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The Ohio State University.

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Lubrication and contact fatigue models for roller and gear contacts.

Record Type:	Electronic resources : Monograph/item
Title/Author:	Lubrication and contact fatigue models for roller and gear contacts./
Author:	Li, Sheng.
Description:	301 p.
Notes:	Adviser: Kahraman Ahmet.
Contained By:	Dissertation Abstracts International70-02B.
Subject:	Engineering, Mechanical. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3346607
ISBN:	9781109018387

Lubrication and contact fatigue models for roller and gear contacts.
Li, Sheng.

Lubrication and contact fatigue models for roller and gear contacts. - 301 p.

Adviser: Kahraman Ahmet.

Thesis (Ph.D.)--The Ohio State University, 2009.

Pitting is a surface or sub-surface initiated contact fatigue failure that is commonly observed in lubricated contacts of widely used machine components such as gears and bearings. Such contacts often experience combined sliding and rolling motions under sizable normal loads. Material properties and geometry of contacting surfaces, operating conditions (normal load, relative sliding and speed), surface texture (roughness amplitude and direction) as well as lubrication parameters all influence the contact fatigue lives of such components.

ISBN: 9781109018387Subjects--Topical Terms:

783786
Engineering, Mechanical.

Lubrication and contact fatigue models for roller and gear contacts.
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020 $a 9781109018387
035 $a (UMI)AAI3346607
035 $a AAI3346607
040 $a UMI $c UMI
100 1 $a Li, Sheng. $3 1035681
245 1 0 $a Lubrication and contact fatigue models for roller and gear contacts.
300 $a 301 p.
500 $a Adviser: Kahraman Ahmet.
500 $a Source: Dissertation Abstracts International, Volume: 70-02, Section: B, page: 1299.
502 $a Thesis (Ph.D.)--The Ohio State University, 2009.
520 $a Pitting is a surface or sub-surface initiated contact fatigue failure that is commonly observed in lubricated contacts of widely used machine components such as gears and bearings. Such contacts often experience combined sliding and rolling motions under sizable normal loads. Material properties and geometry of contacting surfaces, operating conditions (normal load, relative sliding and speed), surface texture (roughness amplitude and direction) as well as lubrication parameters all influence the contact fatigue lives of such components.
520 $a In this study, a physics-based methodology has been developed for predicting contact pitting fatigue lives of lubricated rough surface contacts in relative sliding. The methodology includes a robust boundary/mixed elastohydrodynamic lubrication (EHL) model to predict normal and shear stresses acting on contact surfaces, a mechanics model to predict the three-dimensional stress state time histories into the contacting bodies, and a multi-axial fatigue life criterion to predict crack initiation fatigue life.
520 $a First, focusing on a general two-dimensional (point) contact problem, a new EHL model is proposed to predict the surface normal and shear stress distributions in a robust and accurate way. This model uses a unified formulation that can handle any level of asperity interactions without any numerical difficulties. An asymmetric integrated control volume approach is employed to minimize the discretization errors, achieving high levels of accuracy with relatively coarser computational grid meshes. This discretization scheme combined with the Discrete Fast Fourier Transform method used to compute the elastic deformations reduces the computational time significantly. The mixed EHL model predictions are compared to published experiments to assess its accuracy. The three-dimensional stress state of contacting bodies due to the predicted normal and shear stress distributions are computed and a multi-axial contact fatigue criterion based on a characteristic plane approach is employed to predict crack initiation pitting life of the contact. A twin-disk type test methodology is developed to perform contact fatigue experiments. The proposed model predictions and experimental data are shown to agree well.
520 $a Next, the general methodology developed for point contact problems is expanded to develop a contact fatigue model for spur and helical gears. Each helical gear tooth is modeled by a number of narrow face width spur gear slices staggered according to the helix angle. Each narrow gear slice is assumed to have line contact with time varying parameters such as radius of curvature, normal load, sliding ratio and rolling speed. A novel one-dimensional mixed EHL model with these time-varying parameters is developed in association with a gear load distribution model. The predicted normal and surface shear stresses are then used to compute the state of stresses into the gear teeth. Various characteristic-plane and critical-plane type multi-axial fatigue criteria are considered to predict the crack initiation pitting life of the gear pair. At the end, the gear contact fatigue prediction methodology is then used to simulate the rotating gear pitting experiments from a companion study. A good agreement between the model and the predictions is demonstrated when the characteristic plane approach is used.
590 $a School code: 0168.
650 4 $a Engineering, Mechanical. $3 783786
690 $a 0548
710 2 $a The Ohio State University. $3 718944
773 0 $t Dissertation Abstracts International $g 70-02B.
790 $a 0168
790 1 0 $a Ahmet, Kahraman, $e advisor
791 $a Ph.D.
792 $a 2009
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3346607