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Abstract: The objective of the present work is to study the effects of flexural boundary conditions on buckling and postbuckling behavior of axially compressed quasi-isotropic laminate, (+45/−45/0/90)2 s with various shaped cutouts (i.e., circular, square, diamond, elliptical–vertical and elliptical–horizontal) of various sizes using the finite element method. The FEM formulation is based on first order shear deformation theory and von Karman’s assumptions are used to incorporate geometric nonlinearity. The 3-D Tsai-Hill criterion is used to predict the failure of a lamina while the onset of delamination is predicted by the interlaminar failure criterion. It is observed that the laminates clamped and simply supported on all edges have the highest and lowest buckling and postbuckling strength, respectively, irrespective of cutouts shape and size. It is also noted that a fully clamped laminate with large size elliptical–vertical cutout can take higher compressive buckling load than the laminate without cutout for same boundary condition. [Copyright &y& Elsevier]

Abstract: This paper discusses the influence of thermal distortion to compression failure load of polymer matrix composite panels in fire. The thermal gradient along the thickness of the panel, caused by low thermal conductivity, induces transverse deformation field even without external mechanical loads, known as thermal distortion. The deformation field of thermal distortion obtained from combined thermal–mechanical analysis is presented in terms of non-dimensional parameters that represent thermal and mechanical properties, including those in phase transition at high temperature range, and dimensional lengths. A failure model is proposed to assess the transition from Euler buckling to plastic compression failure under the influence of thermal distortion. For large slenderness ratio, the panel is failed by Euler buckling. For small slenderness ratio, the panel is failed by plastic failure mechanism, where the analysis quantifies the influence of thermal distortion to the reduction of load-bearing capacity. The compression failure mechanism under the influence of thermal distortion is discussed for developing quantitative approach to design polymer matrix composite structures in fire. [Copyright &y& Elsevier]