scholarly journals Influence of tangential displacement on the adhesion strength of a contact between a parabolic profile and an elastic half-space

2017 ◽  
Vol 4 (8) ◽  
pp. 161010 ◽  
Author(s):  
Valentin L. Popov ◽  
Iakov A. Lyashenko ◽  
Alexander E. Filippov
Keyword(s):  
Half Space ◽  
Adhesion Strength ◽  
Adhesion Force ◽  
Tangential Force ◽  
Elastic Half Space ◽  
Tangential Displacement ◽  
Bodies Of Revolution ◽  
Parabolic Profile ◽  
Rotationally Symmetric ◽  
Adhesive Contacts

The adhesion strength of a contact between a rotationally symmetric indenter and an elastic half-space is analysed analytically and numerically using an extension of the method of dimensionality reduction for superimposed normal/tangential adhesive contacts. In particular, the dependence of the critical adhesion force on the simultaneously applied tangential force is obtained and the relevant dimensionless parameters of the problem are identified. The fracture criterion used coincides with that suggested by Johnson. In this paper, it is used to develop a method that is applicable straightforwardly to adhesive contacts of arbitrary bodies of revolution with compact contact area.

scholarly journals Influence of Tangential Displacement on the Adhesion Force between Gradient Materials

2020 ◽  
Vol 65 (3) ◽  
pp. 205
Author(s):  
I. A. Lyashenko ◽  
Z. M. Liashenko
Keyword(s):  
Normal Force ◽  
Adhesion Force ◽  
Tangential Force ◽  
Adhesive Contact ◽  
Critical Force ◽  
Tangential Displacement ◽  
Optimal Parameters ◽  
Gradient Materials ◽  
Force Components ◽  
Adhesive Contacts

The influence of a tangential displacement on the strength of the adhesive contacts between gradient materials with different gradings of their properties has been studied. Variants with a controlled force (fixed load) and a controlled displacement (fixed grips) are considered. A relationship between the normal and tangential critical force components at which the contact is destroyed is obtained. It is valid within the whole interval of the gradient parameters, where the detachment criterium is obeyed. The optimal parameters at which the adhesive contact strength is maximum are determined. A case of detachment under the action of only the tangential force, i.e. when the normal force equals zero, is analyzed separately.

Dynamical Response of an Elastic Half-Space to Tangential Surface Loadings

1960 ◽  
Vol 27 (3) ◽  
pp. 559-567 ◽  
Author(s):  
Chi-Chang Chao
Keyword(s):  
Half Space ◽  
Tangential Force ◽  
Elastic Half Space ◽  
The Body ◽  
Plane Boundary ◽  
Tangential Displacement ◽  
Reciprocal Relation ◽  
Dynamical Response ◽  
Static Case ◽  
Vertical Force

Exact and closed-form solutions are obtained for both tangential and vertical surface displacements of a homogeneous isotropic elastic half-space due to the application, at a point on the surface, of a concentrated force tangential to the plane boundary and varying with time as the Heaviside unit function. Similar expressions for the displacements in the interior of the body along a line directly below the applied force are derived. Solutions are obtained by a semi-inverse method with the aid of Laplace and Hankel transforms. The reciprocal relation in the static case, between tangential displacement due to a vertical force and vertical displacement due to a tangential force, is preserved in the dynamic case.

scholarly journals Boundary element method for nonadhesive and adhesive contacts of a coated elastic half-space

2019 ◽  
Vol 234 (1) ◽  
pp. 73-83 ◽  
Author(s):  
Qiang Li ◽  
Roman Pohrt ◽  
Iakov A Lyashenko ◽  
Valentin L Popov
Keyword(s):  
Boundary Element Method ◽  
Boundary Element ◽  
Half Space ◽  
Adhesive Contact ◽  
Elastic Half Space ◽  
Fourier Space ◽  
Numerical Tests ◽  
New Formulation ◽  
Adhesive Contacts ◽  
Element Method

We present a new formulation of the boundary element method for simulating the nonadhesive and adhesive contact between an indenter of arbitrary shape and an elastic half-space coated with an elastic layer of different material. We use the Fast Fourier Transform-based formulation of boundary element method, while the fundamental solution is determined directly in the Fourier space. Numerical tests are validated by comparison with available asymptotic analytical solutions for axisymmetric flat and spherical indenter shapes.

