Using Spiral Notch Torsion Test to Evaluate Fracture Toughness of Fiber-Reinforced Polymeric Composites

摘要

This paper studied the fracture behavior of fiberreinforced composites using the spiral notch torsion test. Cylindrical specimens of fiber-reinforced polymeric composites with spiral notches were fabricated along different orientations with respect to the fiber orientation. The critical loads upon failure under monotonic torsion were recorded at different loading rates. Fractographic characterization revealed novel failure patterns in the fiber-epoxy interfaces, including fiber-matrix delamination and alternative inter- and intra-circular cracks. By incorporating the mechanical properties of the fiber composites, finite element modeling was successfully applied to characterize the effect of material anisotropy on the stress contour around the crack tip for different specimens.