Effect of Surface Ellipticity on Dynamically Loaded Cylindrical Bearings

Goenka, P. K.; Booker, J. F.

doi:10.1115/1.3254535

Cited by 48 publications

(33 citation statements)

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“…It is important to note that for high speed rotating machinery the lubricant viscous effect due to rotation also needs to be considered and included in the analysis. One possible methodology that must be followed to account for both wedge-film and squeeze-film effect is the one proposed by Goenka [44]. This, work presents the details of the Reynold's equation for the more general lubricated circumstances of a spherical joint with lubrication.…”

Section: Thus For the Flow Continuity Combining Eqs (16)-(19) Resumentioning

confidence: 99%

“…In a broad sense, dynamically loaded spherical joints can be classified into two main groups, namely the squeeze-film action and the wedge-film action [43][44][45][46][47][48][49][50]. The first group refers to the situations in which the ball does not rotate significantly about its center, rather the ball moves along some path inside the socket boundaries.…”

Section: Dynamics Of Spherical Jointsmentioning

confidence: 99%

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Spatial rigid-multibody systems with lubricated spherical clearance joints: modeling and simulation

2009

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The dynamic modeling and simulation of spatial rigid-multi-body systems with lubricated spherical joints is the main purpose of the present work. This issue is of paramount importance in the analysis and design of realistic multibody mechanical systems undergoing spatial motion.When the spherical clearance joint is modeled as dry contact; i.e., when there is no lubricant between the mechanical elements which constitute the joint, a body-to-body (typically metal-tometal) contact takes place. The joint reaction forces in this case are evaluated through a Hertzian-based contact law. A hysteretic damping factor is included in the dry contact force model to account for the energy dissipation during the contact process. The presence of a fluid lubricant avoids the direct metal-to-metal contact. In this situation, the squeeze film action, due to the relative approaching motion between the mechanical joint elements, is considered utilizing the lubrication theory associated with the spherical bearings. In both cases, the intrajoint reaction forces are evaluated as functions of the geometrical, kinematical and physical characteristics of the spherical joint. These forces are then incorporated into a standard formulation of the system's governing equations of motion as generalized external forces. A spatial four bar mechanism that includes a spherical clearance joint is considered here as example. The computational simulations are carried out with and without the fluid lubricant, and the results are compared with those obtained when the system is modeled with perfect joints only. From the general results it is observed that the system's performance with lubricant effect presents fewer peaks in the kinematic and dynamic outputs, when compared with those from the dry contact joint model.

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Section: Thus For the Flow Continuity Combining Eqs (16)-(19) Resumentioning

confidence: 99%

Section: Dynamics Of Spherical Jointsmentioning

confidence: 99%

Spatial rigid-multibody systems with lubricated spherical clearance joints: modeling and simulation

2009

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“…It is well known that the exact solution of the Reynolds equation is quite difficult to obtain and, in general, requires a considerable numerical effort [62]. However, it is possible to solve the Reynolds equation analytically by assuming either the first or the second term on the left-hand side of (28) to be null.…”

Section: Hydrodynamic Lubrication Forcesmentioning

confidence: 99%

A new model for dry and lubricated cylindrical joints with clearance in spatial flexible multibody systems

et al. 2010

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A new approach to model and analyze flexible spatial multibody systems with clearance of cylindrical joints is presented in this work. The flexible parts are modeled by using absolute nodal coordinate formulation (ANCF)-based elements, while the rigid parts are described by employing the natural coordinate formulation (NCF), which can lead to a constant system mass matrix for the derived system equations of motion. In a simple way, a cylindrical joint with clearance is composed of two main elements, that is, a journal inside a bearing. Additionally, a lubricant fluid can exist between these two mechanical elements to reduce the friction and wear and increase the system's life. For the case in which the joint is modeled as a dry contact pair, a technique using a continuous approach for the evaluation of the contact force is applied, where the energy dissipation in the form of hysteresis damping is considered. Furthermore, the frictional forces developed in those contacts are evaluated by using a modified Coulomb's friction law. For the lubricated case, the hydrodynamic theory for dynamically loaded journal bearings is used to compute the forces generated by lubrication actions. The lubricated model is based on the Reynolds equation developed for the case of journal bearings with length-todiameter ratios up to 1. Using this approach, the misalignment of the journal inside the bearing can be studied. Finally, two demonstrative examples of application are used to provide results that support the discussion and show the validity of the proposed methodologies.

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“…The first attempt to address this problem was made by Goenka [15], who formulated the hydrodynamic lubrication problem in spherical coordinates and solved the resultant equations using the finiteelement method [16]. A simplified representation of the transient load and angular speed in steady walking reported by Paul [17] was employed in the transient lubrication analysis for both spherical and elliptical bearing surfaces [15,17,18]. A similar analysis was subsequently reported by Ai and Cheng [19], where only one loading component and one angular velocity component were considered.…”

Section: Hydrodynamic Lubrication Analysismentioning

confidence: 99%

Theoretical studies of elastohydrodynamic lubrication of artificial hip joints

Zhang

2006

Proceedings of the Institution of Mechanical Engineers, Part J:

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Theoretical studies of fluid-film lubrication in artificial hip joints are reviewed. The importance of developing effective numerical tools to solve realistic and complex lubrication problems in artificial hip joints has been emphasized. The elastic deformation of the bearing surfaces has been shown to play a dominant role in promoting elastohydrodynamic lubrication in various forms of artificial hip joints using different bearing surfaces. Both the bearing geometry and the structural supports can have a significant effect on the predicted lubricant film thickness. The importance of elastic deformation is further enhanced synergistically with the transient variation in load and speed to ensure a maximum effectiveness of the transient elastohydrodynamic lubrication mechanism in artificial hip joints. The recent application of the fast Fourier transform technique, in conjunction with the finite-element method to calculate the elastic deformation, not only enables more complex structural supports to the acetabular cup to be considered, but also offers the potential of analysing both transient and mixed lubrication problems in artificial hip joints.

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Effect of Surface Ellipticity on Dynamically Loaded Cylindrical Bearings

Cited by 48 publications

References 0 publications

Spatial rigid-multibody systems with lubricated spherical clearance joints: modeling and simulation

Spatial rigid-multibody systems with lubricated spherical clearance joints: modeling and simulation

A new model for dry and lubricated cylindrical joints with clearance in spatial flexible multibody systems

Theoretical studies of elastohydrodynamic lubrication of artificial hip joints

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