现代民机设计中细节疲劳额定强度(DFR)方法占据重要地位。为了研究DFR方法中的参数敏感性问题,针对典型航空材料讨论了在斜度参数和分散性参数两种参数的变化范围内,直接采用波音设计许用值进行DFR计算可能造成的误差水平,并与简单的扰动分析结果进行了对比;推导了基于Gerber方程计算DFR值的新公式,并对其适用性进行了对比分析。结果表明,在上述计算参量中斜度参数对国产材料DFR计算结果影响最敏感;锻铝等延性材料更适于使用基于Gerber方程的DFR公式。
Detail fatigue rating (DFR) method plays an important role in modern civil aircraft design. To study the sensitivity of the parameters in this method, within the range of slope parameter and dispersion parameter, this paper discusses the errors in the DFR calculation for China-made materials by using Boeing design allowable values, and completes a simple perturbation analysis. After deriving a new Gerber-based DFR equation, this paper compares the results calculated by the new Gerber-based DFR equation with those by Boeing’s DFR equation. The results indicate that of all the parameters in the DFR equation the slope parameter is the most sensitive for calculating DFR. The new Gerber-based DFR equation can be used to obtain the DFR more accurately for ductile materials than the equation presented by Boeing.
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