Elliptical Contact Area Between Elastic Bodies Bounded by High Order Surfaces

2005 ◽  
Author(s):  
Emanuel N. Diaconescu
Keyword(s):  
Analytical Solution ◽  
Pressure Distribution ◽  
Fourth Order ◽  
Contact Area ◽  
High Order ◽  
Normal Displacement ◽  
Hertz Theory ◽  
Elastic Bodies ◽  
Surface Normal ◽  
Elliptical Contact

Hertz theory fails when contacting surfaces are expressed by a sum of even polynomials of higher powers than two. An alternative analytical solution implies the knowledge of contact area. In the case of elliptical domains, there are some published proposals for the correlation between pressure distribution and surface normal displacement. This paper identifies the class of high order surfaces which lead to elliptical contact domains and solves a contact between fourth order surfaces.

A Semianalytical Solution for Normal Contacts Involving a Thin Elastic Layer

2008 ◽  
Author(s):  
E. N. Diaconescu ◽  
M. L. Glovnea
Keyword(s):  
Numerical Methods ◽  
Analytical Solution ◽  
Pressure Distribution ◽  
Layer Thickness ◽  
Contact Area ◽  
Elastic Layer ◽  
Constant Thickness ◽  
Elastic Bodies ◽  
Thin Elastic Layer

Many technical assemblies can be modelled by a constant thickness elastic layer pressed between two elastic bodies. These models are solved up to date either by numerical methods or analytically, when the outer bodies are rigid cylinders. This paper advances a semi-analytical solution for the case the outer bodies are identical elastic paraboloids. It is shown that contact area is elliptical having semi-axes dependent on layer thickness and the pressure distribution is half-ellipsoidal.

A Reversed Solution for the Elastic Contacts Between Symmetrical Fourth Order Polynomial Surfaces

2007 ◽  
Author(s):  
E. N. Diaconescu
Keyword(s):  
Numerical Solution ◽  
Pressure Distribution ◽  
Fourth Order ◽  
Contact Area ◽  
Pressure Coefficients ◽  
Order Polynomial ◽  
Fourth Order Polynomial

The paper advances a combined, analytical-numerical solution for the elastic contacts between symmetrical, fourth order polynomial surfaces. This is based on a proposal for contact area and pressure distribution which must generate forth order polynomials for the deformed surface of the halfspace inside contact area. To check this proposal, the normal displacements inside contact area are computed numerically. These agree well with a fourth order polynomial. The effect of contact area and pressure coefficients upon the shape of pressure distribution is evidenced.

scholarly journals Improved Pressure Distribution in Elliptic Elastic Contacts between High-Order Surfaces

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Marilena Glovnea ◽  
Sergiu Spinu ◽  
Emanuel Diaconescu
Keyword(s):  
Pressure Distribution ◽  
Contact Area ◽  
Recurrence Relations ◽  
High Order ◽  
Central Pressure ◽  
Contact Center ◽  
Eighth Order ◽  
Uniform Current ◽  
Derivatives Of ◽  
Contact Parameters

The improvement of mechanical contacts or microcontacts seeks a nearly uniform current density over most of contact area. When microtopography is homogeneous, this aim is achieved if nominal shape of contacting surfaces yields a nearly uniform central pressure which decreases monotonously to zero in contour points. These authors derived recently this shape for circular contacts by employing high-order surfaces. This paper extends this result to elliptical contacts. Some results are used to this end, derived for elliptical elastic contacts between high-order surfaces. As homogeneous high order surfaces lead to a highly nonuniform pressure distribution, central pressure is flattened by making the first derivatives of pressure vanish in contact center. Then, the contacts between fourth, sixth, and eighth, order surfaces are analyzed and recurrence relations for pressure distribution and contact parameters are proposed.

Measurement and Visualization of the Contact Pressure Distribution of Rubber Disks and Tires

1995 ◽  
Vol 23 (4) ◽  
pp. 238-255 ◽  
Author(s):  
E. H. Sakai
Keyword(s):  
Pressure Distribution ◽  
Contact Pressure ◽  
Contact Area ◽  
Light Absorption ◽  
Lateral Force ◽  
Contact Pressure Distribution ◽  
High Definition ◽  
The Road ◽  
Close Relationship ◽  
Processing Techniques

