Experimental study on Mode I interfacial fracture performance of wood-plastic composite panels reinforced by glass fibre-reinforced polymer

Wood-plastic composite (WPC) is a lightweight, corrosion-resistant material. Glass fibre-reinforced polymer (GFRP) reinforcement can effectively improve the mechanical strength of WPC, but the stiffness and deformation incompatibility between GFRP and WPC tends to induce interfacial fracture under loading. Mode I interfacial fracture occurs when high tensile stress is perpendicular to the interface, and investigations on Mode I interfacial fracture behaviour of GFRP-reinforced WPC are insufficient. In this study, double cantilever beam (DCB) tests were conducted to explore the interfacial fracture characteristics of GFRP-strengthened WPC panels. The effects of initial crack length and specimen width on crack growth and load-crack mouth opening displacement (CMOD) responses were systematically analyzed. The interfacial strain energy release rate (GI) was determined via compliance calibration method (CCM). The results indicated that interfacial cracks propagated along the pre-designed interface. A larger initial crack length corresponding to a lower peak load, induced a greater CMOD. Whereas a larger specimen width increased the peak load, but had little effect on CMOD. As the crack propagated to the range of 15–25 mm, GI stabilized within 1.17–1.24 N/mm. The steady-state strain energy release rate (GIR) was relatively insensitive to initial crack length and specimen width.