直升机滑跑地面共振特性研究
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摘要
依据直升机定常滑跑平衡特性分析得到的起落架定常载荷、旋翼操纵量及定常挥舞,结合起落架轮胎和缓冲支柱的静、动特性试验数据,应用自由振动理论计算得到机体侧向和纵向模态特性随滑跑速度的变化规律;采用计入几何耦合的旋翼液压阻尼器动力学模型,计算了定常滑跑时旋翼周期摆振响应,并得到液压阻尼器在"双频"条件下的等效阻尼;应用平面动力学模型分析不同因素对直升机滑跑地面共振的影响。结果表明,滑跑速度会降低机体侧向模态的固有频率;某型直升机旋翼总距为2°时,在22.8~31 km/h范围内定常滑跑时,直升机遇到较大扰动时将发生地面共振,且旋翼总距增加会降低地面共振的滑跑临界速度;直升机定常滑跑时保持小总距,小扰动,则不会发生地面共振。
Bases on helicopter trim analysis at steady running, landing gear loadings, rotor pitch sets and flap responses were obtained. Conjoin with static and dynamic test data of landing gear shock absorber and tire, the variations of fuselage lateral and longitudinal mode characteristics with running speed were resolved from free vibration theory. Kinematic coupling model of hydraulic damper on rotor blade was applied to calculate the cyclic response of blade lead-lag and the damper axial velocity, then equivalent damping of the damper were predicted under"dual frequency"conditions. After that, the influences of different factors on helicopter running ground resonance were analyzed from rotor/fuselage coupled dynamic model. Results showed that the natural frequency of fuselage lateral mode had a decrement due to running speed.Set collective pitch 2-degree, helicopter ground resonance would happen within the range of 22.8 to 31 km/h if large disturbance occurs at steady running. As the collective pitch of rotor increased, helicopter ground resonance occured at a lower running speed. If the collective pitch of rotor kept low, and the disturbance of damper was small as well, helicopter ground resonance could be avoided when steady running.
Bases on helicopter trim analysis at steady running, landing gear loadings, rotor pitch sets and flap responses were obtained. Conjoin with static and dynamic test data of landing gear shock absorber and tire, the variations of fuselage lateral and longitudinal mode characteristics with running speed were resolved from free vibration theory. Kinematic coupling model of hydraulic damper on rotor blade was applied to calculate the cyclic response of blade lead-lag and the damper axial velocity, then equivalent damping of the damper were predicted under"dual frequency"conditions. After that, the influences of different factors on helicopter running ground resonance were analyzed from rotor/fuselage coupled dynamic model. Results showed that the natural frequency of fuselage lateral mode had a decrement due to running speed.Set collective pitch 2-degree, helicopter ground resonance would happen within the range of 22.8 to 31 km/h if large disturbance occurs at steady running. As the collective pitch of rotor increased, helicopter ground resonance occured at a lower running speed. If the collective pitch of rotor kept low, and the disturbance of damper was small as well, helicopter ground resonance could be avoided when steady running.
引文
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[6]胡国才,魏钢,吴靖.滑跑速度对直升机侧向刚度模态频率的影响[J].南京航空航天大学学报,2016,48(4):516-521.HU GUOCAI,WEI GANG,WU JING.Effect of running velocity on helicopter lateral mode frequency[J].Journal of Nanjing University of Aeronautics&Astronautics,2016,48(4):516-521.(in Chinese)
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[8]胡国才,向锦武,张晓谷.黏弹减摆器非线性特性对直升机前飞空中共振的影响分析[J].航空学报,2005,26(2):199-202.HU GUOCAI,XIANG JINWU,ZHANG XIAOGU.Analysis of the effect of nonlinear characteristics of elastomeric lag damper on helicopter air resonance in forward flight[J].Journal of Aviation,2005,26(2):199-202.(in Chinese)
[9]吴靖,胡国才.带定压活门的液压阻尼器力学性能研究[J].华中科技大学学报,2017,45(2):44-49.WU JING,HU GUOCAI.On mechanical features of hydraulic damper with pressure relief valve[J].Journal of Huazhong University of Science and Technology,2017,45(2):44-49.(in Chinese)
[10]LEE Y K,KIM K J.Effects of landing gear nonlinearities on ground resonance of helicopter[C]//14thInternational Congress on Sound and Vibration,Caims:International Institute of Acoustics and Vibration.2007:1693-1699.
