The performance of a concept 3D printed carbon fibre-reinforced polymer mono-parabolic leaf spring

For decades, steel leaf springs have been widely used in automotive suspension systems but concerns over emissions and fuel efficiency remain. Fibre-reinforced composite leaf springs have emerged as a promising alternative due to their excellent strength-to-weight ratio, stiffness, and energy absorption. This study explores the feasibility of using a novel 3D-printed carbon fibre reinforced polymer (CFRP) mono-parabolic leaf spring (PLS) to replace conventional steel springs and reduce vehicle weight. It combines experimental testing, theoretical analysis, finite element modelling using equivalent homogenous material properties, and Scanning Electron Microscopy (SEM) analysis to establish the feasibility of lightweight 3D-printed CFRP leaf spring for automotive applications. A steel multi-leaf spring was mechanically tested, theoretically analysed, and simulated using finite element analysis (FEA), achieving 98.68% accuracy between simulated and actual deflection forces. A CFRP mono-PLS was then designed, 3D printed with optimised fibre reinforcement using Eiger simulations and mechanically tested. An FEA model based on equivalent homogeneous material (EHM) properties was developed, alongside theoretical analysis. Scanning electron microscopy (SEM) was used to examine the microstructure of the printed material. Whilst the results demonstrated significant weight savings with the CFRP spring over steel, the carbon-epoxy spring achieved almost the same weight saving whilst vastly outperforming CFRP in stiffness and maximum bending stress. There are a number of future research opportunities for 3D printing CFRP.