Zeitschriftenartikel: „Traction contactor“

1

Kramarov, Andrey, Denis Batishchev, Irina Bolshenko und Andrey Gummel. „Research of the Influence of a Ferromagnetic Shunt on the Characteristics of the Electromagnetic Actuator of a Low-Voltage Contactor“. Известия высших учебных заведений. Электромеханика 64, Nr. 2 (2021): 44–49. http://dx.doi.org/10.17213/0136-3360-2021-2-44-49.

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The article presents the results of a research of the influence of a ferromagnetic shunt (FMS) on the static and dynamic characteristics of the control electromagnet of the KTP 6000 series contactor by means of computer numerical simulation in the ANSYS Electromagnetic Suite software package. A computer numerical model of an electromagnetic actuator with FMS is proposed and verified, the influence of the geometrical dimensions of the shunt on the static and dynamic characteristics of the electromagnetic actuator of a low-voltage DC contactor is investigated. Recommendations are given for the selection of the FMS dimensions in the design calcu-lation of the valve-type electromagnetic drive, which will increase the dynamic traction force of the electromagnet and reduce its response time.

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Al-Bender, Farid, und Kris De Moerlooze. „A Model of the Transient Behavior of Tractive Rolling Contacts“. Advances in Tribology 2008 (2008): 1–17. http://dx.doi.org/10.1155/2008/214894.

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When an elastic body of revolution rolls tractively over another, the period from commencement of rolling until gross rolling ensues is termed the prerolling regime. The resultant tractions in this regime are characterized by rate-independent hysteresis behavior with nonlocal memory in function of the traversed displacement. This paper is dedicated to the theoretical characterization of traction during prerolling. Firstly, a theory is developed to calculate the traction field during prerolling in function of the instantaneous rolling displacement, the imposed longitudinal, lateral and spin creepages, and the elastic contact parameters. Secondly, the theory is implemented in a numerical scheme to calculate the resulting traction forces and moments on the tractive rolling of a ball. Thirdly, the basic hysteresis characteristics are systematically established by means of influence-parameters simulations using dimensionless forms of the problem parameters. The results obtained are consistent with the limiting cases available in literature and they confirm experimental prerolling hysteresis observations. Furthermore, in a second paper, this theory is validated experimentally for the case of V-grooved track.

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Rajeev, P. T., H. Murthy und T. N. Farris. „Load History Effects on Fretting Contacts of Isotropic Materials“. Journal of Engineering for Gas Turbines and Power 126, Nr. 2 (01.04.2004): 385–90. http://dx.doi.org/10.1115/1.1689364.

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The load history that blade/disk contacts in jet engine attachment hardware are subject to can be very complex. Using finite element method (FEM) to track changes in the contact tractions due to changing loads can be computationally very expensive. For two-dimensional plane-strain contact problems with friction involving similar/dissimilar isotropic materials, the contact tractions can be related to the initial gap function and the slip function using coupled Cauchy singular integral equations (SIEs). The effect of load history on the contact tractions is illustrated by presenting results for an example fretting “mission.” For the case of dissimilar isotropic materials the mission results show the effect of the coupling between the shear traction and the contact pressure.

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Nishimura, T. „Contact Analysis for Collinear Multiple Cracks in Residual Stress Field“. Journal of Pressure Vessel Technology 116, Nr. 2 (01.05.1994): 169–74. http://dx.doi.org/10.1115/1.2929571.

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A method is proposed for analyzing stress intensity factors and crack profiles for collinear multiple cracks perpendicular to welded joints in an infinite plate. Using the basic solution of a single crack and taking unknown density of fictitious tractions, Fredholm integral equations and algebraic equations are formulated based upon traction-free conditions and crack face displacements, respectively. These equations are solved simultaneously, considering the contact effect of crack surfaces. Using the derived density of fictitious tractions, the stress intensity factors and displacements of multiple cracks are determined. Some numerical examples are analyzed.

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Rajeev, P. T., und T. N. Farris. „Numerical analysis of fretting contacts of dissimilar isotropic and anisotropic materials“. Journal of Strain Analysis for Engineering Design 37, Nr. 6 (01.08.2002): 503–17. http://dx.doi.org/10.1243/030932402320950125.

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A numerical method is presented to obtain the contact tractions when two dissimilar isotropic or anisotropic bodies are in partial slip contact. The solution to the governing coupled singular integral equations (SIEs) is obtained by incorporating the appropriate singular behaviour for the contact pressure and the shear traction. The edges of the contact zone and the stick zone are determined by iteration such that the constant multipliers of the singular functions vanish. For anisotropic materials the out-of-plane shear traction is assumed to be very small and hence neglected. The solution method has been successfully verified by comparing its results to solutions available in the literature and to the results obtained by the finite element method (FEM). By modifying the slip function to take into account the remote stress on the half-space, the SIE method can be used to analyse fretting contact problems. The resulting technique efficiently accounts for the effect of load history on the contact tractions and the contact and stick zone sizes. The pronounced effect that load history has on the stick zone size is illustrated.

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Liu, Tie Jun, und Yue Sheng Wang. „The Effect of Poisson’s Ratio on the Contact Traction Distribution of a Functionally Graded Coating“. Advanced Materials Research 197-198 (Februar 2011): 1591–94. http://dx.doi.org/10.4028/www.scientific.net/amr.197-198.1591.