Abstract The contact conditions of a tire with the road surface have a close relationship to various properties of the tire and are among the most important characteristics in evaluating the performance of the tire. In this research, a new measurement device was developed that allows the contact stress distribution to be quantified and visualized. The measuring principle of this device is that the light absorption at the interface between an optical prism and an evenly ground or worn rubber surface is a function of contact pressure. The light absorption can be measured at a number of points on the surface to obtain the pressure distribution. Using this device, the contact pressure distribution of a rubber disk loaded against a plate was measured. It was found that the pressure distribution was not flat but varied greatly depending upon the height and diameter of the rubber disk. The variation can be explained by a “spring” effect, a “liquid” effect, and an “edge” effect of the rubber disk. Next, the measurement and image processing techniques were applied to a loaded tire. A very high definition image was obtained that displayed the true contact area, the shape of the area, and the pressure distribution from which irregular wear was easily detected. Finally, the deformation of the contact area and changes in the pressure distribution in the tread rubber block were measured when a lateral force was applied to the loaded tire.

Mutual influence of the faces contact area and the pre-fracture zone near the tip of the interfacial crack

2020 ◽  
Vol 13 (3) ◽  
pp. 143-161
Author(s):  
M.V. Dudyk
Keyword(s):  
Contact Area ◽  
Fracture Zone ◽  
Mutual Influence ◽  
Interfacial Crack ◽  
Normal Displacement ◽  
Crack Model ◽  
Hopf Equation ◽  
Resistant Material ◽  
Order Of Magnitude ◽  
Crack Faces

BACKGROUND: Under plane strain conditions, a crack model was developed on a plane interface between two different materials, which assumes the existence near its tip of the faces contact area and a narrow lateral pre-fracture zone in a less crack-resistant material of the composite compound. The pre-fracture zone is modeled by the line of normal displacement rupture, on which the normal stress is equal to the tensile strength of the material. Assuming that the dimensions of the pre-fracture zone and the contact zone have the same order of magnitude and are significantly smaller than the crack length, the problem is reduced to the vector Wiener–Hopf equation. METHODS: An approximate method for solving the vector Wiener–Hopf equation was developed, which was used to obtain the equations for determining the sizes of the pre-fracture zone and the contact faces area. The pre-fracture zone orientation was determined from the condition of the potential energy maximum accumulated in the zone. Numerical calculations of the indicated parameters and analysis of their dependences on the configuration and module of external load are executed. RESULTS: A significant mutual influence of the pre-fracture zone and crack faces contact on their sizes and orientation of the zone was revealed.

A method for tire wet grip performance evaluation based on grounding characteristics

2021 ◽  
pp. 095440702110158
Author(s):  
Chen Liang ◽  
Maoqing Shan ◽  
Guolin Wang ◽  
Daqian Zhu ◽  
Xingpeng Chen
Keyword(s):  
Pressure Distribution ◽  
Contact Area ◽  
Central Area ◽  
Principal Component ◽  
Area Ratio ◽  
Width Ratio ◽  
Characteristic Parameters ◽  
Radial Tire ◽  
Optical Test ◽  
Wet Grip

The wet grip performance of tire is one of the important performances affecting vehicle safety. The steering, acceleration, and braking of the vehicle are directly affected by the grounding characteristics between the radial tire and the ground. In order to study the influence of grounding characteristics of the tire on wet grip performance, ten 205/55R16 tires produced by different manufacturers were selected and tested. The grounding characteristics of the tires were tested using an optical test rig for tire grounding pressure distribution, considering inflation pressure distribution, load and wheel alignment. The tire-road contact area was subdivided into five parts, and 69 parameters were used to describe the grounding characteristics. A software was proposed to process the test results automatically, and 69 grounding characteristic parameters of each tire were obtained. Correlation analysis on tire wet grip performance and grounding characteristics was used for selecting the principal parameters. Finally, eight grounding characteristic parameters related to tire wet grip performance was obtained. Among them are five grounding characteristic parameters (central area rectangle ratio, central area width, internal shoulder length-to-width ratio, external and internal shoulder contact area ratio, external and internal shoulder impression area ratio) which have high correlation to tire wet grip performance, and three grounding characteristic parameters (external shoulder width, external shoulder length-to-width ratio, external and internal shoulder width ratio) which have low correlation to the wet grip performance of the tire. The principal component analysis method was used to analyze the highly correlated grounding characteristic parameters, and the regression equation for evaluating tire wet grip performance was fitted. The comparison of experimental and fitted values show that the errors are within 4%. The result demonstrates that, the method for evaluating wet grip performance of the radial tire through tire-road grounding characteristics was achieved.

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