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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Journal of Ocean Engineering and Technology
Journal Basic Information
Journal DOI :
Korean Society of Ocean Engineers
Editor in Chief :
Yun Hae Kim
Volume & Issues
Volume 10, Issue 4 - Nov 1996
Volume 10, Issue 3 - Aug 1996
Volume 10, Issue 2 - May 1996
Volume 10, Issue 1 - Feb 1996
Selecting the target year
Analysis of wave induced vibration of a typical very large floating-type offshore airport platform
Journal of Ocean Engineering and Technology, volume 10, issue 4, 1996, Pages 10~16
The vibration due to progressive ocean waves is analyzed for a typical footing-type offshore airport platform. The platform is modelled as a spring-supported Euler beam and buoyancy change due to wave is considered as excitation force, under the assumption that the wave propagates without distortion by the structure. The results show that the natural frequencies of this structure are distributed very closely and are little affected by boundary conditions and that the response charateristics due to ocean waves are quite different according to the wave frequency. In this study, the wave frequencies are divided into three regions; the resonance region at which the response is governed by the resonance between the natural mode at the wave frequency and the corresponding modal component of the wave excitation force, the bending governed region at which the response is governed by the bending stiffness, and the spring (buoyancy) governed region at which the response is governed by the spring constant ahd therefore is same as the incident wave form.
System identification of truss structures via modal paramenters
Kim, Jeong-Tae ;
Journal of Ocean Engineering and Technology, volume 10, issue 4, 1996, Pages 17~27
Efficient finite element analysis for the ultimate strength estimation of cylindrical structure
Journal of Ocean Engineering and Technology, volume 10, issue 4, 1996, Pages 28~37
A finite element analysis code considering elasto-plastic large deformation is developed to predict the ultimate strength of circular cylinders subject to external pressure loading by introducing a new type of axisymmetric shell element which can take into account the plasticity effect due to the circumferential bending while drastically saving the computing efforts compared with the tree dimensional finite element analysis. It is observed that analsis results of present approach show good agreement with the test results of previous works. Parametric study gives the effects of initial imperfections on ultimate strength ahd this information is recommended to be used to modify the actual test data to the ones which can be used more reasonably in making empirical design formulas.
Fracture behavior using AE method and reliability assessment of CFRP based on absorbed moisture
Journal of Ocean Engineering and Technology, volume 10, issue 4, 1996, Pages 38~50
Recently carbon fiber reinforced plastic (CFRP) has been used structural materials in corrosive environment such as for water, chemical tank and pipes. However, mechanical properties of such materials may be change when CFRP and exposed to corrosive environment for long periods of time. The degradation behavior of carbon fiber/epoxy resin composite material in distilled water is investigated using acoustic emission (AE) technique, Fracture toughness tests are performed on the compact tension specimens that are pilled by two types of
. During the testes, AE test was carried out to monitor the damage of CFRP by moisture absorption. The data was treated by 2-parameter Weibull distribution and the fracture surface was observed by scanning electron microscope.
Fracture toughness and AE Characteristics of Engineering plastic according to thickness
Journal of Ocean Engineering and Technology, volume 10, issue 4, 1996, Pages 51~57
A standard method for the evalution of the fracture toughness of the high polymer materials has not been fully developed in comparison with that for metallic materials, and has not yet established. In this paper, fracture toughness tests using polycarbonate specimens were carried out. The fracture thughness tests using polycabonate specimens were carried out. The fracture toughness of commercial polycarbonate were dependent on the specimen thickness. The specimen thickness is necessary above 8mm to obtain the valid
. A cumulative counts were slightly dependent on specimen thickness.
A study on characteristic adgesive condition at microscopic interfaces and notch shape strength of GFRP composites laminates under low-hot-wet environment
Journal of Ocean Engineering and Technology, volume 10, issue 4, 1996, Pages 58~66
The purpose of this investigation is to estimate the strength with the variations of the notch shape and the adgesive condition at the fiber/matrix micro interface of E-glass/PP laminates. To promote the degradation of the adhesive condition at the fiber/matrix micro interface without matrix dissolution loss, low-, hot-wet and spiking tests were carried out. The absorpotion properties and the tensile properties were compared accrding to the fiber orientation and the content. The results show that, firstly, saturated moisture absorption was reached at 5cycles and their absorptions of RD-40, UD-42 and UD-50 are 0.68%, 0.63%, 0.60%, respectively. Secondly, all the specimens investigated were mostly degraded at 5cycle, whereas UD-50 having ellipse shaped notch the least decrement of strength.
