民用飞机平尾载荷的不确定性及全局灵敏度分析

Uncertainty quantification and global sensitivity analysis of horizontal-tail load for civil aircraft

针对飞行载荷计算输入数据的随机不确定性会导致载荷计算结果波动的现象,采用Monte Carlo模拟方法和基于方差的全局灵敏度分析方法对民用飞机急剧俯仰机动随机平尾载荷进行不确定性及全局灵敏度分析。具体分析了飞机气动特性和重心的不确定性对迎角贡献平尾载荷、升降舵偏度贡献平尾载荷及平尾总载荷的影响,进一步通过全局灵敏度分析找出影响平尾载荷计算结果的主要因素。不确定性分析结果表明:气动特性和重心的不确定性导致迎角贡献平尾载荷的波动程度很大。灵敏度分析结果表明:1)升降舵偏度贡献平尾载荷只受升降舵效率的影响;2)迎角贡献平尾载荷主要受无尾飞机零迎角俯仰力矩系数和重心的影响;3)平尾总载荷受升降舵效率的影响最大,受无尾飞机零迎角俯仰力矩系数及重心的影响次之。此外也验证了方法的有效性,对提高飞行载荷的计算精度有一定的指导意义。

Considering the randomness of input variable used in flight load calculation, the Monte Carlo simulation and the variance-based global sensitivity analysis method were employed to analyze the uncertainty and the corresponding global sensitivity indexes of horizontal-tail load for acute pitch maneuver. In the paper, the influence of aerodynamics and center of gravity(CG) uncertainty, as well as global sensitivity analysis on the horizontal-tail load were presented. The results of uncertainty analysis show that the horizontal-tail load due to angle of attack(AOA) is sensitive to the input uncertainties. From the results of global sensitivity analysis:1)the horizontal-tail load due to elevator is only influenced by the elevator control effectiveness;2) the tail-off pitching moment coefficient with zero AOA and the CG have mainly influence on the horizontal-tail load due to AOA;3)the elevator control effectiveness has the most influence on the total horizontal-tail load, and the tail-off pitching moment coefficient with zero AOA and CG has the second. The validity of the proposed method has been validated, which are useful for promoting the calculation precision of flight load in aircraft design.