Numerical and experimental study of elastohydrodynamic grease lubrication of dimple textured surfaces.

Estimation of friction and wear is a challenging problem, and finding a way to reduce them has been a concern for many years. One of the most interesting ways is to make small dimples on the surface, which increases the preservation of the lubricant in the contact area. Grease behavior is non-Newtonian lubricant, and each type of grease has its unique behavior. In this research, a model for the behavior of grease as a lubricant on surfaces is investigated. Non-conformal surfaces are considered, and their deformation due to the application of load is assumed by elastohydrodynamic contact condition. The film thickness and pressure distribution in the lubricant layer are extracted by modeling the grease behavior. The model considered the transient phenomenon during passing pin over dimple. The effect of parameters such as the diameter and depth of the dimples, the applied load, and the speed of in-contact surfaces can be considered in the model. Finally, a friction estimation formula is developed with these findings. The experimental samples were then examined using a pin-on-disk test apparatus. Measuring friction on textured and flat surfaces was the criterion for comparing the performance of these dimples. The numerical results and experimental results are consistent. The model can successfully estimate the friction coefficient by a 4.5 percent average error. Using textured surfaces shows about 7 percent less friction compared to flat surfaces. [ABSTRACT FROM AUTHOR]