Abstract: Inspired by the loofah sponge’s axially continuous porous core and peripheral hexagonal scaffold, we propose a compact bio-inspired low-frequency vibration isolator. An analytical static model reveals a Quasi-Zero-Stiffness (QZS) region produced by parallel coupling of an axial positive-stiffness spring and a nonlinear hexagonal link–spring unit. A Lagrangian dynamic model and ADAMS multibody simulations predict resonance and transmissibility and are validated by sinusoidal base-displacement tests. With a 5.775 kg payload, the prototype achieves effective isolation above ~?5 Hz and ~?25–30 dB attenuation at 20–22 Hz while retaining comparable load capacity to linear references of similar size. Compared with linear isolators, the designed bio-inspired low-frequency vibration isolator exhibits a lower isolation onset and a broader useful bandwidth under a compact footprint, offering tunable low-frequency isolation via geometric and stiffness parameters (α, k₁, k₃, l).

Key words: Nonlinear dynamics')">Nonlinear dynamics, Vibration isolation, Bio-inspired structure, Loofah sponge