The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Chuanwei Zhang - One of the best experts on this subject based on the ideXlab platform.
-
Effect of surface roughness on the start-stop behavior of air lubricated thrust micro-bearings
Tribology International, 2018Co-Authors: Chuanwei Zhang, Xuqiang Jiang, Liqin Wang, Le GuAbstract:Abstract The start-stop behavior of air lubricated thrust micro-bearings was investigated. The dynamic air bearing force was calculated considering the air rarefaction effect. The Asperity contact force between the rotor face and air bearing surface was calculated. The axial motion of the micro-bearing during the start-stop process was determined. The effects of surface roughness and angular acceleration were discussed. The results showed that an increase in the standard deviation of the Asperity height generated an increase in the air film thickness and a decrease in the air bearing force, leading to an increase in both the Asperity contact force and the contact time during the start-stop process.
-
Effect of air rarefaction on the contact behaviors of air lubricated spiral-groove thrust micro-bearings
Tribology International, 2017Co-Authors: Chuanwei Zhang, Le Gu, Jianyun Wang, Liqin WangAbstract:Abstract The contact behaviors of an air lubricated spiral-groove thrust micro-bearing were investigated. The air bearing force and Asperity contact force of the bearing were calculated considering the effect of air rarefaction and surface roughness. The effect of the groove depth and the standard deviation of Asperity height was discussed. The results showed that the air bearing force decreases significantly when the air rarefaction is considered. This then leads to an increase in Asperity contact force. The depth of spiral grooves and the standard deviation of Asperity height also significantly affect the Asperity contact force of the bearing.
-
effect of disk Asperity size on contact induced head scratches and reader temperature of a thermal flying height control slider disk interface
IEEE Transactions on Magnetics, 2015Co-Authors: Wenping Song, Chuanwei Zhang, Andrey Ovcharenko, Frank E TalkeAbstract:The mechanical and thermal response of a thermal flying height control slider during contacts with a disk Asperity is numerically studied. The effect of Asperity height and Asperity diameter on the scratch dimensions in the read/write shields is investigated, and the maximum temperature at the reader location is determined. The effect of the number of contact cycles is studied.
-
an investigation of thermal Asperity sensors during contact with disk asperities
Microsystem Technologies-micro-and Nanosystems-information Storage and Processing Systems, 2014Co-Authors: Chuanwei Zhang, Andrey Ovcharenko, Min Yang, Neil Knudson, Frank E TalkeAbstract:In this study, a thermo-mechanical finite element model was developed for the response of a thermal Asperity sensor sliding against a disk Asperity. The temperature change of the thermal Asperity sensor due to frictional heating was determined. The effect of disk Asperity material properties and contact conditions is investigated.
Frank E Talke - One of the best experts on this subject based on the ideXlab platform.
-
effect of disk Asperity size on contact induced head scratches and reader temperature of a thermal flying height control slider disk interface
IEEE Transactions on Magnetics, 2015Co-Authors: Wenping Song, Chuanwei Zhang, Andrey Ovcharenko, Frank E TalkeAbstract:The mechanical and thermal response of a thermal flying height control slider during contacts with a disk Asperity is numerically studied. The effect of Asperity height and Asperity diameter on the scratch dimensions in the read/write shields is investigated, and the maximum temperature at the reader location is determined. The effect of the number of contact cycles is studied.
-
an investigation of thermal Asperity sensors during contact with disk asperities
Microsystem Technologies-micro-and Nanosystems-information Storage and Processing Systems, 2014Co-Authors: Chuanwei Zhang, Andrey Ovcharenko, Min Yang, Neil Knudson, Frank E TalkeAbstract:In this study, a thermo-mechanical finite element model was developed for the response of a thermal Asperity sensor sliding against a disk Asperity. The temperature change of the thermal Asperity sensor due to frictional heating was determined. The effect of disk Asperity material properties and contact conditions is investigated.
-
effect of contact conditions during thermo mechanical contact between a thermal flying height control slider and a disk Asperity
Tribology International, 2012Co-Authors: Andrey Ovcharenko, Min Yang, Wenping Song, Bernhard E Knigge, Frank E TalkeAbstract:A three-dimensional thermo-mechanical model is developed for the transient contact between a thermal flying height control (TFC) slider and a disk Asperity. The effect of contact conditions is investigated, including the friction coefficient and the circumferential disk velocity. The damage of the read–write shields due to contacts with disk asperities is studied along with the maximum temperature at the location of the read element. The effect of diameter and material properties of the Asperity is also investigated. Strong dependence of deformation and maximum temperature is observed as a function of the diameter and material properties of the Asperity.