Plastic collapse behaviour of statically indeterminate beams with a crack under concentrated load
Journal of Ocean Engineering and Technology, volume 10, issue 4, 1996, Pages 67~74
The paper focuse on the effect of a crack subjects to collaspe behabiors of statically indeterminate beams under concentrated load. Through the experiment and calculation, it was revealed that the collaspe load of statically indeterminate beams is much higher than that of statically determinate beams. The cumulative AE event counts of statically determinate beams was less than that of statically indeterminate beams, and the center notch beams sas revealed less than that of the side notch beams.
Effect of moisture on interlaminar fracture toughness of CFRP composites
Journal of Ocean Engineering and Technology, volume 10, issue 4, 1996, Pages 75~83
Polymeric composites can be subjected to a wide variety of environmemtal conditions in practical use. One of most important conditions to be considered in the stuctural design using such materials is the miisture envirnment. Thus the moisture effect on interlaminar fracture toughness
of CFRP(carbon fiber reinforced plastic) composed of carbon fibers and epoxy resin is studied in this paper. Specimens were first processed in 25, 50,
flesh water and
sea water for various periods of time. After that, the water absorption and fracture toughness tests were performed under laboratory atmosphere. As result, the specimen processed in
flesh water indicates the highest misture absorbing capability, the second in
flesh water, the third in
sea water, and the specimen in
flesh water does the lowest. The interlaminar fracture toughness
increases, approaches to the maximum, and decreases as the immersion time increases. In case of interlaminar
, the value of the specimen processed in
flesh water turns out to be higher than others. In addition, the scanning electron micrographs(SEM) of fracture surfaces were also examined in order to explain the mechanism of fracture.
Fractal analysis on fracture toughness of particulate composites
Journal of Ocean Engineering and Technology, volume 10, issue 4, 1996, Pages 84~91
A fractal analysis on fracture surface of aluminium-particulate SiC composites was attempted. As the volume fraction of SiC in composites increases, the fractal dimension tends to increase. However, no correlation between the fractal dimension and the fracture toughness in terms of critical energy release rate was observed. Since the fractal dimension represents the roughness of fracture surface, the fracture toughness would be a function of not only fracture surface roughness but also additional parameters. Thus the applicability of fractal analysis to the estimation of fracture toughness must depend on the proper choice and interpretation of additioal paramerters. In this paper, the size of characteristic strctural unit for fracture was considered as an additional parameter. As a result, the size appeared to be a function of only volume fraction of SiC. Finally, a master curve for fracture toughness of aluminium-particulate SiC composites was proposed as a function of fractal dimension and volume fraction of SiC.
A study on fatigue life of Al 7075/CFRP multilayered hybrid composite materials
Journal of Ocean Engineering and Technology, volume 10, issue 4, 1996, Pages 92~102
In this research, to develope the A1 7075/CFRP multilayered hybrid composites, CRALL(Carbon Reinforced aluminum lamiate) specimens were processed by autoclavecuring system that curing temperature, time, surface pretreatment condition of aluminum were constant. Andthe fatigye life and failure mechanism on CFRP volume fraction and fiber orientation of CRALLspecimens were investigated. A fatigue life was greatly influenced by effect of CFRP fiber volume fraction but it was less effected than those of fiber orientation. The fatigue failure arised from interface delamination of CFRP and aluminum sheet after shear fracture of aluminum layer. The failure mechanism is assumed that the aluminum laminates which divide the CFRP into many thim layers tend to arrest the failure propagation.
The behavior of corrosion potential in the mortar-embedded
Journal of Ocean Engineering and Technology, volume 10, issue 4, 1996, Pages 103~108
To syudy the change of prtential in the mortar-embedded precorroded rebar, a half cell method was adapted. The rebar was corroded by the salt spray and then the rebar embedded in the mortar. A saturated copper sulfate feference electrode was used. The corrosion potential of the rebar in the mortar specimen cured in air was increased, whereas that of the rebar cured in water was decreased with aging. The corrosion potential of the rebar in the mortar was decreased with corroded time by the salt spray. As the mortar thickness covered the rebar was increased, the corrosion potential of the rebar in the mortar was increased.
