Design Optimization of a Hybrid Spur Gear Including Tooth Bending Effects

A multiobjective design optimization technique for hybrid gears with sinusoidally shaped interlocks has been developed and applied to a hybrid spur gear. The hybrid gear concept consists of a metallic outer ring to support high tooth contact stress bonded to a composite inner web for weight reduction. Three design objectives were minimized for various geometric parameters controlling the composite–steel interface. Borg MOEA, a multiobjective evolutionary algorithm, was used to generate Pareto-optimal solutions for this design problem. Candidate designs were chosen from the Pareto-optimal set for more detailed analysis. From the results, we infer that the spur hybrid gear studied herein has the potential to decrease gear weight by approximately 27–45%, at the expense of a 22–34% increase in tooth pitch-point deflection, and that the optimal interface has between 15–20 cycles of the sinusoid with an amplitude of 0.25–0.35 mm.