• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.2A
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• pp.43-49
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• 2011

In this study, to analyze the collision behaviors of the bridge super-structure and the vessel which the collision point is located far from its rotation center such as bridge of a vessel and equipments on a barge, the simplified collision model was proposed. The model was configured to denote the mass, stiffness and the nonlinear behaviors of the bridge and the vessel. The nonlinear equation of motions of the proposed model were numerically solved by 4th order Runge-Kutta method. The parametric studies were performed for various collision conditions by the standardized Korean barge vessel in term of barge width, and its effects to the maximum collision load of bridge were analyzed.

• Journal of the Korean Institute of Intelligent Systems
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• v.5 no.2
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• pp.86-96
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• 1995

In this paper the fuzzy extension for the classical engineering mechanics problems is studied. The governing differential equation is derived for the buckling loads of the columns with uncertain mediums: the their own weight and the flexural rigidity. The columns with one typical end constraint(hinged1 clarnped/free) and the other finite rotational spring with fuzzy constant are considered in numerical examples. The vertex method is used to evaluate the fuzzy functions. The Runge-Kutta method and Determinant Search method are used to solve the differential equation and determine the buckling loads, respectively. The membership functions of the buckling load are calculated. The index of fuzziness to quantitatively describe the propagation of fuzziness is defined. According to the fuzziness of governing factors, the varlation of index of fuzziness for buckling load is investigated, and the sensitivity for the end constraints is analyzed.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.4 no.1
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• pp.69-77
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• 1984

In this paper, the governing differential equations for the free vibration of uniform parabolic arches are derived on the basis of equilibrium equations of a small element of arch rib and the D'Alembert principle. A trial eigen value method is used for determining the natural frequencies and mode shapes. And the Runge-Kutta fourth order integration technique is also used in this method to perform the integration of the differential equations. A detailed study is made of the first mode for the symmetrical and anti-symmetrical vibrations of hinged arches with the Span length equal to 10 m. The effects of the rise of arch, the radius of gyration and the rotary inertia on free vibrations are presented in detail in curves and table.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.1
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• pp.9-14
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• 2004

The fluorescent lamp has been successfully modeled by employing the radial variation of particle density and considering driving circuit effects on the characteristics of discharge process. The electron energy distribution is assumed to have a Maxwellian. The electron mobility and the ambipolar diffusion coefficients are considered to vary with an electron energy rather than a simple uniform value. Energy states of mercury atom in the discharge process are regarded as six levels rather than simple 4 or 5 levels. These discharge processes have been accurately solved by numerically employing mixed the FDM and the 2nd Runge-Kutta method. This model was applied to analyzing real circuit. Simulation and experimental results were presented to verify the feasibility of the modeling. Simulation and experimental results were presented to verify the feasibility of the modeling.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2000.11a
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• pp.185-195
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• 2000

This pacer studied on the lateral motion and yaw motion of the gantry crane which is used for the automated container terminal with two driving wheel types. Though several problems are occcurred in driving of gantry crane, they are solved by the motion by the operators. But, if the gantry crane is unmanned, it is automatically controlled without any operation. There are two types, cone and flat t y pin driving wheel shape. In cone type, lateral vibration and yaw motion of crane are issued. In flat type, the collision between wheel-flange and rail or the fitting between wheel-flanges and rail is issued. Especially, the collision between wheel-flange and rail is a very critical problem in driving of unmanned gantry crane. To bring a solution to the problems, the lateral and yaw dynamic equations of the driving mechanism of gantry crane with two driving wheel types are derived. Then, we investigate the driving characteristics of gantry crane. And this study used PD(Proportional-Derivative) Controller to control the lateral displacement and yaw angle of the gantry crane. The simulation result of the driving mechanism using the Runge-Kutta Method is presented in this paper.

