The Rigid-flexible Aerodynamic Coupling Dynamics Of Folding Wing

The morphing configuration of folding wing is conducive to improving the overall performance of aircraft.During the flight,the elastic deformation and folding motion of the folding wing will induce additional aerodynamic forces,which will generate new deformations on the wing structure,thereby generating new aerodynamic forces.This reciprocating coupling effect will make the folded wing response may tend to diverge and cause structural damage.Therefore,the research on the rigid-flexible aerodynamic coupling dynamics of folding wings has certain practical significance and theoretical value.The main research content and results of the thesis are as follows:The wing-body fusion model is selected as the reduced model,and the scale ratio is set,and then the specific model parameters are determined.Three-dimensional model is bulit by using CREO software and programming control is achieved by using ARDUINO software.Finally,the physical model of the folding wing is made.When measuring the folding angle,the Hall angle sensor needs to be placed near the hinge of the included angle at the fold and needs to be fixed.There are certain requirements for the geometric dimensions of the included angle at the fold.Due to the above limitations,a new method of measuring the folding angle based on the angle-frequency relationship is proposed for the specific folding structure.The three-dimensional model of the folding wing is simplified,and ANSYS software is used to analyze the single and two-way fluid-structure coupling dynamics and the influence of parameters of the folding wing under different sizes and different folding angles.The pressure and velocity distribution of the folded wing in the flow field and the relationship between the two and the angle are determined,and the maximum stress and the maximum deformation in the structure field and the relationship between the two and the angle are further determined.The size of the folded wing is further reduced,the scale ratio is 1:5,and the thickness is 0.5mm and0.2mm.The unidirectional and bidirectional fluid-solid coupling characteristics are analyzed,and the modal analysis is performed.Based on the modal vibration experiment,a simplified folding structure model of the folding wing is obtained,and then the global analytical mode is solved and the nonlinear force-frequency relationship of the folding structure is studied.The modal MNF file is obtained by using APDL software,and then joint simulation is obtained by using ANSYS and ADAMS.Two working conditions are analyzed by rigid-flexible coupling when the target angle is 60°.The first working condition is uniform acceleration and then uniform deceleration,and the second working condition is uniform acceleration and then uniform speed and finally uniform deceleration.Under these two conditions,when the midpoint of the outer wing edge reaches the target angle,the maximum displacement difference of the vertical vibration and the ratio of the length of the entire outer wing are analyzed.A simple experimental device is built and experimental samples of the folding wings are processed.A matching finite element model is established,and the angular frequency relationship of the experimental samples at 0.2mm and 0.5mm thickness is obtained by simulation.The first six natural frequencies of the wings at different folding angles are obtained through the frequency sweep experiment,and the comparison curves are drawn.For the model with a thickness of 0.2mm and a folding angle of 60°,the first two modes are obtained through fixed-frequency experiments,and the numerical results are compared with experimental ones.