基于概率的航空发动机飞行换算率改进算法

针对斯贝MK202发动机应力标准对零部件工作寿命评定中未包含各种随机因素的影响,考虑零部件疲劳性能参数的分散性和发动机整机载荷谱的随机性,将实测数据统计分析、零部件应力有限元分析以及蒙特卡罗模拟分析有机结合,提出了基于概率的航空发动机飞行换算率改进算法,以解释航空发动机零部件实际工作寿命存在的差异.经范例验证表明:确定性寿命评定方法的飞行换算率计算结果与改进算法下的平均值相当;对于单次飞行换算率,改进算法的单次飞行换算率平均值比确定性方法的计算结果小2%;对于综合飞行换算率,改进算法的综合飞行换算率平均值比确定性方法的结果小1%;且在改进算法下单次飞行换算率和综合飞行换算率服从正态分布.

Improved algorithm of flight conversion ratio for aero-engine based on probability

For SPEY MK202 engine, the stress standard evaluation methods fail to contain various random factors. In order to explain the differences in the actual working life of engine component, as well as the dispersion of the fatigue characteristic parameters of component and the randomness of the whole engine load spectrum, statistical analysis of measured data, finite element analysis of stress and Monte Carlo simulations of component were combined to put forward the improved algorithm of flight conversion ratio for aero-engine based on probability. Actual example shows: the flight conversion ratio of ascertainable method for life assessment is the average value of the improved algorithm; for a single flight conversion rate, the average conversion rate of improved algorithm is 2% smaller than that of ascertainable method; for comprehensive flight conversion rate, the average conversion rate of improved algorithm is 1% smaller than that of ascertainable method; and the single fight conversion rate and comprehensive flight conversion ratio of improved algorithin are in normal distribution.