试验与服役数据融合的飞机结构安全寿命分析

针对飞机结构安全寿命分析中样本容量偏少的问题,综合考虑结构分散性和载荷分散性的飞机结构疲劳寿命是否服从对数正态分布或威布尔分布的情况,根据等损伤原理,将服役飞机实际飞行小时数等效转化为在同一试验载荷谱下的当量飞行小时数,以实现飞机结构试验疲劳寿命与服役使用数据的融合,采用随机右截尾情形下的极大似然估计方法估算疲劳寿命分布函数的参数,进行飞机结构安全寿命分析;最后以飞机结构疲劳寿命服从对数正态分布为例进行了算例分析,分析结果表明:在相同的可靠度和置信水平下,利用试验数据与服役使用数据融合方法可以显著增大样本容量,从而充分挖掘飞机结构可靠性的储备。

An Analysis of Safe-life for Aircraft Structure Based on the Fusion of Test Data and Service Data

This paper mainly discusses how to reconcile the test results with the service data to solve fatigue safe-life of aircraft structure. Aimed at the fatigue life obedient to the Log-normal distribution or Weibull distribution, the service flying hours and test results can be reconciled directly to analyze the reliability for the aircraft structure. Aimed at the fatigue life disobedient to the Log-normal distribution or Weibull distribution, the service hours can be transformed into the equivalent flying hours at the same test load spectrum according to the equal damage to realize the fusion of the test data and the service data. The parameters of fatigue safe-life distribution function can be estimated by using the method of maximum likelihood function in accordance with the fusion data. The fatigue safe-life for aircraft structure is analyzed by using the estimated parameters and the fusion data. The result shows that the sample capacity is increased obviously after the data fusion, and the life reserve of reliability is excavated adequately by adopting the method of the fusion data under the conditions of the same reliability and confidence level.