Keiji Ogata

Research and Development of Damping Device for Light Weight Mechanical Structure Using Damping Effect Caused by Eddy Current

A base-isolation and vibration control technique has been applied positively to architectural and civil structures after Kobe earthquake, and now the techniques are adopted as general vibration reduction technique for many structures. In such situation, an application of the vibration attenuation device to the small-scale structure has been carried out actively in recent years. Especially, in the important institution of the cities such as a refuge place, a hospital, a school, an information and a communication institution where function maintenance is needed, it is important to maintain its performance of the machinery and equipment in the facility with an upgrade of structural seismic safety. Moreover, in the future, upgrading of seismic safety of the particular equipments is urgent business. This study has been examined a low cost and compact damping device for base-isolation system of light weight mechanical structures like a computer server rack. In this paper, the experimental and analytical results on the basic performances of the damping device using damping effect by Eddy-Current.Copyright

Study on Seismic Safety Improvement of Hanging Type Mechanical Structure in Industrial Facilities During Long Duration Earthquake

A lot of seismic damages of hanging type mechanical structure in industrial facilities were occurred in Great East Japan Earthquake, and the industrial functions stopped at many facilities. Moreover, fallen damage of mechanical structures from a hanging in architectural structure and the falling off of some elements in mechanical structures caused a secondary damage such as severed evacuation route. This study has been carried out to upgrade the seismic safety improvement of hanging type mechanical structure in several industrial and plant facilities from analytical and experimental approaches. In this paper, the experimental result in shaking table test is shown to investigate fallen mechanism of hanging type mechanical structure, and analytical results using nonlinear model with hysteresis damping is described. Furthermore, the evaluation of damage mechanism based on low cycle fatigue damage is conducted.Copyright

Performance Evaluation of Product Type Magnetic Damper Using Eddy-Current Damping Effect

Response control techniques such as a base-isolation and a vibration control have been a general vibration reduction system for upgrading of seismic safety or habitability improvement in civil and architectural structure after Kobe earthquake. In such state in Japan, an application of the vibration reduction device to a small-scale structure has been carried out actively in recent years. Especially, in the important institution of the cities such as refuge place, hospital, school, information and communication institution where function maintenance is needed, it is important to maintain its performance of the machinery and equipment in the facility with an upgrade of structural seismic safety. Moreover, in the future, upgrading of seismic safety of the particular equipments is urgent business. This study has been examined a compact and low cost damping device for a base-isolation system of light weight mechanical structures like a computer server rack. In this paper, experimental and analytical results on the performances of the product type damping device using damping effect caused by Eddy-Current are described.Copyright

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