Prediction of Running-in Behavior for Point Contacts under Mixed Lubrication

Document Type : Research Article

Authors

Department of Mechanical Engineering, Isfahan University of Technology, Isfahan 84156-83111, Iran

Abstract

Tribology concentrates on wear, friction, and lubrication of interacting surface in relative motion. Wear, which is the major cause of material wastage, evolves in three separete stages: running-in, steady-state, and sever wear. Running-in has an important role in loss of material performance and this process involves the evolution of the key tribological parameters. Hence, running-in behavior of a tribocomponent experiencing point contact in mixed lubrication regime is investigated both theoretically and experimentally. The transient wear coefficient during the running-in is predicted using the continuum damage mechanics approach (CDM). Predictions involve the use of the load-sharing concept, taking into account the contribution of the asperities and the lubricant. The experimental work entails a series of pin-on-disk tests. Comparing the results displayed, it is observed that the calculated maximum error in the predicted wear volume and arithmetic mean roughness at each stage running-in are 1% and 5%, respectively. Comparisons of the theoretical prediction and experimental tests of friction coefficient and wear coefficient are found to be in good agreement. Importantly, the model can be used as a guide for selecting the sliding speed or load to achieve the optimum steady-state performance in terms of wear rate or power loss.

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