Research On Geometric Nonlinear Static Aeroelasticity Of Composite Wings With High Aspect Ratio

High-altitude long-endurance UAVs can timeless perform significant military and civilian tasks,such as scouting and overseeing.It is very vital in the prosperity of the economy and the modernization of defense for our nation.So as to cut down energy consumption and increase aerodynamic characteristics,such UAVs generally adopt a high aspect ratio layout,and the application of lightweight composite materials in important wing components is also increasing,which makes the wing structure more and more flexible.Under the action of aerodynamic force,this type of high aspect ratio composite wing is prone to large torsion angles and deformations,which leads to serious geometric nonlinear aeroelastic problems,which has a serious impact on the control property and safety property of the aircraft.Geometric nonlinearity makes the classic linear static aeroelastic analysis method ineffective.Even small changes in the torsional deformation of the wing will have greater effects on the aerodynamic characteristics for the UAV.Therefore,considering the geometric nonlinear problems caused by large deformations,based on the fluid-solid coupling technology,an accurate and efficient solution method for static aeroelasticity is studied,and the impact of the geometric nonlinearity,composite material layer angle,thickness other factors on the static aeroelasticity of high aspect ratio wing are analysed.This is of great meaning to the design of high altitude,long life and high aspect ratio UAV structure.This article mainly completes the following research work:(1)Based on the loosely coupled two-way CFD/CSD coupling method,an accurate geometrically nonlinear static aeroelasticity simulation method is established.Taking the standard model HIRENASD wing as the research object,the reliability of the numerical calculation method is verified(2)Established an accurate structure model of a high aspect ratio wing,and perform numerical simulations on the geometric nonlinear static aeroelasticity of the wings with large flexibility and high aspect ratio.The influence of geometric nonlinearity on the static aeroelasticity of wings with high aspect ratios is studied.(3)A composite wing model with the same thickness as the metal wing is established.At distinct angles of attack,the characteristics of structural and longitudinal aeroelasticity and the stability of the composite wing are studied,and compared with the aluminum alloy wing with equal thickness.(4)Taking the wing structure deformation less than 15% of the half span as the optimization goal,the metal structure of the wing satisfies the strength condition,and the composite material structure of the wing satisfies the Wu-Tsai failure condition as the constraint condition.The Screening method is used to optimize the layup angle of the composite material structure of the wing.Then,the nonlinear static aeroelasticity of the optimized wing is simulated.The effects of the optimization of the composite wing layering angle on the longitudinal aerodynamic characteristics and stability of the wing are analyzed.