Life up and down method for determining WFD average behavior of aircraft structures
-
摘要: 广布疲劳损伤(WFD)问题严重威胁飞机结构的完整性和安全性,为确定支持飞机结构广布疲劳损伤评定和维修大纲的有效性限制,需要先确定飞机结构的广布疲劳损伤平均行为。以疲劳应用统计学中强度升降法的理论为基础,提出了确定飞机结构广布疲劳损伤平均行为的寿命升降法,在不同寿命级上进行疲劳试验,继而进行剩余强度试验,判断剩余强度是否满足要求,当相邻2个寿命级上出现相反结果时,取2个寿命均值为正好满足剩余强度的寿命,重复试验并统计分析得到广布疲劳损伤平均行为。以5细节多部位损伤结构为例,采用提出的寿命升降法,测得了其在指定载荷条件和剩余强度下的广布疲劳损伤平均行为。提出的寿命升降法以疲劳可靠性为理论基础,不依赖于结构的具体形式和受载情况,对多部位损伤和多元件损伤结构均适用。
-
关键词:
- 广布疲劳损伤平均行为 /
- 多部位损伤 /
- 剩余强度 /
- 疲劳统计 /
- 升降法
Abstract: The widespread fatigue damage (WFD) problem is a serious threat to the integrity and safety of aircraft structures.Evaluation of the WFD average behavior is the base for establishing a limit of validity of the engineering data that supports the structural maintenance program. A life up and down method for evaluating the WFD average behavior of aircraft structures was proposed based on the theory of strength up and down method in fatigue applied statistics. The residual strength test was conducted following the fatigue test with a specified fatigue life level (FLL) to determine whether the residual strength meet the requirement. Taking the mean value of the adjacent two FLL with contrasted results as the FLL could lead to a residual strength equal to the required one. By repeating the tests and statistical analysis of the results, the WFD average behavior could be found out. Test on multiple site damage structure with 5-details was conducted with the proposed method, and a WFD average behavior, with a requested residual strength and a specified loading condition, was provided. The proposed method based on the fatigue reliability can be used both in multiple site damage structures and multiple element damage structures, independent of the specific forms of the structures and the load conditions. -
[1] Federal Aviation Administration.Aircraft accident report:Aloha Airlines,Flight 243,Boeing 737-200,N73711,near Maui,Hawaii,April 28,1988:NTSB/AAR-89/03[R].Washington,D.C.:Federal Aviation Administration,1989:1-27. [2] Federal Aviation Administration.Establishing and implementing limit of validity to preventwidespread fatigue damage:AC No.120-104[S].Washington,D.C.:Federal Aviation Administration,2011:1-10. [3] SWIFT T.Widespread fatigue damage monitoring-issues and concerns:95N19488[R].Washington,D.C.:Langley Research Center,1993:27-42. [4] PITT S,JONES R.Multiple-site and widespread fatigue damage in aging aircraft[J].Engineering Failure Analysis,1997,4(4):237-257. [5] HARRIS C E,JAMES C,NEWMAN J,et al.Analytical methodology for predicting widespread fatigue damage onset in fuselage structure[J].Journal of Aircraft,1998,35(2):307-317. [6] 李嘉骞,沈海军.老龄飞机广布疲劳问题研究综述[J].飞机设计,2014,34(1):28-32. LI J Q,SHEN H J.Widespread fatigue problem of aging aircrafts[J].Aircraft Design,2014,34(1):28-32(in Chinese). [7] Federal Aviation Administration.Damage tolerance and fatigue evaluation of structure:AC No.25.571-1C[S].Washington,D.C.:Federal Aviation Administration,1998:2-20. [8] Federal Aviation Administration.Aging aircraft program:Widespread fatigue damage,proposed rule[J].Federal Register,2006,74(71):19927-19951. [9] Federal Aviation Administration.Aging airplane inspections and records reviews:AC No.120-84[S].Washington,D.C.:Federal Aviation Administration,2009:7-14. [10] Federal Aviation Administration.Damage tolerance and fatigue evaluation of structure:AC No.25.571-1D[S].Washington,D.C.:Federal Aviation Administration,2011:5-23. [11] EASTIN R.‘WFD’-what is it and what's ‘LOV’ got to do with it [J].International Journal of Fatigue,2009,31(6):1012-1016. [12] XIE J,LU Y.Study on airworthiness requirements of composite aircraft structure for transport category aircraft in FAA[J].Procedia Engineering,2011,17:270-278. [13] 王生楠,郑晓玲.运输类飞机防止广布疲劳损伤的新规章解读[J].航空学报,2010,31(9):1758-1768. WANG S N,ZHENG X L.Study on proposed rules to preclude widespread fatigue damage for transport category aircraft[J].Acta Aeronautica et Astronautica Sinica,2010,31(9):1758-1768(in Chinese). [14] 詹福宇,杨伟,王生楠,等.确定机队WFD 平均行为的方法研究[J].西北工业大学学报,2013,31(1):103-108. ZHAN F Y,YANG W,WANG S N,et al.A method for determining WFD average behavior of aircraft fleet[J].Journal of Northwestern Polytechnical University,2013,31(1):103-108 (in Chinese). [15] DIXON W J,MOOD A M.A method for obtaining and analyzing sensitivity data[J].Journal of the American Statistical Association,1948,43:109-126. [16] 高镇同.疲劳应用统计[M].北京:国防工业出版社,1986:336-343. GAO Z T.Applied statistics in fatigue[M].Beijing:Defense Industrial Press,1986:336-343(in Chinese).
点击查看大图
计量
- 文章访问数: 1032
- HTML全文浏览量: 115
- PDF下载量: 440
- 被引次数: 0