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Summary This paper proposes a novel passive mass damper, namely, asymmetric nonlinear energy sink (Asym NES), which is characterized by integrating linear and nonlinear restoring forces to mitigate the unwanted responses of building structures. The Asym NES, configured based on a cubic NES, consists of an auxiliary mass connected to the primary structure through a linear and nonlinear springs. These two springs are statically balanced at a deformed position, producing an asymmetric restoring force in the Asym NES. The study commences with a detailed working principle of the Asym NES, and the equations of motion of an Asym NES‐attached system are derived. Subsequently, experimental studies on the Asym NES designed for a small‐scale three‐story steel frame are conducted; the natural frequencies of which can be altered by changing the number of columns per story. Moreover, the performance of the Asym NES is compared with a tuned mass damper (TMD) and a cubic NES under impulsive excitations. Test results demonstrate the effectiveness of the Asym NES as well as its robustness against changes in the structural frequency. Following the experimental studies, the validated Asym NES model is further applied in the numerical investigation on a six‐story benchmark building to highlight its effectiveness and robustness in potential practical applications. Besides the impulsive excitations, an ensemble of 106 seismic ground motions with wide‐ranged energies is applied to the structures with original and decreased frequencies. Numerical results show that the proposed Asym NES is as effective as the in‐tune TMD in response mitigation under seismic excitations and exhibits strong robustness against changes in both the energy level and the structural frequency. The ingenious design and excellent efficiency of the Asym NES can offer a promising type of high‐performance device for structural control under extreme events.

This paper presents a track nonlinear energy sink (track NES) and a single-sided vibroimpact track nonlinear energy sink (SSVI track NES) as effective control strategies to mitigate the seismic response of high-rise buildings. The study commences with the analytical models of the track NES and the SSVI track NES and the state-space description of the control system. Subsequently, single-objective and multi-objective optimizations are conducted, and the performance of these devices is evaluated comprehensively in terms of control effectiveness and economic factors when attached to a representative 32-story high-rise building. Numerical results show that the SSVI track NES exhibits strong robustness against changes in the structural stiffness and the input energy level. Compared with the track NES and tuned mass damper, the multio-bjectively designed SSVI track NES is shown to be the most cost-effective device because it has a very small stroke and requires only slight damping. The cost-effectiveness of the SSVI track NES is also demonstrated on a 20-story shearframe building. Additionally, the seismic performance of the SSVI track NES can be further improved by adjusting the position of the impact surface. Therefore, the track NES and, more so, the SSVI track NES can be designed as highly cost-effective control strategies and offer a promising solution for seismic response mitigation of high-rise buildings. KEYWORDSCost-effectiveness, high-rise building, multio-bjective optimization, single-sided vibro-impact, track nonlinear energy sink, tuned mass damper 1 | INTRODUCTION Structural control technologies have been widely recognized as effective solutions to enhance structural functionality and safety against natural and manmade hazards. Tuned mass dampers (TMDs) are one of the most commonly used passive vibration absorbers in engineering practice due to its relative simplicity. A TMD consists of a secondary mass connected to the controlled primary structure through a linear spring and a viscous damper. By resonating with the primary structure, the TMD is able to positively affect the dynamic property of the primary structure and dissipate energy effectively. Early applications of TMDs have been directed toward mitigation of wind-induced responses, especially for high-rise buildings and flexible structures. [1][2][3][4][5] Numerous studies have been dedicated to the optimal design of TMDs, [2][3][4]6] and there exists many examples of TMDs in super high-rise buildings, such as the Milad Tower [4] and the Shanghai World Financial Center Tower. [5] In recent studies, TMDs have also attracted interests in vibration control of structures under seismic excitations. Although a variety of numerical and experimental studies have been carried out to obtain optimal parameters of TMDs for seismic response mitigation, [6][7][8][9][10][11] shortcomings of TMDs for this purpose have also AMD Active mass damper DOF Degree of freedom EOM Equation of motion MR damper Magnetorheological damper MTMD Multiple tuned mass damper NES Non...