Gears are components that transmit rotational motion by engaging the gear teeth. Since gears are used in the power transmission system, their failure will lead to the mechanism failure. So, predicting failure factors is important to ensure a proper design. Tooth surface failure includes cases such as wear, pitting and spalling. Considering that experimental studies of fatigue phenomena are time-consuming and expensive, it is necessary to improve numerical models and bring them as close as possible to real conditions. The aim of this research is to present a numerical model to predict the subsurface fatigue crack initiation and growth under cyclic contact loading. In this study, Abaqus software was used for 2D modeling of a pair of teeth in contact. The analysis was performed using standard finite element method with progressive crack growth. The crack growth angle was determined according to the improved Richard criterion. The results showed that the maximum ΔKII position, with about 9% error, has the best agreement with the experimental spalling. So, the maximum ΔKII position was proposed as a criterion for determining the subsurface crack initiation position. The stress intensity factor of initial subsurface crack left and right tips is the same, and so, both tips start to grow simultaneously. In this model, the improved Richard criterion was used to determine the crack growth angle, which leads to the prediction of a spalling with dimensions close to the experimental spalling. The predicted spalling length showed a difference of about 6% compared to the experimental spalling.
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Heirani,H and Farhangdoost,K . (2026). Numerical study of subsurface crack growth in the spalling phenomenon of a spur gear tooth. Science and Technology in Mechanical Engineering, 4(2), 257-269. doi: 10.22034/stme.2025.544154.1164
MLA
Heirani,H , and Farhangdoost,K . "Numerical study of subsurface crack growth in the spalling phenomenon of a spur gear tooth", Science and Technology in Mechanical Engineering, 4, 2, 2026, 257-269. doi: 10.22034/stme.2025.544154.1164
HARVARD
Heirani H, Farhangdoost K. (2026). 'Numerical study of subsurface crack growth in the spalling phenomenon of a spur gear tooth', Science and Technology in Mechanical Engineering, 4(2), pp. 257-269. doi: 10.22034/stme.2025.544154.1164
CHICAGO
H Heirani and K Farhangdoost, "Numerical study of subsurface crack growth in the spalling phenomenon of a spur gear tooth," Science and Technology in Mechanical Engineering, 4 2 (2026): 257-269, doi: 10.22034/stme.2025.544154.1164
VANCOUVER
Heirani H, Farhangdoost K. Numerical study of subsurface crack growth in the spalling phenomenon of a spur gear tooth. STME. 2026;4(2):257-269 (In Persian). doi: 10.22034/stme.2025.544154.1164
Science and Technology in Mechanical Engineering