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Elastohydrodynamic Lubrication

# Film Thickness and Asperity Load Formulas for Line-Contact Elastohydrodynamic Lubrication With Provision for Surface Roughness

[+] Author and Article Information
M. Masjedi

Department of Mechanical Engineering,  Louisiana State University, 2508 Patrick Taylor Hall, Baton Rouge, LA 70803

M. M. Khonsari1

Department of Mechanical Engineering,  Louisiana State University, 2508 Patrick Taylor Hall, Baton Rouge, LA 70803Khonsari@me.lsu.edu

1

Corresponding author.

J. Tribol 134(1), 011503 (Feb 24, 2012) (10 pages) doi:10.1115/1.4005514 History: Received August 22, 2011; Revised December 09, 2011; Published February 10, 2012; Online February 24, 2012

## Abstract

Three formulas are derived for predicting the central and the minimum film thickness as well as the asperity load ratio in line-contact EHL with provision for surface roughness. These expressions are based on the simultaneous solution to the modified Reynolds equation and surface deformation with consideration of elastic, plastic and elasto-plastic deformation of the surface asperities. The formulas cover a wide range of input and they are of the form f(W, U, G, $σ¯$, V), where the parameters represented are dimensionless load, speed, material, surface roughness and hardness, respectively.

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## Figures

Figure 1

Effect of surface roughness on the film thickness (W = 1 × 10−4 , U = 1 × 10−11 G = 4500, V = 0.01)

Figure 2

Effect of surface roughness on the pressure distribution (W = 1×10−4 , U = 1 × 10−11 G = 4500, V = 0.01) (a): σ¯=5×10-6 (smooth), (b): σ¯=2×10-5, (c): σ¯=5×10-5

Figure 3

Effect of dimensionless load on dimensionless central film thickness (U = 1 × 10−11 , G = 4500, V = 0.01)

Figure 4

Effect of dimensionless load on asperity load ratio (U = 1 × 10−11 , G = 4500, V = 0.01)

Figure 5

Effect of dimensionless speed on dimensionless central film thickness (W = 1 × 10−4 , G = 4500, V = 0.01)

Figure 6

Effect of dimensionless speed on asperity load ratio (W = 1 × 10−4 , G = 4500, V = 0.01)

Figure 7

Effect of dimensionless hardness on dimensionless central film thickness (W = 1 × 10−4 , U = 1 × 10−11 , G = 4500)

Figure 8

Effect of dimensionless hardness on asperity load ratio (W = 1 × 10−4 , U = 1 × 10−11 , G = 4500)

Figure 9

Comparison between Pan and Hamrock, Dowson and Toyoda, Moes, and current central film thickness equation (Eq. 19) for given data

Figure 10

Comparison between Pan and Hamrock, Dowson and Higginson, Moes, and current minimum film thickness equation (Eq. 20) for given data

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