Analysis Of Fracture Mechanics For An UAV’s Wing

In this thesis，a study about calculating and analysing stress intensity factor forwings of an UAV has been presented. The studying about stress intensity factor of theUAV structure will provide bases for subsequent UAV structural fracture mechanics.And UAV fracture mechanics has been studied rarely at home and abroad, so thesignificance of solving the stress intensity factor for the UAV wing structure is greatpractically and applicationally.In this article, based on the practical engineering, the static strength of the UAV hasbeen calculated, and the stress intensity factor for the different UAV wing structural hasbeen solved, which provided a method for analysing the fracture properties of the UAVwing structure, and provided datum for selecting structure type．This article is divided into six parts, including the introduction, fracture mechanics,UAV structural modeling and aerodynamic loads analysis, the static strength analysis ofthe UAV, the Fracture Mechanics Analysis of UAV, Summary and Outlook. In the end,the stress intensity factor of the main structures of the wing ribs, skin and beamstructure are obtained.The main work of the thesis is as follows:Firstly，the static strength of the UAV has been analysed. The aircraft model has beencreated by using Catia, based on the particular UAV structural drawings. Then, theaerodynamic loads is analysed by using Fluent, and the static strength is calculated byusing fluid-structure interaction method inANSYS Workbench.Secondly, the stress intensity factor of the UAV wing structure has been calculated. Thestress intensity factor on ribs, pipe girder and skin structure of the UAV wing arecalculated respectively. The stress intensity factor of rib structure with three kinds ofcrack forms, such as penetrated crack,deep crack and surface crack, are calculated. Thefinite element method is used to calculating the stress intensity factor of rib structurewith penetrated crack, and the analytical method is used to calculating the stressintensity factor of rib structure with deep cracks and surface cracks. The stress intensityfactor of pipe girder with corner cracks is calculated by energy slip method. The stressintensity factor of skin structure with Penetrated crack is calculated by the estimationmethods. The aim of this research work is to provide a reference for later in depth study ofthe UAVstructure fracture mechanics.