Abstract

To reveal the resonance suppression mechanism of the blood circulation in dragonfly wings, a numerical modeling method of dragonfly wings based on Voronoi diagrams is proposed, and the changes in mass, aerodynamic damping, and natural frequencies caused by blood circulation in veins are investigated. The equivalent mass of blood, boundary conditions, and aerodynamic damping are calculated theoretically. Modal analysis and harmonic response analysis of wing models with different blood circulation paths are performed using the finite-element method (FEM). The vibration reduction ratio δ is introduced to compare the damping efficiency of different mass regions. Finally, a natural frequency testing device is constructed to measure the natural frequencies of dragonfly wings. The results indicate that the shape, mass, and natural frequencies of the dragonfly wing model constructed by numerical method agree well with reality. The mass distribution on the wing can be altered by blood circulation, thereby adjusting the natural frequencies and achieving resonance suppression. The highest δ of 1.013 is observed in the C region when blood circulates solely in secondary veins, but it is still lower than the δ of 1.017 when blood circulates in complete veins. The aerodynamic damping ratio (1.19–1.79%) should not be neglected in the vibration analysis of the beating wing.

中文翻译：

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静脉血液循环对数值方法构建蜻蜓翅膀共振抑制的影响

摘要

为了揭示蜻蜓翅膀血液循环的共振抑制机制，提出了一种基于Voronoi图的蜻蜓翅膀数值模拟方法，研究了静脉血液循环引起的质量、气动阻尼和固有频率的变化。从理论上计算了血液的当量质量、边界条件和气动阻尼。采用有限元法（FEM）对不同血液循环路径的机翼模型进行模态分析和简谐响应分析。引入减振比δ来比较不同质量区域的阻尼效率。最后搭建了固有频率测试装置来测量蜻蜓翅膀的固有频率。结果表明，数值方法构建的蜻蜓翅膀模型的形状、质量和固有频率与实际情况吻合较好。血液循环可以改变机翼上的质量分布，从而调整固有频率并实现共振抑制。当血液仅在二级静脉中循环时，在C区观察到最高的δ1.013，但它仍然低于血液在完全静脉中循环时的δ1.017。在拍打翼的振动分析中不应忽略气动阻尼比（1.19-1.79%）。