Go to the main menu
Skip to content
Go to bottom
REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Journal of the Korean Society of Marine Engineering
Journal Basic Information
Journal DOI :
Korean Society of Marine Engineers
Editor in Chief :
Volume & Issues
Volume 27, Issue 7 - Nov 2003
Volume 27, Issue 6 - Sep 2003
Volume 27, Issue 5 - Jul 2003
Volume 27, Issue 4 - Jul 2003
Volume 27, Issue 3 - May 2003
Volume 27, Issue 2 - Mar 2003
Volume 27, Issue 1 - Jan 2003
Selecting the target year
Mathematical Model of Shock Absorber for Performance Prediction of Automobile
Park, Jae-Woo ; Lee, Jong-Heon ; Kim, Jin-Wook ;
Journal of the Korean Society of Marine Engineering, volume 27, issue 4, 2003, Pages 467~478
Automotive shock absorber may not be regarded as only one(simple) damping machine because it is composed of many components, and shows non-linear damping characteristics. No matter how advanced form of shock absorber is developed, the oil shock absorber can not be neglected. because their structures are based on the oil shock absorber. Therefore it is essential to accurately analyze the dynamic characteristics of oil shock absorber. It stands mainly roi damper valve tuning which nowadays is still exhaustively done by means of ride work. In this study, damping mechanism and dynamic characteristics for oil shock absorber of twin tube type are analyzed, based on the mathematical model considering internal flow and pressure. For the reliability of numerical prediction. the database is constructed within the limit of adequate reliability. Finally, the programmed system that gives out necessary specification by inputting damping specification and tolerance is to be constructed.
Operating Performances of PV Energy Generation System with MPPT
Oh, Jin-Seok ; Kim, Mark-Spatt ; Lee, Yun-Hae ; Jun, Sang-Tae ; Yea, Seung-Hwan ; Kim, Byeong-Deok ; Lee, Yoon-Sik ; Ji-Young ;
Journal of the Korean Society of Marine Engineering, volume 27, issue 4, 2003, Pages 479~486
This paper presents the Performance of PV(Photovoltaic) system. the design of MPPT and the battery characteristic. The output power of PV depends on the environmental factors such as insolation and cell temperature. It is proposed that the MPPT is based on an simple power control algorithm. Furthermore the converter has to maintain the optimum duty ratio. A switching strategy of converter for battery may Protect against excessive discharge and overcharge. This paper includes discussion on system reliability power quality and effects of the randomness of the wind and the solar radiation on system design.
Gravity Level Dependency of Gas-Liquid Two-Phase Flow
Choi, Bu-Hong ;
Journal of the Korean Society of Marine Engineering, volume 27, issue 4, 2003, Pages 487~493
More reliable design of thermal transport. Power acquisition and thermal management systems requires the through understanding of the flow hydrodynamic. the differences and similarities between the two-phase flow characteristics of two-Phase flow influenced by the gravity levels. The data of flow Patterns, void fraction, frictional pressure drop associated with their characteristics were obtained at
. 1g and 2g. Flow patterns and void fraction data obtained at three gravity levels were compared with each other and previous models and correlations.
A Study on Dynamic Crack-Tip Fields in a Strain Softening Material
Jang, Seok-Ki ; Xiankui Zhu ;
Journal of the Korean Society of Marine Engineering, volume 27, issue 4, 2003, Pages 494~502
The near-tip field of mode-I dynamic cracks steadily propagating in a strain softening material is investigated under plane strain conditions. The material is assumed to be incompressible and its deformation obeys the
flow theory of plasticity. A power-law stress-strain relation with strain softening is adopted to account for the damage behavior of materials near the dynamic crack tip. By assuming that the stresses and strain have the same singularity at the crack tip. this paper obtains a fully continuous dynamic crack-tip field in the damage region. Results show that the stress and strain components the same logarithmic singularity of (In(R/r))
, and the angular variations of filed quantities are identical to those corresponding to the dynamic cracks in the elastic-perfectly plastic material.
