Eyüp Yeter

The effects of cutouts on buckling behavior of composite plates

Abstract Cutouts such as circular, rectangular, square, elliptical, and triangular shapes are generally used in composite plates as access ports for mechanical and electrical systems, for damage inspection, to serve as doors and windows, and sometimes to reduce the overall weight of the structure. This paper addresses the effects of different cutouts on the buckling behavior of plates made of polymer matrix composites. To study the effects of cutouts on buckling, loaded edges are taken as fixed and unloaded edges are taken as free. Finite element analysis is also performed to predict the effects of different geometrical cutouts, orientations, and position of cutouts on the buckling behavior. The results show that fiber orientation angle and cutout sizes are the most important parameters on the buckling loads. For all types of cutouts the buckling loads decrease dramatically by increasing the fiber orientation angle. It is observed that minimum buckling load is reached when 45° fiber angle is used, and after this angle critical buckling load begins to increase. Also, it is concluded that while fiber orientation angle is 0°, elliptical cutout has the highest buckling load and while fiber orientation angle is 45°, circular cutout has the highest buckling load.

The effect of hybridization and boundary conditions on damping and free vibration of composite plates

Abstract In this study, the influence of hybridization on natural frequency and damping properties of laminated composite plates consisting of various combinations of fibers and boundary conditions are examined. Carbon (C), Kevlar® (K), and S-glass fibers are used as reinforcement with epoxy resin for hybridization. Experiments are conducted on hybrid composites under the combinations of clamped, free, and simply supported boundary conditions. Natural frequency analyses of hybrid composites are performed using finite element analysis software ANSYS. Vibration test results obtained from experimental and numerical studies are compared with each other. Results show that hybridizations with three different fibers and their substitutions in the layers have strongly effected the damping and vibration characteristics of composite plates.

Natural frequency response of laminated hybrid composite beams with and without cutouts

Abstract This study deals with the effect of hybridization on the natural frequency of woven laminated hybrid composite beams with and without cutouts under the clamped-free boundary condition. Woven carbon, Kevlar and S-glass fibers with epoxy were used for the production of hybrid composites. Natural frequencies of the hybrid composite beams were experimentally determined for [(0/90)3]S stacking sequence. Numerical analyses were performed to investigate the influences of fiber orientation angles, circular and rectangular cutouts, cutout size ratios and positions on natural frequency. Good agreement between experimental and numerical results was found from a comparison of natural frequencies. The results shows that the fiber type used in the layers, cutout size and position on the beam strongly effects the natural frequency.

Effects of cutouts on natural frequency of laminated composite plates

Abstract In this study, the effects of cutouts (circular, square, triangular and elliptical), cutout position and fiber orientations of laminated composite plates on natural frequencies are investigated. In order to study the effects of cutouts on natural frequencies of the composite plates, experiments have been carried out. Finite element analysis is also performed to predict the effects of different cutouts, cutout position, fiber orientation and length of the plate on natural frequencies for E-glass/polyester. Several outcomes and behavioral characteristics are discussed. These outcomes include the cutout shape, cutout orientation and fiber orientation angle. It has been seen that all of the experimental and finite element results are very close to each other. It has also been concluded that the natural frequency of composite plate is affected by the fiber orientation and cutout location but not considerably affected by cutout shape. The results show that fiber orientation angle and cutout location are the most important parameters on the natural frequency. When the fiber orientation angle increases, both bending and twisting natural frequencies decrease. Maximum natural frequency occurs on [(0/90)4]S laminated plate.