Exploring the light-weighting potential of steel reinforced with FRP

In the drive for light-weighting in many industries, optimum material selection is at the forefront of research. The use and study of fibre reinforced composite (FRP) materials and light-weight metallics is especially prominent. It is widely recognised however that the continued use of steel has many advantages including cost, ease of fabrication and recyclability. A light-weighting opportunity exists for creating hybrids of steel and FRP possibly providing a solution to the ever increasing pressures exerted on automotive designers. Reinforcing steel with composites is not unknown. In many industries, aging metallic structures are already in use. Replacing them would be a costly and inefficient way of dealing with this aging (cracking, corrosion, wear, etc.), and retrospective reinforcement techniques using composites are sometimes used. This paper focuses on the characterisation of high strength automotive grade steel with a fibre reinforced polyamide (PA6 GF60) laminate. Initial characterisation of this hybrid was done by quasi-static three point bend testing on coupons of two thicknesses of steel. Using LS-DYNA, a model was created and validated against the mechanical testing results. The opportunity for down gauging of the steel has been shown in the mechanical testing as well as with the model, opening a wide range of applications. It has been found hybrids offer a 40 % increase in specific stiffness with respect to steel only. The project is ongoing and will continue to investigate an automotive substructure.