On The Research Of The Response Of Aircraft Structure Subjected To The Fluctuating Pressure And Crack Propagation Phenomena

Aircrafts flying is subjected to fluctuating pressure at a supersonic speed. The so-calledfluctuating pressure is a typical random excitation distributing on the out surface of aircraft, whichmay induce violent random vibration of structure and even result in destroy of structure. In order toenhance the aircraft structural reliability, this paper is devoted to the response of aircraft structuresubjected to fluctuating pressure, and its related crack propagation phenomena. The main contents ofthis paper are listed as follow:Firstly, different basic fluctuating pressure environment related to the aircraft are summarized inthis paper. Some statistical parameters for fluctuating pressure imposed on the outside surface of theaircraft were obtained according to engineering estimation formulae. The influence of the spatialcorrelation of fluctuating pressure to the response of simply supported beam and plate is analyzedtheoretically. The finite element meshing criteria is obtained according to wave theories, and thetheoretical solution is compared with the finite element solution.Then, taking an aircraft with double cone cylinder structure as a model, calculate its randomresponse use finite element analysis software MSC.Patran/Nastran and give the rational explanationon its analytical procedure and matters needing attention. The power spectral densitymean and squareresponse of aircraft structure subjected to the fluctuating pressure is calculated while the spatialcorrelation of fluctuating pressure was taken into consideration. The results show that the spatialcorrelation of loads can’t be neglected. It has great influence on the calculation accuracy.Finally, as to the typical beam structure of air crafts, the paper takes XFEM to analyze its crackpropagation procedure, both the time and the way of the crack propagation is simulated.