• 한국전산유체공학회:학술대회논문집
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• 2005.10a
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• pp.235-238
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• 2005

The unsteady supersonic flow over two- and three-Dimensional cavities has been analyzed by the integration of unsteady Reynolds-Averaged Navier-Stokes(RANS) with the k - w turbulence model. The unsteady flow is characterized by the periodicity due to the mutual relation between the shear layer and the internal flow in cavities. Numerical method is upwind TVD scheme based on the flux vector split with the Van Leer limiters, and time accuracy is used explicit 4th stage Runge-Kutta scheme. Cavity flows are Comparison of two- and three-dimensional. The cavity has a L/D ratio of 3 for two-dimensional case. and same L/D and W/D ratio is 1 for three-dimensional case. The Mach and Reynolds numbers are held constant at 1.5 and 450000 respectively. For the three-dimensional case, the flow field is observed to oscillate in the 'shear layer mode' with a feedback mechanism that follow Rossiter's formula. On the other hand, the self-sustained oscillating flow transitions to a 'wake mode' for the two-dimensional simulation, with more violent fluctuations inside the cavity.

• Journal of Korean Society of Steel Construction
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• v.9 no.2 s.31
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• pp.221-228
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• 1997

The main purpose of this paper is to determine the dynamic optimal shapes of simple beam-columns with the constant volume. The parabolic function is chosen as the variable equation for the depth of regular polygon cross-section. The ordinary differential equation including the effect of axial load is applied to calculate the natural frequencies. The Runge-Kutta and Regula-Falsi methods are used to integrate the differential equation and compute the frequencies, respectively. Then the dynamic optimal shape whose lowest natural frequency is highest is determined by reading the critical value of the frequency versus section ratio curve plotted by the frequency data. In the numerical examples, the simple beam-columns are analysed and the numerical results of this study are shown in tables and figures.

• Structural Engineering and Mechanics
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• v.50 no.4
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• pp.487-500
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• 2014

An analytical solution for the nonlinear in-plane free oscillations of the suspended cable which contains the quadratic and cubic nonlinearities is investigated via the homotopy analysis method (HAM). Different from the existing analytical technique, the HAM is indeed independent of the small parameter assumption in the nonlinear vibration equation. The nonlinear equation is established by using the extended Hamilton's principle, which takes into account the effects of the geometric nonlinearity and quasi-static stretching. A non-zero equilibrium position term is introduced due to the quadratic nonlinearity in order to guarantee the rule of the solution expression. Therefore, the mth-order analytic solutions of the corresponding equation are explicitly obtained via the HAM. Numerical results show that the approximate solutions obtained by using the HAM are in good agreement with the numerical integrations (i.e., Runge-Kutta method). Moreover, the HAM provides a simple way to adjust and control the convergent regions of the series solutions by means of an auxiliary parameter. Finally, the effects of initial conditions on the linear and nonlinear frequency ratio are investigated.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2006.05a
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• pp.310-313
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• 2006

The present study aims at investigating the effectiveness of a new passive cavity flow control technique, sub-cavity. The characteristics of cavity flow oscillation with the device are compared with those with other control techniques tested previously, including a triangular bump and blowing jet. In the computation, the three-dimensional, unsteady Navier-Stokes equations governing the supersonic cavity flow are solved based on an implicit finite volume scheme spatially and multi-stage Runge-Kutta scheme temporally. Large eddy simulation (LES) is carried out to properly predict the turbulent features of cavity flow. The present results show that the pressure oscillation near the downstream edge dominates overall time-dependent cavity pressure variations, and the amplitude of the pressure oscillation can be reduced in the presence of a sub-cavity.

• Journal of Astronomy and Space Sciences
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• v.17 no.1
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• pp.107-116
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• 2000

This paper presents the preliminary survey and simulation results of the prediction of Leonid stream's orbital motion. Based on the model survey on eject velocity and perturbation of meteoroid particles, a simulation program was developed and applied to orbital motion of Leonid stream. The Jones ejection distribution model was used to describe the particle's eject velocity and the orbital dynamic model includes perturbations of major planet's gravity. DE405 ephemeris file generated by Solar System Dynamics Group at Jet Propulsion Laboratory in NASA was used for the planet's ephemeris calculations. Solar radiation pressure were also considered in the simulation and 8th order Runge-Kutta algorithm was used a numerical integration method.