Performance-based optimization of inerter-assisted T-NESs considering SSI effects

Abstract

Track-Nonlinear Energy Sinks (T-NESs) are dynamic absorbers characterized by nonlinear restoring forces derived from their custom-designed curved track shapes. Given their ability to manage frequency changes resulting from damage, determining their optimal track shape within a Reliability-Based Design Optimization (RBDO) framework is advantageous, as it allows for a probabilistic assessment of damage scenarios across different limit states. Additionally, since Soil–Structure Interaction (SSI) also affects the host structure’s frequencies, it can amplify frequency shifts caused by stiffness degradation, thus impacting the optimal solution. Despite this, existing literature on T-NES optimization has yet to address SSI effects, even from a deterministic perspective. Moreover, while the integration of inerter devices has been extensively studied in traditional Tuned Mass Dampers (TMDs), more recently in Pendulum Tuned Mass Dampers (PTMDs) with circular tracks, and in spring-based Nonlinear Energy Sinks (NESs), their incorporation to enhance T-NES efficiency remains unexplored, even in deterministic studies, and is an open research area. Therefore, this article introduces a novel RBDO procedure for optimizing the track shape of inerter-assisted Track-Nonlinear Energy Sinks (T-NESIs) in buildings subjected to ground accelerations, taking into account SSI effects. The objective is to minimize the expected life-cycle damage costs associated with slight, moderate, and extensive damage limit states. A generic rational function, derived from the Padé expansion of the circle equation, is used instead of imposing fixed polynomial shapes with predetermined orders. The case study involves a 10-story building in Concepción, Chile. The results show that both T-NES and T-NESI significantly reduce life-cycle costs compared to an uncontrolled structure, with T-NESI outperforming T-NES.