The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
The rolling or sliding contact of an elastic cylinder and a layered foundation has been investigated. The substrate of the foundation was modeled as a two-dimensional elastic half-space. The one-dimensional Maxwell model was used to describe the normal and tangential compliance of the viscoelastic surface layer bonded to the substrate. Conditions of partial and full slip within the contact area were...
Following the formation of corrugations on a two-disk machine in the laboratory, theoretical analysis predicted that contact damping would be an effective factor to prevent corrugations. One idea to get high contact damping is the use of high damping materials. Recently a high damping alloy was developed in Japan and there is the possibility of applying it in wheel-rail systems. The value of the logarithmic...
A well-developed 'squat' grows at about 10° to the upper surface of the rail. It is observed that this shallow angled rolling contact fatigue crack may change its growth direction; either to branch downwards and grow at about 55° to the rail surface or to branch upwards. Various research workers have shown that the crack is subjected to a characteristic sequence of tensile and shear stresses. The...
Previous elastic-plastic stress analyses of rolling contact have not produced accurate results of shear strain accumulation because the plasticity models applied in contact analysis were not designed to handle long term ratchetting behavior of a material. In this work, we studied the residual stresses and progressive shear strain ratchetting for the line rolling contact problems utilizing a recently...
The effects of varying contact pressure and creepage on the early stages of rolling contact fatigue in three pearlitic rail steels have been investigated in the laboratory under water lubricated conditions. In the test machine used, a non-contacting eddy current probe detected very small fatigue cracks and was used to stop tests before spalling could destroy the fatigue initiation sites in order that...
Microstructural changes and propagation of subsurface cracks during rolling contact have been studied to clarify rolling contact fatigue of 0.44%C–1.71%Mn induction-hardened bearing steels, using the specimens with different induction-hardened layer. The specimens were pre-treated to form lower bainite and induction-hardened to form fine martensite in shallow induction-hardened layer or coarse martensite...
Hard coatings, which are used to protect surfaces that are subjected to contact loading, may fracture or delaminate from their substrates. A simple model of this process is presented. The coating is idealized as a brittle elastic layer of uniform thickness, which is bonded to the surface of a half-space. The coating, substrate, and interface are assumed to contain microcracks. The solid is loaded...
Wear of steel (AISI M-50 and AISI 52100) bearing balls in lubricated rolling contact with ground and ground-and-lapped silicon nitride rods was studied using a ball-on-rod rolling-contact-fatigue (RCF) tester. The steel balls suffered significant wear in rolling contact with the as-ground (R a = 0.18 μm) silicon nitride rods. The wear volume loss was approximately linear with the rolling distance...
In this paper, we introduce an approximate algorithm for two-dimensional elastic-plastic rolling/sliding line contact which admits arbitrary forms of kinematic hardening models for nonproportional cyclic plasticity. The new hybrid scheme combines attractive features of the McDowell and Moyar and Sehitoglu and Jiang approaches, enabling prediction of subsurface cyclic plasticity and residual stresses...
Results of the study into the forms of surface failure of cross-linked polystyrene, polycarbonate and polymethylmethacrylate resulting from rolling contact are presented. Also the influence of two different lubricating liquids on the time to failure is quantitatively assessed and discussed. Under the contact stress ranged from 1.5 to 2.6 GPa it was found that in case of certain polymers the surface...
Using a simple modification, a pin-on-disk tribometer was converted to enable roller-on-disk contact. The roller-on-disk geometry was successfully used in wear tests of short to medium duration with a partially-stabilised zirconia disk and a hardened steel roller. The resulting worn surfaces on the ceramic were similar in appearance to those generated by more conventional rolling contact wear testing.
A simple mechanical model has been built to demonstrate some phenomena associated with rolling contact. The model consists of an aluminium bicone (wheelset) and two cylindrical steel rods coated with a layer of polymer. Using this model rolling contact was investigated experimentally and an attempt made to interpret results with available theories for solid elastic bodies. It appeared that none of...
Wear of silicon nitride balls and rods was studied in lubricated rolling contact using a ball-on-rod rolling contact fatigue (RCF) tester. The wear response of both the elements, balls and rods, was transient. The nature of the transient was dependent on the initial surface roughness of the rod, while the total volume loss increased with the initial contact stress. Bearing-grade balls (R a ...
Rolling contact stress and failure analyses were conducted for the Hadfield steel (manganese steel) and the Bainitic alloy (J7). The first alloy is used in diamond crossings and frogs in the railroad industry while the second alloy is a candidate for such applications. A series of fatigue experiments were conducted on these alloys to establish the damage parameters. The proposed fatigue damage parameter...
The role of the strain hardened layer playing in pitting formation during rolling contact is analyzed using the fracture mechanics approach. The other governing factors are the initial crack length, crack angle, contact force, friction on all contact surfaces, and the hydraulic pressure of trapped fluid acting on the crack surfaces. Mode I and II stress intensity factors and the strain energy density...
A new rolling testing apparatus was developed on a tension–compression hydraulic machine with a high precision. The aim of this paper is to study the transition of wear mechanisms of steels with the increase of tangential friction force between contact surfaces in rolling. The wear modes were particularly analyzed during the passage from rolling to mixed rolling–sliding contact.
A calculational model for investigation of the fracture processes and durability of the surface contact zones of rolling bodies has been proposed within the framework of the fatigue fracture mechanics concepts. Unidirection rolling in conditions of dry friction and boundary lubrication has been investigated. The model basis is the algorithm step-by-step construction of the crack growth paths developed...
A model of the fatigue behaviour of three-dimensional (3D) semi-elliptical shallow-angle rolling contact fatigue (RCF) cracks was developed by combining numerically obtained (3D FEM) linear elastic fracture mechanics (LEFM) crack front loading histories with mixed-mode fatigue crack growth rate data. The model was applied for the ''squat'' type of crack-typical of rail RCF failure, to predict (i)...
In this paper the mechanism of effects of structure elastic deformations of bodies in rolling contact on rolling contact performance is briefly analyzed. Effects of structure deformations of wheelset and track on the creep forces of wheel and rail are investigated in detail. General structure elastic deformations of wheelset and track are previously analyzed with finite element method, and the relations,...
Researches on wear and fatigue in rolling contact from a tribological viewpoint are introduced. Transmission of traction and accompanying microslip in the contact region play critical roles in these phenomena. First, a quantitative analysis of wear in rolling contact with microslip is introduced, and it is shown that a simplified microslip theory can explain its behavior. Second, a marked change in...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.