Integrated Multi-Physics Design of a GGG40 Agricultural Trailer Wheel Hub: Concurrent Topology Optimisation and CFD-Based Lubrication Enhancement

Wheel hubs in heavy-duty agricultural trailers operate under demanding conditions comprising rough terrain, impact loads, and highly variable load spectra. Current design practice relies predominantly on experience-based sizing rather than systematic multi-physics analysis. This study presents an integrated design methodology combining finite element analysis (FEA), density-based topology optimisation, and computational fluid dynamics (CFD) to concurrently improve the structural and tribological performance of a GGG40 spheroidal graphite cast iron agricultural trailer wheel hub. A reference commercial hub geometry was modelled and analysed under multiple load conditions with a safety factor of 5. Critical stress regions were identified, and the free design volume was optimised while preserving all functional surfaces. The optimised design achieved 35% mass reduction (14.9 to 9.6 kg), 30% lower maximum von Mises stress (235 to 165 MPa), and up to 40% stress reduction in the bearing seat region. Oil-circulation channels integrated into the bearing housing raised mean lubrication flow velocity by 28% and eliminated stagnation zones, yielding a more homogeneous oil-film distribution and directly benefiting bearing tribological performance. The proposed framework provides a manufacturable engineering methodology that concurrently addresses structural integrity and lubrication performance in agricultural wheel hub design.