Laminated Composite Beam Structure Of The Thermal Post-buckling Behavior

In this thesis, nonlinear static responses of laminated composite beams, subjected to uniform distributed thermal loadings, are studied. The main contents of it are as follows:1. Firstly, according to the survey of the corresponding literatures, an outline about the related research results, and advances in the structural mechanical behaviors of laminated composite beams and plates are summarized. Especially, the macroscopical mechanical responses of laminated composite beams and plates , subjected to thermal and mechanical loadings, are reviewed in details.2. Nonlinear large deformation problem of laminated composite beams is investigated. Firstly, based on the Reddy's higher order shear deformation theory together with von Karman's geometrical nonlinear theory , the generalized nonlinear governing equations and boundary condition for large deformation of laminated composite beams, subjected to uniform temperature rising, are obtained by using Hamilton's principles. In order to simplify the problem to get numerical solution, it assumes that the beam is subjected only to uniform temperature rising. Cross-ply and angle-ply laminated composite beam are considered with several kinds of boundary conditions, including pinned-pinned, pinned-fixed and fixed-fixed. By using shooting method, the above mentioned strongly nonlinear boundary value problem of ordinary differential equations are solved numerically. The numerical solutions of critical thermal buckling and post-buckling of cross-ply and angle-ply laminated composite beams, are obtained by accurately considering transverse shearing of beam, The deformation parameters of the laminated composite beams versus thermal loading and material mechanical properties, and the effect of thermal loading on deformations of beams are discussed in details.3. On the basis of the accurately geometrically nonlinear theory, nonlinear governing equations of thermal bending for axially extensible two-layer laminated beams, subjected to temperature loadings were established. Theequations include tension-bending coupling in the deformation because of the transversely non-uniform characteristic of materials. The numerical solution of thermal bending for two-layer laminated beams, with immovably simply supported ends and subjected to a transversely uniform temperature rising, were obtained by using shooting method. As an example, the equilibrium paths and the equilibrium configurations of the beams composed of steel and copper were obtained, the effects of geometrical and physical parameters on the deformation were investigated and analyzed.