Contact Mechanics of a High Load Capacity Piston Pin

2008 ◽  
Author(s):  
Don Cao ◽  
Gary L. Doll
Keyword(s):  
Film Thickness ◽  
Contact Mechanics ◽  
Diesel Engines ◽  
Load Capacity ◽  
Three Dimensional ◽  
Dynamic Contact ◽  
High Load ◽  
Lubricant Film Thickness ◽  
Connecting Rod ◽  
High Load Capacity

A novel piston pin design is proposed for diesel engines having higher load capacity than current pin designs. This shaped piston pin incorporates a stress-reducing profile with lubricant film thickness enhancing features on the surface. Three dimensional FEA models were built and are used to model the dynamic contact between the piston and connecting rod interfaces with a standard piston pin and the new piston pin design.

Misalignment in Thrust Bearings Including Thermal and Cavitation Effects

1987 ◽  
Vol 109 (1) ◽  
pp. 108-114 ◽  
Author(s):  
H. Heshmat ◽  
Oscar Pinkus
Keyword(s):  
Film Thickness ◽  
Thermal Effects ◽  
Hydrodynamic Force ◽  
Load Capacity ◽  
High Load ◽  
Thrust Bearings ◽  
Angular Extent ◽  
Minimum Film Thickness ◽  
Parallel Surfaces ◽  
High Load Capacity

This paper offers an analysis and computer solutions for misaligned thrust faces, including thermal effects and proper cavitation boundary conditions. The geometries analyzed range from full 2π arcs to pads of 27 deg angular extent, for both parallel surfaces and standard tapered-land thrust bearings. It is shown that, except for parallel surfaces, no cavitation occurs in thrust bearings, even under severe misalignment; that the gain in hydrodynamic force versus a decrease in minimum film thickness is most favorable at low and moderate levels of misalignment; and that for high load capacity, small arcs (many pads) are preferred to large ones.

An Air Layer Modeling Approach for Air and Air/Vacuum Bearings

1997 ◽  
Vol 119 (3) ◽  
pp. 388-392
Author(s):  
J. M. Pitarresi ◽  
K. A. Haller
Keyword(s):  
Load Capacity ◽  
Load Resistance ◽  
High Load ◽  
Air Bearing ◽  
Air Bearings ◽  
Bearing Surface ◽  
Know How ◽  
Modeling Approach ◽  
Vibrational Characteristics ◽  
High Load Capacity

Air layer supported bearing pads, or “air bearings” as they are commonly called, are popular because of their high load capacity and low in-plane coefficient of friction, making them well suited for supporting moving, high accuracy manufacturing stages. Air/vacuum bearings enhance these capabilities by giving the bearing pad load resistance capacity in both the upward and downward directions. Consequently, it is desirable to know how to model the air layer between the bearing pad and the bearing surface. In this paper, a simple finite element modeling approach is presented for investigating the vibrational characteristics of an air layer supported bearing. It was found that by modeling the air layer as a bed of uniform springs who’s stiffness is determined by load-displacement tests of the bearing, a reasonable representation of the response can be obtained. For a bearing supported by air without vacuum, the dynamic response was very similar to that of a freely supported bearing. The addition of vacuum to an air bearing was found to significantly lower its fundamental frequency which could lead to unwanted resonance problems.

A one-stage, high-load capacity separation actuator using anti-friction rollers and redundant shape memory alloy wires

2015 ◽  
Vol 86 (12) ◽  
pp. 125005 ◽  
Author(s):  
Yan Xiaojun ◽  
Huang Dawei ◽  
Zhang Xiaoyong ◽  
Liu Ying ◽  
Yang Qiaolong
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Load Capacity ◽  
High Load ◽  
One Stage ◽  
High Load Capacity

A Three-Dimensional Model of Line-Contact Elastohydrodynamic Lubrication for Heterogeneous Materials with Inclusions

2016 ◽  
Vol 08 (02) ◽  
pp. 1650014 ◽  
Author(s):  
Kun Zhou ◽  
Qingbing Dong
Keyword(s):  
Film Thickness ◽  
Half Space ◽  
Surface Deformation ◽  
Three Dimensional ◽  
Elastohydrodynamic Lubrication ◽  
Lubricant Film ◽  
Line Contact ◽  
Lubricant Film Thickness ◽  
Equivalent Inclusion Method ◽  
Surface Contact

This paper develops a three-dimensional (3D) model for a heterogeneous half-space with inclusions distributed periodically beneath its surface subject to elastohydrodynamic lubrication (EHL) line-contact applied by a cylindrical loading body. The model takes into account the interactions between the loading body, the fluid lubricant and the heterogeneous half-space. In the absence of subsurface inclusions, the surface contact pressure distribution, the half-space surface deformation and the lubricant film thickness profile are obtained through solving a unified Reynolds equation system. The inclusions are homogenized according to Eshelby’s equivalent inclusion method (EIM) with unknown eigenstrains to be determined. The disturbed half-space surface deformations induced by the subsurface inclusions or eigenstrains are iteratively introduced into the lubricant film thickness until the surface deformation finally converges. Both time-independent smooth surface contact and time-dependent rough surface contact are considered for the lubricated contact problem.

Analyzing characteristics of high-speed spindle bearing under constant preload

2017 ◽  
Vol 232 (5) ◽  
pp. 568-581 ◽  
Author(s):  
Thi-Thao Ngo ◽  
Van-The Than ◽  
Chi-Chang Wang ◽  
Jin H Huang
Keyword(s):  
Film Thickness ◽  
Thermal Effects ◽  
High Speed ◽  
Dynamic Contact ◽  
Contact Angles ◽  
Lubricant Film ◽  
Contact Forces ◽  
Transfer Model ◽  
Lubricant Film Thickness ◽  
Spindle Bearing

Bearings play an important role in a high-speed spindle. Its characteristics are often influenced by speed and thermal effects. This paper presents an approach that combines an inverse method with a high-speed ball bearing model to determine the characteristics of a high-speed spindle bearing under constant preload in actual working conditions. With temperature distribution in the entire spindle obtained by the experimental inverse heat transfer model from the authors’ previous results, the change in bearing parameters is then calculated and subsequently replaced in the bearing model to analyze the change in bearing characteristics. As a result, thermal effects on a bearing’s dynamic contact angles, contact forces, contact stress, stiffness, and lubricant film thickness are presented. Moreover, analysis results indicate that a bearing’s stiffness and lubricant film thickness nonlinearly vary with the increase in speed, and the thermal effect significantly affects the lubricant film thickness. The results presented herein may be applied to develop a dynamic model for a high-speed spindle using a constant preload and provide useful information to avoid failure in lubrication.

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