Seismic performance and adaptive control mechanisms of inter-story isolated structures equipped with nonlinear negative stiffness devices

Zhang, Yafei, Hu, Yuchen, Li, Liping, Ji, Guangyao, Fu, Changrong and Sun, Li 2026. Seismic performance and adaptive control mechanisms of inter-story isolated structures equipped with nonlinear negative stiffness devices. Structures 88 , 111903. 10.1016/j.istruc.2026.111903

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Abstract

This study investigates the seismic response of inter-story isolated structures (IIS) equipped with nonlinear negative stiffness devices (NNSD), addressing the limited application of semi-active NNSD control strategies in such systems, as most existing studies have focused on passive configurations. A suite of ground motions with different frequency contents, intensity levels, and temporal distribution patterns (e.g., single-peak and multiple-peak records) is considered. Nonlinear time-history analyses are conducted to compare two control schemes: the passive NNSD (P-NNSD), which operates at a fixed compression ratio, and the displacement-triggered semi-active NNSD (DTSA-NNSD), which adjusts its compression ratio in stages according to the isolation story displacement. Key response indices include isolation story displacement, superstructure acceleration, and device force demand. Both schemes reduce isolation displacement and superstructure acceleration relative to the uncontrolled system, while DTSA-NNSD shows consistently better performance within the considered IIS configuration and ground motion set, achieving reductions of up to 40% in isolation displacement and up to 30% in superstructure acceleration. The control efficiency depends on ground motion characteristics: records with multiple separated acceleration peaks benefit more from DTSA-NNSD, whereas motions dominated by a single concentrated peak exhibit limited acceleration reduction. Hysteresis results indicate that DTSA-NNSD behaves similarly to P-NNSD below a prescribed displacement threshold; once exceeded, it switches to a low-compression-ratio state and mobilizes larger negative-stiffness forces. This adaptive activation reduces the effective stiffness of the isolation story, limits seismic energy transfer to the superstructure, and promotes energy dissipation by enabling the inherent damping of the isolation system to be more effectively mobilized. DTSA-NNSD thus enables “on-demand” negative stiffness and offers a promising semi-active control framework whose broader applicability and implementation feasibility warrant further validation.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Schools > Engineering
Additional Information:	License information from Publisher: LICENSE 1: URL: http://creativecommons.org/licenses/by-nc-nd/4.0/, Start Date: 2027-04-21
Publisher:	Elsevier
ISSN:	2352-0124
Date of Acceptance:	15 April 2026
Last Modified:	29 Apr 2026 09:00
URI:	https://orca.cardiff.ac.uk/id/eprint/186695

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