Tensile Strength Prediction of Fibre-Hybrid Composites: A Multiscale Approach (HyComp)

With the growing environmental concerns, lightweight structural designs are becoming increasingly important as they help meet the global emission regulations. Fibre-reinforced composites are the current state-of-the-art for lightweight structures and their use is rising exponentially in a wide range of applications from aerospace to sporting goods. They exhibit a range of useful material properties—notably specific stiffness and strength—whilst affording rich design flexibility. Fibre-hybridisation further increases the design space for tailoring and is a promising strategy for improving toughness and damage tolerance, which otherwise are low for traditional non-hybrid composites. By combining two or more fibre types, a better balance in mechanical properties is obtained which often leads to synergetic effects or to properties that neither of the constituents possesses. Due to these advantages, fibre-hybrid composites rapidly gaining market share in structural applications.
Even though fibre-hybrid composites are attractive, they also pose more challenges in terms of their strength predictions. Under tension, composites suffer a range of failures typically associated with fibre breakage, matrix cracks or interfacial issues; these mechanisms interact in a complicated way at a variety of physical length-scales. The added complexity of having more than one fibre type further increases the complexity in the modelling of mechanistic processes. Therefore, there is a need for developing a modelling framework to predict the strength of fibre-hybrid composites, considering the failure mechanisms on multiple length-scales. Using the model, one can understand better the influencing parameters on the failure of fibre-hybrids without the need for extensive experimental campaigns. Ultimately, this development may lead to novel materials that enable new applications, not possible at this moment.