• Journal of the Computational Structural Engineering Institute of Korea
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• v.12 no.4
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• pp.661-669
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• 1999

이 논문은 탄성지반위에 놓인 원호형 곡선보의 자유진동에 관한 연구이다. 회전관성 및 전단변형을 고려하여 두 개의 매개변수로 표현되는 탄성지반위에 놓인 원호형 곡선보의 자유진동을 지배하는 미분방정식을 유도하고, 이를 수치적분기법과 시행착오적 행렬값탐사법이 결합된 수치해석기법으로 해석하였다. 회전-회전, 회전-고정 및 고정-고정의 단부조건을 갖는 곡선보의 최저차모드 3개의 고유진동수를 산출하였다. 곡선보의 수평높이 지간길이비, Winkler 지반계수, 전단지반계수에 따른 고유진동수 변화를 분석하였으며, 회전관성 및 전단변형의 영향을 고찰하였다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.3A
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• pp.251-258
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• 2009

This paper deals with the strongest beams with the solid regular polygon cross-section, whose volumes are always held constant. The differential equation of the elastic deflection curve of such beam subjected to the concentrated and trapezoidal distributed loads are derived and solved by using the double integration method. The Simpson's formula was used to numerically integrate the differential equation. In the numerical examples, the clamped-clamped and clamped-hinged ends are considered as the end constraints and the linear, parabolic and sinusoidal tapers are considered as the shape function of cross sectional depth. As the numerical results, the configurations, i.e. section ratios, of the strongest beams are determined by reading the section ratios from the numerical data obtained in this study, under which static maximum behaviors become to be minimum.

• Proceedings of the KIPE Conference
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• 2019.11a
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• pp.100-101
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• 2019

본 논문은 유도전동기 고정자 자속 기준 벡터제어에서, 슬립 관계식과 순환 최소자승법을 이용하여 회전자 저항 및 고정자 과도 인덕턴스를 동시에 추정하는 알고리즘을 제안한다. 모의실험을 수행하여, 추정 회전자 저항과 고정자 과도 인덕턴스가 제안된 방법에 의해 각각 실제 값에 수렴함을 보인다.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.14 no.1
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• pp.87-93
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• 2001

이 논문은 사하중에 의한 정적 처짐을 갖는 변단면 보의 자유진동에 관한 연구이다. 사하중이 작용하는 변단면 보의 자유진동을 지배하는 상미분방정식을 유도하고 이를 수치해석하여 최 저차 3개 모드의 고유진동수 및 진동형을 산출하였다. 수치해석 예제에서는 선형 변단면과 등분포 사하중을 채택하였다. 지점조건으로는 회전-회전, 회전-고정, 고정-고정 보를 채택하였다. 수치해석의 결과로 하중강도, 세장비 및 단면비가 고유진동수에 미치는 영향을 분석하였다. 사하중의 영향을 고려한 경우와 고려하지 않은 경우의 진동형을 서로 비교하였다.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.25 no.3
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• pp.185-194
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• 2012

This paper deals with free vibrations of the tapered Timoshenko beam in which both the rotatory inertia and shear deformation are included. The cross section of the tapered beam is chosen as the rectangular cross section whose depth is constant but breadth is varied with the parabolic function. The fourth order ordinary differential equation with respect the vertical deflection governing free vibrations of such beam is derived based on the Timoshenko beam theory. This governing equation is solved for determining the natural frequencies corresponding with their mode shapes. In the numerical examples, three end constraints of the hinged-hinged, hinged-clamped and clamped-clamped ends are considered. The effects of various beam parameters on natural frequencies are extensively discussed. The mode shapes of both the deflections and stress resultants are presented, in which the composing rates due to bending rotation and shear deformation are determined.

• Proceedings of the KIPE Conference
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• 2000.07a
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• pp.191-194
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• 2000

기존의 약계자영역에서의 유도전동기의 고정자자속 기준제어방법은 고정자기준자속을 회전자의 회전속도에 반비례해서 저감시키는 것이다 본 논문에서는 이러한 기존의 방법에 의해서는 최대토크를 얻지 못함을 보이고 최대토크를 얻기 위하여 전압제한조건 토크제한조건 및 전류제한조건을 고려한 새로운 고정자기준자속 선정방법을 제안한다.

• Computational Structural Engineering
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• v.9 no.1
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• pp.133-139
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• 1996

In this paper, an approximate method is developed to obtain the natural frequencies of the out of plane vibration of circular curved beams. The governing differential equations are derived using the dynamic equilibrium equations with the Timoshenko theory, and solved numerically. The Runge-Kutta method and Regula-Falsi method are used to integrate the differential equations and to determine the natural frequencies, respectively. In numerical examples, the hinged-hinged and clamped-clamped end constraints are considered. For each case, the four lowest natural frequencies are reported as functions of four non-dimensional system parameters.

• Journal of KSNVE
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• v.6 no.5
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• pp.587-594
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• 1996

The differential equation governing both the free vibrations and buckling loads of tapered beam-columns of regular polygon cross-section with constant volume were derived and solved numerically. The parabolic and sinusoidl tapers were chosen as the variable depth of cross-section for the tapered beam-column. In numerical examples, the clamped-clamped, hinged-clamped and hinged-hinged end constraints were considered. The variations of frequency parameters and first buckling load parameters with the non-dimensional system parameters are reported in figures, and typical vibrating mode shapes are presented. Also, the configurations of strongest columns were determined.

• Computational Structural Engineering
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• v.9 no.3
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• pp.135-143
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• 1996

The differential equations governing both the free vibrations and buckling loads of tapered beam-columns of circular cross-section with constant volume are derived and solved numerically. The effects of axial load are included in the differential equations. The parabolic equation is chosen as the variable radius of circular cross-section for the tapered beam-column. In numerical examples, the clamped-clamped, clamped-hinged and hinged-hinged end constraints are considered. The variations of the frequency parameters and buckling load parameters with the non-dimensional system parameters are presented in figures and the configurations of strongest columns are obtained.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.38 no.6
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• pp.9-21
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• 2001

This paper defines the mobility and rotatability, and a desired mobility and rotatability that can be achieved by adjusting the distance between two wheels of a mobile robot dynamically. The radii of wheels are assumed to be constant in this paper. If a mobile robot has a fixed axis connecting the two wheels, it may not be able to avoid a sudden obstacle because of the constraint of mobility and rotatability. The focus of this paper is on the instant rotatability with high and stable mobility. That is, by dynamically changing the distance between the two wheels, the mobile robot could get the high rotatability instantly and high mobility with high stability. Supposed that the mobility and rotatability that are defined in this paper are supplied to the design of a mobile robot, it will suggest a theoretical basis on the optimal design of the mobile robot with a given route condition and its states. The experimental data support the validity of the aforementioned mobility and rotatability.