Aeroelasticity study of high span ratio wing with flare folding wingtip

带扩口折叠翼尖的大展弦比机翼气动弹性研究

¹ School of Flight Vehicle and Engineering, Nanchang Hangkong University, Nanchang 330063, China
² The Third Military Representative Office of Army Equipment Department in Nanjing, Nanjing 210000, China

Received: 17 January 2023

Abstract

Flare folding wing-tips rely on the adaptive deformation of the structure to reduce the flight load, which can effectively simplify the control system, and has more advantages in cost and weight. To study the effect of the elastic folding wingtip as a passive load alleviation device, the flexible hinges were used to connect the folding wingtip to the wing, and the Doublet Lattice panel method was used to calculate the aerodynamic loads. Static and dynamic load response and flutter analysis were performed on the folding wingtip configurations with different structural parameters, and the effects of the hinge orientation, stiffness, wingtip weight and wingtip center of gravity position on the load response and flutter behavior were investigated. The results show that the flare folding wingtip can significantly reduce the static and sudden wind loads of the wing with suitable parameters. In the static aeroelastic trim analysis, the folding wingtip can increase the span length by 25% with almost no increase in the wing root bending moment and reduce the trim angle of attack by 0.14°. In the gust response analysis, the maximum wing root bending moment can be reduced by nearly 50% comparing with the fixed wing tip, which is only 17% higher than the baseline model without the wing tip. However, the flutter velocity is reduced, and further optimization is needed to improve the flutter characteristics.

摘要

扩口折叠翼尖依靠结构的自适应变形来降低飞行载荷, 能有效简化控制系统, 在成本和质量上更有优势。为研究弹性折叠翼尖作为被动载荷减缓装置的效果, 使用铰链将翼尖连接到机翼并赋予一定弹性, 对不同的折叠翼尖参数构型进行了静、动载荷响应以及颤振分析, 研究了铰链方向、刚度、翼尖质量与翼尖重心位置对载荷响应与颤振特性的影响。结果表明, 扩口折叠翼尖在合适的参数下能够显著降低机翼的静载荷与突风载荷, 在静气动弹性配平分析中, 折叠翼尖可以使展长增加25%而几乎不增加翼根弯矩, 并使配平攻角降低了0.14°。在突风响应分析中可使最大翼根弯矩相比于固定翼尖减少近50%, 仅比不带翼尖的基准模型高17%。但颤振速度有所降低, 需进一步优化以改善其颤振特性。

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