Using Concentric Multilayer Liquid Dampers to Control Multimodal and Multidirectional Vibrations of Structures

Abstract

This study addresses the challenge of controlling multimodal and multidirectional vibrations in engineering structures during seismic events. Key considerations include accurate damping system modeling, design feasibility, seismic uncertainties, structural complexity, and cost-effectiveness. The research focuses on the concentric multilayer liquid damper (CMLD) for effective vibration control. Essentially, the CMLD consists of multiple tuned liquid column dampers arranged in a toroidal formation, nested within one another in layers. This unique configuration affords the CMLD exceptional vibration control properties: its toroidal design enables it to manage vibrations in any direction within the horizontal plane, while the multilayered nested structure allows for tuning different layers to various frequencies, thereby achieving multimodal vibration suppression. A generalized motion equation for the CMLD, integrated with a multidegree-of-freedom (MDOF) structure, is presented. The equation's reliability is confirmed by comparing its solutions with results from fluid–solid interaction simulations using computational fluid dynamics. A simple design methodology for CMLDs is proposed, aimed at controlling multimodal and multidirectional vibrations. The study uses 15 historical records of bidirectional seismic motions, each with five levels of intensity, to test the CMLD–MDOF structure system. Comprehensive analysis demonstrates the CMLD's effective vibration control performance.

Keywords

multidirectional vibration control / multilayer liquid damper / multimodal vibration control / passive control / seismic design

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