• 대한기계학회논문집
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• 제18권9호
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• pp.2477-2485
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• 1994

Air damper has a great advantage that is independent of temperature change. This paper presents an analysis approach and an application for designing nonviscous air damper with a piston and a cylinder. The objective functions for optimum design is damping coefficient and is maximized by changing two design variables that are length between piston and cylinder and orifice diameter. A digital computer program was developed which determines optimal air damper configuration for maximum damping coefficients. The results were applied to the automatic washer and are confirmed to be valid for the range of operating conditions.

• 한국도로학회논문집
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• 제10권2호
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• pp.27-33
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• 2008

다양한 지반의 모델들을 이용한 감쇠 거동을 식제 지반의 감쇠 거동과 비교하였다. 지반의 감쇠 거동을 예측하기 위해 몇 가지 비선형 지반 모델들을 이용하고 평가하였다. 지반 거동을 대략적으로 잘 묘사하기 위해 비점성 감쇠 및 이력감쇠 거동은 모두 고려하는 복합 감쇠 모델이 개발 되었다. 이 모델의 장점 및 문제점이 논의 되었다.

• 한국지진공학회논문집
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• 제18권6호
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• pp.279-289
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• 2014

Considering a rigorously fluid-structure interaction, a method for an earthquake response analysis of a floating offshore structure subjected to vertical ground motion from a seaquake is developed. Mass, damping, stiffness, and hydrostatic stiffness matrices of the floating offshore structure are obtained from a finite-element model. The sea water is assumed to be a compressible, nonviscous, ideal fluid. Hydrodynamic pressure, which is applied to the structure, from the sea water is assessed using its finite elements and transmitting boundary. Considering the fluid-structure interaction, added mass and force from the hydrodynamic pressure is obtained, which will be combined with the numerical model for the structure. Hydrodynamic pressure in a free field subjected to vertical ground motion and due to harmonic vibration of a floating massless rigid circular plate are calculated and compared with analytical solutions for verification. Using the developed method, the earthquake responses of a floating offshore structure subjected to a vertical ground motion from the seaquake is obtained. It is concluded that the earthquake responses of a floating offshore structure to vertical ground motion is severely influenced by the compressibility of sea water.