E. R. Booser

Bio: E. R. Booser is an academic researcher. The author has contributed to research in topics: Bearing (mechanical) & Fluid bearing. The author has an hindex of 1, co-authored 1 publications receiving 283 citations.

Applied Tribology: Bearing Design and Lubrication

Abstract: Series Preface. Preface. Part I: General Considerations. 1 Tribology - Friction, Wear, and Lubrication. 2 Lubricants and Lubrication. 3 Surface Texture and Interactions. 4 Bearing Materials. Part II: Fluid-Film Bearings. 5 Fundamentals of Viscous Flow. 6 Reynolds Equation and Applications. 7 Thrust Bearings. 8 Journal Bearings. 9 Squeeze-Film Bearings. 10 Hydrostatic Bearings. 11 Gas Bearings. 12 Dry and Starved Bearings. Part III: Rolling Element Bearings. 13 Selecting Bearing Type and Size. 14 Principles and Operating Limits. 15 Friction, Wear and Lubrication. Part IV: Seals and Monitoring. 16 Seal Fundamentals. 17 Condition Monitoring and Failure Analysis. Appendix A Unit Conversion Factors. Appendix B Viscosity Conversions. Index.

Prediction of Mechanical Efficiency of Parallel-Axis Gear Pairs

Abstract: A computational model is proposed for the prediction of friction-related mechanical efficiency losses of parallel-axis gear pairs. The model incorporates a gear load distribution model, a friction model, and a mechanical efficiency formulation to predict the instantaneous mechanical efficiency of a gear pair under typical operating, surface, and lubrication conditions. The friction model uses a new friction coefficient formula obtained by using a validated non-Newtonian thermal elastohydrodynamic lubrication (EHL) model in conjunction with a multiple linear regression analysis. The load and friction coefficient, distribution predictions are used to compute instantaneous torque/ power losses and the mechanical efficiency of a gear pair at any given rotational position. Efficiency measurements from gear pairs having various gear designs and surface treatments are compared to model predictions. Mechanical efficiency predictions are shown to be within 0.1% of the measured values, indicating that the proposed efficiency model is accurate. Results of a parametric study are presented at the end to highlight the influence of key basic gear geometric parameters, tooth modifications, operating conditions, surface finish, and lubricant properties on mechanical efficiency losses.

An Experimental Investigation of Dimple Effect on the Stribeck Curve of Journal Bearings

Abstract: The friction characteristic of a journal bearing with dimpled bushings manufactured using the machining and the chemical etching techniques is investigated. A series of experimental results is presented to examine the effect of dimples on the Stribeck curve. Load, oil type, dimple size, depth and shape are varied to explore their influence on the friction characteristics. It is shown that with proper dimensions of dimples, the friction performance of journal bearings can be improved, particularly for light oils. The results reveal that in mixed lubrication regime, the so-called secondary lubrication effect in the dimpled area is the main mechanism responsible for improvement of performance. Experimental results also indicate that a bushing with etched dimples over the entire circumference offer a better frictional performance than a bushing with dimples etched on half of its circumference.

The Stribeck Curve: Experimental Results and Theoretical Prediction

Abstract: The Stribeck curve plays an important role in identifying boundary, mixed, elastohydrodynamic, and hydrodynamic lubrication regimes. Recent advances in elastohydrodynamic lubrication together with rough surface interaction have made it possible to develop a methodology for predicting the trend of the Stribeck curve. In this paper; we report the results of a series of experiments performed on a journal bearing together with a theoretical prediction of the Stribeck-type behavior. Various loads and oil temperatures are considered. The comparison between the experimental results with a mixed elastohydrodynamic lubrication model for line contacts is indicative of good agreement.

Operando tribochemical formation of onion-like-carbon leads to macroscale superlubricity

Abstract: Stress-induced reactions at the sliding interface during relative movement are known to cause structural or chemical modifications in contacting materials. The nature of these modifications at the atomic level and formation of byproducts in an oil-free environment, however, remain poorly understood and pose uncertainties in predicting the tribological performance of the complete tribosystem. Here, we demonstrate that tribochemical reactions occur even in dry conditions when hydrogenated diamond-like carbon (H-DLC) surface is slid against two-dimensional (2D) molybdenum disulfide along with nanodiamonds in dry nitrogen atmosphere. Detailed experimental studies coupled with reactive molecular dynamics simulations reveal that at high contact pressures, diffusion of sulfur from the dissociated molybdenum disulfide led to amorphization of nanodiamond and subsequent transformation to onion-like carbon structures (OLCs). The in situ formation of OLCs at the sliding interface provide reduced contact area as well as incommensurate contact with respect to the H-DLC surface, thus enabling successful demonstration of superlubricity.