# Research on Multi-Directional Spalling Evolution Analysis Method for Angular Ball Bearing
###### Abstract  
The prediction of spalling failure evolution in the lifespan of aeroengine bearings is crucial for en-suring the safe return of aircrafts after such failures occur. This study examines the spalling failure evolution process in bearings by integrating the proposed spalling region contact stress analysis model with the multi-directional subsurface crack extension analysis model. The results elucidate the general pattern of spalling expansion. Utilizing this methodology, the fatigue spalling fault evolution in bearings is thoroughly analyzed. Additionally, a two-dimensional model has been developed to simulate and analyze crack propagation in the critical direction of the spalling region, significantly enhancing the model's computational efficiency. bearing fatigue spalling; crack growth; finite element simulation; life prediction; angular ball bearing +
Footnote †: journal: Medical and Electrical Engineering  
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prediction model for bearings enables calculating effective prognostics of the remaining useful life after spalling initiation. Such a model will play a significant role in planning the remaining flight mission and guiding maintenance schedules for aeroengine bearings. In aeroengine bearings, spalling represents a predominant failure mode, attributed to their high-speed and high-load characteristics. The spalling region progressively enlarges due to the ongoing contact between the rolling elements and the raceways of the bearing [5; 6; 7]. The cyclic loading between the rolling elements and the raceway can exacerbate the spalling propagation process. Within aeroengine bearings operating under such intricate operating conditions, the direction and rate of spalling propagation become even more elusive to uncover. [PERSON] [8] explicitly demonstrated, through modeling and analysis of fatigue spalling on a railway, that fatigue spall crack propagation analysis is key in the modeling and analysis of spalling. [PERSON] [9] combined finite element analysis with fracture mechanics models when modeling subsurface cracks in rolling bearings. By incorporating the specific loading characteristics of aeroengine bearings and iteratively updating the model, it is possible to complete a propagation analysis of spalling cracks. Lubrication plays a critical and indispensable role in aeroengine bearings. To incorporate lubrication effects, this study directly analyzes the contact stress response under fully lubricated conditions in rolling bearings. [PERSON] and [PERSON] [10] investigated the evolution of the lubrication film in high-speed rolling bearings. [PERSON] [11] further analyzed the influence of bearing material on the lubricating film. [PERSON] [12] proposed a spalling size estimation method based on oil debris monitoring based on experimental data. In the analysis of spalling evolution in aeroengine bearings, it is essential to consider the lubrication effect of the bearing. The modeling and analysis should be conducted using the modified stress response value to accurately assess the impact of lubrication on spalling progression. To establish a spalling evolution model for bearings, it is necessary to calculate the stress around the spalled area. [PERSON] [13] revealed the effect of spalling on the contact stress of a bearing by performing finite element modeling and analysis of the impact process of the roller at the edge of the spalled area. Spalling not only has a direct impact on contact stress but also affects the vibration data of the bearing. [PERSON] [14] conducted a detailed simulation of the microscopic expression of the spalling process by studying a microscopic spalling model of anisotropic veined genesis. [PERSON] [15] developed a dynamic simulation model incorporating spalling to simulate the stress response of thrust ball bearings at the defect location and assessed the relationship between spalling size and load.