Friction, Wear, and Temperature in Sliding Contact

1980 ◽  
Vol 102 (1) ◽  
pp. 107-112 ◽  
Author(s):  
Hamid S. Al-Rubeye
Keyword(s):  
Thermal Model ◽  
Measuring Method ◽  
Spur Gear ◽  
Sliding Contact ◽  
Heating Process ◽  
Line Contact ◽  
Sliding Velocity ◽  
Body Temperatures ◽  
Load Carrying ◽  
Temperature Criterion

The temperature criterion plays a significant part in the attempt to interpret the scoring phenomenon of lubricated load-carrying machine members. Investigations were carried out to examine the correlation of the scoring bulk body temperatures, which have been measured on point and line contact machines using a modified Four-Ball and Spur Gear Tester. The simulation of the thermal model of both systems proved to be the only criterion for the correlation of the desired temperatures. A systematical investigation on the Four-Ball machine using a new temperature measuring method provided the basis to study the heating process of the sliding elements. The results show the influence of the loading and sliding velocity on both the bulk body temperature and the surface temperature.

On the Modeling of Quasi-Steady and Unsteady Dynamic Friction in Sliding Lubricated Line Contact

2009 ◽  
Vol 132 (1) ◽  
Author(s):  
H. Sojoudi ◽  
M. M. Khonsari
Keyword(s):  
Experimental Data ◽  
Friction Coefficient ◽  
Reynolds Equation ◽  
Friction Model ◽  
Sliding Contact ◽  
Dynamic Friction ◽  
Line Contact ◽  
Sliding Velocity ◽  
Friction Behavior ◽  
Lubricated Sliding

A simple but realistic dynamic friction model for the lubricated sliding contact is developed based on decoupling the steady and unsteady terms in Reynolds equation. The model realistically captures the physics of friction behavior both when speed is increased unidirectionally or when operating under oscillating condition. The model can simulate the transition from boundary to mixed to full film regimes as the speed is increased. Two different classes of simulations are performed to show the utility of the model: the so-called quasisteady, where the sliding velocity is varied very slowly, and the oscillating sliding velocity, where the friction coefficient exhibits a hysteresis type behavior. Both categories of simulation are verified by comparing the results with published experimental data.

Effect of Rolling Velocity and Maximum Hertzian Pressure on Fluid Film in Steady State EHL Line Contact with Rough Surface and Linear Piezoviscosity

2014 ◽  
Vol 592-594 ◽  
pp. 1371-1375
Author(s):  
Nitesh Talekar ◽  
Punit Kumar
Keyword(s):  
Surface Roughness ◽  
Steady State ◽  
Film Thickness ◽  
Rough Surface ◽  
Computer Code ◽  
Fluid Film ◽  
Line Contact ◽  
Rolling Velocity ◽  
Load Carrying ◽  
Lubricated Contact

Consideration of surface roughness in steady state EHL line contact is the first step towards understanding the lubrication of rough surface problem. Current paper investigates the use of sinusoidal waviness in the contact; more precisely it gives performance of real fluid in EHL line contact. The effect of various parameters like rolling velocity (U) and maximum Hertzian pressure (ph) on surface roughness by using properties of linear and exponential piezo-viscosity is taken into consideration to evaluate behavior of pressure distribution of load carrying fluid film and film thickness. Full isothermal, Newtonian simulation of EHL problem gives described effects. Spiking or fluctuation of pressure and film thickness curves is expected to show presence of irregularities on the surface chosen and amount of fluctuation depends on certain parameters and intensity of irregularities present. Rolling side domain of-4.5 ≤ X ≤ 1.5 with grid size ∆X=0.01375 is selected. A computer code is developed to solve Reynolds equation, which governs the generation of pressure in the lubricated contact zone is discritized and solved along with load balance equation using Newton-Raphson technique.

