Static and Dynamic Characteristics of an Artificial Wing Mimicking an Allomyrina Dichotoma Beetle’s Hind Wing for Flapping-Wing Micro Air Vehicles

Abstract

The development of flapping-wing micro air vehicles for many applications, such as hazardous environment exploration, reconnaissance, and search and rescue, demands properly designed, biologically inspired wings to produce enough lift force for their operation. To compare an artificial wing with a natural wing in terms of mechanical properties, overall flexural stiffness is frequently measured with a static loading test setup. However, a dynamic testing method to determine wing deformation patterns has not been developed, even though wing deformation patterns may provide more information about the characteristics of artificial wings. A reliable dynamic testing method is crucial to the development of a high-performance artificial wing. Moreover, the relationship between static and dynamic characteristics of the artificial wing is rare in literature. Therefore, in this study, we present a complete analysis of an artificial wing mimicking an Allomyrina Dichotoma beetle’s hind wing by investigating its static and dynamic characteristics separately, as well as the relationship between them. The dynamic characteristics such as natural frequency, mode shape, and damping ratio of two basic vibration modes (first bending and first torsion) in the operating frequency range were determined using a Bruel & Kjaer (B&K) fast Fourier transform analyzer. To verify experimental results, the natural frequencies were calculated by measuring the flexural and torsional stiffness of an artificial wing and solving the respective governing differential equations. The experimental results from the B&K fast Fourier transform analyzer were consistent with the calculated results. Even though natural frequency is important in the design of an artificial wing, mode shapes, which can be determined only by dynamic testing, can provide reliable guidelines for the biomimetic design of insect-scale artificial wings.