Experimental investigation on the quasi-static structural properties of carbon fibre/metal hybrids processed by roll forming

Carbon Fibre Reinforced Metal Hybrid (CFRMH) materials combine high specific strength and stiffness with excellent fatigue resistance and damage tolerance. They are a potential solution for lightweight automotive crash and structural components, but their application is limited due to the lack of cost-effective manufacturing technologies. This study presents a new method for the manufacture of long steel components that are reinforced with a carbon fibre patch via roll forming, a low-cost sheet metal forming process that is heavily applied in the automotive industry. For this, CFRMH sheets are first produced in a hot press and then roll-formed to hollow components that are structurally tested in a 3-point bending test. The material deformation after roll forming and the failure modes after the structural tests are analysed with optical microscopy. The results of this study show that part quality and forming defects after roll forming depend on the carbon fibre orientation and the forming temperature. Depending on the carbon fibre layup, an increase in specific energy absorption of more than 45.6% was achieved compared to the sole steel counterpart. This was related to an intact adhesion at the carbon fibre–steel interface after roll forming, which allowed the carbon fibre patch to effectively absorb the deformation energy. The results suggest that roll forming presents a low-cost alternative for metal hybrid part production with significant potential to reduce weight and increase the structural performance of future automotive components.