Sensorless Speed Control of Induction Motor using Current Compensation
Oh, Sae-Gin ; Kim, Jong-Su ; Kim, Sung-Hwan ;
Journal of the Korean Society of Marine Engineering, volume 27, issue 4, 2003, Pages 503~510
A new method of induction motor drive, which requires neither shaft encoder nor speed estimator, is presented. The proposed scheme is based on decreasing current gap between a numerical model and an actual motor. By supplying the identical instantaneous voltage to both model and motor in the direction of reducing the current difference. the rotor approaches to the model speed. that is. reference value. The indirect field orientation algorithm is employed for tracking the model currents. The performance of induction motor drives without speed sensor is generally characteristic of poorness at very low speed. However, in this system, it is possible to obtain good speed response in the extreme low speed range.
Computation of Stratified Flows using Finite Difference Lattice Boltzmann Method
Kang, Ho-Keun ; Kim, Won-Cheol ;
Journal of the Korean Society of Marine Engineering, volume 27, issue 4, 2003, Pages 511~519
A stratified flow is simulated using the finite difference lattice Boltzmann method (FDLBM). The effect of body force (gravity) in a simple one-dimensional model with the lattice BGK 9 velocity is examined. The effect of body force in the compressible fluid is greatly different from that of the incompressible fluid In a compressible fluid under gravitational force, the density stratification is not sufficient and the entropy stratification is essential. The numerical simulation of a line sink compressible stratified flow in two-dimensional channel is also carried out. The results show that selective withdrawal is established when the entropy of the upper part increases. and the simulated results using FDLB method are satisfactory compared with the theoretical one.
Dynamic Modeling and Model Reduction for a Large Marine Engine
Kim, Chae-Sil ; Jung, Jong-Ha ; Park, Hyung-Ho ;
Journal of the Korean Society of Marine Engineering, volume 27, issue 4, 2003, Pages 520~525
This article provides a dynamic modeling methodology of engines to be accurate with a small number of degrees of freedom for an active vibration control using a top bracing. First. a finite element (FE) model for the engine structure is constructed so that the size of model is as small as possible where the dynamic characteristics of engine are ensured. Second. a technique is studied to obtain the exact mass and stiffness matrices of the FE model. The size of matrices from the FE model is still too large to apply. Finally, a model reduction is. therefore. conducted to make an appropriate dynamic model for designing and simulating a top bracing. In this article, a dynamic model of a large 9 cylinder engine is constructed and reviewed by comparing its natural frequencies and steady state reponses with those of experimental data provided by manufacturer.
A path planning of free flying object and its application to the control of gymnastic robot
Nam, Taek-Kun ; So, Myung-Ok ;
Journal of the Korean Society of Marine Engineering, volume 27, issue 4, 2003, Pages 526~534
Motions of animals and gymnasts in the air as well as free flying space robots without thruster are subject to nonholonomic constraints generated by the law of conservation of angular momentum. The interest in nonholonomic control problems is motivated by the fact that such systems can not stabilized to its equilibrium points by the smooth control input. The purpose of this paper is to derive analytical posture control laws for free flying objects in the air. We propose a control method using bang-bang control for trajectory planning of a 3 link mechanical system with initial angular momentum. We reduce the DOF (degrees of freedom) of control object in the first control phase and determine the control inputs to steer the reduced order system from its initial position to its desired position. Computer simulation for a motion planning of an athlete approximated by 3 link is presented to illustrate the effectiveness of the Proposed control scheme.
A 3-Dimensional Numerical Simulation of Impulse Turbine for Wave Energy Conversion
Lee, Hyeong-Gu ; Lee, Yeon-Won ;
Journal of the Korean Society of Marine Engineering, volume 27, issue 4, 2003, Pages 535~541
This paper describes numerical analysis of the impulse turbine with fixed guide vanes, a high performance hi-directional air turbine having simple structure for wane energy conversion. A 3-dimensional incompressible viscous flow numerical analysis based on the full Reynolds-averaged Wavier-Stokes equations was made to investigate the internal flow behavior Numerical results ate compared with experimental data. As a result, a suitable choice for the one of design factors has been clarified.