基于随动加载的起落架载荷误差评估与修正

Error Evaluation and Modification of Landing Gear Load Based on Self-adaptable Loading Technique

全尺寸飞机柔性起落架静力试验中,起落架受载变形引起加载力线改变,从而带来加载误差。为提高加载准确度,起落架随动加载技术被广泛使用。通过对随动加载模型的分析,得出该加载技术试验过程中理论上依然存在加载误差。采用向量、矩阵运算结合力学平衡方程推导得到随动加载技术误差计算公式和载荷修正公式。选取某型飞机起落架静力试验典型工况(两点滑行刹车)进行载荷误差评估、修正与验证。结果表明:随动加载技术试验过程中航向和垂向最大加载误差小于工程允许的1%误差,侧向加载误差引起的最大约束反力误差小于工程允许的5kN;载荷修正后,最大约束反力误差小于2kN,加载准确度得到了进一步提升。从理论上分析了柔性起落架发生变形后载荷误差并进行修正,研究成果为起落架静强度试验过程中主动载荷和约束点载荷误差分析提供了理论依据。

In static test of flexible landing gear of full-scale aircraft,the loading force lines change due to the deformation of landing gear under load,which result in loading error.In order to improve the accuracy of loading,self-adaptable loading technique of landing gear has been widely used.Through the analysis of the self-adaptable loading model,it is concluded that the loading technology still has loading error in theory.The error calculation formula and load modification formula were derived by using vector and matrix operation combined with mechanical balance equation.Load error was evaluated,modified and verified under typical load case(two-point taxiing brake)of certain type of aircraft landing gear static test.The results show that longitudinal error load and vertical load error are less than 1%permitted by engineering,and the maximum error of constraint reaction caused by lateral load error is less than 5 kN permitted by engineering in the whole process of self-adaptable load test.After load modification,the loading error is less than 2 kN,and the landing gear loading accuracy is further improved.The load error of flexible landing gear after deformation was analyzed and modified theoretically.The research results provide a theoretical basis for the error analysis of active load and constrained load in the static strength test of landing gear.