Finite Element Analysis Of Crack Propagation For UAV Wing’s Rib

The wing is the main component of the fixed-wing aircraft that provides lift tosupport its stable flying in the air, and provides the necessary operating force. Tinycracks that exist in various parts of the wing will become a serious threat to flightsafety, for they will continue to propagate during the flight, eventually lead to fracturefailure. At present, carrying out research in this area is necessary, for the studies onUAV wing’s crack propagation are not sufficient, and the form of crack propagationunder flight loads is lack of knowledge.In this article, based on ABAQUS software platform, the propagation of the wingrib’s initial crack in normal flight load is simulated, the propagation trajectory of crackand the variation of fracture mechanics parameters are summarized, by setting a typeof UAV as engineering background.The main work of the thesis is as follows:(1) The basic theory of fracture mechanics is introduced, the calculation principleof fracture mechanics and the concrete implementation method in ABAQUS aresummarized in detail.(2) The wing’s model is setted up, the aerodynamic load on the cruise state iscalculated. Using ANSYS’s fluid solid coupling function, the stress distribution of thewing is obtained. The initiation and development position of crack on the wing’s rib isdetermined.(3) Based on the ABAQUS software platform, the program module for automaticcrack propagation is written, by using the PYTHON language. Through the concreteexample, it is showed that the reliability and accuracy of the program is high, and canbe applied to practical engineering problems.(4) For cracks are liable to start in the leading edge of the ribs and the connectionbetween rib and spar, the initial crack is placed in these positions. Using the program,the crack propagation is simulated. It is showed that crack propagation morphology,variation of stress intensity factor in the expansion process and crack propagation angle,has close relationship with the crack location and initial crack angle. Crackpropagation morphology can be divided into two kinds generally, one is along the initial direction, not deflect; another deflect greatly in the initial stage of thepropagation, then the propagation direction almostly does not change.A reliable basis for the design of UAV is provided by this research work.