Fatigue and failure analysis of aluminium and composite automotive wheel rims: Experimental and numerical investigation

This paper deals with the adoption of composites in the design of the wheel rims of a sports car. With particular reference to cornering structural performance, the design of a composite wheel rim, produced via Resin Transfer Moulding (RTM) led to a reduction in mass and to an increase in bending stiffness. The adoption of alternatives to aluminium alloys allows the unsprung masses, as well as the total mass of vehicle to be contained. This paper provides a comprehensive view of the fatigue tests used for the wheel rim type-approval, followed by a rundown of wheel rims designed by Ferrari S.p.A from 2009 to present. These wheel rims have been classified in terms of mass and stiffness, and manufacturing process like casting, forging, or RTM. The failure modes of the reference Ferrari 488 GTB wheel rim were compared to those of the new composite wheel. In addition, the interpretation of the failures is supported by the results of Finite Element analyses. Though some initial defects led to a loss of stiffness of the wheel throughout the cornering fatigue test, the experimental results show that composite wheel rims are considered safe and they comply with the homologation targets and the Ferrari S.p.A. regulations.