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This paper deals with the finite frictional contact of a functionally graded coating with considering the effect of Poisson’s ratio. We assume that a functionally graded coated half-space is indented by a rigid spherical punch and that the shear modulus of FGMs varies as exponential function. The whole contact region is divided into the central adhesion zone and the slip annulus. Within the slip annulus, the shear stress is limited by friction. By using the Hankel integral transform technique, the problem is reduced to a set of Cauchy singular integral equations. A numerical method is used to get the contact pressure and tangential tractions in the contact region for different Poisson’s ratio. The results show that the variation of Poisson’s ratio has obvious effect on both normal and tangential tractions. With the increase of ν, the peak value of the normal traction increases and that of the tangential traction decreases.

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Hills, D. A., und A. Sackfield. „Sliding Contact Between Dissimilar Elastic Cylinders“. Journal of Tribology 107, Nr. 4 (01.10.1985): 463–66. http://dx.doi.org/10.1115/1.3261109.

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The problem considered is contact between two dissimilar elastic cylinders, having their axes parallel and sliding in a direction normal to the axes. The traction distribution is determined, as are the resultant stresses generated in each body. It is found that the stresses well within the body are not changed greatly from a classical Hertz analysis, where coupling between the normal and shear tractions is neglected, but that there is a first order modification of surface tensile stresses.

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Munisamy, R. L., D. A. Hills und D. Nowell. „A Numerical Analysis of an Elastically Dissimilar Three-Dimensional Sliding Contact“. Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 206, Nr. 3 (Mai 1992): 203–11. http://dx.doi.org/10.1243/pime_proc_1992_206_116_02.

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A numerical method is employed to find the traction distribution caused by sliding contact between a sphere and an elastically dissimilar half-space. The resulting stress field is compared with a standard Hertzian analysis where coupling between the normal and shear tractions is absent. Significant differences are found at the surface for large values of the coefficient of friction.

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Dow, T. A., R. D. Stockwell und J. W. Kannel. „Thermal Effects in Rolling/Sliding EHD Contacts: Part 1—Experimental Measurements of Surface Pressure and Temperature“. Journal of Tribology 109, Nr. 3 (01.07.1987): 503–10. http://dx.doi.org/10.1115/1.3261486.

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This paper discusses the results of a series of experiments to measure the pressure and temperature distribution between a pair of elastohydrodynamically lubricated (EHD) disks. Three lubricants have been studied: a synthetic paraffinic oil (XRM-109F), a polyphenyl ether (OS-124), and a traction fluid (Santotrac 50). Pressure and temperature readings throughout the contact are presented as three-dimensional plots. Simultaneous measurements of the EHD film thickness, and the tractive force between disks under slip conditions are also included. The variables are disk load and slip at a fixed surface speed. The highest temperatures were measured with the traction fluid which recorded a temperature rise of 50 degrees C through the contact.

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Mocera, Francesco, Aurelio Somà und Andrea Nicolini. „Grousers Effect in Tracked Vehicle Multibody Dynamics with Deformable Terrain Contact Model“. Applied Sciences 10, Nr. 18 (21.09.2020): 6581. http://dx.doi.org/10.3390/app10186581.

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In this work, a multibody model of a small size farming tracked vehicle is shown. Detailed models of each track were coupled with the rigid body model of the vehicle. To describe the interaction between the track and the ground in case of deformable soil, custom defined forces were applied on each link of the track model. Their definition derived from deformable soil mechanics equations implemented with a specifically designed routine within the multibody code. According to the proposed model, it is assumed that the main terrain deformation is concentrated around the vehicle tracks elements. The custom defined forces included also the effects of the track grousers which strongly affect the traction availability for the vehicle. A passive soil failure model was considered to describe the terrain behaviour subjected to the grousers action. A so developed model in a multibody code can investigate vehicle performance and limit operating conditions related to the vehicle and soil characteristics. In this work, particular attention was focused on the results in terms of traction force, slip and sinkage on different types of terrain. Tests performed in the multibody environment show how the proposed model is able to obtain tractive performance similar to equivalent analytical solutions and how the grousers improve the availability of tractive force for certain type of soil characteristics.

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Huang, Shiping, und Anil Misra. „Path-dependent analysis of elastic sphere contact subjected to tangential loading with varying directions“. Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology 226, Nr. 8 (07.03.2012): 678–86. http://dx.doi.org/10.1177/1350650112440414.

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The Cattaneo–Mindlin solutions of contact between elastic spheres and their recent extensions do not consider the sequential application of arbitrarily directed shear forces in the contact tangential plane. For this loading condition, the contact tractions simultaneously undergo loading and unloading. This article presents a path-dependent analysis wherein we use superposition at each loading step to obtain the contact tangential traction, and, subsequently the tangential displacement and compliance. The methodology is illustrated by example calculation of contact shear force–displacement relationship, which shows the formation of hysteretic loop and the noncoaxiality of the shear forces and displacements.

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Xiang, Hui Yu, De Mao Hu, Chong Jie Leng und Yan Jue Gong. „The Finite Element Analysis of Rotor Contact Strength for a High-Speed Traction Motor“. Advanced Materials Research 503-504 (April 2012): 876–79. http://dx.doi.org/10.4028/www.scientific.net/amr.503-504.876.

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In order to evaluate the contact strength of a type of high-speed train traction motor rotor，in this paper, for the high speed test train traction motor under the five working conditions, Based on the established motor rotor 3D model, NX.Nastran environment, the contact pressure between rotor and lamination is analyzed by the finite element and got the stress intensity distribution on the rotor. The five working condition include starting, constant work starting condition, rated, short circuit condition, the highest speed condition. The result shows that for the high speed tractor motor, in the starting conditions, and won't appear rotor shaft and laminated relation between slip. The finite element method is useful to do the contact strength analysis, and thus to improve the design efficiency, increase the reliability of the product, and lay the foundation for the latter design optimization.

