Modular QZS metamaterials with enhanced load adaptability for low-frequency vibration isolation

Abstract This study introduces a modular quasi-zero-stiffness (QZS) metamaterial for low-frequency vibration isolation with adaptable load-carrying capacity. The proposed structure integrates a double-curved beam as a negative stiffness element and two pairs of V-shaped springs as positive stiffness elements, forming an extendable modular metamaterial. These metamaterials provide scalable and tunable load-adaptive performance through multiple modular configurations. Finite element analysis is utilized to optimize the design parameters, ensuring effective and consistent QZS behavior across the modules. A dynamic model, validated using harmonic balance methods, demonstrates the isolation effectiveness under varying loads and excitation amplitudes. By arranging multiple unit modules in series, parallel, or combined configurations, the QZS characteristics scale in a linear and predictable manner, enabling versatile load adaptability and tunability. Quasi-static tests confirm the predicted QZS behavior, while dynamic tests validate the vibration isolation performance. A single unit module attenuates vibrations at 8.6 Hz with a payload of 1420 g, while the modular configuration achieves vibration suppression above 3.6 Hz with a payload of 5680 g, without requiring alterations to the design parameters. These findings underscore the potential of the proposed modular QZS metamaterial for scalable, load-adaptive, and low-frequency vibration isolation in engineering applications.