Optimization of mode-I fracture toughness using the Taguchi method in cellulosic fiber-Grewia Optiva reinforced biocomposites

In this study, underutilized Himalayan natural fiber Grewia Optiva fiber of different lengths was used as reinforcement material. The Taguchi method was applied for the optimization of fiber length, fiber weight percentage, and fiber orientation for epoxy-based Grewia Optiva fiber reinforced composite. The influences of fiber weight percentage at four levels (10-35 wt%), fiber length at four levels (3-45 mm), and fiber orientation at two levels (unidirectional and random to the loading axis) on the mode I fracture toughness was investigated using L16 orthogonal arrays. It was found that the optimum conditions are 30 wt% of fiber, 45mm fiber length, and fiber orientated normal to the loading axis. The mode-I fracture toughness at optimum condition was found as 2.122 +/- 0.094 MPa root m. The tensile, flexural, and impact strength corresponding to optimum fiber, and composite processing conditions are 336.32%, 136.93%, and 308.28% higher as compared to pure epoxy. Scanning electron micrographs of the fractured surfaces indicate good bonding of fiber and matrix and show the major fracture mechanisms such as fiber pull-out and fiber-matrix debonding. The fiber breaking and matrix cracking are found as a minimum.