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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of Ocean Engineering and Technology
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Journal DOI :
Korean Society of Ocean Engineers
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Volume & Issues
Volume 6, Issue 2 - Dec 1992
Volume 6, Issue 1 - Jun 1992
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Scour development around an artificial cylinder on tidal sand ridg in gyeonggi bay, Korea
Choi, J.H. ;
Journal of Ocean Engineering and Technology, volume 6, issue 2, 1992, Pages 10~20
Fatigue Behavior of the Single Spot Welded Joint of Zinc Galvanized Steel Sheets
Journal of Ocean Engineering and Technology, volume 6, issue 2, 1992, Pages 21~34
The behavior of fatigue crack growth in the single spot welded joint of zinc galvanized steel sheets was studied experimentally and analytically based on fracture mechanics. Axial tension fatigue tests were carried out with the BSxGAB specimen that the bare plane(GAB) of monogalvanized steel sheet was spot welded to the double thickness bare steel sheet(BS), and with the GAxGAB specimen that the galvanized plane (GA) was spot welded to the equal thickness bare plane (GAB) 1. The relation between maximum stress intensity factor, K sub(max) and the number of cycles to failure, N sub(f) has shown a linear relation on log-log plot in the spot weld of the zinc galvanized steel sheet. 2. The fatigue strength of BSxGAB specimens is about 23% higher than that of GAxGAB specimens at the fatigue strength of
cycles. And the fatigue life of BSxGAB specimens at the same load range increases 6~9 times higher than that of GAxGAB specimens. 3. The general tendency at the angle of bending(
) in an applied load has changed rapidly at the initial 20% of its life. After then, it has changed slowly. The change at the angle of bending has increased linearly as the load range increases. 4. It has shown a linear relation between the location ratio of initiation
and fatigue life
on the semi-log graph paper. Here
means that the crack distance between main crack and sub-crack, 2L is divided by the nugget diameter, 2r.
(where a and n are material constant.)
Stydy of Pool Boiling under Steady State using Ultrasonic Measurement
Journal of Ocean Engineering and Technology, volume 6, issue 2, 1992, Pages 35~40
A recently developed new technique for measuring the fraction of wetted area has applied to pool boiling of water. The basis of the new applied technique of ultrasonic makes use of the reflection of ultrasonic from the vapour surface to measure the fraction of wetted area values. The results are the measured fraction of wetted area values in nucleate and transition boiling and the pool boiling curve for water under steady state conditions. The measurement of this paper shows a fraction of wetted areaf around 0.98 at the critical heat flux for water.
Random Analysis of Rolling Equation of Motion of Ships Based on Moment Equation Method
Journal of Ocean Engineering and Technology, volume 6, issue 2, 1992, Pages 41~45
In this paper an application technique of moment equation method to solution of nonlinear rolling equation of motion of ships is investigated. The exciting moment in the equation of rolling motion of ships is described as non-white noise. This non-white exciting moment is generated through use of a shaping filter. These coupled equations are used to generate moment equations. The nonstationary responses of the nonlinear system are obtained. The results are compared with those of a linear system.
Seismic Analysis of Rectangular Liquid Storage Structures Ssing Fluid Elements
Journal of Ocean Engineering and Technology, volume 6, issue 2, 1992, Pages 46~54
In this paper, behavior of rectangular storage structures under earthquake loadings are investigated. Linear sloshing is assumed in this study. The effect of the wall flexibility is considered. Eulerian and lagrangian approaches are presented. The Eulerian approach is carried out by solving the boundary value problem for the fluid motion. In the lagrangian approach, the fluid as well as the storage structure is modelled by the finite element method. The fluid region is discretized by using fluid elements. The (1
1)-reduced integration is carried out for constructing the stiffness matrices of the fluid elements. Seismic analysis of the coupled system is carried out by the response spectra method. The numerical results show that the fluid forces on the wall obtained by two approaches are in good agreements. By including the effect of the wall flexibility, the forces due to fluid motion can be increased very significantly.
Effect of Trim Variations on the Ship Structural Responses
Kwon, Young-Sub ;
Journal of Ocean Engineering and Technology, volume 6, issue 2, 1992, Pages 55~70
A Study on the Fatigue Strength Reduction Factor under the High Cycle Bending Fatigue
Pyo, Dong-Keun ;
Journal of Ocean Engineering and Technology, volume 6, issue 2, 1992, Pages 71~75
Study on the Corrosion Fatigue Crack Propagation Behavior of Steel Used for Frame of Vehicles in Marine Environment
Journal of Ocean Engineering and Technology, volume 6, issue 2, 1992, Pages 76~84
In this study, corrosion fatigue test of SAPH45 steel was performed by the use of plane behavior of base metal (BM) and heat affected zone (HAZ) of SAPH45. The main results obtained are as follows: 1) The more aspect ratio (b/t) of corner crack decreases, the more aspect ratio (b/a) takes greatly effect by corrosion. 2) The correlation between the stress intensity factor range (
k) and crack growth rate (da/dN) for weldment in seawater is given by Paris rule as follow: da/dN=C(
K) super(m). Where m is constant, and the value is 3.82-3.84. 3) The accelerative factor (
) of BM and HAZ under seawater is about 1.1-1.9, and (
) of HAZ increases more and more under the low
K region. 4) HAZ is more susceptible to corrowion than BM because of potential of electrode (E sub(c)) of HAZ becomes more less noble potential than that of BM.
