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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean Society of Marine Engineering
Journal Basic Information
Journal DOI :
Korean Society of Marine Engineers
Editor in Chief :
Volume & Issues
Volume 21, Issue 5 - Oct 1997
Volume 21, Issue 4 - Aug 1997
Volume 21, Issue 3 - Jun 1997
Volume 21, Issue 2 - Apr 1997
Volume 21, Issue 1 - Feb 1997
Selecting the target year
Practical Applications of Favorable Residual Stresses
Journal of the Korean Society of Marine Engineering, volume 21, issue 5, 1997, Pages 463~468
A Study on the Waterjet Propulsion in Model Scale
Journal of the Korean Society of Marine Engineering, volume 21, issue 5, 1997, Pages 474~481
Waterjet propulsion generally refers to propulsion of ships by internally mounted pumps with proper ducting. This arrangement of the actuator component of the system leads to the fundamental differences with respects to screw propeller system. In this paper, the basic hydrodynamic characteristics of waterjet propulsion was outlined to clarify the application consideration and proposal for carrying out model self-propulsion tests with waterjet propelled models was presented. The results of model self-propulsion tests carried out in the Hyundai Maritime Research Institute towing tank with catamaran ship were presented.
A Study on the Fatigue Properties of Ti-Ni Shape Memory Alloys
S.Y Kim ; S. Miyazaki ;
Journal of the Korean Society of Marine Engineering, volume 21, issue 5, 1997, Pages 482~490
The effects of strain amplitude. test temperature and stress on the fatigue properties for Ti-Ni wires were investigated using a rotary bending fatigue tester specially designed for wires. The fatigue test results were discussed in connection with the static tensile properties. The DSC measurement was conducted after fatigue test in order to clarify the change of transformation behavior due to the progress of fatigue. Under the temperature below or near the Af, the strain amplitude(
)-failure life (Nf) curve showed to be composed of three straight lines with two turning points. Of the 2 turning points, the upper one was coincident with the elastic limit strain and the lower one with the proportional limit strain. With rising of the test temperature above Af, the pattern of
-Nf curve changed gradually to composition of 2 straight lines. The
-Nf curve shifted depending on test temperature. In the short and medium life zones, the higher the temperature was, the shorter the fatigue life. However, in the long life zone, above the Af temperature, the fatigue life was not affected by the temperature. The transformation enthalpy measured after fatigue test was dependent on Nf,
, and test temperature.
A Study on the Prediction of Pressure ~ Time Histories by Unsteady Gas Flow through the Internal Combustion Engine Exhaust System
M.H.Lee ; J.S.Lee ; B.G.Yu ; K.O.Cha ;
Journal of the Korean Society of Marine Engineering, volume 21, issue 5, 1997, Pages 491~502
This paper describes a theoretical and exprimental investigation of the pressure - time histories of some basic internal combustion engine exhaust systems. The program package is utilized the method of characteristics to solve the general equations of one - dimensional unsteady gas flow. This analysis is then combined with boundary models, based on quasi - steady flow approach, to give a complete treatment of the flow behavior in the exhaust system. Using a rotary valve exhaust simulator, experimental pressure - time histories were obtained. The predictions are com¬pared with measured results and show a high degree of correlation in amplitude and phasing.
A Study on the Robust Speed Control Characteristics of Induction Motor Using State Observer
Journal of the Korean Society of Marine Engineering, volume 21, issue 5, 1997, Pages 503~511
In 3 phase induction motor control system, the speed control using the load torque observer becomes robust against disturbances by means of a feed-forward control of the estimated load torque component. In case of variation of inertia moment, the estimated load torque has error because the observer uses the nominal inertia to estimate the load torque. And so, it is difficult to obtain good speed control characteristics. This paper has two study target strategy. First, we executes feed-forward control with the load torque observer when motor inertia has nominal value and compare it with conventional PI con¬trol. The second strategy estimates inertia moment error using the load torque observer when inertia moment change. The proposed two strategy is confirmed through the computer simulations and the experimental implementations by TMS320C31 microprocessor.
The Effect of Shot Peening on the Bending Strength of Carburized Spur Gear Teeth Based on Fracture Mechanics
Journal of the Korean Society of Marine Engineering, volume 21, issue 5, 1997, Pages 512~521
This paper deals with an evaluation of the residual stress due to shot peening induced in a car¬burized gear tooth and its application to the fatigue crack propagation problem. The residual stress is estimated based on the assumption that the main cause of residual stress is the volume difference between the case and core due to martensitic transformation in cooling, and the influ¬ence of both the reduction of retained austenite and the strain in the surface layer induced by shot peening are considered. The reliability of the method is examined by comparison with stresses measured by the X-ray diffraction method. The stresses intensity factors are computed by the influence function method and the reduction of the factor due to the residual stress is demonstrat¬ed and discussed based on the fracture mechanics.
