Search

The detached houses, in general, have the first natural frequencies in relatively higher range, and their structural deflection is small even though their response acceleration is high. Therefore, the deformation transmitted to damper becomes small, and the dampers have to be designed to obtain a desirable performance against such small amplitude vibrations. For this reason, the new type of damper having the displacement amplification mechanism was developed to solve this problem in this study (“pipe-type-damper”). This paper reports on the results obtained from experiments and analysis of a detached house model using the dampers. In the experiments, the trial damper of 10kN capacity was made, and the experiments were performed to investigate the fundamental characteristics of the pipe-type-damper. As a result, the properties of the pipe-type-damper were expressed by the fractional derivative 3-element model, its restoring force was proportional to the second power of amplification factor by the amplification mechanism. Analytical results obtained by considering the characteristics of damper showed that the pipe-type-damper had good vibration control performance.

The detached houses have the first natural frequencies in higher range, and their structural deflection is small even though their response acceleration is high. Therefore, the deformation transmitted to damper becomes small, and the dampers have to be designed to obtain a desirable performance against such small amplitude vibrations. For this reason, the new type of damper having the amplification mechanism was developed to solve this problem in this study (“pipe-type-damper”). This paper reports on the results obtained from experiments and analysis of a detached house model using dampers. In the experiments, the trial damper of Itf capacity was made, and the experiments were performed to investigate the fundamental characteristics of pipe-type-damper. As a result, the properties of pipe-type-damper were expressed by the non-linear-4-element model, its restoring force was proportional to the second power of amplification factor by the amplification mechanism. Analytical results obtained by considering the characteristics of damper showed that the pipe-type-damper had good vibration control performance.

This paper describes three-dimensional isolation performance of seismic isolation system using air bearings. Long period seismic waves having predominant period of from a few seconds to a few ten seconds have recently been observed in various earthquakes. Also resonances of high-rise buildings and sloshing of petroleum tanks in consequence of long period seismic waves have been reported. Therefore the isolation systems having very long natural period or no natural period are required. In a previous paper [1], we proposed an isolation system having no natural period by using air bearings. Additionally we have already reported an introduction of the system, and have investigated horizontal motion during earthquake in the previous paper. It was confirmed by horizontal vibration experiment and simulation in the previous paper that the proposed system had good performance of isolation. However vertical motion should be investigated, because vertical motion varies horizontal frictional force. Therefore this paper describes investigation regarding vertical motion of the proposed system by experiment. At first, a vertical excitation test of the system is carried out so as to investigate vertical dynamic property. Then a three-dimensional vibration test using seismic waves is carried out so as to investigate performance of isolation against three-dimensional seismic waves.

Many types of dampers have been developed as seismic technique for architectural buildings, and some of these devices have been applied in Japan. In recent years, these dampers begin to be applied to the low-rise structures having the natural frequency in higher range. However, the deflection of low-rise structures is small, and the performance of damper isn’t obtained against small amplitude vibrations. In this study, the new type of damper which has the displacement amplification mechanism has been developed to solve the above problem. To amplify the displacement by applying the principle of leverage, the damper can achieve good performance even if the deformation transmitted to damper is small. This paper reports on the results obtained from loading test of the proposed damper and the vibration control performance of the proposed damper which was investigated by seismic response analysis.Copyright © 2008 by ASME

A seismic isolation floor using a new mechanism to achieve high performance in vertical isolation, was developed. The floor was a partially 3-dimensional isolation floor in which a vertical isolation table was incorporated in a horizontal 2-dimensional isolation floor. The table was suspended from pulleys by wire cables which were connected to coil springs installed horizontally. This mechanism was used to convert vertical movements of the table into horizontal deformations of the springs, and made it possible to provide the table with a very low natural frequency of 0.5 Hz or so. Excitation tests were carried out for an experimental model of the floor on which a computer component was mounted. Through the tests, it was confirmed that the floor had excellent performance in vertical isolation as well as in horizontal isolation. Analytical models for the horizontal and vertical responses of the floor were supported by the experimental results.

半導体製造設備など精密機器用の三次元免震装置として,直線運動機構を利用した水平二次元免震機構と機器取付用テーブルの水平維持が構造的に確保された鉛直動免震機構を組合せた免震装置を考案し,その実用化研究を行った.本論文では,一般には免震が困難と思われがちな空気ばね支持された機器のモデルなどを試作器に搭載して行った水平・鉛直二次元振動実験と応答解析を通して,本装置の振動特性と免震性能を明らかにしている.