Structural Optimization And Simulation Analysis Of Light Fixed Wing Aircraft Fuselage

Facing the economic requirements of the international market and the increasingly stringent demand for lightweight,composite materials are widely used in various fields with their unique advantages.In the field of Aeronautics and Astronautics,composite materials gradually replace the traditional aeronautical materials.As a kind of composite materials,continuous fiber reinforced materials can be designed with high strength,and the advantages of materials can be brought into full play through the optimization of lay up,so as to achieve the effect of weight reduction and gain.However,fiber-reinforced materials will increase the discreteness of design variables and the scale of plying information due to the anisotropy and non-uniformity of their component materials,which increases the difficulty of optimal design.At the same time,after weight reduction optimization,structural performance may be reduced,and damage,cracks and fatigue may appear in advance.Therefore,it is necessary to find an optimization method that can reduce the weight of the structure without greatly reducing the performance of the structure.In this paper,the structure optimization and simulation analysis of the lightweight fixed-wing composite aircraft structure are carried out.The main research contents are as follows:(1)According to the design requirements of the aircraft fuselage,the finite element model of the fuselage structure is established,based on the composite material laminate structure theory,combined with the Opti Struct optimization design software,and the mechanical properties and overall quality of the structure are taken as the optimization targets.Under dense load conditions,the main bearing structure of the fuselage and the layering method of the fuselage skin were optimized.(2)The aerodynamic characteristics of the aircraft are studied using the CFD calculation method,and the changes in the lift coefficient,drag coefficient,lift-to-drag ratio,Mach number and angle of attack of the aircraft in a subsonic low angle of attack flight environment are summarized.To prevent bad aerodynamic problems of the fixed-wing aircraft after weight reduction,and analyze the static stability of the aircraft in longitudinal,lateral and heading.(3)Perform vibration analysis on the whole fixed-wing aircraft.The aircraft is in an unconstrained state during navigation.First,perform a free-mode simulation to analyze its natural frequency and mode shape.Then,based on the results of the modal analysis,select a certain the sweep frequency range simulates the vibration of the aircraft under concentrated and pressure loads.