Fracture fault analysis of main blades girder on a helicopter
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摘要:
针对某型直升机桨叶疲劳断裂、压力传感器未报警故障,通过故障树分析法开展桨叶失效分析、压力信号器故障模式分析,在此基础上探明故障机理。宏、微观断口分析表明:剥落坑从大梁表面的非金属镶嵌物处起始,断口从疲劳剥落坑底部起源,具有明显高周疲劳断裂特征。能谱分析发现,大梁表面存在富Si、O镶嵌物。普查发现压力信号器存在手检功能正常、基准腔压力低的故障模式。综合分析认为,喷丸工艺参数不合理,大梁局部表面存在初始缺陷,在载荷作用下疲劳裂纹在缺陷部位萌生并扩展,大梁裂纹扩展贯穿至内腔时,大梁漏气压力下降,但压力信号器密封失效导致基准腔压力泄漏,告警功能丧失,桨叶监控安全机制失效,穿透裂纹沿大梁两侧方向扩展,23个起落后桨叶断裂。
Abstract:In view of the fatigue fracture fault of the main blade girder of a helicopter and the failure of fault warning from the pressure sensor, a fault tree was applied to analyze the reason of the faults. Blade failure and main fault mode of the pressure sensor were analyzed, based on which the mechanism of the accident was discussed. The results of macro and micro fractographic analysis showed that spalling holes appeared from multiple non-metallic tesseras on the surface of the girder and the fracture appeared from the bottom of the fatigue spalling holes on the external surface of the lower main girder, which demonstrated clear characteristics of fracture caused by high-cycle fatigue. Energy spectrum analysis to the source area of the fracture showed the existence of Si and O-rich tesseras on the surface and sub-surface of the main girder. General investigation carried after the accident showed that the pressure sensor had the fault mode of proper manual inspection function but without warning when the pressure level of the base chamber was low. Comprehensive analysis indicated improper shot-peening parameters. There were initial defects on part of the surface of the main girder, which led to the initiation and extension of fatigue crack from the part of defect because of the fatigue load. Pressure level of the main girder dropped out of air leakage when the fatigue crack extended throughout the inner chamber. Meanwhile, the sealing component of the pressure sensor failed, leading to pressure loss of the base chamber. In this way, the warning function and blade monitoring safety mechanism failed and the crack running through the main girder extended along both directions of the girder, leading to the fracture of the blade after 23 ups and downs.
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Key words:
- helicopter /
- fatigue crack /
- blade girder /
- failure analysis /
- fracture
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表 1 剥落块能谱分析
Table 1. Energy spectrum analysis of spalling block
元素 质量百分比/% 原子百分比/% Mg 0.64 0.72 Al 97.40 97.95 Si 0.91 0.87 Mn 0.26 0.13 Fe 0.31 0.15 Cu 0.43 0.18 表 2 剥落块边缘不导电物质能谱分析
Table 2. Energy spectrum analysis of non conductive substance at the edge of the spalling block
元素 质量百分比/% 原子百分比/% C 13.70 22.08 O 41.18 48.85 Mg 1.18 0.92 Al 12.88 9.06 Si 20.14 13.61 K 0.64 0.10 Ca 7.10 3.36 Fe 0.51 0.17 Ni 0.67 0.22 -
[1] 傅惠民,高镇同. 桨叶可靠性分析方法[J]. 航空动力学报,1991,6(4): 345-348. doi: 10.13224/j.cnki.jasp.1991.04.015FU Huimin,GAO Zhentong. Reliability analysis methods for blades[J]. Journal of Aerospace Power,1991,6(4): 345-348. (in Chinese) doi: 10.13224/j.cnki.jasp.1991.04.015 [2] 徐海滨,张文迪. 直升机主桨叶典型缺陷疲劳性能影响研究[J]. 机械科学与技术,2017(增刊1): 33-39.XU Haibin,ZHANG Wendi. Research on evaluation method of helicopter blade flaw tolerance[J]. Mechanical Science and Technology for Aerospace Engineering,2017(Suppl.1): 33-39. (in Chinese) [3] 柳文林,穆志韬,周凯,等. 直升机动部件的疲劳损伤和可靠性分析[J]. 