Effect of the change of second phase hardness on corrosion fatigue behavior of dual phase steel in 3% nacl solution
Journal of Ocean Engineering and Technology, volume 6, issue 2, 1992, Pages 85~93
The only hardness of 2nd phase of martensite in dual phase steel which was composed of the martensite and ferrite was changed. Fatigue test was conducted by cantilever type of self-made rotated bending fatigue testing machine. The corrosion fatigue fracture behaviors of dual phase steel were investigated in 3% NaCl solution at
cycles. The fatigue strength was increased with increasing the hardness of 2nd phase. The size and number of corrsion pits were influenced by the 2nd phase hardness and pits remain constant in size just after they were transited into cracks. The life of crack initiation was effected by stress level. The shape of relation of
K and da/dn has smaller scattering in it in 3% NaCl solution than that in air. The higher the 2nd phase hardness is, the higher the corrosion fatigue life becomes. Corrosion fatigue fracture behavior was effected by mechanics in case of
Dynamic Interaction of Waves with a Moored Structure
Kim, Chang-Je ;
Journal of Ocean Engineering and Technology, volume 6, issue 2, 1992, Pages 94~102
This paper presents the method of numerical analysis concerned with the hydropdynamic forces and moments of the floating bodies exerted by waves. The analytic methods of hydrodynamic wave forces and moments for large volume structures are generally classified into four categories ; the strip method, the boundary element method, the finite element method, and the potential matching method. In the case of the comparatively large structures, diffraction theory can be applied. However, there are no application limits of diffraction theory which have been known concerning with the analytic method of the rectangular structures. In this paper, the two-dimensional B.E.M. is treated for a moored small rectangular structure in order to evaluate applicability of diffraction theory. Numerical calculation is carried out for the structure. The results are compared with some other ones for verification. The result shows that diffraction theory is applicable to structures smaller than 0.15 in the ratio of the representative structure length d to wave length L for rectangular ones.
Ultimate Transverse Bending Strength Analysis of a SWATH Ship
Journal of Ocean Engineering and Technology, volume 6, issue 2, 1992, Pages 103~112
The calculation method which takes into account the shear lag effects on the ultimate transverse bending moment of a SWATH(Small Waterplane Area Twin Hull) ship has been developed. In case of the ultimate bending strength analysis of conventional monohull ships and general box girder structures, the hypothesis that plane section remains plane after bending can be employed but not in the case of the structures having wide flange. For the ultimate bending strength analysis of such structures, a new method which can take into account the effect of shear lag on the ultimate bending strength has been developed by adopting more reasonable assumption that warping distortion of the section takes place inthe same way as the actual stress distribution. Finally, the proposed method has been applied to a a SWATH cross deck structure.
Study on Cooling Characteristic Improvement in Underwater Wet Arc Welding of TMCP Steelplate
Journal of Ocean Engineering and Technology, volume 6, issue 2, 1992, Pages 113~124
The offshore industry created a need for quality wet weld repairs. Wet welding is a fast method of repair providing sound, structural quality welds. It requires less support equipment than a similar underwater dry weld repair or the alternative mechanical connections. Compared to welds made in air, underwater wet welds are plagued by increased hardness due to rapid quenching by the surrounding water. In this paper is described the experimntal study of improving the cooling rates of wet welds of TMCP steel plate by shielding around weld arc surroundings. The principal results of this experimental investigation can be summarized as follows : By shielding around weld arc surrounding, the cooling rates resulting from wet welds on TMCP steel plate could be lower than that of nonshielded wet welds and the fesibility on high quality of mecanical properties of wet weld on TMCP steel plate was carried out with shielded weld arc surrounding.
Frequency-Dependent Element Matrices for Vibration Analysis of Piping Systems
Journal of Ocean Engineering and Technology, volume 6, issue 2, 1992, Pages 125~132
This paper presents an approach for the derivation of frequency-dependent element matrices for vibration analysis of piping systems containing a moving medium. The dynamic stiffness matrix is deduced from transfer matrix, and, in turn, the frequency-dependent element matrices are derived. Numerical examples show that method gives more accurate results than those obtained using the conventional static shape function based element matrices.
A Study on the Coastal Development Model Due to the Construction of Artificial Island
Journal of Ocean Engineering and Technology, volume 6, issue 2, 1992, Pages 133~142
Beach evolution is of the most important problem is the coastal engineering. Especially, the structure construction through reclamation in the shallow water region nesar the beach will cause many severe problems around the structure. Beach evolution due to the construction of an artificial island in this study was studied using wave transform model and associated of an artificial island in this study was studied using wave transform model and associated sediment transport model. Numerical simulation of the model was applied to the Kwangan beach using the data of waves and shoreline of the area. The combined wave transform model and beach evolution model showed good results. The results show a breakwater will be needed to prevent severe erosion near the eastward Kwangan beach when construction an artificial island in the Suyong Bay. Good results of the study also suggest that the present model can be more widely applied to the prediction of beach evolution.
Numerical Study on Double-Diffusive Convection in a Stratified Trapezoidal Enclosure
Journal of Ocean Engineering and Technology, volume 6, issue 2, 1992, Pages 143~150
Numerical simulation is made of a stably stratified salt-water solution due to lateral heating in an equilateral trapezoidal enclosure using boundary-fitted coordinate in grid generation. Results show four types of the global fluid pattern depending on the buoyancy ratio in the enclosure, i.e., unicell flow pattern for the low buoyancy ratio, layered flow pattern for the increasing buoyancy ratio, layered flow pattern with stagnant zone for the relatively high buoyancy ratio and stagnant flow pattern for the much higher buoyancy ratio.
Effect of Flexibility Variations on Ship Responses
Journal of Ocean Engineering and Technology, volume 6, issue 2, 1992, Pages 151~171