Structure Design And Optimization Of A Solar UAV

Solar UAV has the characteristics of high altitude,long voyage,low cruise speed,solar panels and high aspect ratio.Therefore,the requirements for structure are more stringent.It is difficult for the structure design methods of traditional experience and strength checking to meet the requirements,moreover,the design cycle is long and the workload is heavy.We can fulfill the structural form that satisfies certain objective functions and performance requirements if the modern optimization method such as finite element method is used to design and optimize the key part of solar UAV.This method is more scientific,and it also improves the design of aircraft structures from the experience level to the scientific theory level.In this paper,structures of a new solar UAV are taken as the research object.The main contents are as follows:The aircraft structures of wing-fuselage fusion,double beam-wing rib-skin are selected by analyzing the main performance and structure requirements of the aircraft.Firstly,the 3D model of aircraft is established by CATIA software,and then the simplified model is introduced into the ABAQUS software.It is simulated by CFD aerodynamic analysis.Finally,two conditions of the aircraft surface aerodynamic load data are obtained.According to the aerodynamic loads of aircraft and the principle of variable density method,a topological optimization of wing rib is carried out,and the structures that satisfies two loads are obtained.The results show that the optimized structure has higher utilization rate of materials,and the weight is greatly reduced while meeting the requirements of strength and rigidity comparing the results of optimization and experiential design.According to the results of aircraft aerodynamic analysis,the quasi-strength design for the main beam of the aircraft composite material is adopted.Firstly,the initial layer of the upper and lower margin of the main beam is carried out.Then,multi-objective particle swarm optimization(PSO)with ISIGHT integrated ABAQUS software is applied to optimize the laying thickness,laying angle and laying order of the upper and lower margin for the main beam of the composite material.Finally,the optimization results are analyzed by finite element method.The optimization results show that the new layer structure satisfies the strength requirement while the weight of the main beam is greatly reduced and the force is more uniform.The new main beam structure is better to meet the requirements of the structure design.The work of this paper provides an important reference for the follow-up structure design of UAV.