Effect of transverse vibrations on surface-initiated fatigue in lubricated rolling-sliding contacts

A new experimental setup combining a triple-disc contact fatigue rig and an electrodynamic modal shaker has been developed to facilitate the systematic study on the influence of transverse vibrations on surface fatigue in lubricated contacts relevant to rolling bearing applications. The devised methodology ensures close control of both contact conditions and imposed vibration parameters, so that the influence of a single parameter of interest can be isolated and studied. Tests were conducted with AISI 52100 bearing steel specimens in mixed lubrication regimen at Hertz contact pressures of 3 GPa. The results show that transverse vibrations can significantly accelerate both the initiation and progression of surface fatigue damage with up to two times more damage recorded in present tests with versus without vibrations. It is found that the transverse vibration velocity best correlates with the extent of the surface damage under many contact conditions, so this parameter can be used to assess the potential impact in practical situations. Cracks of up to 5 μ m were detected within the first 100,000 cycles, confirming that crack initiation under transverse vibrations occurs very early in life. The surface damage progression is also much faster with transverse vibrations than without. The likely reason for the accelerated surface fatigue damage under these vibrations is the increased number of roughness asperity contact cycles, resulting in a faster accumulation of surface fatigue damage. These findings can support the development of more reliable mechanical systems where bearings may be subjected to transverse vibrations, such as wind turbines and train axleboxes. • Transverse vibrations accelerate the initiation and progression of fatigue damage. • Surface-initiated fatigue is generated under high 3.0 GPa contact pressures. • Transverse vibrations have the most detrimental impact on rolling element bearings. • Gear contacts are believed not to be affected by such vibrations. • Dry contact numerical simulations ascribe to increased asperity-level contact cycles.