动部件疲劳强度减缩系数确定方法研究

Research on Fatigue Strength Reduction Factor to Helicopter Dynamic Components

摘要:

低周疲劳常采用寿命分散系数描述结构疲劳强度的固有分散性,而高周疲劳采用疲劳强度减缩系数来描述。在分析美、俄、法、英、德、意六国疲劳强度减缩系数取值方法的基础上, 依据统计学理论,假设疲劳强度服从正态和对数正态分布从理论上确定了疲劳强度减缩系数的取值方法。针对我国现役机型特点,建立了母体标准差已知和母体标准差未知时的疲劳强度减缩系数取值方法,通过最后与国外疲劳强度减缩系数取值的分析比较,证明所建立的疲劳强度减缩系数取值方法适合我国直升机飞行使用特点。

Abstract:

The factor of life scatter is used for depicting the dispersibility of fatigue strength in low cycle fatigue, but in high cycle fatigue is the fatigue strength reduction factor. The fatigue strength reduction factor and the cycle counting method have an important effect on the fatigue life of dynamic components. Now rain-flow cycle counting method is the common method adopted by rotorcraft industry. The fatigue strength reduction factors are determined for the known and unknown standard deviation respectively in the assumption of normal distribution and logarithmic normal distribution of the fatigue strength. Based on versus analysis of fatigue strength reduction factors in both U.S. and European helicopter companies, the profitable calculation method is established for home helicopters. Compared to overseas results, the method is reasonable.