| Flapping-wing Aircraft(FWA)is becoming an important field of UAV research with its high efficiency,high maneuverability and good stealth,and has a wide range of applications in civil as well as military fields.In this paper,a space crank-rocker mechanism flapping wing aircraft as the object,the study of the fluid-structure coupling analysis method for the subsequent structural optimization and prototype production provides support.The flight modes of flying organisms such as birds and insects are elaborated,and their motion mechanisms are studied.The different ways of flying organisms to obtain flight power in non-constant fluids are elucidated,and the comparison is conducted to summarize the key of the bionic problem for the study of the flapping wing flying machine.The analysis of the kinematics and dynamics of the flapping wing vehicle was completed.A flapping vehicle was designed,the model was initially examined,the definition of kinematic parameters and kinematic modeling were carried out,and the relationships between the rods were derived.The kinematic simulation was performed in ADAMS,and it was initially determined that the mechanism has sharp return characteristics,and the corresponding curve diagrams were derived,and the parts in the model fit correctly.Using the rigid-flexible coupling analysis,the maximum stress point appeared at the crank hinge by analyzing at different crank speeds.The correctness of the model was verified by numerical method,using mathematical equations to obtain the same motion characteristics.A fluid-structure coupling analysis method for flapping wing aircraft is established.By comparing different turbulence numerical simulation methods,a suitable model was selected,and parameters setting and meshing of fluid domain were adjusted in Workbench environment according to the characteristics of flapping wing.The transient analysis of the aircraft is carried out.It is analyzed that the maximum stress of the transmission mechanism is 114.05 MPa in one cycle,and the maximum deformation occurs at the wing tip.According to the existing fluid-structure coupling analysis principle and method,bidirectional fluidstructure coupling is adopted to analyze the flapping wing.It is determined that the pressure variation of the flapping wing near the flapping plane along the spanwise direction corresponds to that of the velocity field in one flapping period,and the maximum velocity around the wing is 6.7m/s.The maximum stress of the wing in the coupling field is55.62 MPa.The calculation method of wing aerodynamic force is expounded.By comparing lift curve and drag curve,it is concluded that the flapping wing’s rising force is greater than drag,the maximum lift force is 1.5N,and the maximum flight drag is 0.03 N.Through the analysis of flexible flapping wing,it is concluded that flapping wing will produce a certain thrust,which is consistent with the theory.It provides an important basis for the next design of flapping wing aircraft. |
