scholarly journals Skidding and cage whirling of angular contact ball bearings: Kinematic-hertzian contact-thermal-elasto-hydrodynamic model with thermal expansion and experimental validation

2022 ◽  
Vol 166 ◽  
pp. 108427
Author(s):  
Shuai Gao ◽  
Steven Chatterton ◽  
Paolo Pennacchi ◽  
Qinkai Han ◽  
Fulei Chu
2017 ◽  
Vol 140 (2) ◽  
Author(s):  
Nikhil D. Londhe ◽  
Nagaraj K. Arakere ◽  
Ghatu Subhash

The analytical expressions currently available for Hertzian contact stresses are applicable only for homogeneous materials and not for case-hardened bearing steels, which have inhomogeneous microstructure and graded elastic properties in the subsurface region. Therefore, this article attempts to determine subsurface stress fields in ball bearings for graded materials with different ball and raceway geometries in contact. Finite element models were developed to simulate ball-on-raceway elliptical contact and ball-on-plate axisymmetric contact, to study the effects of elastic modulus variation with depth due to case hardening. Ball bearings with low, moderate, and heavy load conditions are considered. The peak contact pressure for case-hardened steel is always more than that of through-hardened steel under identical geometry and loading conditions. Using equivalent contact pressure approach, effective elastic modulus is determined for case-carburized steels, which will enable the use of Hertz equations for different gradations in elastic modulus of raceway material. Nonlinear regression tools are used to predict effective elastic modulus as a weighted sum of surface and core elastic moduli of raceway material and design parameters of ball–raceway contact area. Mesh convergence study and validation of equivalent contact pressure approach are also provided. Implications of subsurface stress variation due to case hardening on bearing fatigue life are discussed.


2015 ◽  
Vol 19 (5) ◽  
pp. 1835-1844 ◽  
Author(s):  
Radivoje Mitrovic ◽  
Ivana Atanasovska ◽  
Natasa Soldat ◽  
Dejan Momcilovic

The research of influence of operation temperature on the thermal expansion and main parameters of radial ball bearings is presented in this paper. The main bearing parameters are identified in accordance with the increasing requests concerning stability and load capacity. A series of Finite Element Analyses is performed for quasi-static analysis of all identified bearing parameters during contact period in referent temperature. Then, the dependence of bearing material characteristics on the operation temperature is discussed. Few series of Finite Element Analyses are performed for a particular radial ball bearing type, with characteristics in accordance with manufacturer specifications, for several operation temperatures. These two problems analyses include consideration of relation between the initial radial clearance, thermal expansion strains and contact deformations of the parts of the bearing assembly. The results for radial ball bearing parameters are monitored during a ball contact period for different temperatures and the appropriate discussion and conclusions are given. The conclusions about the contribution of developed procedure in defining the optimum operation temperature range are shown.


Author(s):  
Zhiyong Zhang ◽  
Xiaoting Rui ◽  
Yushu Chen ◽  
Wenkai Dong ◽  
Lei Li

Ball bearings are essential parts of mechanical systems to support the rotors or constitute the revolute joints. The time-varying compliance (VC), bearing clearance and the Hertzian contact between the rolling elements and raceways are three fundamental nonlinear factors in a ball bearing, hence the ball bearing can be considered as a nonlinear system. The hysteresis and jumps induced by the nonlinearities of rolling bearings are typical phenomena of nonlinear vibrations in the rolling bearing-rotor systems. And the corresponding hysteretic impacts have direct effects on the cleavage derivative and fatigue life of the system components. Therefore, the behaviors of hysteresis and jumps are given full attentions and continued studies in the theoretical and engineering fields. Besides, many researchers have done a lot of calculations to depict the various characteristics of bifurcations and chaos in the rolling bearings and their rotor systems, but few researches have been addressed on the inherent mechanism of the typical intermittency vibrations in rolling bearings. With the aid of the HB-AFT (the harmonic balance method and the alternating frequency/time domain technique) method and Floquet theory, this paper will investigate deeply the resonant hysteresis and intermittency chaos in ball bearings.


2001 ◽  
Vol 45 (04) ◽  
pp. 289-301 ◽  
Author(s):  
A. N. Simos ◽  
E. A. Tannuri ◽  
C. P. Pesce ◽  
J. A. P. Aranha

In an earlier work Leite et al (1998) developed a heuristic hydrodynamic model, based on the shrtwing theory, for the horizontal current forces on an FPSO system. The proposed model was quasi-explicit in the sense that it depends on the ship's main dimensions and on only three hydrodynamic coefficients, namely, the friction coefficient Cf for head on incidence, the drag coefficient CY for a cross-flow, and the related yaw moment coefficient lCY. As discussed in Leite et al (1998), these coefficients could even be estimated from the ITTC friction curve and from Hoerner's sectional results, which would then turn the hydrodynamic model explicit. The model has been tested against experimental results for the horizontal force coefficients, obtained both at IPT and at the Marin wave tank, and it has also been confronted with bifurcation experiments for a turret configuration realized at IPT. The agreement rendered good results in all cases tested. The heuristic approach has now been extended to incorporate the yaw velocity terms while preserving the quasi-explicit feature of the original model. The main purpose of the work herein is to present such a development together with some experimental validation. Using Froude scaling of different ships in distinct ballast conditions, the horizontal forces and moment in the yaw rotating tests were measured at IPT and at Marin and compared with those predicted by the heuristic model, the observed agreement again being fair enough. In an accompanying paper in this issue, the derived mathematical model is tested against experiments that emulate a single-point mooring of a tanker ship in order to disclose the model's ability to cope with the main dynamic features of the fishtailing instability problem.


