Buckling Behavior Analysis Of Functionally Graded Cylindrical Shell Under Complex Environment

Functionally graded materials (FGMs), made from a mixture of two or more material, have been ragarded as one of the advanced inhomogeneous composite materials. By gradually varying the volume fraction of the constituent materials, FGM possesses the gradient in properties eliminates the mismatch of mechanical properties induced by the interface, with great application in various special environments and bearing complex loads. This material has the features of high mechanical strength, thermal shock resistance, high temperature performance, etc. which gradually encourages FGMs widely used in precision instruments, aerospace, automation fields.In this paper, as the research of the functionally graded materials, assuming the material properties of FGMs vary smoothly through the structure thickness according to a power law distribution of the volume fraction of constituent materials, considering temperature field effect, electric field effect and geometry nonlinear factors, established equations of functionally graded cylindrical shell structure's motion control and heat conduction under complex environment. Based on plate and shell theory, multi-field coupling, the principles of thermodynamics conduction and viscoelastic theory, comprehensively applying Galerkin method, the finite difference method, Newmark method and iterative procedure synthetically, the bending problem of multi-field coupling functionally graded cylindric shell, buckling analysis for a ring-stiffened functionally graded cylindrical, the nonlinear creep buckling and postbuckling analyses for a viscoelastic FGM cylindrical shell with initial deflection, buckling and post- buckling analyses for a laminated cylindrical shell of functionally graded material with the piezoelectric fiber reinforced composite in thermal environments are solved. And discussed the effects of all the above factors on buckling and postbuckling behaviors of the FGM cylindrical shell structure, reveals FGM cylindrical shell structure's failture mechanism under complex environment.This thesis work will enrich and develop intelligent material structural mechanics, multi-field coupling mechanics, non-linear mechanics and viscoelastic mechanics, provides theoretical basis for safety evaluation, optimum design and on-line detection, etc. of functionally graded structures, and has important theoretical and practical value.