic body at the same time and stays in contact at all its points from then on. The disk is assumed to be rigid, i.e. it does not allow the particles of the elastic body in the contact area to move relative to each other in a direction perpendicular to the plane boundary. For the relative motion of these particles parallel to the face of the disk several conditions are considered, representing perfect lubrication, various degrees of viscous friction and perfect adherence. With the help of various Mellin transformations a method is indicated which leads to an expansion of the motion in powers of the Laplace transform variable. The case of perfect adherence needs some special consideration, and a simple approximation for the static problem is found. The case of perfect lubrication is then treated in more detail by a different method which replaces the condition of constant normal displacement in the contact area by an equivalent number of requirements for certain averages over the normal displacement in the contact area. The condition of rigidity for the disk is not exactly satisfied, but it is possible to judge the accuracy of the approximation (with the help of asymptotic expansions in the Laplace transform variable) at the initial time, when discrepancies are largest. The concept of ‘mode of vibration’ is introduced. Any transient in the coupled system of elastic body and rigid disk can be described as superposition of modes, each of which is an exponentially damped harmonic oscillation of the coupled system with a frequency and damping constant independent of the particular transient. The motion of the impinging disk is then seen to be dominated mostly by the lowest mode, provided the mass of the disk is not too small. The displacement perpendicular to the boundary outside of the contact area has been calculated. This calculation is not more difficult than the corresponding one in the case of a point-like source at the plane boundary of an elastic solid. Numerical computations were carried out for the case of perfect lubrication with the help of the Elecom digital computer in order to determine the first two modes and their contributions to the motion of the disk. As long as Poisson’s ratio for the elastic solid exceeds 1/4, the results do not depend strongly on the value of Poisson’s ratio. The ratio of the areal mass densities of the disk to the elastic solid is the main parameter of the theory. The shear wave velocity of the elastic solid determines the time scale of the motion.

Mechanics of a thin anisotropic elastic layer and a layer that is bonded to an anisotropic elastic body or bodies

2007 ◽  
Vol 463 (2085) ◽  
pp. 2223-2239 ◽  
Author(s):  
T.C.T Ting
Keyword(s):  
Boundary Conditions ◽  
Thin Layer ◽  
Elastic Body ◽  
Elastic Layer ◽  
Elastic Half Space ◽  
The Body ◽  
Thin Layers ◽  
Effective Boundary ◽  
Effective Boundary Conditions ◽  
Anisotropic Elastic

When a very thin elastic layer is bonded to an elastic body, it is desirable to have effective boundary conditions for the interface between the layer and the body that take into account the existence of the layer. In the literature, this has been done for special anisotropic elastic layers. We consider here the layer that is a general anisotropic elastic material. The mechanics of a thin layer is studied for elastostatics as well as steady state waves. It is shown that one-component surface waves cannot propagate in a semi-infinite thin layer. We then present Love waves in an anisotropic elastic half-space bonded to a thin anisotropic elastic layer. The dispersion equation so obtained is valid for long wavelength. Finally, effective boundary conditions are presented for two thin layers bonded to two surfaces of a plate and a thin layer bonded between two anisotropic elastic half-spaces.

Surface Displacement of a Convective Elastic Half-Space Under an Arbitrarily Distributed Fast-Moving Heat Source

1965 ◽  
Vol 87 (3) ◽  
pp. 729-734 ◽  
Author(s):  
F. F. Ling ◽  
V. C. Mow
Keyword(s):  
Heat Source ◽  
Half Space ◽  
Fast Moving ◽  
Constant Velocity ◽  
Surface Displacement ◽  
Elastic Half Space ◽  
Normal Displacement ◽  
Two Dimensional ◽  
Moving Heat Source ◽  
Thermoelasticity Theory

A solution of the normal displacement of the elastic half-space under an arbitrarily distributed fast-moving heat source of constant velocity within the two-dimensional quasi-static, uncoupled thermoelasticity theory is presented. The surface of the half-space is allowed to dissipate heat by convection. Moreover, an example associated with the problem of elastohydrodynamics is given.

Deformation of a Flexible Disk Bonded to an Elastic Half Space—Application to the Lung

1980 ◽  
Vol 102 (3) ◽  
pp. 234-239 ◽  
Author(s):  
S. J. Lai-Fook ◽  
M. A. Hajji ◽  
T. A. Wilson
Keyword(s):  
Half Space ◽  
Poisson’S Ratio ◽  
Radial Strain ◽  
Lung Parenchyma ◽  
Elastic Half Space ◽  
Poisson's Ratio ◽  
Normal Displacement ◽  
Direct Estimate ◽  
Analytic Expressions ◽  
Flexible Disk

An analysis is presented of the deformation of a homogeneous, isotropic, elastic half space subjected to a constant radial strain in a circular area on the boundary. Explicit analytic expressions for the normal and radial displacements and the shear stress on the boundary are used to interpret experiments performed on inflated pig lungs. The boundary strain was induced by inflating or deflating the lung after bonding a flexible disk to the lung surface. The prediction that the surface bulges outward for positive boundary strain and inward for negative strain was observed in the experiments. Poisson’s ratio at two transpulmonary pressures was measured, by use of the normal displacement equation evaluated at the surface. A direct estimate of Poisson’s ratio was possible because the normal displacement of the surface depended uniquely on the compressibility of the material. Qualitative comparisons between theory and experiment support the use of continuum analyses in evaluating the behavior of the lung parenchyma when subjected to small local distortions.

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