Tomoyoshi Watakabe

Research and Development of Vibration Control Device by Using Displacement Amplification Mechanism

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

Research and Development of Locally Installed Dampers Suitable for Industrial and Non-Industrial Structures by Using Displacement Amplification Mechanism

In Japan, many types of dampers are installed into various structures to reduce excessive responses during earthquakes. The demand for high performance, low cost dampers with wide range of applicability requires new developments in this area. This paper describes two new types of dampers using the displacement amplification mechanism. One of the dampers is designed to be installed in the connection of a column and a beam (“connecting-corner-damper”). The other is a damper of brace type, which enables to reduce the brace strength economically by adding the spring tension (“brace-damper”). Both dampers are designed to transmit displacements efficiently, and economically. This paper reports on the static loading test performed to investigate the fundamental characteristics of the viscoelastic material used as damping material in two dampers. Also, it describes the earthquake response analysis of an actual structure using dampers. The experimental results confirm that the viscoelastic material used in two dampers has displacement-, frequency- and temperature-dependent properties. The properties of the viscoelastic material are described by the non-linear-4-element model. Analytical results obtained by considering the characteristics of the viscoelastic material and the effect of the amplification mechanism principle confirm that each damper has good vibration control performance.Copyright