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We examine numerically the uniaxially compressed stability of triaxially woven fabric (TWF) composites employing a proposed geometrically nonlinear finite composite plate element model with volume segmentation ABD constitutive relation, taking advantage of greatly reduced degrees of freedom. From satisfactory agreement with results from literature, numerous boundary conditions are explored for various aspect ratios in the buckling analysis. High dependencies of post-buckling patterns on plate aspect ratios are observed, from which a computationally time-saving characteristic equations have been defined before the occurrence of post-buckling state for practical convenience, best described on the basis of logarithmic critical buckling load and stiffness factor. These buckling characteristics have a direct general correlation to TWF’s aspect ratios and boundary rigidities. [ABSTRACT FROM AUTHOR]

In this study, the buckling and compressive failure of adhesively-bonded stepped-lap joints (with/without composite patches) composed of pultruded glass fiber-reinforced polymer composite laminates was investigated experimentally and numerically. Two-component epoxy adhesive was used for bonding purposes. Composite patches were woven glass-epoxy layer. They were added onto the conventional stepped-lap joints so that additional load transfer paths were created and localized stress concentrations near joint edge were reduced. The axial compression tests were performed and the results revealed that the buckling and failure load of new stepped lap composite joints with composite patches were significantly higher than the conventional stepped lap joints. The influence of the overlap length was evaluated. For both types of joints, a small increase was observed in failure loads by increase of the overlap length. Numerical results showed a very good agreement with experimental results. [ABSTRACT FROM AUTHOR]

The in-plane load-bearing capacity of marine composite plates is an area that has received little attention, in contrast to the significantly larger buckling and post-buckling studies available on aeronautical composites. The aim of this study is to investigate experimentally the strength to failure of large woven composite panels and correlate the results with finite element analyses. The tests performed were able to demonstrate the well-known sensitivity of the panels to boundary conditions and panel imperfection size, which is also reflected in a parametric study carried out in Abaqus/Standard. Two-dimensional stress-based failure criteria were implemented via a user-defined field (USDFLD) subroutine to detect matrix and fiber damage, which allows progressive damage to be modeled. A modification of Hashin’s failure criteria proved to be the most effective in capturing both the size and location of the damage and obtain a good approximation of the load—displacement history and surface strains. [ABSTRACT FROM AUTHOR]

This paper contributes newly developed closed-form buckling solutions for generic one-edge-free problems common to partially disbonded composite structures. These solutions are shown to be accurate by comparison with experimentally measured buckling loads which are also reported in this paper. The buckling of partially disbonded regions in adhesive joints is a safety concern due to the potential for ensuing buckling-driven disbond growth. In order to design structures to be tolerant to these flaws, closed-form expressions that predict buckling load have been developed based on a one-edge-free buckling model. Comparison of the closed-form predictions with the finite element results verifies the accuracy of the solutions. Validation of these analyses was achieved by comparison with the experimentally determined buckling loads. These were measured to fall within a range of predicted values, as defined by the choice of boundary condition opposite the disbonded flange-free-edge: either clamped or simply-supported. Assumption of either boundary condition provides upper- and lower-bound predictions of buckling in partially disbonded joint flange configurations. [ABSTRACT FROM AUTHOR]