An experimental study on the influence of intralaminar damage on interlaminar delamination properties of laminated composites

Coupling between intralaminar and interlaminar damage plays a significant role in accurately predicting delamination and final failure. However, insufficient experimental data are available for models of this phenomenon. In this paper, we proposed a two-step experiment on cross-ply laminates to quantitatively study the influence of in-plane strain on the interlaminar fracture toughness. First, we performed a tensile test on the [0₂/90₂]_s cross-ply laminates to introduce various extents of intralaminar damage. Next, we bonded a backing adherend of [0₆] plies to the cross-ply, so we could probe the delamination properties through a subsequent double cantilever beam (DCB) test. We identified the effective fracture toughness G_c,eff by the compliance calibration method. We found that intralaminar damage promotes fiber bridging in the transverse direction, which finally influence the out-of-plane properties significantly.