三參數威布爾分布置信限的確定和C-R-S-N曲線的擬合

The Determination of Confidence Limits for Weibull Distribution of Three-parameter and the Fitting of C-R-S-N Curves

摘要: 論述了利用三參數威布爾分布描述機械零件疲勞壽命,并在一定置信度下求R-S-N曲線的方法.即根據試驗所得的應力-壽命樣本,運用優化方法對三多數威布爾分布參數進行估計;并在一定置信度下,求出不同可靠度的疲勞壽命,進而擬合出C-R-S-N曲線,求出相應的疲勞極限應力值.

Abstract: The paper discusses the use of Weibull distribution of three-parameter to describe the fatigue life of machine element, and proposes a new method to fitting R-S-N curves under certain confidence. The parameters of three-parameter Weibull distribution are estimated by optimization, based on the samples of stress-life from tests. The fatigue life at each different reliability is then calculated under centain confidance. Thereafter the C-R-S-N curves can be fitted and the corresponding fatigue limit stress is evaluated