• 소음진동
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• 제8권3호
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• pp.524-532
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• 1998

The purpose of this paper is to investigate the free vibrations of horizontally curved beams resting on Winkler-type foundations. Based on the classical Bernoulli-Euler beam theory, the governing differential equations for circular curved beams are derived and solved numerically. Hinged-hinged, hinged-clamped and clamped-clamped end constraints are considered in numerical examples. The free vibration frequencies calculated using the present analysis have been compared with the finite element's results computed by the software ADINA. Numerical results are presented to show the effects on the natural frequencies of curved beams of the horizontal rise to span length ratio, the foundation parameter, and the width ratio of contact area between the beam and foundation.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 춘계학술대회논문집
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• pp.706-711
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• 2000

This paper deals with the free vibrations of horizontally curved beams on an elastic foundation. Taking into account the effects of rotatory inertia and shear deformation, the differential equations governing free vibrations of noncircular curved beams resting on Pasternak-type foundations are derived and solved numerically. The lowest three natural frequencies for parabolic curved beams with hinged-hinged and clamped-clamped end restraints are calculated. Numerical results are presented to show the effects on the natural frequencies of the non-dimensional system parameters: the horizontal rise to span length ratio, the Winkler foundation parameter, the shear foundation parameter, and the width ratio of contact area between the beam and foundation.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2010년도 춘계학술대회 논문집
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• pp.72-73
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• 2010

In this paper, the main noise sources and its radiated noise levels of upwind horizontal-axis wind turbines are experimentally and theoretically investigated. Theoretical predictions for indentifying the dominant source locations are made by using the empirical noise prediction model of Brooks et al. (1989) for the airfoil self noise. Through the comparison of theoretical results with the experimental results, turbulence-boundary-layer-trailing-edge (TBL-TE) noise is revealed to be the dominant source over all frequency range and separation and stall (S-S) noise is possibly important in the relative lower frequency range compared with TBL-TE noise.

• 한국공간구조학회논문집
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• 제10권2호
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• pp.69-76
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• 2010

적층고무 면진장치의 전단강성 뿐만 아니라 인장강성 및 압축강성을 실험적으로 구한 후 비선형 해석 프로그램을 이용하여 면진장치를 모델링 하였다. 수평력을 받는 면진된 골조의 면진장치에 전도에 의한 인장응력이 발생되게 하기 위하여 큰 초기변위를 부여한 자유진동 실험을 해석적으로 수행하였다. 적층고무 면진장치는 인장에 약하기 때문에 면진장치에서의 들림 현상을 해석적으로 구하기 위하여 면진장치의 수직방향 강성들이 해석 모델에 적절히 반영되어야 한다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2011년도 추계학술대회 논문집
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• pp.438-439
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• 2011

Magnetic levitation control system of a metal ball was designed using combined PID and fuzzy logic, in which two electromagnets are used to control the vertical and horizontal position of the ball. Single synchronization coil sensor was used to detect the vertical position. Electric power is differentially supplied to two electromagnets so that the ball can move horizontally. In the experiment 25 cm diameter metal ball was levitated and successfully controlled to move horizontally.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 춘계학술대회논문집
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• pp.387-392
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• 2002

A portable mould oscillation analyzer with an integrated computer, developed by POSCO, records the movement of the mould in every spatial direction. The system uses the gap sensors to measure the mould movement (displacement) in two horizontal directions according to the mould narrow and broad faces and the vertical strokes in the four corners of mould. The gap sensor is a non-contacting minute displacement-measuring device using the principle of high frequency eddy current loss. The mould oscillation diagnostic system integrates the gap sensors, their converters and the industrial portable computer with plug-in data acquisition boards. In an own expert module, which is included in the diagnosis program, one can obtain much information about the mould oscillation equipment.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2014년도 추계학술대회 논문집
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• pp.141-145
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• 2014

A minimally appropriate time delay of audio data processing is investigated for rendering virtual sound source direction in real-time head-tracking environment under headphone listening. Less than 3.7 degree of angular mismatch should be maintained in order to keep desired sound source directions in virtually fixed while listeners are rotating their head in a horizontal plane. The angular mismatch is proportional to speed of head rotation and data processing delay. For 20 degree/s head rotation, which is a relatively slow head-movement case, less than total of 63ms data processing delay should be considered.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 춘계학술대회논문집
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• pp.388-391
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• 2006

In the development of sheet-handling machinery, it is important to predict the static and dynamic behavior of the sheets with a high degree of reliability because the sheets are fed and stacked at such a high speed. Flexible media behaves geometric nonlinearity of large displacement and small strain. In this paper, static and dynamic analyses of flexible media are performed by FEM considering geometric nonlinearity. Linear stiffness matrix and geometric nonlinear stiffness matrix based on the Co-rotational(CR) approach are derived and numerical simulations are performed by Updated Newton-Raphson(UNR) method and Newmark integration scheme.

• 한국의류학회지
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• 제20권3호
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• pp.452-466
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• 1996

The purpose of this study is to proviede basic data for designing sports-brassiere by a questionnaire survey about sports-brassieres preferences and physiological wearing test. The results of the survey and the physiological wearing tests on sports-brassieres are as follow; 1. According to the survey, dissatisfied factors on the sports-brassiere are "drooping and vibrating of the breasts". Preferable factors are supporting breasts by stretch and seldom changing its position by motion. The bigger cup-size and more hemispherical-type causes more discontent than flat-type. 2. The shape of breasts is oval, on what ground, horizontal line is longer than vertical. For the cross section of bust line, shirts type.brassiere is more gently curved than cup-brassiere. 3. The feeling of wearing comfort is correlated with bust.up, shield, close adhesion. The vibration of breasts is correlated with covering urea and close adhesion, and the changing band's position by movement, close adhesion. Too much covering area or strain are in inverse correlation of the comfort. 4. The rate of prevention of vibration is 75~80% on superior sports-brassieres, which has broad covering area and excellent close adhesion. adhesion.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2002년도 가을 학술발표회 논문집
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• pp.11-16
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• 2002

The differential equations governing free vibrations of the elastic, horizontally curved beams with unsymmetric axis are derived in Cartesian coordinates rather than in polar coordinates, in which the effect of torsional inertia is included. Frequencies are computed numerically for the sinusoidal curved beams with both clamped ends and both hinged ends. Comparisons of natural frequencies between this study and SAP 2000 are made to validate theories and numerical methods developed herein. The convergent efficiency is highly improved under the newly derived differential equations in Cartesian coordinates. The lowest four natural frequency parameters are reported, with and without torsional inertia, as functions of three non-dimensional system parameters: the horizontal rise to chord length ratio, the span length to chord length ratio, and the slenderness ratio.