Buckling behavior of 1 × 1 rib knitting laminated plates with cutouts

The purpose of this study is to investigate the cutout shape effects on the buckling behavior of 1 × 1 rib knitting glass/epoxy laminated plates in three different knitting tightness levels as low, medium and high. The composite plate is produced five plies as [0°]5Course by using hand lay-up technique. In order to investigate the shape effects, five different plates are used such as, without cutout (W-C), central circular/elliptical cutout (C/E-C), central square/rectangular cutout (S/R-C), edge semi-circular/semi-elliptical cutout (SC/SE-C), and edge semi-square/semi-rectangular cutout (SS/SR-C). In addition, circular/elliptical diameter-to-plate width ratio and square/rectangular length-to-plate width ratio effects on buckling load of 1 × 1 rib knitting glass/epoxy plates are also investigated. The experimental buckling loads of plates are obtained by clamping from two edges and then these results are compared with the results calculated from the numerical analysis. ANSYS 10 commercial software is used for numerical study. A good agreement was obtained between finite element method and experimental measurements. Results are showed that the buckling loads depend on the cutout area and the level of tightness.