海军航空工程学院学报,2005,20(6): 620-622.LIU Wenlin,MU Zhitao,ZHOU Kai,et al. Fatigue damage and reliability analysis of helicopter moving parts[J]. Journal of Naval Aeronautical Engineering Institute,2005,20(6): 620-622. (in Chinese) [4] 朱作涛,穆志涛,辛素玉,等. 某型直升机主桨叶裂纹扩展寿命研究[J]. 无损检测,2009,31(3): 188-191.ZHU Zuotao,MU Zhitao,XIN Suyu,et al. Research of crack growth life for certain helicopter’s main blade[J]. Nondestructive Testing,2009,31(3): 188-191. (in Chinese) [5] 张钰,王翔空,喻文. 旋翼桨叶压力信号器常见故障分析[J]. 长沙航空职业技术学院学报,2020,20(4): 52-55. doi: 10.13829/j.cnki.issn.1671-9654.2020.04.012ZHANG Yu,WANG Xiangkong,YU Wen. Common fault analysis of rotor blade pressure signal[J]. Journal of Changsha Aeronautical Vocational and Technical College,2020,20(4): 52-55. (in Chinese) doi: 10.13829/j.cnki.issn.1671-9654.2020.04.012 [6] 杨华高,洪海华. 一起典型主桨叶大梁裂纹故障的分析与处理[J]. 直升机技术,2019(1): 30-32. doi: 10.3969/j.issn.1673-1220.2019.01.007YANG Huagao,HONG Haihua. Analysis and measures about a typical main rotor blade spar crack failure[J]. Helicopter Technique,2019(1): 30-32. (in Chinese) doi: 10.3969/j.issn.1673-1220.2019.01.007 [7] NEWMAN A J,BAUGHMAN M J,WALLACE A T. Investigation of cracks found in helicopter longerons[J]. Engineering Failure Analysis,2010,17(2): 416-430. doi: 10.1016/j.engfailanal.2009.08.016 [8] SHANIAVSKI A A. Scale levels for fatigue fracture mechanisms of in-service crack growth in longerons of helicopter rotor blades[J]. International Journal of Fracture,2004,128(1/2/3/4): 17-24. [9] SHANYAVSKIY A,TOUSHENTSOV A. Multiaxial fatigue of in-service aluminum longerons for helicopter rotor-blades[J]. Frattura ed Integrita Strutturale,2016(37): 22-27. [10] 周海京, 遇今. 故障模式、影响及危害性分析与故障树分析[M]. 北京: 航空工业出版社, 2003. [11] PHIBBS E,KUWAMOTO S H. Fault-tree analysis[J]. IEEE Transactions on Reliability,1974,R-23(4): 266-266. doi: 10.1109/TR.1974.5215269 [12] 张栋, 钟培道, 陶春虎, 等. 失效分析[M]. 北京: 国防工业出版社, 2004. [13] 雷键. 直8机旋翼大梁疲劳试验方法研究以及与进口大梁对比试验分析[J]. 直升机技术,1999(1): 38-42.LEI Jan. Investigation of fatigue test method and comparison analysis with import blade test for Z8 rotor blade[J]. Helicopter Technique,1999(1): 38-42. (in Chinese) [14] 刘高扬,陈星,朱定金,等. 主桨叶大梁疲劳断裂断口定量分析研究[J]. 失效分析与预防,2020,15(3): 184-190.LIU Gaoyang,CHEN Xing,ZHU Dingjin,et al. Quantitative analysis technique of fatigue fracture of main blade girder[J]. Failure Analysis and Prevention,2020,15(3): 184-190. (in Chinese) [15] 刘新灵, 张峥, 陶春虎. 疲劳断口定量分析[M]. 北京: 国防工业出版社, 2010. [16] 刘新灵, 张卫方, 陶春虎, 等. 不同断口定量分析疲劳寿命模型应用对比[J]机械工程材料, 2008, 32(5): 4-6.LIU Xinling, ZHANG Weifang, TAO Chunhu, et al. Comparison between two models for quantitative fractography analysis of fatigue life [J]. Material of Mechanical Engineering, 2008, 32(5): 4-6. (in Chinese) [17] 赵子华, 张峥, 吴素君, 等. 金属疲劳断口定量反推研究综述[J]机械强度, 2008, 30(3): 59-63.ZHAO Zihua, ZHANG Zheng, WU Sujun, et al. Survey of quantitative reverse deduction from fatigue fracture surface of metals [J]. Mechanical Strength, 2008, 30(3): 59-63. (in Chinese) [18] 陈星,刘新灵. 断口定量分析技术在损伤容限设计中的应用[J]. 失效分析与预防,2015,10(4): 221-225. doi: 10.3969/j.issn.1673-6214.2015.04.006CHEN Xing,LIU Xinling. Application of quantitative analysis technique to damage tolerance design[J]. Failure Analysis and Prevention,2015,10(4): 221-225. (in Chinese) doi: 10.3969/j.issn.1673-6214.2015.04.006 [19] 胡仁伟, 刘文珽. 直升机动部件断裂谱的编制方法研究[J]. 北京航空航天大学学报, 1996, 22(3): 332-336.HU Renwei, LIU Wenting. Study on compiling method of fracture spectrum of helicopter moving parts[J]. Journal of Beijing University of Aeronautics, 1996, 22(3): 332-336. (in Chinese) -

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