Translaminar mode-I fracture toughness experiment of pultruded GFRP laminates using extended compact tension specimen

This paper conducted experiments and theoretic analysis of the fracture performance of pultruded GFRP (Glass Fiber Reinforced Polymers) laminates. The mode-I fracture toughness of pultruded GFRP laminates was evaluated by the eccentrically loaded, Extended Compact Tension (ECT) specimen. The geometry of specimen and experimental procedure refer to ASTM E1922. A total of 16 specimens were tested, which included 0 degrees and 90 degrees roving orientation. Finite element analysis with the Virtual Crack Closure Technique (VCCT) was implemented to calibrate the experimental results. A correction function for normalized notch length was proposed for pultruded GFRP translaminar fracture toughness. Carpet plot was designed to discuss the relationship between fiber volume ratio and fracture toughness, which demonstrated that the fracture toughness strongly correlated with the fiber volume ratio. Also, the effect of fraction of 0 degrees layers on fracture toughness and material orthotropy was studied. The relationship of material orthotropy parameter and fracture toughness was discussed.