Movable-track nonlinear energy sinks with customizable restoring forces

This study introduces movable-track nonlinear energy sinks (MT-NESs) featuring customizable restoring forces. MT-NESs employ a novel track-spring configuration where the track parts themselves act as the movable mass, significantly reducing device dimensions and weight. The paper commences with the development of MT-NESs. A small-scale MT-NES is then experimentally realized on a two-story structure under impulsive excitation, validating the accuracy of the numerical model. Subsequently, a design example for seismic protection of the structure is presented, where the track shape, and thus the restoring force of the MT-NES, is designed for specific structure and excitation conditions. Comparative analyses with counterpart devices under seismic and impulsive excitations demonstrate the robust performance of the designed MT-NES, which closely aligns with the design objectives. This study underscores the flexibility of MT-NESs in generating customizable restoring forces within a compact configuration, positioning them as effective solutions for addressing control challenges beyond the capabilities of conventional mass dampers.