Damage Tolerance Analysis Of The Connecting Structure In The Central Wing Of Aircraft

In recent years,many new structures and designs of aircraft have emerged with the progress of material science and aircraft design concepts.Therefore,it has become an important subject to make fatigue life analysis and damage tolerance analysis.The damage tolerance design is the main guarantee for the safety of aircraft structures.And it can ensure the aircraft structures not to suffer catastrophic damage in its service life with the optimization of material selection,structural layout and detail design.In this thesis,the damage tolerance analysis of the connection area between the panel of the central wing and the beam under it is conducted.And the analysis is associated with the demand of the damage tolerance analysis of a new type of plane,based on engineering reality.The following works are conducted in this thesis.Firstly,finite element software is used to calculate the static state of the part so as to determine the risk point of it,and the stress severity factor method is used to calculate the stress near the nail hole.Secondly,the displacement extrapolation method is used to calculate the stress intensity factor to provide theoretical basis for the damage tolerance analysis.Thirdly,a program is written in this thesis to realize the establishment of the load spectrum used in the damage tolerance analysis,and the cycle-by-cycle method is used to calculate the crack growth life.Fourthly,the residual strength analysis of this area is also conducted.At last,the maintenance cycle and structural suggestions are given based on above calculation results.In this thesis,the damage tolerance analysis of the structure is combined with engineering,which provides methods and techniques for the damage tolerance analysis of other similar structures.