Experimental investigation of fracture toughness in injection molded long fiber reinforced thermoplastics

The variations of fracture toughness K-c in injection molded 50% E-glass long fiber reinforced polypropylene are investigated. Plaques at different sets of processing conditions have been produced and specimens have been obtained at preselected spatial locations, both in the in-flow and cross-flow directions. The effect of part morphology, which consists of through-thickness layers, was evaluated experimentally by measuring the fracture toughness at locations where a crack initiation is produced prior to the measurement. The results show a strong effect of processing conditions and spatial locations on the fracture toughness as a result of variations in the through-thickness layered structure.