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Hirst, W., und J. W. Richmond. „Traction in Elastohydrodynamic Contacts“. Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 202, Nr. 2 (März 1988): 129–44. http://dx.doi.org/10.1243/pime_proc_1988_202_098_02.

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The magnitude of the traction in elastohydrodynamic lubrication is influenced by at least two non-Newtonian effects. At very high pressures, the lubricant becomes noticeably viscoelastic and behaves as an elastic solid when the shear stress is small. At high values of the shear stress, the relation between the stress and the shear rate becomes non-linear and, when thermal effects are insignificant, conforms to the Eyring expression for viscosity. In general, however, the elastic region, the non-linear isothermal region and the thermal region are not separate and distinct but merge gradually into each other. This makes it difficult, experimentally, to determine the magnitude of the parameters controlling the behaviour of the fluid and, conversely, to predict from them the shape of the traction curve. The present paper examines these problems and shows that the major uncertainty is caused by the dearth of knowledge of the thermal properties of fluids at very high pressures. [These have been measured in an associated investigation by Richmond et al. (1).] It is shown that, when the correct values of the thermal properties are used and allowance is also made for the merging of the various regions of the traction curve, parameters may be derived from which the shape of the traction curve can be predicted within experimental error. In the non-linear region the Eyring relation is obeyed at pressures well above the usual glass transition pressure and it is concluded that in the extreme conditions of shear stress typical of elastohydrodynamic lubrication the glassy state is not achieved.

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De Pascalis, Chiara, Carlos Pérez-González, Shailaja Seetharaman, Batiste Boëda, Benoit Vianay, Mithila Burute, Cécile Leduc, Nicolas Borghi, Xavier Trepat und Sandrine Etienne-Manneville. „Intermediate filaments control collective migration by restricting traction forces and sustaining cell–cell contacts“. Journal of Cell Biology 217, Nr. 9 (06.07.2018): 3031–44. http://dx.doi.org/10.1083/jcb.201801162.

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Mesenchymal cell migration relies on the coordinated regulation of the actin and microtubule networks that participate in polarized cell protrusion, adhesion, and contraction. During collective migration, most of the traction forces are generated by the acto-myosin network linked to focal adhesions at the front of leader cells, which transmit these pulling forces to the followers. Here, using an in vitro wound healing assay to induce polarization and collective directed migration of primary astrocytes, we show that the intermediate filament (IF) network composed of vimentin, glial fibrillary acidic protein, and nestin contributes to directed collective movement by controlling the distribution of forces in the migrating cell monolayer. Together with the cytoskeletal linker plectin, these IFs control the organization and dynamics of the acto-myosin network, promoting the actin-driven treadmilling of adherens junctions, thereby facilitating the polarization of leader cells. Independently of their effect on adherens junctions, IFs influence the dynamics and localization of focal adhesions and limit their mechanical coupling to the acto-myosin network. We thus conclude that IFs promote collective directed migration in astrocytes by restricting the generation of traction forces to the front of leader cells, preventing aberrant tractions in the followers, and by contributing to the maintenance of lateral cell–cell interactions.

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Jaffar, M. J. „A general solution to the axisymmetric frictional contact problem of a thin bonded elastic layer“. Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 211, Nr. 7 (01.07.1997): 549–57. http://dx.doi.org/10.1243/0954406971521935.

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The configuration of a thin elastic layer bonded firmly to a rigid substrate and pressed by a spherical punch has been used as a model to many problems arising in the field of biomechanics. This work presents a rigorous analysis of a thin bonded layer indented by a punch of general profile in the presence of the radial tangential traction. The method is based on perturbation theory. Formulae for stresses, strains and deformations are derived in terms of layer thickness, material properties and surface tractions. The results are illustrated by the evaluation of the expressions for several simple punch shapes. The influence of friction on the results is also examined. Good agreement is found between the present solution and the results reported in the literature.

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Loewenthal, S. H. „Spin Analysis of Concentrated Traction Contacts“. Journal of Mechanisms, Transmissions, and Automation in Design 108, Nr. 1 (01.03.1986): 77–84. http://dx.doi.org/10.1115/1.3260788.

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Spin, the result of a mismatch in contact radii on either side of the point of rolling, has a detrimental effect on traction contact performance. It occurs in concentrated contacts having conical or contoured rolling elements, such as those in traction drives or angular contact bearings, and is responsible for an increase in contact heating and power loss. This investigation examines the kinematics of spin-producing contact geometries and the subsequent effect on traction and power loss. The influence of lubricant traction characteristics and contact geometries that minimize spin are also addressed.

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Reddyhoff, T., H. A. Spikes und A. V. Olver. „Improved infrared temperature mapping of elastohydrodynamic contacts“. Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology 223, Nr. 8 (02.06.2009): 1165–77. http://dx.doi.org/10.1243/13506501jet499.

