Numerical and experimental investigation of aero-structural characteristics and performance of distributed compliance morphing wings
Numerical and experimental investigation of aero-structural characteristics and performance of distributed compliance morphing wings
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分布式柔顺变形机翼航空结构特性和性能的数值和实验研究
DOI：
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发表时间：
2015
期刊：
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通讯作者：
P. Ermanni
中科院分区：
文献类型：
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作者：
G. Molinari;A. F. Arrieta;P. Ermanni
变形机翼由于可以获得最佳的变形形状而具有获得更高的气动效率的潜力，这是采用传统离散控制面的机翼所不能达到的特性。本文评估了基于全柔性变形结构的变形翼概念的气动和结构性能。在这项调查中，我们表明，足够的控制权，可以实现使用所提出的设计。变形机翼的元件，特别是空间分布的柔性结构，几何形状和基于智能材料的驱动机构，通过并行的气动结构优化，考虑静态和动态气动弹性效应来确定。由于在优化过程中考虑了整个机翼结构，所有部件（包括分布式作动器）都被用作承载元件，从而提高了最终设计的结构效率。为实现主动变形对滚转的充分控制，以1.6m翼展模型飞机为对象，优化制造了一对柔性机翼。制造的机翼的实际气动弹性响应在风洞试验期间进行了实验评估，这些风洞试验是在不同的速度、攻角和致动水平下进行的。在风洞试验期间，对在保持高气动效率的同时实现升力和滚转力矩变化的能力进行了实验研究，并与数值预测进行了比较。结果表明，所提出的概念是能够实现滚转力矩与传统的解决方案，并足以保证飞行的可控性。此外，翼型的效率在主动变形时不受影响，并且在某些条件下升阻比甚至得到改善。这导致使用所提出的变形技术来有效地改变由机翼产生的升力的可能性，而不需要改变飞机俯仰，从而允许最小化总阻力。
Morphing wings have the potential to achieve higher aerodynamic efficiency owing to the optimal deformed shapes they can obtain, a characteristic not attainable by wings employing conventional discrete control surfaces. This paper assesses both the aerodynamic and the structural performance of a morphing wing concept based on fully compliant morphing structures. In this investigation we show that sufficient control authority in roll can be achieved using the proposed design. The elements of the proposed morphing wing, in particular, the spatially distributed compliant structure, the geometry, and the smart material-based actuation mechanisms, were determined through a concurrent aero-structural optimization which considered both static and dynamic aeroelastic effects. As the entire wing structure is taken into account during the optimization, all components -- including the distributed actuators -- are exploited as load carrying elements, thereby increasing the structural efficiency of the final design. A pair of compliant wings was optimized and manufactured for a 1.6 m wingspan model airplane, with the goal of achieving sufficient control authority in roll by means of active morphing. The actual aeroelastic response of the manufactured wings was experimentally assessed during wind tunnel tests, which were performed at different speeds, angles of attack, and actuation levels. The ability of achieving variation in lift and in rolling moment, while maintaining a high aerodynamic efficiency, is investigated experimentally during the wind tunnel test campaign, and compared to the numerical predictions. The results show that the proposed concept is able to achieve rolling moments comparable to conventional solutions, and sufficient to guarantee the controllability of the flight. Furthermore, the efficiency of the airfoil is not penalized when actively deformed, and in some conditions the lift-to-drag ratio is even improved. This leads to the possibility of using the presented morphing technique to efficiently vary the lift produced by the wings, without the need of changing the aircraft pitch and thus allowing minimization of total drag.