VARIABLE ANGLE TOW COMPOSITES FOR LIGHTWEIGHT AND SUSTAINABLE ABRIDGE DESIGN

The increasing use of composite materials in civil structures has led to a demand for designs that reduce environmental impact, extend service life and save costs. This study proposes the use of Variable Angle Tow (VAT) composite laminates to further improve the structural efficiency of civil structures, particularly bridge girders. VAT composite laminates have the unique ability to change fibre orientation pointwise over the structure, providing enhanced stiffness tailoring capabilities compared to traditional laminates where fibre angles are constant. To the best of our knowledge, this is the first study to investigate the use of VAT composite laminates in civil structures. Previous research has shown the success of VAT composites in aerospace engineering, where they have been used to tailor structures' stiffness and optimise their postbuckling behaviour. In this study, we show that the use of VAT composite laminates in bridge girders improves their buckling and postbuckling behaviours, increases their overall stiffness, and outperforms traditional straight fibre laminates. Numerical investigations using both in-house and commercial finite element software were conducted to assess the benefits of VAT composite laminates. Results from a multi-objective optimisation for different spans show that VAT composite laminates provide superior performance compared to traditional straight fibre laminates, thereby opening up new design scenarios for bridge structures.