A method is developed to simulate the fatigue crack growth in a carburized gear tooth considering the effect of residual stress. The calculation of stress intensity factor and the fatigue crack growth rates in the case layer are estimated by the experimental formula obtained in this study. The crack growth of carburized gears is measured by a crack gauge, and the validity of the simulation is confirmed. The critical length of initial crack which corresponds to the fatigue strength is introduced in the method, and a new design procedure of carburized gears is proposed based on the critical length of crack. As an example of the application of the procedure, the size effect is tried to discuss.

Abstract
 1. Introduction
 2. Stress intensity factor considering the effect of residual stress
 3. Estimation of crack growth rate in case layer
 4. Simulation of Crack Growth in Carburized Gear Teeth
 5. Design procedure for the strength of carburized gears
 5. Conclusion
 Acknowledgment
 Reference

• 정봉수(전북대학교 융합기술공학부) | Bong-Soo JEONG