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An effective means of studying lubricant rheology within elastohydrodynamic contacts is by detailed mapping of the temperature of the fluid and the bounding surfaces within the lubricated contact area. In the current work, the experimental approach initially developed by Sanborn and Winer and then by Spikes et al., has been advanced to include a high specification infrared (IR) camera and microscope. Besides the instantaneous capture of full field measurements, this has the advantage of increased sensitivity and higher spatial resolution than previous systems used. The increased sensitivity enables a much larger range of testable operating conditions: namely lower loads, speeds, and reduced sliding. In addition, the range of test lubricants can be extended beyond high shearing traction fluids. These new possibilities have been used to investigate and compare the rheological properties of a range of lubricants: namely a group I and group II mineral oil, a polyalphaolephin (group IV), the traction fluid Santotrac 50, and 5P4E, a five-ring polyphenyl-ether. As expected, contact temperatures increased with lubricant refinement, for the mineral base oils tested. Using moving heat source theory, the measured temperature distributions were converted into maps showing rate of heat input into each surface, from which shear stresses were calculated. The technique could therefore be validated by integrating these shear stress maps, and comparing them with traction values obtained by direct measurement. Generally there was good agreement between the two approaches, with the only significant differences occurring for 5P4E, where the traction that was deduced from the temperature over-predicted the traction by roughly 15 per cent. Of the lubricants tested, Santotrac 50 showed the highest average traction over the contact; however, 5P4E showed the highest maximum traction. This observation is only possible using the IR mapping technique, and is obscured when measuring the traction directly. Both techniques showed the effect of shear heating causing a reduction in traction.

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TAKEHARA, Koh. „Traction of Rolling Contact Drives“. Journal of the Society of Mechanical Engineers 88, Nr. 805 (1985): 1361–66. http://dx.doi.org/10.1299/jsmemag.88.805_1361.

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Nosonovsky, M., und G. G. Adams. „Steady-State Frictional Sliding of Two Elastic Bodies With a Wavy Contact Interface“. Journal of Tribology 122, Nr. 3 (18.01.2000): 490–95. http://dx.doi.org/10.1115/1.555391.

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Dry frictional sliding of two elastic bodies, one of which has a periodic wavy surface, is considered. Such a model represents the frictional sliding of two nominally flat surfaces, one of which has periodically spaced asperities. The dependence of the true contact area on loading is analyzed by using the plane strain theory of elasticity. Fourier series and integral transform techniques are applied to reduce the problem to an integral equation which is solved using a series of Jacobi polynomials. For steady-state dynamic frictional sliding with given values of the friction coefficient, materials constants, and sliding velocity, the dependence of the contact zone length on the remotely applied tractions is determined. The results indicate a decrease of the minimum applied traction required to close the gap between the bodies, with an increase of the friction coefficient and/or the sliding velocity. A resonance exists as the sliding velocity approaches the Rayleigh wave speed of the flat body. [S0742-4787(00)01403-X]

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Jones, I. A., P. Wang und A. A. Becker. „Constrained least-squares solution and regularization in inverse boundary element analysis of photoelastic models involving contact“. Journal of Strain Analysis for Engineering Design 46, Nr. 8 (31.10.2011): 709–26. http://dx.doi.org/10.1177/0309324711424680.

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Existing work by the present team has involved the development of an inverse boundary element approach for fitting unknown boundary conditions to full-field stress data obtained using photoelasticity, treating the displacements on the unknown region as the solution variables. However, the recovered boundary conditions sometimes show unrealistic features such as negative contact pressures or shear tractions which exceed realistic frictional values; noisy or incomplete input data make these problems worse and can make the results oscillatory. The work described here exploits available constrained least-squares techniques in order to express the contact conditions as linear inequality constraints upon the displacement solution. A variant of Tikhonov regularization is also used to penalize against oscillatory traction distributions on the unknown boundary. The chosen implementation, solved using the LSSOL algorithm, can handle the issue of rigid-body motion without the need for manual imposition of restraints. The technique is illustrated using simulated and real examples, demonstrating that the technique correctly reconstructs the individual principal stresses.

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Chen, Shaohua, und Huajian Gao. „Non-slipping adhesive contact of an elastic cylinder on stretched substrates“. Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 462, Nr. 2065 (11.11.2005): 211–28. http://dx.doi.org/10.1098/rspa.2005.1553.

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The plane strain problem of an elastic cylinder in adhesive contact with a stretched substrate is studied via a generalized JKR model taking into account the transmission of both tangential and normal tractions across the contact interface. The width of the contact region is determined from the Griffith energy balance near the contact edge. In the absence of external loading, the tangential traction is found to have a negligible effect on the contact size. As an external stress is applied to stretch the substrate, the contact solution exhibits three distinct regimes characterized by two threshold strains: (i) the size of the contact region is hardly affected by the applied loading when the substrate strain is below the first threshold level; (ii) the contact size decreases quickly with stretch as the substrate strain increases to between the two threshold levels; (iii) the contact size approaches zero when the substrate strain exceeds the second threshold level. Interestingly, these results share a number of common features with the experimentally observed cell reorientation on a cyclically stretched substrate. An approximate solution is presented in an appendix to represent the numerical results in closed form.

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Tozaki, Yasuyoshi, Akihiko Umeda, Hiroyuki Sonobe, Susumu Matsumoto, Takeshi Yoshimi und Isamu Shiotsu. „Performance Evaluation of Innovative Micro-Traction-Drive-Utilized Angular-Contact Bearing“. Journal of Tribology 128, Nr. 2 (27.09.2005): 262–66. http://dx.doi.org/10.1115/1.2162177.

