Additional Information:• Abstract:The paper describes a combined tribodynamics analysis (dynamics and contact tribology) of cylindrical roller bearings of a heavy duty truck transmission under high applied loads. The dynamic analysis provides the transient variations in contact load. It also determines the vibration spectrum of the bearing as well as that of contact dynamics. It is shown that with sufficient preloading and/or interference fitting a widely spread loaded region results, which reduces bearing-induced vibration. The transient tribological analysis, including thermal analysis with a novel and realistic lubricant inlet boundary condition demonstrates that nonNewtonian mixed elastohydrodynamic regime of lubrication is prevalent, but with reduced friction compared with unrealistic dry Coulombic friction, which is often assumed in literature.

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Circular point contact EHD pressure distributions were investigated under various operating conditions using a thin film piezo‐resistive pressure transducer. A series of controlled experiments, in which the active element of the transducer is positioned at various contact cross‐sections, was carried out. The results are analysed and presented in the form of isobars. The pressure distribution closely describes the Hertzian pressure profile with a secondary pressure peak appearing prior to and near the exit constriction.

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In applications requiring high load carrying capacity, conforming contacting pairs with a relatively large contact footprint are used. These include circular arc, Novikov, and Wildhaber gears found, for example, in helicopter rotors. Closely conforming contacts also occur in many natural endo-articular joints, such as hips, or their replacement arthroplasty. The main determining factors in contact fatigue are the sub-surface shear stresses. For highly loaded contacts, classical Hertzian contact mechanics is used for many gears, bearings, and joints. However, the theory is essentially for concentrated counterforming contacts, where the problem is reduced to a rigid ellipsoidal solid penetrating an equivalent semi-infinite elastic half-space. Applicability is limited though, and the theory is often used inappropriately for contacts of varying degrees of conformity. This paper presents a generic contact mechanics approach for the determination of sub-surface stresses, which is applicable to both highly conforming as well as concentrated counterforming contacts. It is shown that sub-surface shear stresses alter in magnitude and disposition according to contact conformity, and lead to the different modes of fatigue failure noted in practice.