The study of mixed convection in a rectangular enclosure for indoor air control
Journal of Ocean Engineering and Technology, volume 10, issue 4, 1996, Pages 109~117
The numerical and experimental studies on the mixed convection of a rectangular enclosure for indoor air control has been studied numerically using the finite volume method and experimentally with holographic interferometry and Laser apparatus. The parameters studied here are Pr= 0.71,
and the positions of an outlet. The results show streamlines, isothrems, velocity distributions and photograph of holographic interferometry and streamlines. It is found that the minimum cell occurs at Re=100, Gr=10000. The mean Nusselt numbers can be expressed by the correlation equation
The comparison of numerical and experimental results shows a good agreement.
A study on the flow characteristics of non-Newtonian fluid flows in dividing tubes
Journal of Ocean Engineering and Technology, volume 10, issue 4, 1996, Pages 118~127
Flow patterns of fluid flow in dividing trbe were visualized, and the energy losses due to dividing were measured in laminar dividing flow of the viscoelastic fluid and its solution in tube junctions with dividing angles of
. Two separation zones were observed. swelling of the streamline to the main tube or to lateral tube was observed. The sizes of the separation zones depend on the Reynolds number, the dividing angle and the dividing flow rate. The energy loss coefficients decrease with increasing Reynolds number, but their decreasing rate decreases with increasing Reynolds number as the sizes of the separation zone increase. The effect of dividing angle on the energy loss coefficients and separation is greater for main tube than for the lateral tube.
A study on the characteristics of soots formation in spray flame for DI diesel engine
Journal of Ocean Engineering and Technology, volume 10, issue 4, 1996, Pages 128~140
To analyze a formation process of the soots in spray flame in the combustion chamber, an optically accessible DI Diesel engine was used for visualization. The images of the flames and soots were visualiaed with high speed camera by Schlieren method and Light extinction method. The spray flame and soot images on the films were analyzed at the various engine operating conditions. Soot distributed widely in spray flame and its concentration was about
at the position close by nozzle tip of spray flame region, however it decreased below
at the corner of combustion chamber due to soot oxidation.
Bearing capacity analysis of stone column in soft clay soils
Journal of Ocean Engineering and Technology, volume 10, issue 4, 1996, Pages 141~148
Use of stone column for deep ground treatment in soft clay soils is an effective method. The stone column significantly increases load carrying capacity of the soft clay soil. A analysis method for bearing capacity of stone column in soft clay soil is developed. The capacity made by developed method are compared wity observed values from field load test and a reasonable correlation is noted.
A study on the wave control function of ecosystem control structures
Journal of Ocean Engineering and Technology, volume 10, issue 4, 1996, Pages 149~159
Multipurpose development of the coast and ocean can be considered as multifunction construction combining the functions of coastal protection, waterfront amenity and creation or rehabilitation of habitats. Multfunction development of coastal and ocean spaces can be accomplished by applying the ecosystem control structure of artificial habitats which will cultivate fishing ground with ecological harmony to the coastal protection system. To evaluate the applicability of ecosystem control structures as as fundamental coastal protection structure, wave control function of the structure is studied by numerical and physical analyses. Dimensional analysis and hydraulic experiment point out the importance of width and crest depth of ecosystem control structure, construction water depth and wave steepness. Wave control efficiency is estimated by the attenuation coefficient
according to wave steepness
, relative constructed water depth
, relative berm width
and relative crest depth
of eosystem control structure. Empirical fomulas are suggested based on the results of model test by applying the multiple model based on this experimental results and numerical wave shoaling-dissipation-breaking model appears to be valid for the analysis of wave transformation around ecosystem control structure in the coastal waters.
Development of a sea environmental monitoring system using wire and wireless communication
Journal of Ocean Engineering and Technology, volume 10, issue 4, 1996, Pages 160~165
This paper introduces a sea environmental monitoring system for measuring pH,DO, level and temperature. This system is developed using a personal computer(PC) and multiple single board computers. A PC communicates with the single board computers by awireless communication method and transfers data to another personal computer for processing data by a modem. The values of pH,Do,level and temperature, which are basic components to estimate sea environment, are real-timely processed in the single board computer at each stations, and transferred to the monitoring PC. These data are graphically shown on the PC monitor and logged on the data processing system in the form of file. Using the wire and wireless communication system, user can constantly analyze the acquired data and detect the sea contamination.