scholarly journals A STUDY ON GROSS SLIP AND FRETTING WEAR OF CONTACTS INVOLVING A POWER-LAW GRADED ELASTIC HALF-SPACE

2019 ◽  
Vol 17 (1) ◽  
pp. 47 ◽  
Author(s):  
Markus Hess
Keyword(s):  
Half Space ◽  
Power Law ◽  
Fatigue Cracks ◽  
Tangential Force ◽  
Contact Problems ◽  
Elastic Half Space ◽  
Fretting Wear ◽  
Partial Slip ◽  
Graded Materials ◽  
Closed Form Solutions

For the steady wear state of two contact problems involving power-law graded materials, closed-form solutions are derived in terms of pressure distribution and limiting shapes of profile. Both gross slip of an initially flat-ended cylindrical punch on a power-law graded half-space and the load-controlled fretting wear under partial slip of an initially parabolic indenter are studied. In the case of gross slip at fixed penetration depth there exists a certain exponent of elastic inhomogeneity, for which the effective volume change takes its maximum value. To minimize wear due to fretting under partial slip, an amplitude dependent design of the material gradient is necessary. For large amplitudes of the tangential force a gradient ranged from a soft surface to a hard ground is beneficial, small amplitudes require a reverse gradient characterized by a hard surface and a soft ground. However, the choice of the material gradient also has a decisive influence on the strength of stress singularities at the contact edge and thus the initiation of fretting fatigue cracks, which is why it is discussed in more detail.

Plastic Yield Conditions for Adhesive Contacts Between a Rigid Sphere and an Elastic Half-Space

2008 ◽  
Vol 131 (1) ◽  
Author(s):  
Yu-Chiao Wu ◽  
George G. Adams
Keyword(s):  
Half Space ◽  
Microelectromechanical Systems ◽  
Elastic Half Space ◽  
Contact Theory ◽  
Rigid Sphere ◽  
Plastic Yield ◽  
Curve Fit ◽  
Axis Of Symmetry ◽  
Adhesive Contacts ◽  
Yield Conditions

Hertz contact theory allows the onset of yielding to be predicted for those contacts in which the effect of adhesion can be neglected. However, in microscale contacts, such as those that occur in microelectromechanical systems (MEMS), yielding will occur for lower loads than those predicted by Hertz. For such cases, the Johnson–Kendall–Roberts (JKR), Derjaguin–Muller–Toporov (DMT), and Greenwood–Johnson (GJ) theories extend the Hertz theory to include the effect of adhesion. The present study gives yield conditions for the JKR, DMT, and Greenwood–Johnson theories of adhesion. Attention is first focused on the initiation of yield along the axis of symmetry of an elastic half-space contacted by a rigid sphere. The results show that the critical loads for the three adhesion theories are close together, but differ significantly from that predicted by Hertz. In fact, it is possible for yielding to occur due to adhesion alone, without an external load. A curve-fit formula is given for the yield load as a function of an adhesion parameter for different Poisson’s ratios. Results are then obtained for the onset of plastic deformation away from the axis of symmetry using the Greenwood–Johnson theory of adhesion.

The efficiency of application of virtual cross-sections method and hypotheses MELS in problems of wave signal propagation in elastic waveguides with rough surfaces

2016 ◽  
pp. 3564-3575 ◽  
Author(s):  
Ara Sergey Avetisyan
Keyword(s):  
Half Space ◽  
Cross Sections ◽  
Classical Method ◽  
Signal Propagation ◽  
Elastic Half Space ◽  
Layered Systems ◽  
Surface Layers ◽  
Inhomogeneous Surface ◽  
Wave Signal ◽  
The Impact

The efficiency of virtual cross sections method and MELS (Magneto Elastic Layered Systems) hypotheses application is shown on model problem about distribution of wave field in thin surface layers of waveguide when plane wave signal is propagating in it. The impact of surface non-smoothness on characteristics of propagation of high-frequency horizontally polarized wave signal in isotropic elastic half-space is studied. It is shown that the non-smoothness leads to strong distortion of the wave signal over the waveguide thickness and along wave signal propagation direction as well.  Numerical comparative analysis of change in amplitude and phase characteristics of obtained wave fields against roughness of weakly inhomogeneous surface of homogeneous elastic half-space surface is done by classical method and by proposed approach for different kind of non-smoothness.

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