Determination of impact fracture toughness of polyethylene using arc-shaped specimens

This paper describes a methodology for the determination of the impact radial fracture toughness, GIC, of cylindrical polymeric molded parts using arc-shaped specimens. The proposed methodology is an extension of the ISO/DIS 17281 Standard which states that for brittle behavior, a basically linear relationship exits between the fracture energy, U; and the energy calibration factor, φ. This relationship allows calculating the critical strain energy release rate from the slope of the U vs. φ plot. An expression for the energy calibration factor, φ, for the arc-shaped specimen is proposed in this work, by combining tabulated functions and finite element results. The methodology is applied to test high density polyethylene arc-shaped specimens taken from cylinder walls.