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Computational fracture mechanics based FATIG3D program was used to simulate contact fatigue life of rough surface contacts in boundary to mixed lubrication regimes. Two-rollers contact fatigue tests were conducted and test results were compared with calculated contact fatigue lives. Calculated contact fatigue life agreed with test results well with the selected set of input data. The effect of several important parameters in the input data on contact fatigue life was evaluated computationally using FATIG3D. These parameters include: oil pressure distribution, crack face friction, direction of friction, friction coefficient, initial crack length, Hertzian stress, and residual stress distributions. The results obtained in this work improved basic understanding and the application of FATIG3D in simulating contact fatigue behavior.

As a part of a major research program with the aim of improving heavy truck drive axle fuel efficiency, this work focuses on seal friction torque test development and establishing pinion seal and wheel seal friction torque baseline data. Pinion seal and wheel seal friction torque was measured. The effect of speed and temperature on pinion seal friction torque was assessed. The effect of several coatings on pinion seal friction torque was evaluated. Pinion seal friction torque was also calculated and calculation result was compared with test data. Finally the impact of seal friction and bearing friction on total drive axle power loss was discussed.

In spite of being a popular topic in technical publications, scuffing between piston ring face and cylinder liner is an extremely unpredictable and hard-to-reproduce phenomenon that significantly decreases engine performance. This paper will discuss results of metallurgical and metrological (post-mortem) examinations of the scuffing between hard and soft cylinder liners and different piston ring coatings after field, engine and bench testing. Detailed metallurgical analysis describes the lubricity mechanism between various piston ring coatings and iron cylinder liner at different temperatures with and without oil. The paper will explain the origin of the scuffing through lack of or inadequate lubrication at top dead center, particularly for hardened iron heavy-duty diesel cylinder liners.