DIMENSIONAL CHANGES AND REDISTRIBUTION OF RESID¬UAL STRESSES DUE TO INNER LAYER REMOVAL OF RESID¬UALLY STRESSED CYLINDRICAL COMPONENTS
Journal of the Korean Society of Marine Engineering, volume 21, issue 5, 1997, Pages 522~526
EFFECT OF INITIAL SALT CONCENTRATION ON THE FREEZING OF BINARY MIXTURE SATURATED PACKED BED
Journal of the Korean Society of Marine Engineering, volume 21, issue 5, 1997, Pages 527~534
Freezing of an aqueous sodium cWoride solution (Nacl- H20) saturating a packed bed with ini¬tial salt concentrations of 5, 10, 15(k by weight is investigated experimentally in a rectangular cav¬ity. The system was cooled from the top, bottom and a vertical side wall. For the freezing experi¬ments from below, there was little effect of the initial salt concentration throughout the freezing process, and the global freezing rate was not affected by the initial salt concentration. For the freezing from above, the size of the mush region decreased and the mushlliquid interface became flatter as the initial liquid concentration is decreased. For the freezing from vertical side wall, reheating of the mixture was intensified with an increase in the initial salt concentration. For Ci= 5%, supercooling was observed only at the early times of freezing process, but for Ci= 15% small supercooling was observed throughout the freezing process.
Effect of the Corrosive Solution Conditions and Scan Rate to the Electrochemical Corrosion on the AISI 304 Stainless Steel
Journal of the Korean Society of Marine Engineering, volume 21, issue 5, 1997, Pages 535~541
The effect of concentration of each solution( HCI,
), scan rate and polished surface condition on the corrosion of AISI 304 Stainless Steel were investigated, utilizing the Method ASTM G5 - 87. It can be concluded that: 1) For the same concentration(i.e. 1N) of each solution the corrosion rate is the highest in HCI and lowest in
. Also, the difference of values of
generated for each solution is significant. 2) As the concentration of the solution
is increased (O.5N, 1N, 2N) the values of
are increased. 3) In case of existence of SCN ion of O.OlN, the values of iCTIt and ip generated are approximately 100 times and 1.4 times higher respectively, than in the case of non - existence of
. However the existence of
doesn't affect the value of
. 4) The values of
are increased due to the increase of scan rate. But the values of
do not depend on the scan rate. 5) The
value depends greatly on oxygen in the solution, but the changes in values of
due to the oxygen are insignificant. 6) If a component is polished using #400, #600 and #800 wet polish paper, the effect of surface condition on variations of values of
is slightly significant.
A Study on the Fatigue Strength of the Welds of Membrane Type LNG Tank
Journal of the Korean Society of Marine Engineering, volume 21, issue 5, 1997, Pages 542~548
In this study an evaluation method of fatigue strength of membrane type LNG tank is presented with FEM analysis and experimental approach of seam and raised edge welds. The study contains the following : l)FEM analysis of test specimens 2)Fatigue tests of seam and raised edge welds 3)Estimation of cumulative damage factor of the welds on the basis of safe life design concept complying with the rules of classification society 4)Review of the effect of mean stress on the fatigue strength 5)Modelling of fatigue life of the welds which is changeable by weld heights With the results obtained in this study, a model
for seam and raised edge welds having a given weld height is proposed to be useful for designers and inspectors.
Calculation of Heat Transfer Coefficients by Steady State Inverse Heat Conduction
Journal of the Korean Society of Marine Engineering, volume 21, issue 5, 1997, Pages 549~556
The inverse heat conduction problems is the calculation of surface heat transfer coefficients by utilizing measured temperature. The numerical technique of finite element analysis and optimizition is introduced to calculate temperatures and heat transfer coefficients. The calculated heat transfer coefficients and temperature distribution are good agreement with the results of direct analysis. The inverse method has been applied to the control valve of nuclear power plant.