Sliding Contact Between Dissimilar Elastic Bodies

1988 ◽  
Vol 110 (4) ◽  
pp. 592-596 ◽  
Author(s):  
A. Sackfield ◽  
D. A. Hills
Keyword(s):  
Elastic Constants ◽  
Carrying Capacity ◽  
Sliding Contact ◽  
Hertzian Contact ◽  
Load Carrying Capacity ◽  
Two Dimensional ◽  
Careful Choice ◽  
Elastic Bodies ◽  
Load Carrying ◽  
Two Bodies

An analysis is presented of the stresses induced by sliding between two bodies having different elastic constants. It is assumed that the bodies are plane (i.e., two dimensional), are symmetrical with respect to a line perpendicular to the plane of contact, and are smooth and continuous. It is shown that a careful choice of profile leads to a better load carrying capacity than for a Hertzian contact, but that the severity of the stresses induced is greater than for uncoupled sliding, i.e., where the bodies have similar elastic constants.

The Wear Characteristics of Graphene as an Atomically-Thin Protective Coating

2012 ◽  
Author(s):  
Emil Sandoz-Rosado ◽  
Elon J. Terrell
Keyword(s):  
Protective Coatings ◽  
Solid Lubricants ◽  
Atomistic Simulations ◽  
Great Promise ◽  
Load Carrying Capacity ◽  
Sliding Velocity ◽  
Substrate Rigidity ◽  
Macro Scale ◽  
Load Carrying ◽  
The Impact

Lamellar atomically-thin sheets such as graphene (and its bulk equivalent graphite) and molybdenum disulfide have emerged as excellent solid lubricants at the macro scale and show great promise as protective coatings for nanoscopic applications. In this study, the failure mechanisms of graphene under sliding are examined using atomistic simulations. An atomic tip is slid over a graphene membrane that is adhered to a semi-infinite substrate. The impact of sliding velocity and substrate rigidity on the wear and frictional behavior of graphene is studied. In addition, the interplay of adhesive and abrasive wear on the graphene coating is also examined. The preliminary results indicate that graphene has excellent potential as a nanoscale due to its atomically-thin configuration and high load carrying capacity.

Effect of Design Parameters on Lubrication Behavior of Spur Gear Pairs

2017 ◽  
Author(s):  
Yanfang Liu ◽  
Qiang Liu ◽  
Peng Dong
Keyword(s):  
Power Loss ◽  
Elastohydrodynamic Lubrication ◽  
Spur Gear ◽  
Design Parameters ◽  
Curvature Radius ◽  
Gear Pair ◽  
Sliding Velocity ◽  
Rolling Velocity ◽  
Lubrication Performance ◽  
Meshing Process

An involute spur gear pair meshing model is firstly provided in this study to achieve relevant data such as rolling velocity, sliding velocity, curvature radius etc. These data are needed in a transient, Newtonian elastohydrodynamic lubrication (EHL) model which is provided later. Based on these two models, the behavior of an engaged spur gear pair during the meshing process is investigated under dynamic conditions, film thickness, pressure, friction coefficient etc. could be achieved through the models. Then, power loss under certain operating condition is calculated. Relationship between power loss and lubrication performance is also analyzed.

Optimum Heating Control Method to Keep a Given Temperature Rising Speed of a Plate During Rapid Thermal Processing

2008 ◽  
Author(s):  
Shigeki Hirasawa ◽  
Sadanori Toda
Keyword(s):  
Thermal Processing ◽  
Thermal Model ◽  
Control Method ◽  
Rapid Thermal Processing ◽  
Good Method ◽  
Correlation Equation ◽  
Measuring Error ◽  
Heating Process ◽  
Time Step ◽  
Optimum Heating

In rapid thermal processing of semiconductor wafers, it is very important to keep a given temperature rising speed of the wafer during the heating process. We calculated the effect of various heating control methods on the error of the temperature rising speed of the wafer. We calculated the PID control, the control method by correcting with temperature rising speed, the control using a thermal model, the control using a prepared correlation equation, and the combined methods. We found that the combined method with a thermal model and rising speed is a good method to decrease the error of the temperature rising speed. The minimum error of the temperature rising speed at 700°C is less than 0.1°C/s during the temperature rising process of 100°C/s and the monitoring time step of 0.05 s. We calculated the effects of control-delay-time and measuring error of the monitoring temperature on the error of the temperature rising speed.

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