A Finite Element Analysis of Surface Pocket Effects in Hertzian Line Contact

During start up and shut down of heavily loaded rolling/sliding contacts, the lubricant film separating the surfaces is extremely thin and not fully developed. The load is supported by both the solid and the lubricant. Under extreme conditions, there is no lubricant film and the load is solely supported by the solid contact. However, when surface pockets are engineered on the surface of rolling/sliding elements, lubricant can be trapped in the pockets and deform with the pockets. Finite element analysis [FEA] of the deformation of a single empty pocket indicates that the volume of the pocket significantly decreases under an applied load. Therefore, when the pocket is filled with a lubricant, the lubricant will undergo significant compression. This compression enables lubricant to support part of the load and provide beneficial effects, such as reducing friction and expelling the lubricant during start up and shut down. This research presents an FEA model of a rigid cylinder in contact with an elastic and/or elastic-linear-kinematic-hardening-plastic half space with lubricant filled surface pocket(s). Results of lubricant filled pockets are compared with those of empty pockets. The results demonstrate the beneficial effects of load sharing mechanism by the lubricant. [S0742-4787(00)00801-8]