PIV Analysis of Cubic Channel Cavity Flow
Journal of the Korean Society of Marine Engineering, volume 21, issue 5, 1997, Pages 557~563
The unsteady flow in three-dimensional cubic cavity with narrow channel at upper region is investigated experimentally for three kinds of Reynolds number, 1*10/sup 4/, 3*10/sup 4/ and 5*10/sup 4/ based on the cavity width and cavity inlet mean flow velocity. Instant velocity vectors are obtained simultaneously at whole field by PIV(Particle Image Velocimetry). Wall pressure distributions are estimated using Poisson equation from the velocity data. Results of PIV reveal that severe unsteady flow fluctuation within the cavity are remarkable at all Reynolds numbers and sheared mixing layer phenomena are also found at the region where inlet driving flow is collided with the clock-wise rotating main primary vortex. Instant velocity profiles reveal that deformed forced vortex formation is observed throughout the entire region and spanwise kinetic energy migration is conspicuous.
A Fundamental Study on Sea Water Freezing Behavior in a Rectangular Vessel Cooled from Below
Journal of the Korean Society of Marine Engineering, volume 21, issue 5, 1997, Pages 564~570
The most important factor for the desalination system is the fresh water production cost dependent upon the possible energy source which should be obtained easily and with low price. Recently in Korea the demand of LNG, as a cheap and clean energy which does not cause an environmental problem, has sharply been increased. In general, LNG is storaged in a tank as a liquid state below -162 'C. When it is serviced, however, the LNG absorbs energy from a heating source and transforms to the gaseous state with high pressure. During this process a huge amount of cold energy accumulated in LNG is wasted. This waste cold energy can be utilized for producing fresh water from sea water using a sea water freezing desalination system. In order to develop a sea water freezing desalination system and to establish its design technique, a qualitative and quantitative data regarding the freezing behavior of sea water is needed in advance. The goal of this study, therefore, are to reveal the freezing mechanism of sea water, to measure the freezing rate, and to investigate the freezing heat-transfer characteristics. The experimental results help to provide a general understanding of the sea water freezing behavior in a Rectangular vessel cooled from below.
A Study on the Upright Control of an Inverted Triangle
Journal of the Korean Society of Marine Engineering, volume 21, issue 5, 1997, Pages 571~578
This paper presents a method for designing a control system to stand upright inverted triangle. A linearized model is obtained form the nonlinear system by Taylor series expansion and a state controller is designed based on the model. After implementing the control system which is combined control law and estimator with reference input, experiments are carried out to stand upright inverted triangle at any angluar position.
A Study on the Optimun Speed Measurement for the Speed Control of a Diesel Engine
Journal of the Korean Society of Marine Engineering, volume 21, issue 5, 1997, Pages 579~583
A diesel Engine rotates vibratively because of alternative explosion strokes. Traditional measurement of a diesel engine speed is carried out by measuring output voltage of FV convertor from input signals of MPU(magnetic pickup unit) or of DC tachometer. Because these measurement include also vibrative rotation of a diesel engine, an analog filter is often used to eliminate high frequency noises due to periodic explosion stroke. But by this method these high frequency noises do not eliminated effectively because noise frequencies are changed according to diesel engine speed. In this paper, author proposes a new measurement method of a diesel engine revolution which read digital signal directly from MPU and prove the utility of proposed method through the real experiment.
A Study on Improvement of Cathodic Protection Design of Harbour Marine Steel Structure
Journal of the Korean Society of Marine Engineering, volume 21, issue 5, 1997, Pages 584~590
Harbour marine steel structures, which are served in severe marine environment, should be protected in appropriate method to reduce corrosion problems. Cathodic protection, one of the protection methods in terms of practical and economical point of view is being widely used to marine steel structures mentioned above. Recently it has been reported that the life of Al alloy anode with sacrificial anode for protection of harbour marine steel structures was shortened significantly than the original design life. In this study, the optimum cathodic protection design of harbour marine steel structures was investigated with parameter of sea water pollution degree.
A Study on Development of Velocity Measuring Method by PTV-AOM
Journal of the Korean Society of Marine Engineering, volume 21, issue 5, 1997, Pages 591~597
Instantaneous velocity distribution within coaxial circular pipe for measurement velocity of high speed is acquired simultaneously by applying the 2-dimensional PTV system consisting of a pulse generator(AOM:Acousto-Optical Modulator), a continuous-output laser and a PC image grabber together with experimental apparatus. The basic mechanism of AOM and vector identification method and performance-related image processing techniques are discussed. Representative measuring regions
mm are selected and instantaneous vectors are represented and fully developed turbulent flow of maximum velocity up to about 1.0 m/sec is obtained.