Energy absorption mechanisms during dynamic fracturing of fibre-reinforced composites

Abstract

Dynamic photoelastic experiments were conducted to study crack propagation in fibrereinforced materials and, in particular, to determine the energy losses occurring during the crack growth and arrest process. This study utilized modified compact tension specimens which were fabricated from polyester matrix and different reinforcing fibres. The effect of the fibre-matrix interface on energy absorbed was also studied. The energy absorbed was partitioned into two parts: that absorbed in the fracture process zone associated with the crack tip, and the energy lost outside this zone. Results show that fibre reinforcement reduces the energy absorbed in the fracture process zone by about 10% for well-bonded and 15% for partly debonded fibres. For the same initial strain energy, this reduction in fracture energy manifests itself in reduced K _ID and lower crack-jump distance as compared to monolithic specimens. Reinforced specimens are found to retain a higher strain energy after crack arrest. The energy absorbed outside the fracture process zone for monolithic and well-bonded fibres is about 45% of the initial strain energy, while for partly debonded fibres it is about 55%.