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Traction drive makes oil film between two rollers, and power is transmitted by oil film shearing. It has the following characteristics. (1) Traction drive can be operated at low level of vibration and noise, so they are more suitable at higher speed rotations than gear. (2) Traction drive can change continuously the distance from the contact point of the rotating part to the axis of rotation; it is useful in continuously variable transmission (CVT). Generally-fixed-reduction-ratio-type traction drive is developed for the purpose of use by high-speed rotation taking advantage of the feature of characteristic (1). On the other hand, the authors have developed a micro drive system for transmission; a micro-traction-drive based on the structure of an angular ball bearing is advantageous over geared speed reducers, for small scale equipment requiring high numbers of revolutions. A micro-traction-drive is easily manufactured by modifying angular bearings and tapered roller bearings for which preload inner race and outer race act as thrust force. The driving force is transmitted by the contact of the retainer with the rolling element in the rotating direction. The test of the experimental model of micro-traction-drive using an angular ball bearing of 10mm inner diameter, 30mm outer diameter, and 9mm width was carried out. Power-absorbing-type test equipment was made and the input and output torque, number of revolutions, temperature, noise, and state of lubrication were measured. With the same test equipment, the micro-traction-drive was compared to the equivalent type planetary gear with outer diameter of 32mm on the market. In comparison with commercially available speed reducers, the planetary gear system, the newly developed micro-traction was found to bear superior performance in terms of allowable transmission torque, efficiency, noise, and other characteristics.

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Papangelo, A., M. Ciavarella und J. R. Barber. „Fracture mechanics implications for apparent static friction coefficient in contact problems involving slip-weakening laws“. Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 471, Nr. 2180 (August 2015): 20150271. http://dx.doi.org/10.1098/rspa.2015.0271.

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We consider the effect of differing coefficients of static and dynamic friction coefficients on the behaviour of contacts involving microslip. The classic solutions of Cattaneo and Mindlin are unchanged if the transition in coefficients is abrupt, but if it occurs over some small slip distance, the solution has some mathematical similarities with those governing the normal tractions in adhesive contact problems. In particular, if the transition to dynamic slip occurs over a sufficiently small area, we can identify a ‘JKR’ approximation, where the transition region is condensed to a line. A local singularity in shear traction is then predicted, with a stress-intensity factor that is proportional to the square root of the local contact pressure and to a certain integral of the friction coefficient–slip distance relation. We can also define an equivalent of the ‘small-scale yielding’ criterion, which enables us to assess when the singular solution provides a good approximation. One consequence of the results is that the static coefficient of friction determined from force measurements in experiments is significantly smaller than the value that holds at the microscale.

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Yan, Ji-Feng, und Gan-Yun Huang. „A double-Hertz model for adhesive contact between cylinders under inclined forces“. Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 475, Nr. 2221 (Januar 2019): 20180589. http://dx.doi.org/10.1098/rspa.2018.0589.

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A generalized double-Hertz (D-H) model has been proposed to consider the adhesive contact between an elastic cylinder and an elastic half space under inclined forces. The normal traction is exactly the same as that in the conventional D-H model. The shear traction of finite value is distributed into a slipping zone and a non-slipping zone. In the slipping zone, the shear traction is proportional to the compressive pressure. With the model, adhesive contact behaviour between cylinders has been numerically illustrated. The shear-induced peeling has been demonstrated. The value of the ratio for shear traction to normal traction larger than friction coefficient has been found in part of the non-slipping zone. Those altogether are consistent with experiments.

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Gong, Z. Q., und K. Komvopoulos. „Thermomechanical Analysis of Semi-infinite Solid in Sliding Contact With a Fractal Surface“. Journal of Tribology 127, Nr. 2 (01.04.2005): 331–42. http://dx.doi.org/10.1115/1.1792691.

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A thermomechanical analysis is presented for a semi-infinite elastic solid sliding against a rigid, rough surface characterized by fractal geometry. A piecewise-linear distribution of the contact pressure was obtained by superposition of overlapping triangular pressure elements. The normal surface displacements due to the effects of contact pressure, shear traction, and thermoelastic distortion caused by frictional heating are incorporated in the influence coefficients of the matrix-inversion method. Results for a smooth, cylindrical surface sliding over a semi-infinite elastic solid demonstrate the accuracy of the analysis and provide reference for comparison with results obtained with the rough (fractal) surface. The effects of surface topography and interaction between neighboring asperity microcontacts on the surface and subsurface temperature rise and stress field of the elastic semi-infinite solid are discussed in the context of numerical results. The significance of frictional heating on the contact pressure, temperature rise, and stresses is interpreted in terms of the Peclet number and topography (fractal) parameters. The results provide insight into the likelihood for cracking and plastic flow at the surface due to the combined effects of mechanical and thermal surface tractions.

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Ganz, Arthur, Mireille Lambert, Alexandre Saez, Pascal Silberzan, Axel Buguin, René Marc Mège und Benoît Ladoux. „Traction forces exerted through N-cadherin contacts“. Biology of the Cell 98, Nr. 12 (Dezember 2006): 721–30. http://dx.doi.org/10.1042/bc20060039.

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Jacod, B., C. H. Venner und P. M. Lugt. „A Generalized Traction Curve for EHL Contacts“. Journal of Tribology 123, Nr. 2 (08.06.2000): 248–53. http://dx.doi.org/10.1115/1.1308021.

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In this paper the subject of friction prediction is revisited, with the aim of obtaining a general formula predicting the coefficient of friction over a wide range of operating conditions. By means of full numerical simulations of the smooth isothermal elliptic contact, and assuming an Eyring non-Newtonian behavior, the coefficient of friction is computed for a wide range of operating conditions. It is shown that with respect to sliding friction, all results can be presented on a single generalized friction curve relating a reduced coefficient of friction to a characteristic nondimensional shear stress. Finally, it is shown that some measured data presented in the literature when presented in terms of the derived parameters closely follow the derived behavior, which provides a validation of the theoretical results.

