in design and optimization process of laminated composite structures, the number of layers, layer angles, stacking sequence, material types and etc should be specified. each of aforesaid parameters can be applied as a design variable. in this paper the target is to minimize the weight of laminated composite pin loaded structures. the laminated composite structures are designed based on the load...

Fourteen composite honeycomb sandwich panels were tested to failure under compressive loading. The test specimens included panels with both eight and twenty-four ply graphite-bismaleimide composite facesheets and both titanium and graphite-polyimide core materials. The panels were designed to have the load introduced through fasteners attached to pairs of steel angles on the ends of the panels ...

This paper describes the experimental investigation on the effect of ply thickness on the first ply failure, delamination, and the subsequent final failure of graphite/epoxy composite laminates. The laminates considered in this paper are a cross-ply and two quasi-isotropic laminates containing thin plies in the desired interface. The onset of the first ply failure and delamination, and the stre...

A continuum damage model for the prediction of the onset and evolution of intralaminar failure mechanisms and the collapse of structures manufactured in fiber-reinforced plastic laminates is proposed. The failure mechanisms occurring in the longitudinal and transverse directions of a ply are represented by a set of scalar damage variables. Crack closure effects under load reversal are taken int...

Foam core sandwich composites are widely used in primary structural components of launch vehicles and spacecraft. These structures exhibit complex failure modes and are highly sensitive to butt-joints, core mismatches, impact damage, voids, and facesheet delaminations. 3D Fiber Reinforced Foam Cores (3DFRFC) represent a new class of core material designed to replace standard foam core in future...

This paper presents the application of micro/macromechanics models and optimization techniques for the optimum design of pultruded glass fiberreinforced plastic composite I-beams with respect to material architecture: fiber orientations and fiber percentages. The beams are subjected to transverse loading, and beam deflection, buckling resistance and material failure are considered as multiple o...

Results of an analytical and experimental study to characterize the structural response of two compression-loaded variable stiffness composite panels are presented and discussed. These variable stiffness panels are advanced composite structures, in which tows are laid down along precise curvilinear paths within each ply and the fiber orientation angle varies continuously throughout each ply. Th...

The first form of damage in composite laminates is often matrix microcracks that are defined as intralaminar or ply cracks across the thickness of the ply and parallel to the fibers in that ply (see reviews in [1,2]). Tensile loading, fatigue loading, environment, and thermal cycling can all lead to microcrack formation. Microcracks can form in any ply that has a significant component of the ap...

Experimental and theoretical approaches are studied via the first-ply failure strength on anti-symmetrically laminated composite elevated floor plates with various length-to-depth ratios, aspect ratios, and optimal fibre orientations subjected to central point loads. Optimal angle-ply orientations of anti-symmetric [θ/ − θ . . .]−S laminated composite plates designed for maximum stiffness were ...