Structural dynamics and smart helicopter rotor blades

近年来，申请人的研究计划的主要焦点是开发具有高度保真度的直升机智能旋翼桨叶的数学模型。这种模型将被用来研究衰减与直升机旋翼桨叶操作相关的不期望的动态响应的可能性。在本研究计划的前一阶段，已经开发了智能叶片的连续模型。该模型代表了一个薄壁，封闭截面，主动复合梁，采用压电纤维作为致动器，在结构上集成到碳纤维复合材料中，形成宏观纤维复合材料（MFC）。该建议有两个目标：1）现有的智能旋翼桨叶模型没有考虑现代直升机旋翼桨叶中可能存在的初始扭转的影响。根据目前的提议，这一能力将被纳入现有的数学模型。此外，在各种地面和航空航天结构中使用开口截面薄壁自适应梁的想法，例如，具有由自适应薄壁开口部分组成的翼梁的转子叶片也被提出作为新概念。在下一阶段的控制方程，以确定开口截面，薄壁，主动MFC梁的横截面刚度也将开发。2)本研究的第二个目的是研究智能MFC旋翼叶片控制舰载直升机叶片航行现象的有效性。BSP是指舰载直升机旋翼在低转速时可能发生的叶片大弹性变形，特别是在高风致空气动力载荷和公海上剧烈船舶甲板运动的联合作用下。结果，叶片可能与直升机的机身或尾梁接触，从而导致机身严重损坏，并危及飞行机组人员和船舶甲板人员的安全。

A major focus of the applicant's research program in the recent years has been the development of a mathematical model for a helicopter smart rotor blade with a high degree of fidelity. Such a model will be used to investigate the possibility of attenuating undesirable dynamic responses associated with operation of helicopter rotor blades. A continuous model of a smart blade has already been developed in the previous phase of this research program. The model represents a thin wall, closed-section, active composite beam that incorporates piezoelectric fibres as actuators that are integrated structurally into a carbon fibre composite to form Macro Fibre Composites (MFC). This proposal has two objectives: 1) the existing model of smart rotor blades does not take into account the effect of initial twist that could be present in modern helicopter rotor blades. This capability will be integrated into the existing mathematical model under the current proposal. Moreover, the idea of using open cross-section thin-wall adaptive beams in various terrestrial and aerospace structures, e.g., rotor blades with spars consisting of adaptive thin-wall open sections, is also being proposed as a novel concept. In the next phase the governing equations to determine the cross-sectional stiffnesses of open-section, thin wall, active MFC beams will also be developed. 2) Investigation of the effectiveness of smart MFC rotor blades to control Blade Sailing Phenomenon (BSP) in ship-board helicopters is the second objective of this proposal. BSP refers to large elastic deformation of blades that can occur at low rpms of rotors on shipboard helicopters, especially under the combined effect of high wind-induced aerodynamic loads and severe ship deck motion at high seas. As the result, the blades can come into contact with the fuselage or tailboom of the helicopter causing substantial airframe damage and comprising the safety of flight crew and the ship deck personnel.