• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 춘계학술대회논문집
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• pp.115-120
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• 2001

A gyroscope is a rotating body possessing one axis of symmetry and whose rotation about the symmetry axis is relatively large compared with the rotation about any other axis. Tuning fork is this type of structure that various modem gyro-sensors are based on. In this paper, dynamic behavior of a cantilevered beam subjected ta a base rotation with respect to the eccentric axis that is parallel to the beam axis is analyzed. The final equations of motion in terms of generalized coordinates can be solved with numerical scheme with various values of angular velocities and angular accelerations of the rotating axis. In contrast to the case of rotating cantilever beam like helicopter blade, the rotational motion with respect to the beam axis has effect to decrease the stiffness of the beam and has unstable region depending on the magnitude of the rotational angular velocity and angular acceleration.

• 한국디지털건축인테리어학회논문집
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• 제11권4호
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• pp.39-46
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• 2011

This Study is about the Axis used for creating forms of interior spaces in representative works of Peter Eisenman architecture. The plans, elevations, photos of interior spaces of his architecture were collected and analysed. In conclusion, the methods using axises were classified in the axises crossing right angle and the rotating axises crossing right angle. The rotating axis were divided into one-angle rotating and multi-angle rotating. The axises were rotated on the plan or rotated on the elevation. The axises crossing right angle were used for dividing, assembling, transforming and composing different proportions of rectangles in interior spaces. The rotating axises crossing right angle were used for creating divers forms such as triangle, quadrilateral, and polygon. The one-angle rotating emphasizes directions of axises in interior spaces. The multi-angle rotating emphasizes decentered directions in interior spaces. The parts created while crossing axises three-dimensionally were opened or filled. The axises were used dynamically and three-dimensionally for diversity of forms in interior spaces of Peter Eisenman architecture.

• 한국유체기계학회 논문집
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• 제11권3호
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• pp.43-49
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• 2008

The pump control valve is a butterfly valve that has an eccentric rotating axis. It is not only used as a butterfly valve to control the flow rate or pressure, but also as a check valve to prevent backward flow. A new design method of eccentric rotating axis is proposed to design the valve. The height of the rotating axis is determined through flow field analysis. A general purpose of computational fluid dynamics software system, Fluent is used to simulate the fluid flow. Flow field analysis is performed for various heights of the rotating axis and different opening angles of the valve. A characteristic function is defined for estimating the flow characteristics based on the results of flow field analysis. The characteristic function is defined in order to determine the height of the rotating axis. An optimization problem with a characteristic function is formulated to determine the amount of eccentricity. The height of the Totaling axis of the valve is determined through solving the optimization problem.

• 대한기계학회논문집A
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• 제25권4호
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• pp.645-653
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• 2001

It is well known that natural frequencies increase when a cantilever beam rotates about the axis perpendicular to its longitudinal axis. Such phenomena that are caused by centrifugal inertia forces are often referred to as the stiffening effects. Occasionally it is necessary to control the variation of a natural frequency or the maximum stress of a rotating beam. By changing the thickness of the rotating beam, the modal or the stress characteristics can be changed. The thickness of the rotating beam is assumed to be a cubic spline function in the present work. An optimization method is employed to find the optimal thickness shape of the rotating beam. This method can be utilized for the design of rotating structures such as turbine blades and aircraft rotary wings.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 춘계학술대회논문집A
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• pp.643-648
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• 2000

It is well known that natural frequencies increase when a cantilever beam rotates about the axis perpendicular to its longitudinal axis. Such phenomena that are caused by centrifugal inertia forces are often referred to as the stiffening effects. Occasionally it is necessary to control the variation of a natural frequency of a rotating beam. By changing the thickness of the rotating beam, the modal characteristics can be changed. The thickness of the rotating beam is assumed to be a cubic spline function in the present work. An optimization method is employed to find the optimal thickness shape of the rotating beam. This method can be utilized usefully for the design of rotating structures such as turbine blades and aircraft rotary wings.

• 한국소음진동공학회논문집
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• 제24권2호
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• pp.131-138
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• 2014

Vibration measurement of rotating shafts by installing sensors such as accelerometers or displacement sensors is costly and dangerous in some cases. As an alternative method, vibration measurement using camera images has been researched because sensor installation is not needed and displacement of a rotating shaft can be directly evaluated. This paper also suggests the enhanced technique applicable to the measurement of vibration of a large-scale rotating shaft. The concurrent methods based on camera images use marks, which are hardly applicable to rotating shafts. The proposed method measures vibration without any marks by evaluating shape errors. The working principle of the method is described and verified by a series of experiments.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.746-751
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• 2003

When a cantilever beam rotates about the axis perpendicular to its longitudinal axis, its natural frequencies vary. This phenomenon which is caused by centrifugal inertia forces is often referred to as the stiffening effects. Since the variation of natural frequencies often creates critical problems for the rotating structures, it is necessary to control the variation of natural frequencies. As the cross section of a rotating cantilever beam varies, natural frequencies can be changed. The thickness and the width of the cantilever beam are assumed to be cubic spline functions in the present work. An optimization method is employed to find the optimal thickness and width of the rotating beam. This result can be used for the design of rotating structures such as turbine and helicopter blades.

• 한국정밀공학회지
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• 제24권7호
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• pp.60-68
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• 2007

This paper presents an efficient 5-axis roughing method for centrifugal impeller. The efficient roughing is minimization of cutting time through minimizing tool tilting and rotating motions. To minimized cutting time, machining area is divided into sub-cutting regions using control points on hub curves and shroud curves of blade used to design and analyze centrifugal impeller. For sub-cutting regions, diameters of cutting tools are determined as big as possible. Then, tool paths are generated with the tilting axis and rotating axis of 5-axis machine limited and fixed, which can give more efficient machining speed and machining stability than the conventional methods. Experimental results show that the proposed method is more efficient than the conventional methods to mill with the only one cutting tool without dividing area and the previous methods to mill with simultaneous 5-axis processing with dividing area.

• 한국안광학회지
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• 제10권4호
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• pp.255-259
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• 2005

난시 교정용 콘택트렌즈 착용 시 렌즈의 축 방향을 정확하게 하지 않을 경우이거나, 착용 후 순목 시 안검 등에 의해 콘택트렌즈가 회전할 경우가 있다. 이러한 현상이 있을 경우 완전교정상태가 잘못 교정된 상태로 되기 때문에 안정피로를 유발하여 시력의 저하를 가져올 수 있다. 이런 이유로 콘택트렌즈가 어느 정도 회전했는지의 파악이 필요하다. 콘택트렌즈가 회전했다면 착용 후 굴절검사에서 잔류 난시가 검출될 것이다. 이것을 이용해서 우리는 콘택트렌즈의 회전량을 계산하는 프로그램을 개발하였다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2008년도 추계학술대회논문집
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• pp.348-353
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• 2008

A vibration analysis for a rotating cantilever beam with the tapered cross section is presented in this study. The stiffness changes due to the stretching caused by centrifugal inertia forces when a tapered cantilever beam rotates about the axis perpendicular to its longitudinal axis. When the cross section of cantilever beam are assumed to decrease constantly, the mass and stiffness also change according to the variation of the thickness and width ratio of a tapered cantilever beam. Such phenomena result in variations of natural frequencies and mode shapes. Therefore it is important to the equations of motion in order to be obtained accurate predictions of these variations. The equations of motion of a rotating tapered cantilever beam are derived by using hybrid deformation variable modeling method and numerical results are obtained along with the angular velocity and the thickness and width ratio.