A comparative investigation of static and dynamic behaviors in hybrid metal-composite and steel helical gears

The aim of this work is to provide in-depth examination of metal-composite hybrid gears that successfully merge significant weight reduction with improved or maintained Noise, Vibration, and Harshness (NVH) properties. A nonlinear finite element method was employed for designing hybrid gears, optimizing mass reduction and Static Transmission Error (STE) as main source of excitation. Experimental methods, including static and dynamic transmission errors, run-ups, and transmitted vibrations were analyzed to compare hybrid gear pairs with their steel counterpart. Results demonstrated significant discrepancies in vibration characteristics between standard and hybrid gear pair configurations. Notably, the hybrid configurations, particularly the innovative solution incorporating a viscoelastic layer, showed superior performance in vibration dampening despite being 50% lighter than its steel counterpart. The research underscores the inherent differences between hybrid and standard gears, relating the observed behaviors to static and dynamic excitations and their impact on the energy distribution between meshing harmonics. Findings suggest that hybrid gear pairs offer a potential pathway for improving noise and vibration comfort in mechanical systems without compromising on weight reduction.