Conceptualization design and analysis of lightweight composite rims for a formula student race car with a review of existing concepts

Abstract

This article presents a structured design process for lightweight carbon fiber rims tailored to an electric Formula Student race car. Unlike prior work that focuses mainly on geometry or material selection, the contribution here is an integrated design approach that enables geometry-invariant laminate sizing and is grounded in a structured review of existing CFRP rim and wheel concepts. The process includes the concept development, structural finite element analysis, and the integration of manufacturing considerations within a framework tailored to the resource and time constraints typical of Formula Student projects. This review clarifies typical mass savings, concept choices, and validation strategies and provides the reference frame for the subsequent design. Drawing on this review, three design solutions were evaluated: a composite rim with an aluminum center disk, a full composite spoke rim, and a full composite flange rim. Considering the integration with the existing vehicle architecture and manufacturing feasibility, the hybrid rim with a metallic center disk was selected. A suitable laminate design was achieved iteratively via finite element simulations to meet strength and stiffness requirements. The final configuration, a symmetric stacking sequence with alternating 0 and 45 plies of woven carbon fiber fabric, is governed by the displacement limits under the cornering load case. Safety margins against strength and fatigue failure were confirmed for all relevant Formula Student load cases. Eventually, manufacturability aspects were incorporated in an enhanced numerical simulation that reflects realistic ply draping and supports the preparation of tooling and layup definition. The developed rim satisfies the camber-angle stiffness requirement and maintains safety factors of approximately 1.5 in compression and 1.8 in tension and achieves weight savings of 49% compared to an aluminum reference. This reduction approximately halves the rim’s polar mass moment of inertia and, together with the 3% vehicle mass reduction, is expected to improve acceleration, braking response, and ride quality for the Formula Student car. Still, the main contribution of this article lies in a transferable methodology for CFRP rim design that combines the laminate design process with realistic manufacturing and vehicle integration constraints and is informed by the synthesized literature on composite rims for Formula Student and automotive applications.