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Zhang, Y., X. Zhang und W. Tobler. „A Systematic Model for the Analysis of Contact, Side Slip and Traction of Toroidal Drives“. Journal of Mechanical Design 122, Nr. 4 (01.04.1999): 523–28. http://dx.doi.org/10.1115/1.1290248.

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This paper presents a systematic model for the design and analysis of toroidal traction drive continuously variable transmissions (CVT). The contacts between the input disk, the roller and the output disk of the traction drive are formulated using the classical Hertzian contact theory. The traction force and side slip force occurring in CVT operation are modelled based on the elasto-hydrodynammic theory and are correlated to the traction drive geometric and kinematic parameters. The model allows for the quantitative analysis of traction drive operation under various torque inputs and over the desired ratio range. [S1050-0472(00)01004-7]

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Ciavarella, M., J. Joe, A. Papangelo und J. R. Barber. „The role of adhesion in contact mechanics“. Journal of The Royal Society Interface 16, Nr. 151 (Februar 2019): 20180738. http://dx.doi.org/10.1098/rsif.2018.0738.

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Adhesive (e.g. van der Waals) forces were not generally taken into account in contact mechanics until 1971, when Johnson, Kendall and Roberts (JKR) generalized Hertz’ solution for an elastic sphere using an energetic argument which we now recognize to be analogous to that used in linear elastic fracture mechanics. A significant result is that the load–displacement relation exhibits instabilities in which approaching bodies ‘jump in’ to contact, whereas separated bodies ‘jump out’ at a tensile ‘pull-off force’. The JKR approach has since been widely used in other geometries, but at small length scales or for stiffer materials it is found to be less accurate. In conformal contact problems, other instabilities can occur, characterized by the development of regular patterns of regions of large and small traction. All these instabilities result in differences between loading and unloading curves and consequent hysteretic energy losses. Adhesive contact mechanics has become increasingly important in recent years with the focus on soft materials (which generally permit larger areas of the interacting surfaces to come within the range of adhesive forces), nano-devices and the analysis of bio-systems. Applications are found in nature, such as insect attachment forces, in nano-manufacturing, and more generally in industrial systems involving rubber or polymer contacts. In this paper, we review the strengths and limitations of various methods for analysing contact problems involving adhesive tractions, with particular reference to the effect of the inevitable roughness of the contacting surfaces.

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30

Taylor, Adam G., und Jae H. Chung. „Analysis of tangential contact boundary value problems using potential functions“. Royal Society Open Science 6, Nr. 3 (März 2019): 182106. http://dx.doi.org/10.1098/rsos.182106.

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This paper presents an analysis technique of high-order contact potential problems and its application to an elastic settlement analysis of a shallow foundation system subjected to a combined traction boundary condition. Closed-form solutions of potential functions are derived for an elastic half-space subjected to bilinear tangential traction boundary conditions over rectangular surface regions. Using the principle of superposition, the present solutions provide a means to form an approximate and continuous solution of elastic contact problems with higher-order tangential boundary conditions. As an application example, an elastic settlement analysis of a rigid footing founded on a dense granular soil is performed under a tangential traction boundary condition prescribed in an analogy with the stress equilibrium states of static sandpiles. A generalized solution approach to combined normal and tangential traction boundary value problems is discussed in the context of foundation engineering.

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YAMAUCHI, Hideaki, Kazuhiko SAKAGUCHI, Takashi MATSUOKA und Masayoshi MURAKI. „EHL Traction Characteristic under High Contact Pressure“. Proceedings of Conference of Kanto Branch 2004.10 (2004): 425–26. http://dx.doi.org/10.1299/jsmekanto.2004.10.425.

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32

Varentsov, V. M., A. I. Bur’Yanovatyy und M. A. Ivanov. „Energy accounting in AC substations in case of transit currents flowing through the contact network“. Vestnik of the Railway Research Institute 76, Nr. 5 (28.10.2017): 294–300. http://dx.doi.org/10.21780/2223-9731-2017-76-5-294-300.

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The purpose of the work is to clarify the methodology for determining the electric power consumption of traction substations of AC electric power for the transit of external power supply. The conditions for the emergence of significant transit through traction networks of external power supply are revealed. Using the example of the Ushaped scheme for the replacement of power transmission lines, it is shown that the intersystem power fluxes along the electric power transmission lines of the external power supply exert the greatest influence on the transit currents along the traction networks. For analysis, the local and transit components of the power flow are identified and a typical section of the electrical network is considered, containing three electrical connections at voltages of 330, 110 and 27.5 kV. In this case, the most significant factor affecting transit through the traction network is the transverse component of voltage drop, since its compensation in this network is difficult. Methods for estimating the transit current of a traction network are given. An engineering technique for estimating the electric power consumption for transit by software is proposed. Authors show the necessity and possibility of using the KORTES package for estimating transit currents of the traction network caused by external power supply. The results of calculations for two sections of different railways based on the data of the Regional Dispatch Office are presented. The influence of regional and traction loads on the path of transit currents is considered. Obtained relationships and developed methodology allow estimating the electric power consumption of traction substations for the transit of the power of external power supply.

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Shantarenko, Sergei, Evgeny Ponomarev und Anatoly Borodin. „Contact interaction “brush – collector” and working efficiency of locomotive traction electric motor“. MATEC Web of Conferences 239 (2018): 01037. http://dx.doi.org/10.1051/matecconf/201823901037.