-
simulation of Asperity contacts at the head disk interface of tri pad sliders during steady state flying
Tribology Transactions, 1997Co-Authors: Michael H Wahl, Haesung Kwon, Frank E TalkeAbstract:A model for Asperity contacts at the head/disk interface has been developed that allows for elastic Asperity deformations based on an experimentally derived function for the contact pressure. The model predicts the distributed contact pressure, the contact force and the apparent area of contact on the air bearing surface of the slider. A second approach that assumes entirely rigid asperities is employed to verify the asymptotic behavior of the contact force as the Asperity stiffness increases. Further results are reported for the elastic Asperity method and the dependence of the contact force, contact area and flying height on various operating conditions is investigated. The comparison between numerical calculations and experimental results shows excellent qualitative agreement. Presented as a Society of Tribologlsts and Lubrication Engineers paper at the ASME/STLE Tribology Conference in San Francisco, California, October 13–17, 1996
Le Gu - One of the best experts on this subject based on the ideXlab platform.
-
Effect of surface roughness on the start-stop behavior of air lubricated thrust micro-bearings
Tribology International, 2018Co-Authors: Chuanwei Zhang, Xuqiang Jiang, Liqin Wang, Le GuAbstract:Abstract The start-stop behavior of air lubricated thrust micro-bearings was investigated. The dynamic air bearing force was calculated considering the air rarefaction effect. The Asperity contact force between the rotor face and air bearing surface was calculated. The axial motion of the micro-bearing during the start-stop process was determined. The effects of surface roughness and angular acceleration were discussed. The results showed that an increase in the standard deviation of the Asperity height generated an increase in the air film thickness and a decrease in the air bearing force, leading to an increase in both the Asperity contact force and the contact time during the start-stop process.
-
Effect of air rarefaction on the contact behaviors of air lubricated spiral-groove thrust micro-bearings
Tribology International, 2017Co-Authors: Chuanwei Zhang, Le Gu, Jianyun Wang, Liqin WangAbstract:Abstract The contact behaviors of an air lubricated spiral-groove thrust micro-bearing were investigated. The air bearing force and Asperity contact force of the bearing were calculated considering the effect of air rarefaction and surface roughness. The effect of the groove depth and the standard deviation of Asperity height was discussed. The results showed that the air bearing force decreases significantly when the air rarefaction is considered. This then leads to an increase in Asperity contact force. The depth of spiral grooves and the standard deviation of Asperity height also significantly affect the Asperity contact force of the bearing.
Dirk J. Schipper - One of the best experts on this subject based on the ideXlab platform.
-
Modelling of ploughing in a single-Asperity sliding contact using material point method
Wear, 2019Co-Authors: Tanmaya Mishra, G. C. Ganzenmüller, Matthijn De Rooij, Meghshyam Shisode, Javad Hazrati, Dirk J. SchipperAbstract:Abstract Loading and sliding of a rigid Asperity over a substrate results in friction due to shearing of the contact interface and deformation of the substrate. In this article, we introduce the Material Point Method (MPM) based numerical tool to study friction during ploughing of a soft-smooth metallic sheet by a rigid-spherical Asperity. The numerical model incorporates a dislocation based physical model for substrate material deformation and interfacial shear strength at the Asperity- substrate contact. Initially, the numerical output has been validated using results obtained from the analytical models available in the literature for single-Asperity sliding. Finally, the depth of the ploughed wear profile and the overall coefficient of friction obtained from the numerical simulations has been compared with the data obtained from the ploughing experiments and are shown to be in good agreement. Hence, the developed MPM model can be established as a robust tool to model ploughing in a single-Asperity sliding contact.
-
The influence of stick–slip transitions in mixed-friction predictions of heavily loaded cam–roller contacts
Proceedings of the Institution of Mechanical Engineers Part J: Journal of Engineering Tribology, 2018Co-Authors: Shivam S. Alakhramsing, Matthijn De Rooij, Mark Van Drogen, Dirk J. SchipperAbstract:A load-sharing-based mixed lubrication model, applicable to cam–roller contacts, is developed. Roller slippage is taken into account by means of a roller friction model. Roughness effects in the dry Asperity contact component of the mixed lubrication model are taken into account by measuring the real surface topography. The proportion of normal and tangential load due to Asperity interaction is obtained from a dry contact stick–slip solver. Lubrication conditions in a cam–roller follower unit, as part of the fuel injection equipment in a heavy-duty diesel engine, are analyzed. Main findings are that stick–slip transitions (or variable Asperity contact friction coefficient) are of crucial importance in regions of the cam where the acting contact forces are very high. The contact forces are directly related to the sliding velocity/roller slippage at the cam–roller contact and thus also to the static friction mechanism of Asperity interactions. Assuming a constant Asperity contact friction coefficient (or assuming that gross sliding has already occurred) in highly loaded regions may lead to large overestimation in the minimal required cam–roller contact friction coefficient in order to keep the roller rolling. The importance of including stick–slip transitions into the mixed lubrication model for the cam–roller contact is amplified with decreasing cam rotational velocity.
