Incorporating the effects of liquid displacement exceedance and associated air entrainment in passive tuned liquid column damper design

Abstract

Traditionally, the optimization of tuned liquid column dampers (TLCDs) has favored larger length ratios (the ratio of the horizontal liquid column length to the total liquid column length), assuming they always yield better performance. However, this conventional approach often overlooks the vulnerability of TLCDs with large length ratios to strong vibrations, which can lead to air being drawn into the horizontal pipe and reducing damping efficiency. To address this, a novel two-phase design framework that treats the excitation intensity as a critical design parameter is proposed. This framework optimizes three key parameters: length ratio, area blocking ratio of the orifice (related to flow resistance), and frequency tuning ratio (the liquid-to-structure frequency ratio), while explicitly considering the negative impact of air entering the horizontal pipe on TLCD performance. The process begins with the use of closed-form solutions and numerical search methods, based on the classical TLCD model, to determine the optimized frequency tuning ratio in the frequency domain. Subsequently, a newly developed generalized TLCD model, which accounts for the effects of air entering the horizontal pipe, is employed to perform time-domain analyses across a wide range of excitation amplitudes and parameter combinations. The results identify the optimized length and blocking ratios that balance efficiency and robustness, revealing specific conditions under which conventional designs underperform. These findings provide a more realistic design philosophy for TLCDs, ensuring reliable vibration control performance under design excitation amplitudes, especially during high-intensity events.