Experimental and numerical investigation of the fatigue behavior of radial journal bearing manufactured from za-27 alloy

The fatigue behavior of radial journal bearings manufactured from ZA-27 alloy was investigated through experimental and numerical approaches under different bearing widths and loading conditions. In the experimental studies, the number of load cycles at which the first fatigue crack initiated was determined. The fatigue regions and crack distributions in the bearings were thoroughly examined using Optical Microscopy (OM), Scanning Electron Microscopy (SEM), and Energy Dispersive Spectroscopy (EDS) techniques. The maximum oil film pressures in the bearings were determined through numerical analyses at time steps corresponding to every 7.5° increment in crank angle under dynamic loading conditions. Based on the results, the critical crank position at which the maximum film pressure occurred was identified, and fatigue analyses were performed based on this characteristic time step. The findings revealed that maximum film pressures developed in regions subjected to the highest loads, where fatigue cracks also predominantly initiated and propagated. Furthermore, bearings manufactured from ZA-27 alloy demonstrated slightly higher fatigue performance compared to conventional white metal-based bearings commonly used in engine applications, indicating the potential of ZA-27 as an alternative bearing material.