-
Modelling material transfer on a single Asperity scale
Wear, 2013Co-Authors: M.b. De Rooij, G. Van Der Linde, Dirk J. SchipperAbstract:In many adhesive wear processes, transfer of material from the donor surface results in the formation of lumps or a continuous layer on the countersurface. The morphology of the transferred layer is important for the tribological behaviour of the resulting interface. If the lumps formed on the countersurface are harder than the donor surface, abrasion of the donor surface will be the consequence of adhesive lump formation. In particular, the formation of sharp and hard lumps will be detrimental for the donor surface. A model will be presented for the geometrical development of a single lump such that the transferred material forms a lump that can resist the forces that will act on it. The initial geometry of the individual ploughing Asperity is based on measured height data of the harder, ploughing surface and is represented by an equivalent pyramidal shape with a hexagonal base. After determination of the initial shape, geometrical changes due to material transfer are modelled. An important aspect in this is that the shape should be mechanically stable, so not fail due the ploughing forces. Based on this model, the geometrical development of an Asperity over time is simulated. From the results it can be seen that the orientation of the Asperity with respect to the velocity vector is an important factor. The best orientation of the Asperity to reduce lump growth is an angle of around 10° between the velocity vector and the major length of the Asperity. Contrary to the orientation, the geometrical dimensions of the Asperity are of minor importance for lump growth. Typical geometrical characteristics of the growing lump are compared with experiments. The results of the model will be discussed in the context of galling behaviour taking place in deep drawing processes.
-
modelling of static friction in rubber metal contact
Tribology International, 2007Co-Authors: E L Deladi, M.b. De Rooij, Dirk J. SchipperAbstract:A static friction model for contact between rough rubber and metal surfaces is developed. This model is based on the contact of a viscoelastic–rigid Asperity couple. Single Asperity contact is modelled in such a way that the asperities stick together in a central region and slip over an annulus at the edge of the contact. The slip area increases with increasing tangential load. Consequently, the static friction force is the force when the slip area is equal to the contact area. Using the model, the traction distributions, contact area, tangential and normal displacement of two contacting asperities are calculated. The single Asperity model is then extended to multi-Asperity contact, suitable for rough surfaces. This model allows calculation of the above-mentioned parameters for two rough surfaces (a rubber and a metal one) subjected to normal and tangential loads. A parametric study will be presented. The results are qualitatively in good agreement with those found in literature.
Liqin Wang - One of the best experts on this subject based on the ideXlab platform.
-
Effect of surface roughness on the start-stop behavior of air lubricated thrust micro-bearings
Tribology International, 2018Co-Authors: Chuanwei Zhang, Xuqiang Jiang, Liqin Wang, Le GuAbstract:Abstract The start-stop behavior of air lubricated thrust micro-bearings was investigated. The dynamic air bearing force was calculated considering the air rarefaction effect. The Asperity contact force between the rotor face and air bearing surface was calculated. The axial motion of the micro-bearing during the start-stop process was determined. The effects of surface roughness and angular acceleration were discussed. The results showed that an increase in the standard deviation of the Asperity height generated an increase in the air film thickness and a decrease in the air bearing force, leading to an increase in both the Asperity contact force and the contact time during the start-stop process.
-
Effect of air rarefaction on the contact behaviors of air lubricated spiral-groove thrust micro-bearings
Tribology International, 2017Co-Authors: Chuanwei Zhang, Le Gu, Jianyun Wang, Liqin WangAbstract:Abstract The contact behaviors of an air lubricated spiral-groove thrust micro-bearing were investigated. The air bearing force and Asperity contact force of the bearing were calculated considering the effect of air rarefaction and surface roughness. The effect of the groove depth and the standard deviation of Asperity height was discussed. The results showed that the air bearing force decreases significantly when the air rarefaction is considered. This then leads to an increase in Asperity contact force. The depth of spiral grooves and the standard deviation of Asperity height also significantly affect the Asperity contact force of the bearing.
