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Gust response analysis of flexible aircraft with aerodynamic nonlinearity
BI Ying, YANG Chao, WU Zhigang
School of Aeronautic Science and Engineering, Beijing University of Aeronautics and Astronautics, Beijing 100191, China
Abstract:Aiming at the gust response of high aspect ratio flexible aircraft, the unsteady aerodynamic considering the nonlinear effect at high angle of attack (AOA) was calculated in time domain by combining the modified Theodorsen method with the strip theory. Based on the nonlinear aerodynamic in time domain, the aeroelastic model of high aspect ratio flexible aircraft with gust disturbance was established, and a novel method applied to gust response analysis with nonlinear aerodynamic was integrally developed. The method was validated by carrying out numerical simulation and method validation basing on a general flexible aircraft, and the gust induced load at wingtip and center of gravity (CG) were compared between linear and nonlinear cases. Numerical results show that the nonlinear effect of aerodynamic at high AOA obviously influences the gust response of the flexible aircraft, and the gust induced load at wingtip reduces as much as 41.7% compared with linear case. The aerodynamic nonlinear effect cannot be ignored for flexible aircraft.
Key words: aerodynamic nonlinearity     aeroelastic     high aspect ratio     gust response     Theodorsen method
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1 气动力非线性气弹系统建模

1.1 修正的Theodorsen方法

1.1.1 加入阵风干扰项

 wg—阵风速度幅值;lg—阵风尺度. 图 1 1-cos型阵风剖面 Fig. 1 Profile of 1-cos gust

1-cos型阵风的速度剖面可表示为

1.1.2 考虑非线性升力系数

1.1.3 Theodorsen方法的时域化

1.2 非线性阵风响应系统建模

 图 2 大展弦比飞机片条划分示意图 Fig. 2 Schematic diagram of strip definition of high aspect ratio aircraft

2 离散阵风时域响应分析

 图 3 考虑气动力非线性的柔性飞机阵风响应原理图 Fig. 3 Schematic gust response diagram of flexible aircraft with aerodynamic nonlinearity
3 算例及结果分析

3.1 模型描述

 图 4 大展弦比飞机有限元模型 Fig. 4 Finite element model of high aspect ratio aircraft

 参数 数值 参数 数值 全机质量/kg 1738 翼展/m 63 x向质心/m 4.966 弦长/m 3 俯仰惯量/(kg·m2) 3.24×104 展弦比 21

 图 5 机翼一弯模态 Fig. 5 First bending mode of wing

 图 6 机翼二弯模态 Fig. 6 Second bending mode of wing

3.2 弹性效应的影响

 图 7 刚性和弹性情况下翼尖的瞬时攻角对比 Fig. 7 Comparison of transient AOA at wingtip between rigid and flexible cases

 图 8 刚性和弹性情况下附加过载对比 Fig. 8 Comparison of gust additional induced load between rigid and flexible cases
3.3 气动力非线性的影响

 图 9 线性和非线性情况下升力系数对比 Fig. 9 Lift coefficient comparison of linear and nonlinear cases

 图 10 线性与非线性情况下瞬时攻角对比 Fig. 10 AOA comparison of linear and nonlinear cases

 图 11 线性与非线性情况下附加过载对比 Fig. 11 Comparison of gust additional induced load between linear and nonlinear cases
3.4 阵风尺度的影响

 图 12 不同阵风尺度下的附加过载对比 Fig. 12 Comparison of gust additional induced load under various gust scales
4 结 论

1) 对于大展弦比飞机,弹性效应对其阵风响应分析结果影响显著,不可忽略.

2) 气动力的大攻角非线性特性对飞机不同位置处的附加过载均有较明显的影响,一般表现为卸载作用.

3) 不同阵风尺度对大展弦比柔性飞机的阵风响应结果有一定影响,随着阵风尺度增加,阵风响应减小.

 [1] Tang D, Dowell E H.Experimental and theoretical study of gust response for high-aspect-ratio wing[J].AIAA Joural, 2002, 40(3): 419-429. Click to display the text [2] Tang D, Grasch A.Gust response for flexibly suspended high-aspect ratio wings[J].AIAA Journal, 2010, 48(10): 2430-2444. Click to display the text [3] Patil M J, Taylor D J.Gust response of highly flexible aircraft[C]//47th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference.Reston: AIAA, 2006, 1: 456-468. [4] Su W H, Cesnik C E S.Nonlinear aeroelasticity of a very flexible blended-wing-body aircraft[J].Journal of Aircraft, 2010, 47(5): 1539-1553. Click to display the text [5] Ricciardi A P, Patil M J.Evaluation of quasi-static gust loads certification methods for high-altitude long-Endurance aircraft[J].Journal of Aircraft, 2013, 50(2): 457-468. Click to display the text [6] 高洁, 王立新, 周堃. 大展弦比飞翼构型飞机阵风载荷减缓控制[J].北京航空航天大学学报, 2008, 34(9): 1076-1079. Gao J, Wang L X, Zhou K.Gust load alleviation control of aircraft with large ratio flying wing configuration[J].Journal of Beijing University of Aeronautics and Astronautics, 2008, 34(9): 1076-1079(in Chinese). Click to display the text [7] 陈磊. 弹性飞机阵风减缓控制与风洞试验方法研究[D].北京: 北京航空航天大学, 2011. Chen L.Studies on flexible aircraft gust alleviation control and wind tunnel test[D].Beijing: Beijing University of Aeronautics and Astronautics, 2011(in Chinese). Click to display the text [8] 谢长川, 吴志刚, 杨超. 大展弦比柔性机翼的气动弹性分析[J].北京航空航天大学学报, 2003, 29(12): 1087-1090. Xie C C, Wu Z G, Yang C.Aeroelastic analysis of flexible large aspect ratio wing[J].Journal of Beijing University of Aeronautics and Astronautics, 29(12): 1087-1090(in Chinese). Click to display the text [9] 陈桂彬, 邹丛青, 杨超. 气动弹性设计基础[M].北京: 北京航空航天大学出版社, 2010: 65-73. Chen G B, Zou C Q, Yang C.Aeroelastic design basis[M].Beijing: Beihang University of Press, 2010: 65-73(in Chinese). [10] 赵永辉. 气动弹性力学与控制[M].北京: 科学出版社, 2007: 323-324. Zhao Y H.Aeroelasticity and control[M].Beijing: Science Press, 2007: 323-324(in Chinese). [11] 金长江, 肖业伦. 大气扰动中的飞行原理[M].北京: 国防工业出版社, 1992: 5-7. Jin C J, Xiao Y L.Flight theory in atmospheric disturbances[M].Beijing: National Defence Industry Press, 1992: 5-7(in Chinese). [12] Tang D, Dowell E H.Experimental and theoretical study of gust response for high-aspect-ratio wing[J].AIAA Journal, 2002, 40(3): 419-429. Click to display the text [13] Karpel M, Moulin B, Chen P C.Dynamic response of aeroservoelastic systems to gust excitation[J].Journal of Aircraft, 2005, 42(5): 1264-1272. Click to display the text [14] Azoulay D, Karpel M.Characterization of methods for computation of aeroservoelastic response to gust excitation[C]//47th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference.Reston: AIAA, 2006, 6: 4138-4152. Click to display the text

#### 文章信息

BI Ying, YANG Chao, WU Zhigang

Gust response analysis of flexible aircraft with aerodynamic nonlinearity

Journal of Beijing University of Aeronautics and Astronsutics, 2015, 41(7): 1208-1214.
http://dx.doi.org/10.13700/j.bh.1001-5965.2014.0492