Assessment of delamination growth due to matrix cracking in hybrid Glass-Kevlar composite laminates using experimental, numerical and analytical methods

In this study, the growth of induced delamination in off axes composite laminates has been investigated. Glass-Epoxy composite laminates and Glass-Kevlar-Epoxy hybrid composite laminates with cross-ply [0₄/90_n]_s and angle-ply [30₄/90_n]_s and [45₄/90_n]_s composite layup, containing a low density matrix crack in 90° layers have been made. Then they have been subjected to tensile loading in experimental tests in order to investigate the growth delamination from the location of the matrix cracking and to measure the stiffness degradation. The experimental observations reflect the effects of hybridization and staking sequences on the induced delamination growth for the first time. In addition, the growth of delamination in the considered composite laminates have been studied numerically in ABAQUS software using the cohesive zone method and the required fracture energy for the analysis was obtained using relative characterization test. Finally, using a simple analytical model, the stiffness degradation due to the growth of delamination was calculated and compared with the experimental and numerical results. The obtained results reveal the employing the Glass-Kevlar-Epoxy hybrid laminate enhances the stiffness as well as the capacity of delamination growth in comparison with Glass-Epoxy with the same thickness.