Flexible Insect Wing Of The Constitutive Relation And The Static And Dynamic Characteristics

Bionic study of insect flight started with the appearance of MAV concept recent years. Traditional aerodynamics cannot explain the mechanism of insect flight, and new aerodynamic is being explored intensively. Some researcher forecast that the reason of insect overcoming aerodynamic limits relies on tow points: flapping and flexibility. Aerodynamical is optimized through the tow special mechanism. This thesis research some important problem related to the tow points: structure of insect wing, material, static and dynamic mechanical properties, flapping mode and wing deformation etc.Projecting fringe technique is applied to measure 3-d shape and deformation under static load. 4-step phase shift technique is applied to get phase. This technique is very suitable for the measurement of insect's wing, which could be immune of background noise very good. And the modulation analysis based weighted leas-squares approach for phase unwrapping increase the measurement precision.For the first time, a viscoelastic constitutive relation model related to the deformation of the dragonfly wing was established, that is, the standard linear solid model. Viscosity property of insect wing increase the dynamic stiffness of flapping wing, to avoid the appearance of big deformation while insect flaps its wing in high speed. The FEA results display viscosity property increase insect's anti-vibration function. Viscoelastic model was examined by FEA of dynamic deformation response for a model dragonfly wing under the action of the periodical inertial force in flapping motion, compared with the elastic constitutive relation model at the same time. Results show that the elastic model is not consistent with reality, as the resultant amplitude of elastic deformation is too large, furthermore, considerable higher-frequency components is produced. However, the viscoelastic deformation agrees well with the experiment. As a result, the viscoelastic constitutive relation model is confirmed to be the proper description of the insect wing material.Doppler vibrometer which is based on the Doppler principle was used to stimulate the wing of dragonfly, recording the frequency curves of speed and getting its natural frequencies and modes .And also, we analyze the experimental results, discussing some characteristcs of the dragonfly's wing structures and flexibility.A novel and practical stereo camera system which uses only one camera and a biprism in front of the camera is applied to measure the kinematic parameters of free flight dragonfly and obtain many experimental data ,including body position and attitude, wing deformation, flapping angle, torsional angle etc, which will be very useful for the analyses of aerodynamics on insect flight. The flexibility of deformation is investigated spatially.A new method modeling finite elemental wing model is introduced, which refer to wing's static and dynamic mechanical representation and not get specific and detailed parameters of geometric and material.