From Single Tooth Bending Fatigue (STBF) Test Data to S-N Curves for Design（齒輪彎曲疲勞SN曲線測試）

主講人 : Prof. Carlo Gorla

Report investigates the statistical treatment of Single Tooth Bending Fatigue test data for gear root strength evaluation and its implications in load spectrum analysis. Employing Maximum Likelihood estimation and Statistics of Extremes, we compare advanced models with standardized approaches. Results reveal significant discrepancies in fatigue knee positioning: STBF tests typically indicate knees below 5×10? cycles, contrasting with ISO’s assumption of 3×10? cycles, which aligns more closely with meshing gear behavior. The Crossland multiaxial fatigue criterion highlights non-proportional stress histories under operational conditions, while Palmgren-Miner- d load spectrum assessments demonstrate that STBF-derived curves yield conservative predictions (10–20% lower safety factors) compared to ISO. We recommend using STBF data for fatigue limit estimation while adopting ISO SN curves for lifetime predictions, ensuring a balance between conservatism and practicality. This work underscores the need for experimental validation in translating STBF results to meshing gears and advocates integrating rigorous statistical methods with standardized  works for reliable gear design under variable loading.

主講人簡介：

Carlo Gorla，博士，米蘭理工大學機械工程系教授，第二屆國際齒輪大會主席，AGMA（美國齒輪制造商協會）學術委員。長期從事齒輪動力傳動相關研究工作，包括航空傳動設計、疲勞失效機理及齒輪效率噪聲等。在國際權威學術期刊與國際會議上發表論文100多篇，累計引用2000余次。多次擔任科學委員會主席、聯合主席、委員，受邀擔任國際會議的主持人和特邀報告人。擔任Journal of Mechanical Design、Mechanism and Machine Theory、Meccanica等多項國際科學期刊的審稿專家。