On the Interfacial Fracture Mechanics of Long-fibre Reinforced Polymer Composites

Fibre-reinforced polymer composites are being widely adopted as the de facto material for automotive lightweight design, but lack the material models capable of accurately predicting fracture. To address this research gap, three large-scale experimental studies are undertaken to characterize thermoset polymers during cure, understand the fibre-matrix interfacial bond strength, and predict the fracture of random long-fibre composites via the energy of fracture. In conjunction with the Fraunhofer Project Center in London, Ontario, sample sheet moulded composites were used to verify the key findings with several industrial composite samples. With refined interfacial strength measurement methods, and accurate predictions of the composite residual strength, the fracture toughness of composites has been more accurately determined than previous research. These improvements directly translate to improved material and fracture models for fibre reinforced polymer composites. It is thus determined that utilizing the interfacial strength of a composite, failure can be predicted with increased confidence