应用有限元分析结合试验数据，获得随机振动环境下飞行器径向连接螺栓的载荷功率谱密度（PSD）；采用基于弯曲效应的载荷与应力的线性关系，获取螺栓头根部的名义应力功率谱密度；基于Dirlik经验公式，获取应力随机过程的峰值概率密度函数和预期波峰数，联合Miner线性累积损伤模型及经应力集中系数修正的材料S-N曲线，评估径向连接螺栓头根部振动疲劳寿命，获得的结果与试验螺栓头断裂现象符合，并确定螺栓断裂原因为低频共振疲劳。
The Power Spectrum Density (PSD) of the radial connection bolts of an aircraft in the random vibration environment was obtained combing finite element analysis with test data. The linear relationship between load and stress based on the bending effect was adopted to obtain the nominal stress PSD of root part of radial connection bolt. The peak value probability density and the expected wave crest number in the stress stochastic process were obtained by using Dirlik empirical formula. Based on the Miner fatigue damage theory and the material S-N curve revised by the stress concentration coefficient, the vibration fatigue life of root part of radial connection bolt was estimated. The result was consistent with the countersunk bolt fracture in the random vibration test. It is confirmed that the reason for connection bolt fracture was low frequency resonance fatigue.
[1] 熊峻江.疲劳断裂可靠性工程学[M].北京:国防工业出版社,2008:1-192. XIONG J J. Reliability engineering of fatigue fracture[M]. Beijing:National Defense Industry Press, 2008:1-192(in Chinese).
[2] 肖寿庭,杜修德.飞机结构振动疲劳问题[C]//第六届全国疲劳学术会议论文集(下), 1993:634. XIAO S T, DU X D. Vibration fatigue problem of aircraft structure[C]//Proceedings of the 6thNational Conference on Fatigue(Next), 1993:634(in Chinese).
[3] 航空航天工业部飞行试验中心飞机强度规范研究室翻译.美国军用规范飞机强度和刚度:MIL-A-8860B(AS)[S]. 1988. Aircraft Strength Specification Research of Flight Test Center in Aerospace Industry Translated.Strength and stiffness of aircraft of the U.S. military specification:MIL-A-8860B(AS)[S]. 1988(in Chinese).
[4] 航空工业部630研究所.军用飞机强度和刚度规范(振动):GJB 67.8-1985[S].1985:1-12.630 Institute of Aviation Industry. Specifications of strength and stiffness for the military aircraft (vibration):GJB 67.8-1985[S]. 1985:1-12(in Chinese).
[5] 姚启杭,姚军.工程结构的振动疲劳问题[J].应用力学学报,2006,23(1):12-17. YAO Q H, YAO J. Vibration fatigue in engineering structures[J]. Chinese Journal of Applied Mechanics, 2006, 23(1):12-17(in Chinese).
[6] 刘文光,陈国平,贺红林,等.结构振动疲劳研究综述[J].工程设计学报,2012,19(1):1-8. LIU W G, CHEN G P, HE H L,et al. Review of studying on vibration fatigue[J]. Chinese Journal of Engineering Design, 2012, 19(1):1-8(in Chinese).
[7] OSGOOD C C. Fatigue design[M]. Oxford:Pergamon Press, 1982:1-523.
[8] CRANDALL S H. Random vibration[M]. New York:Technology Press of MIT and John Wiley and Sons, 1958:1-423.
[9] CRANDALL S H, MARK W D. Random vibration in mechanical systems[M]. New York:Academic Press, 1963:1-166.
[10] OLDYREV P P A. On the influence of loading frequency on the multi cycle fatigue of organ plastics[J]. Mekhanika Kompozit Material, 1983, 4(3):629-633.
[11] DAMIR A N, ELKHATIB A, NASSEF G. Prediction of fatigue life using modal analysis for grey and ductile cast iron[J]. International Journal of Fatigue, 2007, 29(26):499-507.
[12] 游令非,张建国,周霜,等.航空发动机限寿件疲劳可靠度计算新方法[J].航空学报,2019,40(12):223228. YOU L F, ZHANG J G, ZHOU S, et al. A new method for fatigue reliability calculation of aero engine limited life parts[J]. Acta Aeronautica et Astronautica Sinica, 2019, 40(12):223228(in Chinese).
[13] WANG R J, SHANG D G. Fatigue life prediction based on natural frequency changes for spot welds under random loading[J]. International Journal of Fatigue, 2009, 31(2):361-366.
[14] HEARN G, TESTA R B. Modal analysis for damage detection in structures[J]. Jounal of Structural Engineering, 1991, 117(10):3042-3063.
[15] 董保童,施荣明,朱广荣.随机振动载荷作用下的结构疲劳寿命估算[J].飞机设计,2001,9(3):36-41. DONG B T, SHI R M, ZHU G R. Structural fatigue life prediction under random vibration loadings[J]. Aircraft Design, 2001, 9(3):36-41(in Chinese).
[16] 张亦波,陈迪,成正强,等.铝合金薄板冲击后疲劳试验与谱载寿命研究[J/OL].航空学报,[2020-11-30].http://kns.cnki.net/kcms/detail/11.1920.V.20201127.1716.014.html. ZHANG Y B, CHEN D, CHENG Z Q, et al. Fatigue experiments and lifetimes evaluating for post-impact sheets of alumi-num-alloys under block spectrum loading[J/OL]. Acta Aeronautica et Astronautica Sinica,[2020-11-30].http://kns.cnki.net/kcms/detail/11.1920.V.20201127.1716.014.html.
[17] FANG S E, PERERA R. Power mode shapes for early damage detection in linear structures[J]. Journal of Sound and Vibration, 2009, 324(1):40-56.
[18] 高金贺.飞机结构联接件振动损伤特性研究[D].沈阳:沈阳航空工业学院,2006:1-58. GAO J H. An investigation of failure character under vibration loading for areoplane joint structure[D]. Shenyang:Shenyang Instigute of Aeronautical Engineering, 2006:1-58(in Chinese).
[19] DILENA M, MORASSI A. Damage detection in discrete vibrating systems[J]. Journal of Sound and Vibration, 2006, 289(4/5):830-850.
[20] 李超.基于功率谱密度的疲劳寿命估算[J].机械设计与研究,2005,21(2):6-8. LI C. An approach based on power spectral density for fatigue life estimation[J]. Machine Design and Research, 2005, 21(2):6-8(in Chinese).
[21] 刘鸿文.材料力学[M].北京.高等教育出版社,1992. LIU H W. Mechanics of materials[M]. Beijing:Higher Education Press,1992(in Chinese).
[22] 航空结构连接件疲劳分析手册[M].西安:结构强度研究所,1985. Fatigue Analysis Handbook of Aeronautic Structure Connector[M]. Xi'an:Aircraft Strength Research Institute, 1985(in Chinese).
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