The Effects of Circular Cutout and Hybridization to the Failure Behavior of Graphite Epoxy and Kevlar Epoxy Composite Laminates

This paper aims to investigate the effects of circular cutout and hybridization to the failure behavior of Graphite Epoxy and Kevlar Epoxy composite laminates under uniaxial tension. The composite laminates made of Graphite Epoxy, Kevlar Epoxy and their hybridizations were modelled using commercially available finite element analysis software, ANSYS APDL. The laminates were modelled without and with circular cutout. Using the available built-in failure criteria function, the failure loads for all cases were determined for various angles of fiber orientation. The laminate was having the lamination scheme of [θ₄/0₄/−θ₄]_s and failure at every increment of 10° angle, where θ, ranges from 0 to 90° were analyzed. Numerical validations were also carried out prior to the failure analysis. It is obvious that the cutout significantly weaken the laminates but it is interesting to observe that arranging fiber angles 45–90° could slightly improve the laminates, compared to smaller fiber angles. In contrary, the hybridization does not have significant effect on failure behavior of Graphite Epoxy and Kevlar Epoxy composite laminates, nevertheless it provides options to balance between strength and material costs. In all cases, the generated failure curves suggested that the failure behavior of composite laminates is very much dependent on the angles of fiber orientation. In terms of the effect of cutout, it is found that the cutout reduced the strength of the laminates significantly compared to the laminates without cutout. Nevertheless, there is slight improvement of strength when the fiber angle, θ, is arranged between 20 and 90°. The findings prove that the current study is useful and this knowledge could be expanded in designing composite laminates.