Crack Growth Analysis Of Aircraft Skin Used By Extended Finite Element Method

Extended finite element method is a new effective method for modeling the crackgrowth process, which inherits mature theories and techniques of traditional finiteelement method. Extended finite element method overcomes disadvantages of fractureanalysis of traditional method such as too refined mesh around the crack tip andre-meshing when crack propagation. In this dissertation, extended finite elementmethod is used to simulate the crack growth process of aircraft skin connection. Theinfluence of structure details such as countersink and rivet holes pitch to the crackgrowth life is studied. The main contents are as follows:1. The basic theories and implemental process of damage tolerance analysis arereviewed. Several methods of calculating the stress intensity factor are studied. It isproved that the extended finite element method is the most efficient method.2. Since ABAQUS cannot perform the crack growth automatically, an Excelmacro interface program is developed. By comparing the result analyzed by NASGRO,the interface program is validated to be correct and reliable.3. The crack growth analysis of rivet hole of typical aircraft skin connection isachieved by using the interface program. The analysis results show that the structuredetails such as countersink and rivet holes pitch reduce the crack growth lifesignificantly. Through a large number of calculations, charts and figures areformulated to quantify the influence of structure detail.The studies in this dissertation could be utilized in engineering application ofcrack growth life prediction and damage tolerance analysis of airplane structure.