Lightweight Optimization of a Steering Knuckle for Additive Manufacturing: Experimental Characterization and Numerical Assessment

The increasing demand for lightweight components has intensified interest in additively manufactured aluminum alloys and structural optimization strategies. This study investigates the lightweight optimization of a Formula SAE steering knuckle intended for laser-based powder bed fusion of metals (PBF-LB/M) through an integrated methodology combining experimental material characterization, manufacturing-process simulation, finite element analysis, and geometry optimization. PBF-LB/M-fabricated AlSi10Mg and AlSi10Mg/SiC specimens were experimentally characterized through tensile and comparative high-cycle fatigue testing, while Charpy impact testing and fractographic analysis were performed on the AlSi10Mg/SiC composite. The experimental results indicated that SiC reinforcement did not improve mechanical performance under the investigated processing conditions, highlighting the potential influence of reinforcement dispersion, interfacial integrity, and process-induced heterogeneities. Component-level numerical investigations were conducted exclusively for AlSi10Mg. The PBF-LB/M manufacturing process was simulated using Simufact Additive to assess residual stresses and geometric distortion following support and base-plate release. Subsequently, structural finite element analysis under representative Formula SAE loading conditions provided the basis for geometry optimization. The optimized steering knuckle achieved a 45.1% mass reduction, from 1.13 to 0.62 kg, with a maximum von Mises stress of approximately 89 MPa and a minimum safety factor of 2.52 under the investigated static loading conditions. These findings demonstrate the potential of combining experimental material characterization with process simulation and structural optimization for lightweight AlSi10Mg components. The AlSi10Mg/SiC results are limited to specimen-level characterization, and its component-level structural performance remains to be investigated.