“Statistical Investigation of Parameters influence in fracture toughness of glass fibre reinforced composites

The objective of the work was to investigate statistical analysis of fracture toughness of the glass fiber reinforced composites at different stacking sequences, strain rate and crack length. The glass reinforced vinylester composites pre pared by hand layup technique with stacking sequences of 0/90, 45/-45 and chopped strand orientations. 3-point bending for fracture toughness test for various notch depth ratio’s as per linear elastic fracture mechanics concept was conducted. Further the initial notch depth method was adopted to find the critical stress intensity factor KIC for the given notch depth ratio. Design of experiment using Taguchi L9 array was formulated to understand the influence of parameters on fracture toughness. The result of surface methodology showed the stacking sequence of [45/ -45/0/90/Chopped]3s, with strain rate of 0.5 mm/min and without notch having the highest fracture toughness of 81.36 Mpam, when compared to Al 6061 alloy which has the fracture toughness of 33.09 Mpam. The specimens failed due to fiber pull out, de-bonding and also fiber breakage during the loading conditions, which was evident by SEM