Fatigue life analysis of diesel engine journal bearings based on accelerated life testing
Abstract
Bearing failures are a leading cause of engine faults, and fatigue is one of the most common failure modes in journal bearings. Studying fatigue life is crucial for understanding the evolution of journal bearing failure. In this paper, the fatigue properties of engine bearings under different operating conditions were investigated. First, accelerated life tests on journal bearings were conducted. Combined with parameter estimation, a fatigue acceleration model was established to evaluate statistical life indicators of bearing fatigue failure under various operating conditions. Then, the surface cyclic stress considering lubrication condition was calculated, and the relationship between cyclic stress and fatigue life was developed. By integrating accelerated testing and numerical simulation, the evolution of fatigue regions on the bearing surface was systematically analyzed under the influence of load, rotational speed, and clearance. The results show that increasing load intensifies asperity contact at the bearing edges, causing fatigue failure regions to migrate toward the edges. Meanwhile, variations in rotational speed and clearance affect the hydrodynamic effect, influencing both the distribution of fatigue regions and fatigue life. The calculated fatigue regions align with experimental observations, validating the proposed methodology. This study provides valuable methods and insights for fatigue life analysis of journal bearings.