Numerical Analysis Of Mechanical Properties Of Composites Bionic Wings

Flapping wing micro air vehicle(FMAV)can produce both lift and thrust at the same time,having the advantages of high energy efficiency,low noise,good concealment and landing easily and so on.FMAV can play an important role on Military and Civilian field in future.Recently,domestic and international research on FMAV made a lot of achievements,but the FMAV study involve multidisciplinary technology,factors to be solved mainly include: effects of flapping wing in low Reynolds number and unsteady flow condition,miniaturization of the key components of new materials and optimization technique of flexible wing,experimental research methods for FMAV.The future development trend of FMAV is: ultra micro development,cross city building or indoor task,networking operations like bees,and new intelligent bionic micro air vehicle.The structure of insect wing is light and strong,it is similar as composite material.The classical theory of composite laminates and its application in software ANSYS are expounded.the natural frequency and vibration mode of 2D model?3D model and the 3D model considered sandwich structure of dragonfly wing were analyzed by means of finite element method in this paper.Modal analysis results showed that the zigzag cross-section structure can significantly improve the natural frequencies of the dragonfly wing,sandwich structure had slightly negative effect on dynamic performance.The first nature frequency of 3D model is much larger than the flapping frequency of the dragonfly,so resonance damage will not occur.Then a group of simplified model of dragonfly wing were established and the first three natural frequency curves with the wrinkling height and protein ratio in the vein were drawed.The optimum wrinkle height is 0.5 millimeters,and the optimum protein ratio is between 1/2 and 3/4.A structure analysis was conducted in this study on membrane flapping-wing aerial vehicles based on composite material models in order to study the mechanical performance of flapping wing under aerodynamic and inertial forces.The results show that among the four orientation angles(0,90,45 and-45 degree)of composite fiber on the single layer plate,using-45 degree can get the least stress,having optimal mechanical properties of single layer plates.Among the orientation angle combinations of composite fiber(-45/0?-45/45?-45/90?0/45?0/90?45/90)on the double-layer plate,using 45/ 90 degree can get the least stress and least deformation.The maximum normal stress and shear stress zone of the whole and each layer are generated at the root of the beam.The stress distribution is reasonable and the mechanical property is better.The double-layer plate is similar to micro structure of insect wing.This is because the principal stress direction of the 45/90 composite ply is-22.5o,which is consistent with the laws of the biological wing in nature.The study can possess the guide acting for the design of bionic FMAV.