• 한국자동차공학회논문집
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• 제8권1호
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• pp.163-171
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• 2000

The aim this study is to provide fundamental informations for the development of magneticfluid damper. To achieve the aim. the damping effect of magneticfluid is investigated by experiments that the diameter of inner circular bar and the input amplitude vary in the magnetic field generated by the permanent magnet and the electromagnet. From the study, the following conclusive remarks can be made. As the diameter of inner circular bar and the input amplitude increase. the damping effect is improved. And we can know that as the contact area between inner circular bar and magneticfluid increases, damping ratio is improved. Also we consider the cases that there is magnetism generated by electromagnet and DC voltage is supplied to electromagnet from 10V to 50V by 10V. In these cases, the amplitude ratio decreases sharply from 1.8 1.0 And for these cases, the damping ratio is .745.

• 한국소음진동공학회논문집
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• 제25권12호
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• pp.856-865
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• 2015

In a high-speed press, numerous moving links are interconnected and each link executes a constrained motion at high speed. As a consequence, high-level dynamic unbalance force and unbalance moment are transmitted to the main frame of the press, which results in unwanted vibration and significantly degrades manufacturing accuracy. Dynamic unbalance force and unbalance moment inevitably transmits high-level vibrational force to the foundation on which the press is installed. Minimizing the vibrational force transmitted to the foundation is critical for the protection of both the operators and the surrounding structures. The whole task should be carried out in two steps. The first step is to reduce dynamic unbalance based upon kinematic and dynamic analyses. The second step is to design and build an optimal vibration isolation system minimizing the vibrational force transmitted to the foundation. Firstly, the dynamic design method is presented to reduce dynamic unbalance force and moment. For this a 3D CAD software was utilized and a computer program was written to compute dynamic unbalance force and moment. Secondly, the design method for vibration isolation system is presented. The method for designing coil springs and viscous dampers are explained in detail.