[11]MONTERRUBIO L,SHARF I.Influence of landing-gear design on helicopter ground resonance[J].Canadian Aeronautics and Space Journal,2002,48:133-144.
[12]杨礼芳.飞机轮胎刚度及尾轮摆振仿真分析[D].南京:南京航空航天大学,2012.YANG LI FANG.The simulation analysis on the tire stiffness and tail-wheel shimmy of a aircraft[D].Nanjing:Nanjing University of Aeronautics&Astronautics,2012.(in Chinese)
[13]张文静.直升机非线性“地面共振”分析研究[D].南京:南京航空航天大学,2010.ZHANG WENJING.Analysis of nonlinear helicopter ground resonance[D].Nanjing:Nanjing University of Aeronautics&Astronautics,2010.(in Chinese)
[14]REBECCA A S,RAMKUMAR K,NORMAN M W.Mechanisms-based analysis for elastomerical lag damper behavior under single and dual frequency excitation[C]//AIAA Applied Aerodynamics Conference.AIAA,2001:1537.
[15]FELKER F F,LAU B H,MCLAUGHLIN S,et al.Nonlinear behavior of an elastomeric lag damper undergoing dual-frequency motion and its effect on rotor dynamics[J].Journal of the American Helicopter Society,1987,34(4):45-53.
[16]许勤勇,殷士辉,徐玉貌.直升机地面滑跑飞行力学研究[J].直升机技术,2015(2):6-10.XU QINYONG,YIN SHIHUI,XU YUMAO.Flight dynamics analysis of helicopter taxiing[J].Helicopter Technique,2015(2):6-10.(in Chinese)
[17]魏钢,胡国才,吴靖.直升机地面滑跑平衡特性研究[C]//第33届直升机年会.景德镇:中国航空学会直升机分会,2017:89-94.WEI GANG,HU GUOCAI,WU JING.Analysis of helicopter running balance features[C]//33thHelicpter Society.Jingdezhen:Helicopter Branch of Chinese Society of Aeronautics and Astronautics,2017:89-94.(in Chinese)
[18]胡国才.减摆器非线性特性及其对直升机旋翼/机体耦合动稳定性影响研究[D].北京:北京航空航天大学,2003.HU GUOCAI.Nonlinear characteristics of blade lag dampers and its effect on helicopter rotor/airframe coupled dynamic stability[D].Beijing:Beijing University of Aeronautics&Astronautics,2003.(in Chinese)
[2]诸德培.摆振理论及防摆措施[M].北京:国防工业出版社,1984:1-24.ZHU DEPEI.Shimmy theory and suppressing measure[M].Beijing:National Defense Industry Press,1984:1-24.(in Chinese)
[3]熊程刚.直升机旋翼-起落架系统动力学特性分析研究[D].南京:南京航空航天大学,2013.XIONG CHENGGANG.Analysis of dynamic characteristics for helicopter’s landing gear-rotor system[D].Nanjing:Nanjing University of Aeronautics&Astronautics,2013.(in Chinese)
[4]米里.直升飞机计算和设计(第二卷):振动和动强度[M].北京:国防工业出版社,1976:230-236.MI LI.Helicopter calculation and design(the second volume):vibration and dynamic strength[M].Beijing:National Defense Industry Press,1976:230-236.(in Chinese)
[5]胡国才,刘湘一,刘书岩,等.舰面状态直升机机体在起落架上的固有频率分析[J].海军航空工程学院学报,2012,27(6):639-644.HU GUOCAI,LIU XIANGYI,LIU SHUYAN,et al.Analysis of helicopter natural frequencies on landing gear at ship-borne conditions[J].Journal of Naval Aeronautical and Astronautical University,2012,27(6):639-644.(in Chinese)