2019 ◽  
Vol 109 (05) ◽  
pp. 342-346
Author(s):  
C. Brecher ◽  
T. Motschke ◽  
M. Fey

Die präzise Simulation mechanischer Systeme erfordert neben Steifigkeitswerten für Koppelelemente, die Kenntnis von Dämpfungswerten. Im Gegenteil zu Gleitlagern sind die physikalischen Effekte in Wälzlagern, die zur Energiedissipation führen, nur mit sehr großem rechnerischen Aufwand numerisch beschreibbar und experimentell validierte Modelle besitzen nur in engen Betriebsgrenzen Gültigkeit. Als Hauptdämpfungsquellen wurden bisher Kugel-Laufbahn-Kontakte sowie die Passungen der Lagerringe identifiziert. Letztere werden in diesem Beitrag untersucht. Ziel ist eine Aussage über Grenzen, innerhalb derer sich der Einfluss von Fugendämpfung bewegt   The dynamic simulation of mechanical systems requires reliable stiffness and damping values to enable meaningful results. Especially the inclusion of coupling elements into the simulation always leads to challenges regarding the interpretation of predicted results. Unlike journal bearings, there are no analytical models for roller and ball bearings that allow the prediction of damping values, whereas the prediction of stiffness values is already state of the art. In the past, the Hertzian contact as well as the bearing interfaces were identified as the main damping sources, but till today, no reliable models have been derived. This article deals therefore with a method to quantify the influence of bearing interface damping parameters.


2019 ◽  
Vol 11 (11) ◽  
pp. 168781401988975
Author(s):  
Dinh Sy Truong ◽  
Byung-Sub Kim ◽  
Jong-Kweon Park

Bearing stiffness directly affects the dynamic characteristics in a high-speed spindle system and plays an important role in terms of manufacturing quality. We developed a new approach for predicting the thermal behavior of a high-speed spindle, calculated the thermal expansion, and generated a bearing stiffness matrix for angular contact ball bearings. The heat convection of spindle housing in air, the balls in lubricant, the spindle shaft in quiescent air, and the bearing inner ring surfaces were determined. Heat sources such as bearing friction, and the heat contributed by the built-in motor, were simulated using an analysis systems (ANSYS) steady-state thermal model. The results were imported into a static ANSYS structural model. Ball thermal expansion was calculated based on changes in the coordinates of nodal points on the ball surface. Finally, a thermally affected bearing stiffness matrix was generated by applying the Newton–Raphson technique. Decreases in the bearing radial, axial, angular, and coupling stiffness values as rotational spindle speed increased were calculated. Also, the stiffness coefficients at a specific speed increased significantly caused by the thermal effects. Finally, for validation, the bearing stiffness was compared to that calculated using an earlier thermal network approach.


Author(s):  
G. Chen ◽  
C. G. Li ◽  
D. Y. Wang

In this paper, a new rotor-ball bearings-support-stator coupling system dynamic model with rubbing coupling faults is established for practical aeroengine. In the model, the rubbing fault is modeled, the stator motion is considered, the flexible support and squeeze film damper are established, and the nonlinear factors of ball bearing, such as the clearance of the bearing, the nonlinear Hertzian contact force between balls and races, and the varying compliance vibration because of the periodical variety of the contact position between balls and races, are modeled. The numerical integral method is used to obtain the system responses, the effect of support stiffness on rotor responses is studied using a vibration amplitude-rotating speed plot, and the characteristics of the rubbing fault is analyzed using a 3D cascade plot. An aeroengine tester with a stator is established to carry out the rubbing fault experiments, the simulation results from the rotor-ball bearings-support-stator coupling model are compared with the experimental results, and the consistency of the results show fully the effectiveness of the new rotor-ball bearings-support-stator coupling model with rubbing fault.


2001 ◽  
Vol 45 (04) ◽  
pp. 302-314
Author(s):  
E. A. Tannuri ◽  
A. N. Simos ◽  
A. J. P. Leite ◽  
J. A. P. Aranha

The extended hydrodynamic model derived in Simos et al (2001), where the yaw velocity terms have been incorporated to the model proposed by Leite et al (1998) while preserving its quasi-explicit feature, is used here to study some typical dynamic problems of moored ships, specifically the fishtailing shtailing instability that may occur in a single-point mooring (SPM) system. Since the intention was to check the hydrodynamic model, the hawser was assumed rigid to avoid the complex dynamics that may occur when the actual hawser slackens and the obtained results were confronted with experimental ones, obtained at the IPT wave tank. The agreement is very good in the sense that not only the limit-cycle amplitudes are compatible but also the time series are very similar. For the VLCC model in ballasted condition (40%) the fishtailing shtailing instability occurs only for a relatively high current velocity and some Froude effect is then detectable. Using results from the static bifurcation experiment an ad hoc correction is proposed for such effect, showing a relatively close agreement between experiments and the theoretical model. This Froude effect correction is, however, not relevant for an actual SPM system subjected to a usual ocean current.


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