Body Freedom Flutter of High Aspect Ratio Flying Wings
Body Freedom Flutter of High Aspect Ratio Flying Wings
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DOI：
10.2514/6.2005-1947
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发表时间：
2005-04
期刊：
影响因子：
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通讯作者：
M. Løve;P. S. Zink;Paul Wieselmann;H. Youngren
中科院分区：
文献类型：
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作者：
M. Løve;P. S. Zink;Paul Wieselmann;H. Youngren
本文介绍了根据空军研究实验室（AFRL）传感器飞行器计划合同研制的后掠飞翼飞机的气动弹性分析结果。这种布局的特点是大展弦比，非常灵活的机翼，后掠角为30 °.这种构型，像柔性飞翼的其他示例一样，易于发生由刚体短周期模态与机翼弯曲耦合而导致的体自由颤振（BFF）。NASTRAN有限元模型（FEM）用于初始气动弹性颤振分析。从有限元法推导出机翼的刚度和质量特性，建立了用于ASWING气动结构分析的机翼近似梁模型。开环飞机的颤振分析探讨了机翼刚度、高度和重心（CG）位置的权衡，以确定被动方法是否能将颤振速度提高到可接受的水平。在增加闭环俯仰轴自动驾驶仪的情况下，进行了类似的颤振分析，以使飞机在更宽的静裕度范围内稳定。初步结果表明，BFF是一个问题，在飞行包线的低海拔部分，主动颤振抑制系统应探讨为未来的工作。
The paper presents results of aeroelastic analysis on a swept flying wing aircraft developed under contract for the Air Force Research Laboratory (AFRL) SensorCraft program. This configuration is characterized by a high aspect ratio, very flexible wing with 30 sweep. This configuration, like other examples of flexible flying wings, is prone to body freedom flutter (BFF) that results from coupling of the rigid body short period mode with wing bending. A NASTRAN finite element model (FEM) is used for an initial aeroelastic flutter analysis. Stiffness and mass properties are derived from the FEM to construct an approximate beam model of the wing for ASWING aero-structural analysis. Flutter analysis for the open loop aircraft explores trades in wing stiffness, altitude and center-ofgravity (CG) location to determine whether passive means can increase flutter speed to acceptable levels. A similar flutter analysis is performed with the addition of a closed loop pitch axis autopilot to stabilize the aircraft over a wider range of static margin. Initial results indicate that BFF is an issue over lower altitude portions of the flight envelope and that active flutter suppression systems should be explored for future work.