Publications Internationales

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Author: search.filters.author.Bezazi, A.

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    Modelling damage of composite laminates with different stacking sequences
    (2013) Benbelaid, S.; Bezzazi, B.; Bezazi, A.
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    Flexural fatigue behavior of cross-ply laminates.An experimental approach
    (2003) Bezazi, A.; El-Mahi, A.; Berthelot, J. M.; Bezzazi, B.
    Within an experimental approach we describe the mechanical behavior of different resin-epoxy laminates reinforced with cross-ply Kevlar and glass fibers under conditions of static and cyclic three-point bending. In static tests, we consider the effect of stacking sequence, the thickness of 90°-oriented layers, reinforcement type on the mechanical behavior of laminates under loading and on realization of various damage modes leading to rupture. Cyclic loading studies have been performed in two steps. In the first stage, we inquire into the dependence of the behavior and durability of four glass fiber-reinforced laminate-types on the stacking sequence; the second stage is devoted to studying the dependence of cyclic strength and fatigue behavior of laminates on the reinforcement type. Fatigue tests are carried out in load-control regime for glass and hybrid (Kevlar + glass) fiber laminates. Fatigue curves are constructed in coordinates “stress – number of cycles until fracture” from the criteria corresponding to a drop in stiffness by 5 and 10%. Analysis of the results obtained permits evaluation of the effect of the stacking sequence and the reinforcement type on the behavior of cross-ply laminates in cyclic loading. The presence of Kevlar fibers accounts for nonlinear behavior of laminates in static tests and for low cyclic strength in fatigue tests under three-point bending
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    Experimental analysis of behavior and damage of sandwich composite materials in three-point bending. Part 2. Fatigue test results and damage mechanisms
    (2009) Bezazi, A.; El Mahi, A.; Berthelot, J. M.; Bezzazi, B.
    The analysis of stiffness degradation and the identification of damage mechanisms during and after fatigue tests of sandwich panels with PVC foam cores have been performed. The sandwich panels with cross-ply laminates skins made of glass fiber and epoxy resin were manufactured by vacuum moulding and subjected to three-point bending tests. Two PVC cores of similar type but with differing densities were investigated. The effect of core density and thickness on the damage behavior was highlighted. Using the cyclic life criterion, fatigue curves were plotted according to two models and compared with those of the literature. It has been demonstrated that the sandwich SD 2, with the higher core density, withstands a higher load and possesses greater rigidity in static tests, combined with an enhanced fatigue resistance, when compared to sandwich SD 1 which has a lower core density
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    Experimental analysis of behavior and damage of sandwich composite materials in three-point bending. part 1. static tests and stiffness degradation at failure studies
    (2007) Bezazi, A.; El Mahi, A.; Berthelot, J. M.; Bezzazi, B.
    The analysis of stiffness and the identification of rupture mechanisms during and after static tests of sandwich panels and their components have been investigated. The sandwich panels, having cross-ply laminates skins made of glass fibre and epoxy resin were manufactured by vacuum moulding and subjected to three-point bending tests. Two polyvinyl chloride cores of similar type but with differing densities were investigated. The effect of core density and its thickness on the behavior and the damage was highlighted. In terms of stiffness and load at failure, the sandwich structure has better mechanical characteristics compared to its components
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    Cross-ply laminates under static three-point bending : a numerical development model
    (2012) Benbelaid, S.; Bezzazi, B.; Bezazi, A.
    This paper considers damage development mechanisms in cross-ply laminates using an accurate numerical model. Under static three points bending, two modes of damage progression in cross-ply laminates are predominated: transverse cracking and delamination. However, this second mode of damage is not accounted in our numerical model. After a general review of experimental approaches of observed behavior of laminates, the focus is laid on predicting laminate behavior based on continuum damage mechanics. In this study, a continuum damage model based on ply failure criteria is presented, which is initially proposed by Ladevèze. To reveal the effect of different stacking sequence of the laminate; such as thickness and the interior or exterior disposition of the 0° and 90° oriented layers in the laminate, an equivalent damage accumulation which cover all ply failure mechanisms has been predicted. However, the solution algorithm using finite element analysis which implements progressive failure analysis is summarized. The results of the numerical computation have been justified by the previous published experimental observations of the authors