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The working efficiency of locomotive traction electric motors of direct current is largely determined by the reliability of the collector-brush assembly. The paper presents the results of simulation of the contact interaction “brush-collector” in the traction electric motor of an electric locomotive. The influence of the structural features of the brush holder, the conditions and operating modes on the contact area “brush-collector”, and the quality of switching is considered. Technical solutions for improving the current collection quality in the contact “brush-collector” and ensuring the working efficiency of traction electric motors of locomotives are proposed.

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Sluzalec, T. „A traction contact problem governed by hemivariational inequalities for a mixed formulation of Stokes equation“. Mathematics and Mechanics of Solids 22, Nr. 3 (05.08.2016): 420–33. http://dx.doi.org/10.1177/1081286515595673.

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In this paper the traction contact problems for Stokes equation are discussed and the Stokes equation is considered in a mixed formulation. We prove the existence and uniqueness of the weak solution for a mixed formulation of Stokes equation with traction contact. The traction contact is described by subdifferential boundary conditions. For this problem we present a variational formulation in a form of a hemivariational inequality for the velocity field.

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35

Kato, Kohshiro, Masana Kato und Katsumi Inoue. „Influence of Materials and Contact Geometry of Rollers on Traction Behavior of Traction Drive.“ Transactions of the Japan Society of Mechanical Engineers Series C 60, Nr. 571 (1994): 1013–19. http://dx.doi.org/10.1299/kikaic.60.1013.

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36

Wang, Jiugen, und Jianrong Tan. „Numerical Simulation of Traction in Rolling/Sliding Contacts“. Journal of Tribology 119, Nr. 4 (01.10.1997): 869–74. http://dx.doi.org/10.1115/1.2833898.

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A new model of traction in elastohydrodynamically lubricated contact is presented to study shear stress distributions. Results of full numerical analyses of elliptical contacts under rolling and sliding are presented. This study is confined to elastohydrodynamically lubricated contacts of relatively low load. Effects of dimensionless parameters such as speed, normal load, and elliptical parameter and coefficient of limiting shear stress on shear stress distributions have been analyzed. Moreover, the influence of slide-roll ratio on visualized shear stress in EHD contacts has been studied. It has been found that the higher slide-roll ratios induce higher maximum shear stress. Shear stresses in fluid film and those on surfaces vary with many factors that reveal the mechanism of traction in EHD conjunction zones.

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Aggarwal, Bhakat B., und Richard L. Bovenkerk. „Traction Forces at Solid-Lubricated Rolling/Sliding Contacts“. A S L E Transactions 29, Nr. 2 (Januar 1986): 196–202. http://dx.doi.org/10.1080/05698198608981678.

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38

Bao, Jun Hua, und Wei Dong He. „Finite Element Contact Analysis of Locomotive Traction Gears“. Advanced Materials Research 459 (Januar 2012): 19–24. http://dx.doi.org/10.4028/www.scientific.net/amr.459.19.

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The parametric solid models and assemble model are built in Pro/Engineer software system on the base of basic parameters of locomotive traction gears. The dedendum transition curves of teeth are fit by inputting the accurate coordinates of real curve of tooth that machined by gear hob after analyzing the envelopment processing of tooth. Assembling the driving and driven gears in Pro/Engineer system, and then the assemble model is imported into ANSYS software system, the settings of finite element analysis are defined, the finite element contact analysis of the driving and driven gears is done in ANSYS software. The accurate stress distributions of contact stress of teeth surfaces and the bending stress of dedendum of teeth are obtained base on the simulation calculations and post-processing in ANSYS. The calculation results are accurate compared with the real stress condition of teeth, so it can be the base of optimization design of gears for further research.

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Sano, Toshinari, Masashi Inoue und Fumihiro Itoigawa. „Improvement of Temperature Prediction Method for Traction Contact“. SAE International Journal of Engines 9, Nr. 3 (05.04.2016): 1891–901. http://dx.doi.org/10.4271/2016-01-1110.

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40

Bao, Jun Hua, und Wei Dong He. „Finite Element Contact Analysis of Locomotive Traction Gears“. Advanced Materials Research 459 (Januar 2012): 19–24. http://dx.doi.org/10.4028/scientific5/amr.459.19.

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41

ICHIMARU, Kazunori, und Toru MIYACHI. „Contact Stress Analysis with Consideration of Tangential Traction“. Proceedings of Conference of Kyushu Branch 2002.55 (2002): 237–38. http://dx.doi.org/10.1299/jsmekyushu.2002.55.237.

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42

Wannop, John William, Geng Luo und Darren Stefanyshyn. „Footwear traction and lower extremity non-contact injury“. Footwear Science 3, sup1 (Juni 2011): S166—S167. http://dx.doi.org/10.1080/19424280.2011.575832.

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43

De Pauw, Jan, Jeroen Van Wittenberghe und Patrick De Baets. „Traction and wear mechanisms during roll-slip contact“. International Journal Sustainable Construction & Design 1, Nr. 1 (06.11.2010): 59–67. http://dx.doi.org/10.21825/scad.v1i1.20396.

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In the transportation industry every vehicle that makes contact with the road and propels itself, is subjected to roll-slip in the wheel-road interface. Therefore a good understanding of this phenomenon is important. This article describes roll-slip contacts in general, with extra attention for the wheel-rail contact which is commonly used. Firstly the contact area and the pressure distribution that occur when a normal load is applied between two bodies is discussed. On this base, the traction mechanisms for static and rolling configurations are shown. Lastly, wear mechanisms and two different wear maps are shown which are very useful and commonly used in wear mapping of roll-slip contacts. A good agreement with field measurements can be obtained.

