Experimental investigation of two-dimensional delamination in GFRP laminates

The 2D delamination behavior of composite laminates under quasi-static out-of-plane opening loading has been experimentally investigated. A circular embedded pre-crack was introduced in the center and at the midplane of the laminates. To investigate the effect of the fiber architecture on the fracture behavior, six different types of fabrics were selected. Increasing load-displacement curves were obtained due to the increasing crack front length during propagation. During the loading process, stiffening and softening mechanisms were activated. The stretching of the laminates, constituted the main stiffening mechanism that appeared and increased as the plate opened. Once the crack started growing, a corresponding softening due to crack propagation occurred together with a secondary stiffening mechanism, fiber bridging. These stiffness-related mechanisms were reflected in the compliance and clearly differentiate 2D- from 1D-delamination.