Mechanical Property Analysis And Reformation Study On Bionic Dragonfly Wing

After millions of years of evolution,dragonfly has developed into a creature with high flying abilities.Its wing structure has great functional characteristics,which provides a rich data base for the development of flapping wing micro aero vehicle(FWMAV).In recent years,researchers made great contributions to the study of dragonfly wing structure,dynamics,flight control,etc.These contributions markedly promoted the ranges of dragonfly wings applications.At present,the research field on the dragonfly wing shows the fact that the research result on aerodynamic characteristics ahead of the mechanical performance analysis,numerical simulation is better than the experimental verification.Dragonfly uses a very light wing to provide the lift force during flight,thus we can see the advantages of mechanical properties.Obviously,it's of significance to do research on mechanical strength of dragonfly's flapping wing.From observation,we know that the wings have a lot of features,which make contribution to its mechanical strength.In this subject,finite element method(FEM)is used to analyze the force distribution of wing models with different characteristics(such as veins distribution,corrugation,etc.).FEM is also used to compare the effect of different characteristics on the mechanical properties of the wing to explore the mechanical characteristics of the wing,in order to provide the theoretical basis for the wing reformation.Therefore,in this paper,numerical simulation and experimental verification methods are combined to study the mechanical properties of some of the wing structures by solving the stress-strain,the concentrated stress distribution and the frequency of vibration modes.In order to investigate the influence of the distribution of veins on the mechanical properties of the wing,two simplified wing models and one optimized wing model were designed.Two kinds of non-uniform loads were loaded on the surface of wing.Results show that when removing the vein branches which are away from the wing root will help to eliminate stress concentration.Result also shows that removing vein branch of from this part has the least effect on wing strength.To explore the influence of corrugation on wing,numerical simulations on different numbers and angles of corrugations were conducted.Results show that wing has the highest stiffness with single corrugation of 90°.In addition,the wing model was processed and printed,the experimental platform was designed and built,the wing model was fixed on the experimental platform and subjected to the force,and the experimental results were compared and explained with the numerical simulation results.To study the effect of section shape on the mechanical properties of wing,four groups of gourd-shaped cross-section,circular section and elliptical section were designed and their mechanical properties were compared.Results show that the mechanical performance with elliptical is better than that of gourd cross-section and circular section.With controlling variable method,models with different kinds of material properties were tested.Result shows that the stiffness of wing is mainly determined by vein,rather than membrane.