Nonlinear Finite Element Analysis Of Aircraft Cabin Components

With the continuous development of aerospace technology, military aircraft,especially fighters continue to move toward the direction of the high speed,operational performance, and long life cycle. During the flight, some components offront part of the cabin will have a large deformation under the external load. Usually,it is solved as a linear problem. It has great significance to solve the aforementionedproblem with nonlinear methods.The front part of cabin is as the research object in this paper, in whichgeometric nonlinear analysis and stability analysis are carried. The concrete work isas follows:The structures are modified according to the actual force, by means ofremoving the minimal impact parts, such as chamfering, through-hole structure andweight loss dug cut. Then the models are imported into ANSYS. Each component isselected for appropriate unit, and given constants and material properties formeshing. MPC method and Boolean operations are used to assembly the model. Atlast，the Finite element model is obtained.The algorithm of the Newton-Rapson method has been combined witharc-length method for the geometric nonlinear analysis of the major structures, suchas the first and second boxes、girders、skins and so on. And both the maximumdisplacement and stress are been drawn to find the dangerous parts. Then the firstframe is improved and verified still have sufficient strength and stiffness.The non-linear buckling analysis method has been used for stability analysis ofthe skin and filler cap. The ideal critical buckling load and buckling modes areachieved by linear buckling analysis. Then the initial defects and nonlinear are beenintroduced. Load displacement curve is achieved by using the arc-length methoditerative solution, from which the actual critical load of the structure can be seenclearly. The results show that the load does not exceed the buckling load. So thestructures meet stability requirements.In conclusion, the stress and displacement of the cabin components and thecritical load when buckling are obtained by analyzing. It is of great significance tothe analyzing and improving the structure.