• 한국자동차공학회논문집
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• 제21권2호
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• pp.122-130
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• 2013

Rail geometries such as cant, grade and curvature can be easily represented by means of a track coordinate system. In this analysis, in order to derive a dynamic and constraint equation of a wheelset, the track coordinate system is used as an intermediate stage. Dynamic and constraint equations of railway vehicle bodies except the wheelset are written in the Cartesian coordinate system as a conventional method. Therefore, whole dynamic equations of a railway vehicle are derived by combining wheelset dynamic equations and dynamic equations of railway vehicle bodies. Constraint equations and constraint Jacobians are newly derived for the track coordinate system. A process for numerical analysis is suggested for the derived dynamic and constraint equations of a railway vehicle. The proposed dynamic analysis of a railway vehicle is validated by comparison against results obtained from VI-RAIL analysis.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1987년도 한국자동제어학술회의논문집; 한국과학기술대학, 충남; 16-17 Oct. 1987
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• pp.52-57
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• 1987

In this paper, it is dealt with the dynamic motion equations for a robot arm. Four kinds of the dynamic equations which are the Lagrange-Euler equations, the Recursive L-E equations, the Newton-Euler equations and the improved N-E equation are derived on robot PUMA 600. Finally the algorithms on these equations are programmed using PASCAL. and are compared with each other. As the results, it is found that the improved N-E equations has the most fastest execution time among the equations and can be used in real time processing.

• 충청수학회지
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• 제26권4호
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• pp.869-878
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• 2013

We study boundedness of solutions of dynamic equations on time scales by using Lyapunov-type functions.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 추계학술대회논문집
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• pp.994-999
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• 2002

The Pendulum Automatic Dynamic Balancer is a device to reduce the unbalanced mass of rotors. For the analysis of dynamic stability and behavior, the nonlinear equations of motion for a system including the Pendulum Balancer are derived with respect to polar coordinate by Lagrange's equations. And the perturbation method is applied to find the equilibrium positions and to obtain the linear variation equations. Based on the linearized equations, the dynamic stability of the system around the equilibrium positions is investigated by the eigenvalue problem. Furthermore, in order to confirm the stability, the time responses for the system are computed from the nonlinear equations of motion.

• 한국산학기술학회논문지
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• 제14권10호
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• pp.4733-4738
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• 2013

본 연구에서는 구속조건을 가진 기계계의 동적 평형위치를 다물체 동역학 해석방법을 이용하여 계산하였다. 다물체계에서 얻어지는 시간 구속조건을 가진 구속조건식과 동역학식으로부터 독립좌표계로 이루어진 동적평형식을 유도하였다. 동적 평형식은 구속조건식과 함께 비선형 대수방정식의 형태로서 Newton-Raphson 방법을 이용하여 수치해를 구하였다. 제안된 동적 평형 계산 방법을 조속기에 적용하여 동적 평형위치를 구하였다. 해석결과는 상용 프로그램의 동역학해석을 통한 평형위치의 결과와 비교하여 타당성을 검증하였다. 조속기의 회전 각속도에 대한 평형위치를 계산하고 설계 파라미터에 대한 평형위치의 영향을 분석하였다.

• Structural Engineering and Mechanics
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• 제13권3호
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• pp.329-343
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• 2002

In this research, the dynamic stability of an orthotropic elastic conical shell, with elasticity moduli and density varying in the thickness direction, subject to a uniform external pressure which is a power function of time, has been studied. After giving the fundamental relations, the dynamic stability and compatibility equations of a nonhomogeneous elastic orthotropic conical shell, subject to a uniform external pressure, have been derived. Applying Galerkin's method, these equations have been transformed to a pair of time dependent differential equations with variable coefficients. These differential equations are solved using the method given by Sachenkov and Baktieva (1978). Thus, general formulas have been obtained for the dynamic and static critical external pressures and the pertinent wave numbers, critical time, critical pressure impulse and dynamic factor. Finally, carrying out some computations, the effects of the nonhomogeneity, the loading speed, the variation of the semi-vertex angle and the power of time in the external pressure expression on the critical parameters have been studied.

• Steel and Composite Structures
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• 제15권1호
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• pp.57-79
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• 2013

This paper studies the dynamic instability of laminated composite plates under thermal and arbitrary in-plane periodic loads using first-order shear deformation plate theory. The governing partial differential equations of motion are established by a perturbation technique. Then, the Galerkin method is applied to reduce the partial differential equations to ordinary differential equations. Based on Bolotin's method, the system equations of Mathieu-type are formulated and used to determine dynamic instability regions of laminated plates in the thermal environment. The effects of temperature, layer number, modulus ratio and load parameters on the dynamic instability of laminated plates are investigated. The results reveal that static and dynamic load, layer number, modulus ratio and uniform temperature rise have a significant influence on the thermal dynamic behavior of laminated plates.

• 대한수학회보
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• 제45권2호
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• pp.299-312
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• 2008

In this paper, we establish some oscillation criteria for nonautonomous second order neutral delay dynamic equations $(x(t){\pm}r(t)x({\tau}(t)))^{{\Delta}{\Delta}}+H(t,\;x(h_1(t)),\;x^{\Delta}(h_2(t)))=0$ on a time scale ${\mathbb{T}}$. Oscillatory behavior of such equations is not studied before. This is a first paper concerning these equations. The results are not only can be applied on neutral differential equations when ${\mathbb{T}}={\mathbb{R}}$, neutral delay difference equations when ${\mathbb{T}}={\mathbb{N}}$ and for neutral delay q-difference equations when ${\mathbb{T}}=q^{\mathbb{N}}$ for q>1, but also improved most previous results. Finally, we give some examples to illustrate our main results. These examples arc [lot discussed before and there is no previous theorems determine the oscillatory behavior of such equations.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 추계학술대회논문초록집
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• pp.396.2-396
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• 2002

Dynamic stability and behavior are analyzed fur Pendulum Automatic Dynamic Balancer which is a device to reduce an unbalanced mass of rotors. The nonlinear equations of motion for a system including a Pendulum Balancer are derived with respect to polar coordinate by Lagrange's equations. The perturbation method is applied to find the equilibrium positions and to obtain the linear variation equations. Based on linearized equations, the dynamic stability of the system around the equilibrium positions is investigated by the eigenvalue problem. (omitted)

• Kyungpook Mathematical Journal
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• 제47권3호
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• pp.425-438
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• 2007

In this paper, we establish some new oscillation criteria for a second-order delay dynamic equation $$u^{{\Delta}{\Delta}}(t)+p(t)u(\tau(t))=0$$ on a time scale $\mathbb{T}$. The results can be applied on differential equations when $\mathbb{T}=\mathbb{R}$, delay difference equations when $\mathbb{T}=\mathbb{N}$ and for delay $q$-difference equations when $\mathbb{T}=q^{\mathbb{N}}$ for q > 1.