Research On Buckling Behavior For The Functionally Graded Material Cylindrical Shells

With the development of modern science and technology, material technology has improved continuously. The FGM (Functionally Graded Materials) eliminates the interfacial stress of ordinary laminated composites in the emergence of a large number of new composite material. It was widely applied in the main structure of aviation, aerospace and nuclear industries for thermal protection layer. FGM material with a variety of structural forms in the application process, in which the cylindrical shell structure prone to buckling failure.FGM cylindrical shell structure is widely used for rocket fuel tank, to improving the structure of the anti-buckling capacity, we generally used the form of a grid reinforcement to improve the structural stability. During using it bearing thermal loads and mechanical loads effect, so its coupling buckling study is necessary. This paper studies the buckling behavior of functionally gradient material cylindrical shells under the combined thermal and mechanical load, the main contents are:(1) A brief introduction and application of functionally graded material. And we also give some use of cylindrical shell in structural engineering, analyzes the research status cylindrical shell buckling.(2) Gives the expression of functionally graded material properties under thermal loading, introduces the basic theory of shell buckling, and according to Reddy higher order shear deformation theory derived the expression for general displacement of cylindrical shell. In the expression the shear strain in the thickness direction follow a parabolic distribution, and it contains no shear correction coefficient, eliminates different correction coefficient selected caused confusion, and account the transverse shear effects of moderately thick cylindrical shell;(3) Based on Reddy higher order shear deformation theory derived moderately thick cylindrical shell bulking control equations, separation of variables is employed to obtain the accurate buckling solutions, by comparison with the existing classical theory Donnell results verify the exact solution method the results, we found that transverse shear effect can't be ignored in medium thickness cylindrical shells under clamped boundary conditions, we also discuss the influence of the volume fraction index and temperature field for the critical stress;(4) At last we discussed the buckling of the grid stiffened cylindrical shell, superposition principle is used to discuss the impact of grid rib structure, during the calculation process we consider the torsional and shear stiffness of rid. Finally, by a numerical example to discuss the influence of parameters on the ribs functionally graded material cylindrical shell structure stability, by adjust rib's parameters reasonable can reduce weight, improve structural stability, the results have important reference for practical engineering design.