Optimization Design Of High Aspect Ratio Wing Composite Material For Gust Alleviation

High-altitude-long-endurance aircraft has attracted more and more attention because of its superior flight performance.This kind of aircraft generally has high aspect ratio wings,and the geometric nonlinear characteristic is obvious.The additional load caused by gust in flight brings a large dynamic structural load to the aircraft,which not only shortens the fatigue life of the aircraft,but also affects the maneuverability.Using aeroelastic tailoring technology for gust load alleviation design has gradually become one of the key technologyies in the development of the aircraft.In this paper,the finite element model of the high-aspect ratio wing structural is established.Unsteady aerodynamic force is calculated by Double Lattice Method.Through modal and flutter analysis,the effects of every modal on the aeroelastic stability of the wing structure are obtained.According to the gust response calculation method,the mathematical models are established of discrete gust and random gust.By using aeroelastic dynamic response analysis,we can get the wing load under the influence of two types of gust field models.Considering the geometric nonlinearity effect,NASTRAN software is redeveloped by using DMAP language.So that we can solve the wing static aeroelastic deformation under self-weight and the flight conditions.And we can also get the modal at the static equilibrium position by using the DMAP language.The aeroelastic dynamic stability and discrete gust response analysis are performed by using this modal.The effects of geometric nonlinear on dynamic stability and dynamic response are discussed.Based on the multi-disciplinary optimization design platform ISIGHT,the NASTRAN and C++ programs are integrated.During aeroelastic tailoring optimization process,the wing root maximum bending moment is taken as the optimization target,the flutter critical velocity is selected as the constraint condition,and the composite skin layer angles are taken as the design variables.The optimization results show that the composite wing skin layer design method is feasible and practical for the gust load alleviation of high aspect ratio wings.