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Seo, Jung Won, Hyun Mu Hur, Sung Tae Kwon, Jae Boong Choi und Young Jin Kim. „Effects of Residual Stress and Traction Force on the Contact Fatigue Life of Railway Wheels“. Key Engineering Materials 326-328 (Dezember 2006): 1067–70. http://dx.doi.org/10.4028/www.scientific.net/kem.326-328.1067.

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Damage often occurs on the surface of railway wheels due to wheel-rail contact fatigue. Since the wheel failure can cause derailment causing the loss of life and property, it should be removed prior to the wheel failure. The effect of surface removal on contact fatigue life has been investigated by many researchers, however, the effects of residual stress and traction force have not been reported yet. The railway wheel reserves the initial residual stress due to the manufacturing process, and this residual stress is changed by the thermal stress induced by braking. Also, the traction force is usually applied along with residual stress on wheels of locomotive and electric motor vehicle. In this study, the effect of surface removal on the contact fatigue life for a railway wheel has been evaluated by applying the rolling contact fatigue test. Also, the effect of traction force and change of residual stress on the contact fatigue life has been estimated by applying finite element analysis. It is found that the residual stress is a dominant factor determining the surface removal depth as far as the traction coefficient is less than 0.15. If the traction coefficient is greater than 0.2, however, the surface removal depth is observed to be independent on the residual stress.

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Nikas, George K. „Miscalculation of film thickness, friction and contact efficiency by ignoring tangential tractions in elastohydrodynamic contacts“. Tribology International 110 (Juni 2017): 252–63. http://dx.doi.org/10.1016/j.triboint.2017.02.022.

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46

Wang, Shao, T. F. Conry und C. Cusano. „Thermal Non-Newtonian Elastohydrodynamic Lubrication of Line Contacts Under Simple Sliding Conditions“. Journal of Tribology 114, Nr. 2 (01.04.1992): 317–27. http://dx.doi.org/10.1115/1.2920890.

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A computationally simple formulation for the stationary surface temperature is developed to examine the thermal non-Newtonian EHD problem for line contacts under simple sliding conditions. Numerical results obtained are used to develop a formula for a thermal and non-Newtonian (Ree-Eyring) film thickness reduction factor. Results for the maximum surface temperature and traction coefficient are also presented. The thermal effects on film thickness and traction are found to be more pronounced for simple sliding than for combined sliding and rolling conditions.

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47

Ja¨ger, J. „A New Principle in Contact Mechanics“. Journal of Tribology 120, Nr. 4 (01.10.1998): 677–84. http://dx.doi.org/10.1115/1.2833765.

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Two nonrotating elastic half-planes in quasi-static contact without coupling of the normal and tangential surface stresses are analyzed in this paper. It is proved that the tangential traction under constant normal forces and increasing tangential forces is equal to the difference between the actual normal pressure and the pressure for a smaller contact area, multiplied by the coefficient of friction. Every stick area corresponds to a contact area (or a configuration of multiple contact areas) that is smaller than the present contact area. In the same way as the contact area develops with increasing pressure, the stick area recedes with increasing tangential traction. General loading scenarios are solved by superposition of oblique increments under constant angles. As an example, this principle is applied to a rigid surface of the form Akxk, in contact on 0 ≤ x ≤ a and with a corner at x = 0, indenting an elastic half-plane.

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Houpert, L. „New Results of Traction Force Calculations in Elastohydrodynamic Contacts“. Journal of Tribology 107, Nr. 2 (01.04.1985): 241–45. http://dx.doi.org/10.1115/1.3261033.

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The lubricant shear modulus G and Ree-Eyring shear stress τ0 are determined in this work by using Roelands’, rather than Barus’, relationship for calculating the lubricant viscosity. When using Roelands’ viscosity, elastic effects in the lubricant tend to be negligible, especially when inlet shear heating and displacement of the center of pressure are considered. These results are illustrated by examples in which inlet shear heating has been calculated, or when the lateral traction force obtained by spinning was known. In some cases, elastic effects are indeed present, though much reduced, and this leads to greater values of the lubricant shear modulus. The Ree-Eyring shear stress found when using the Roelands’ viscosity is also greater.

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ODA, Satoshi, und Kouitsu MIYACHIKA. „Traction characteristics in concave and convex roller pair contacts.“ Transactions of the Japan Society of Mechanical Engineers Series C 53, Nr. 492 (1987): 1869–76. http://dx.doi.org/10.1299/kikaic.53.1869.

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50

Lee, Dong Hyong, Jung Won Seo und Seok Jin Kwon. „Numerical Analysis of the Effect of Slip Ratio on the Fatigue Crack Initiation Life in Rolling Contact“. Advanced Materials Research 891-892 (März 2014): 1791–96. http://dx.doi.org/10.4028/www.scientific.net/amr.891-892.1791.

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This paper presents a numerical analysis of the effect of slip ratio on the fatigue crack initiation life, considering the tangential traction on the rolling contact surface. The distribution of tangential traction and contact stresses on the contact surface, when rolling contact occurs between two cylindrical test specimens, are obtained using three-dimensional finite element analysis. The effect of slip ratio on the fatigue crack initiation life was evaluated by applying multiaxial fatigue criteria based on critical plane approaches. As a result, the 3D-FE model developed well represent the distribution of tangential traction and contact stresses on the contact surface at stick-slip condition, which is differ from the static or full sliding contact condition. As the slip ratio increases, the maximum tangential traction also increases in slip zone and the location of maximum stress closer to the contact surface in stick zone. The fatigue strength decreased with the increase in the slip ratio. Therefore, it is clear that the slip ratio has an important role in prediction of fatigue crack initiation life on the rolling contact surface.

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