Design And Strength Analysis Of 10 Kg Civilian Composite Fixed-wing UAV

In this paper,the basic principle of composite mechanics and the application of finite element method in structural design analysis are introduced.According to the performance requirements of micro and small-sized fixed-wing UAV,the concept design parameters of civil composite fixed-wing UAV with maximum takeoff weight of 10 kg are determined by referring to the Aircraft Design Manual and the Strength and Stiffness Regulation of UAV.According to the main design requirements and performance parameters of UAV,the structure of UAV is preliminarily designed.The configuration of the power system,the layout of the structure and the geometric dimensions of the components are determined.Three-dimensional models of the wing,fuselage,horizontal stabilizer,vertical stabilizer,wing-body connector,pod are established.Virtual assembly of the UAV is carried out.and the rationality of the structure design is checked.The T-300 3k fabric reinforced 934 epoxy resin composite material is chosen to manufacture the wing,fuselage and empennage of the UAV.The single box beam structure with closed rectangular cross section edge strip is adopted to improve the performance of the wing structure.Aeronautical 7075 aluminum alloy is chosen to manufacture the wing-body connector.The finite element models of the wing,fuselage and empennage are established.The strength,stiffness and stability of the airframe structure are checked by using the maximum stress strength criterion.The carbon fiber laminate structure of the wing skin is optimized.The weight of the skin is reduced by 121.6 grams,about 11.94% of the initial weight of the wing.The manufacture moulds of horizontal tail skin and beam edge strip of UAV are designed and manufactured.The horizontal tail is manufactured by manual wet laying and vacuum curing at room temperature.The static loading experiment of horizontal tail is carried out.Based on the experimental data,the stiffness reduction method is used to modify the finite element model of horizontal tail.The strain relative error between the experiment data and the analysis value of the modified finite element model is reduced below 20%.The reliability of the finite element model of the horizontal tail is verified.The strength,stiffness and stability of the UAV structure with modified material parameters are checked.