飞机典型结构当量初始缺陷尺寸分布模型研究  

An Equivalent Initial Flaw Size Distribution Model of Typical Aircraft Structures

作　　者：冯浩凌 许希武[2] 古兴瑾[2] 俞晓楠 FENG Haoling;XU Xiwu;GU Xingjin;YU Xiaonan(College of Aerospace Engineering,Nanjing University of Aeronautics&Astronautics,Nanjing 210016,China;State Key Laboratory of Mechanics and Control for Aerospace Structures,Nanjing University of Aeronautics&Astronautics,Nanjing 210016,China)

机构地区：[1]南京航空航天大学航空学院,南京210016 [2]南京航空航天大学航空航天结构力学及控制全国重点实验室,南京210016

出　　处：《南京航空航天大学学报》2024年第3期438-446,共9页Journal of Nanjing University of Aeronautics & Astronautics

摘　　要：利用结构耐久性分析技术可以在保证飞机结构可靠性的同时,有效提高飞机结构的经济性。应用结构耐久性分析技术,对某型飞机飞行载荷谱作用下一种7B04-T651高强铝合金典型疲劳结构的原始疲劳质量(Initial fatigue qualit,IFQ)进行了研究。开展了3级不同应力水平下的飞行载荷谱疲劳试验研究;利用极大似然估计法处理基于三参数Weibull分布的裂纹萌生时间分布的参数估计问题,利用蒙特卡罗法对比验证了该方法的正确性,提出使用对数样本矩处理当量初始缺陷尺寸(Equivalent initial flaw size,EIFS)分布以获取通用当量初始缺陷尺寸分布模型;建立描述该典型结构的原始疲劳质量模型,验证其当量初始缺陷尺寸小于许用规定的0.125mm;最后通过对该典型结构的原始疲劳质量分析,验证了通用化方法的正确性和实用性,并且建立了结构在不同应力区、不同指定裂纹尺寸和不同可靠度下的寿命估计模型。The use of structural durability analysis technology can effectively improve the economic efficiency of aircraft structures while ensuring their reliability.This paper utilizes the structural durability analysis technique to study the initial fatigue quality(IFQ)of a typical fatigue structure of 7B04-T651 high-strength aluminum alloy under the action of flight load spectrum of a certain type of aircraft.Firstly,the maximum likelihood estimation method is applied to the parameter estimation problem of crack initiation time distribution based on three-parameter Weibull distribution.The Monte Carlo method is used to verify the correctness of this approach.Secondly,fatigue tests under three different stress levels are carried out on the flight load spectrum.The logarithmic sample moment approach is proposed to process the equivalent initial flaw size distribution to obtain its general model.In addition,the initial fatigue quality model describing the typical structure is established,which verifies that the equivalent initial flaw size(EIFS)is less than the allowable 0.125 mm.By analyzing the initial fatigue quality of the typical structure,the correctness and practicability of the generalization method is demonstrated,and the life estimation model of this typical structure is built under different stress zones,different specified crack sizes and different reliability levels.

关 键 词：原始疲劳质量 裂纹萌生时间 当量初始缺陷尺寸 极大似然估计 铝合金 

分 类 号：V215.5[航空宇航科学与技术—航空宇航推进理论与工程]