[6]胡国才,魏钢,吴靖.滑跑速度对直升机侧向刚度模态频率的影响[J].南京航空航天大学学报,2016,48(4):516-521.HU GUOCAI,WEI GANG,WU JING.Effect of running velocity on helicopter lateral mode frequency[J].Journal of Nanjing University of Aeronautics&Astronautics,2016,48(4):516-521.(in Chinese)
[7]张晓谷.直升机动力学设计[M].北京:航空工业出版社,1995:80-99.ZHANG XIAOGU.Helicopter dynamics design[M].Beijing:Aviation Industry Press,1995:80-99.(in Chinese)
[8]胡国才,向锦武,张晓谷.黏弹减摆器非线性特性对直升机前飞空中共振的影响分析[J].航空学报,2005,26(2):199-202.HU GUOCAI,XIANG JINWU,ZHANG XIAOGU.Analysis of the effect of nonlinear characteristics of elastomeric lag damper on helicopter air resonance in forward flight[J].Journal of Aviation,2005,26(2):199-202.(in Chinese)
[9]吴靖,胡国才.带定压活门的液压阻尼器力学性能研究[J].华中科技大学学报,2017,45(2):44-49.WU JING,HU GUOCAI.On mechanical features of hydraulic damper with pressure relief valve[J].Journal of Huazhong University of Science and Technology,2017,45(2):44-49.(in Chinese)
[10]LEE Y K,KIM K J.Effects of landing gear nonlinearities on ground resonance of helicopter[C]//14thInternational Congress on Sound and Vibration,Caims:International Institute of Acoustics and Vibration.2007:1693-1699.
[11]MONTERRUBIO L,SHARF I.Influence of landing-gear design on helicopter ground resonance[J].Canadian Aeronautics and Space Journal,2002,48:133-144.
[12]杨礼芳.飞机轮胎刚度及尾轮摆振仿真分析[D].南京:南京航空航天大学,2012.YANG LI FANG.The simulation analysis on the tire stiffness and tail-wheel shimmy of a aircraft[D].Nanjing:Nanjing University of Aeronautics&Astronautics,2012.(in Chinese)
[13]张文静.直升机非线性“地面共振”分析研究[D].南京:南京航空航天大学,2010.ZHANG WENJING.Analysis of nonlinear helicopter ground resonance[D].Nanjing:Nanjing University of Aeronautics&Astronautics,2010.(in Chinese)
[14]REBECCA A S,RAMKUMAR K,NORMAN M W.Mechanisms-based analysis for elastomerical lag damper behavior under single and dual frequency excitation[C]//AIAA Applied Aerodynamics Conference.AIAA,2001:1537.
[15]FELKER F F,LAU B H,MCLAUGHLIN S,et al.Nonlinear behavior of an elastomeric lag damper undergoing dual-frequency motion and its effect on rotor dynamics[J].Journal of the American Helicopter Society,1987,34(4):45-53.
[16]许勤勇,殷士辉,徐玉貌.直升机地面滑跑飞行力学研究[J].直升机技术,2015(2):6-10.XU QINYONG,YIN SHIHUI,XU YUMAO.Flight dynamics analysis of helicopter taxiing[J].Helicopter Technique,2015(2):6-10.(in Chinese)
[17]魏钢,胡国才,吴靖.直升机地面滑跑平衡特性研究[C]//第33届直升机年会.景德镇:中国航空学会直升机分会,2017:89-94.WEI GANG,HU GUOCAI,WU JING.Analysis of helicopter running balance features[C]//33thHelicpter Society.Jingdezhen:Helicopter Branch of Chinese Society of Aeronautics and Astronautics,2017:89-94.(in Chinese)
[18]胡国才.减摆器非线性特性及其对直升机旋翼/机体耦合动稳定性影响研究[D].北京:北京航空航天大学,2003.HU GUOCAI.Nonlinear characteristics of blade lag dampers and its effect on helicopter rotor/airframe coupled dynamic stability[D].Beijing:Beijing University of Aeronautics&Astronautics,2003.(in Chinese)