본 연구에서는 동조액체기둥감쇠기의 비선형감쇠항을 등가점성감쇠항으로 치환한 등가선형 동조액체기둥감쇠기 모델을 유도하였으며 동조액체기둥감쇠기의 동적거동인 고유진동수와 감쇠비를 이론적으로 파악하였다. 동조액체기둥감쇠기에 일정한 전기장을 형성한 후 동조액체기둥감쇠기의 수직운동에 의해 발생되는 가변전압을 측정하여 수조 내부의 수위로 변환하는 식을 유도하였다. 또한 본 연구에서 제안한 동조액체기둥감쇠기의 수위측정 시스템의 타당성을 검증하기 위하여 고가의 전기 용량식 파고계와 비교 및 검증하였다. 마지막으로 본 연구에서 제안한 수위측정 시스템을 동조액체기둥감쇠기에 적용, 진동대 실험을 실시하여 고유진동수와 감쇠비를 파악하였고, 이론상의 고유진동수와 실험상의 고유진동수가 일치하였음을 확인하였으며, 진동수비 변화에 따른 동조액체기둥감쇠기의 감쇠비 변화를 확인하였다.

The objective of this study is to investigate design parameters of a tuned liquid column damper(TLCD), which is affected by various excitation amplitudes, through shaking table test. Design parameters of a TLCD are examined based on the equivalent tuned mass damper(TMD) model of a TLCD, in which the nonlinear damping of a TLCD is transposed to equivalent viscous damping. Shaking table test is carried out for a TLCD specimen subjected to harmonic waves with various amplitudes. Transfer functions are ratios of liquid displacement of TLCD and control force produced by a TLCD, respectively, with respect to the acceleration excited by a shaking table. They are derived based on the equivalent TMD model of a TLCD. Then, the variation of design parameters according to the excitation amplitude is examined by comparing analytical transfer functions with experimental ones. Finally, the dissipation energy due to the damping of a TLCD, which is experimentally observed from the shaking table test, is examined according to the excitation amplitude. Comparisons between test results and analytical transfer functions showed that natural frequencies of TLCD and the ratio of the liquid mass in a horizontal column to the total liquid mass does not depend on the excitation amplitude, while the damping ratio of a TLCD increases with larger excitation amplitudes.

The purpose of this study is to verify the transfer function of input acceleration and output control force based on linearizing a damping term of Tuned Liquid Column Damper(TLCD) with nonlinearity analytically. In addition, analysis is conducted for dynamic characteristics according to the design parameter such as section ratio of both vertical and horizontal column and the level of liquid in the vertical column which is used for tuning method. The dynamic characteristics is identified by the analysis for the natural frequency, damping ratio and effective mass ratio of TLCD and a shaking table test for the transfer function. The results indicates that the level of liquid and section ratio affect the characteristics of damping ratio and mass ratio. Damping and mass ratio increase as the section of vertical column of TLCD decreases due to turbulence in the elbow of TLCD.

본 연구의 목적은 첫째, 비선형성을 포함하는 액체기둥진동흡진기(LCVA)의 감쇠항에 대한 등가선형화된 운동방정식을 바탕으로하여 가진입력인 진동대 가속도와 출력인 제어력의 관계인 전달함수를 해석적인 식으로 규명하는 것이다. 둘째, LCVA의 주요설계변수인 수직기둥과 수평기둥의 단면적비의 변화에 따른 진동특성분석이다. 셋째, 동조의 수단으로 이용되는 수직기둥 액체의 높이를 변화시켜 진동특성을 분석하는 것이다. LCVA를 진동대 위에 설치하고 가진하여 제어력을 측정하여 실험 전달함수를 구하였다. 이것을 해석적인 전달함수와 비교 및 최적화작업을 수행하여 LCVA의 진동특성변수에 영향을 미치는 고유진동수, 감쇠비 및 질량비 등을 파악하였다. 실험결과, 액체 수위 및 단면적비의 변화에 따라 감쇠비 및 참여질량비의 특성이 변화하였다. 수직기둥과 수평기둥이 교차하는 엘보우에서 액체의 흐름 변화로 인하여, LCVA 실험체의 수직기둥 단면적이 작아질수록 감쇠비와 참여질량비가 증가하였다.

This paper presents equivalent linear system for 76-story benchmark building with nonlinear tuned liquid column damper (TLCD). The response characteristic of benchmark building for the deterministic wind loads is investigated. And then, the equivalent linear system is obtained first in terms of equivalent linear damping and second in terms of equivalent single degree of freedom system. Numerical results show that these equivalent linear systems can almost exactly predict the controlled structural responses when compared with the nonlinear TLCD system. Finally, an equation for estimating the peak response of structure subjected to harmonic load is derived. This equation does not require any iteration process which is essential in the analysis using equivalent linear system for TLCD.

Experimental investigation of the tuned liquid column damper (TLCD) is a primal factory task prior to its installation at a site and is mainly undertaken by a real-time hybrid simulation. In this study, a noncontact standalone vision sensing system is developed to replace a series of the conventional sensors installed at the TLCD tested. The versatile measurements of the system is theoretically and experimentally evaluated through a wide range of lab scale dynamic tests.