Circular delamination effects on buckling behaviour of the laminated composite plates with circular hole

II ABSTRACT In this study, the critical buckling loads depend on the delamination diameter around the hole and fiber rotation angles of the layers have been investigated in the rectangular laminated composite plates which have the circular hole in the centre and the circular delamination around the hole. In this investigation, the plate has been clamped from the two edges and the loaded uniaxially from the clamped edges. This investigation has been performed numerically and experimentally. The prepared laminated composite plates for the experimental studies have been become from eight layers (four symmetric layers). In the layers, woven glass fiber as fiber and epoxy as resin have been used. The width of the plates is 200 mm, the height of the plates is 160 mm and the thickness of the plates is 1,6 mm and the plates have a hole whose diameter is 0i=4O mm in the centre. The delamination diameter of these plates which have single delamination in the centre of the layers changes as 02=0 mm (without delamination), 02=80 mm, 02=120 mm and 02=16O mm. In the experimental studies, the loading has been applied only in the direction of 0 degree [0°] fiber orientation angle. Also for the numerical studies, three dimensional (3D) finite elements models which have a hole whose diameter is 0i=4O mm in the centre and the different delamination sizes in the centre of the layers have been established with assistance of ANSYS 6.1 finite element analysis program. Also, to investigate to the effect of the fiber orientation angle change, [0°]s, [15°]s, [30°]s and [45°]s fiber orientations have been analyzed. In this study, firstly, the comparison between experimentally results which were obtained from the prepared test specimens and numerical results of these testIll specimens has been done. Then, it has been seen that a good agreement between experimental results which were obtained and numerical results and in additional the numerical buckling load results of the other finite elements models which have different delamination diameters and different fiber orientation angles have been obtained. Finally of all of the numerical and experimental studies, it has been seen that the different fiber orientation angles affected the critical buckling loads and the important decreases in the critical buckling loads were occurred after a certain value of the delamination diameter.