Anti-impact performance of an STF-based shock absorber with countersink damping holes for gearbox

Abstract Gearboxes, as essential components of mechanical transmission systems, are extensively used in aerospace, automotive, and marine engineering. However, they are susceptible to shock and vibration under external impacts and complex operating conditions, necessitating effective energy dissipation solutions. Shear thickening fluid (STF), a non-Newtonian fluid characterized by remarkable impact resistance and energy dissipation capacity, was employed in this study to develop a novel shock absorber incorporating countersink damping holes. This design utilizes both the intrinsic energy dissipation of STF and the additional frictional dissipation induced by the countersink structure. The energy absorption mechanism of the STF-based shock absorber was investigated through compressive and impact tests. The absorber was integrated into a gearbox impact isolation system, and its maximum isolation efficiency reaches 86% under shock resistance tests, demonstrating the STF-based shock absorber’s high impact mitigation capability. This work proposes a structural enhancement for STF-based shock absorbers used in the gearbox system and validates their practical applicability in dynamic mechanical protection systems.