Design And Analysis Of Morphing Wingtip Based On Rigid-flexible Hybrid Structure

Morphing aircraft can continuously adaptively adjust the shape of the wing according to the flight mission and changes in the external environment to obtain optimal flight performance.It has great application prospects in the aviation field in the future.An important research direction of the morphing aircraft is to realize the deformation of the wingtip,which can improve the maneuverability of the morphing aircraft,increase the lift-to-drag ratio and range,and reduce the induced drag and the level of the airport.The wingtip of the morphing aircraft needs to be deformed while bearing aerodynamic loads.Based on the research progress of morphing wingtips,this paper proposes a morphing wingtip model based on a rigid-flexible hybrid structure,and conducts structural design,morphing analysis and tests taking into account the deformation capacity and bearing capacity of the wingtips.The content of this paper is as follows.Firstly,according to the deformation principle of the morphing wingtip,an electromechanical-truss drive mechanism is proposed,and silicone rubber is used as the material of the model skin.Through finite element simulation analysis,the load-bearing capacity of the driving mechanism was studied,and its key design parameters were determined.Use the hyperelastic constitutive model and MATLAB software to fit the test data of the silicone rubber skin to obtain the Mooney-Rivlin model material constants.The morphing of the model was simulated to verify the deformation angle of the model,and the influence of the skin thickness on the morphing of the model was explored.Secondly,in view of the detachment problem,the connection performance of the flexible skin and the rib is conducted.In order to determine the connection mode of the skin and the rib,the tensile test was carried out by making test pieces.According to the determined connection method,the influence of the skin size parameters on the connection performance is explored.The thickness and connecting hole’s diameter of the skin are determined.According to tensile test results of the specimens with different hole spacing and simulation analysis results of the model morphing,the spacing and distribution of the connecting holes on the upper and lower wing surfaces of the ribs are determined.Better connection performance is obtained between the skin and the wing ribs.Finally,the model was manufactured and assembled,and the correctness of the finite element model and the results of the tensile test was verified by the comparison test of the solid model morphing.The sensor is used to measure the displacement of the model’s turning deformation,and the deformation angle of the model is calculated with the help of formulas to verify the accuracy of the structural design parameters.In order to measure the displacement of the model structure,a cantilever beam test was performed on the model.Calculate the stiffness of the model before and after deformation,and analyze the change of stiffness.