• Proceedings of the Korean Geotechical Society Conference
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• 2002.03a
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• pp.357-364
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• 2002

This paper describes the feasibility of compacting subgrade layer in thicker lifts than currently permitted as 20 cm. This project involved constructing and testing a full scale test section in highway. Soil stiffness in field was evaluated by a nondestructive testing method, called Geogage. Quality control tests and FE Analysis were also conducted. Typical dynamic compaction roller of 11ton weight is applied for full scale test and a Mohr-Coulomb model and Plane strain condition are used for FE Analysis. The results showed that compaction-induced stress and dissipated energy are mainly depend on depth of soil and it could be possible to increase thickness of a lift.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.05a
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• pp.250-253
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• 2005

This paper is investigates the separation shock of payload fairing. Separation test of subscale PLF using half separation device and half PLA is performed. Resulting shock loads at equipment bay and fairing joint are measured. Pyroshock estimation is performed using AUTOSEA Pyroshock Module. Input data to analysis model is obtained from the separation test results of subscale PLF. And model of AUTOSEA is updated comparing results between tests and analysis.. This enables us to validate the AUTOSEA model. Tuned model of subscale PLF and separation device is used to update full scale model, and the shock analysis result of full scale model is estimated in this paper. This paper also discusses the results regarding the difficulty of structural modeling and its numerical implementation in AutoSEA2 Software.

• Journal of the Korean Society for Railway
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• v.9 no.1 s.32
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• pp.12-17
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• 2006

The bridge to be analyzed is a self-anchored suspension bridge which is constructed within the country. Forced vibration test was performed with oscillator for verification of safety, maintenance and management. In this study, the feasibility of deduction was verified with the modified analysis model by comparing natural frequency, natural mode and damping ratio of the real bridge, which are obtained from the vibration test of the whole bridge after construction of 3-dimensional self-anchored cable suspension bridge, with the eigenvalue of analytic computation model and evaluating them. As a result of study, the friction of bridge bearing must be considered to get the natural frequencies of flexural vibration, and evaluating the polar moment of inertia is critical factor in analysis modeling in case of torsional vibration. The logarithmic damping ratio of the test appeared to exceed the ordinary one assumed at the design phase.

• Wind and Structures
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• v.14 no.4
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• pp.301-319
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• 2011

The full-scale measurements are compared with the wind tunnel test results for the long-span roof latticed spatial structure of Shenzhen Citizen Center. A direct comparison of model testing results to full-scale measurements is always desirable, not only in validating the experimental data and methods but also in providing better understanding of the physics such as Reynolds numbers and scale effects. Since the quantity and location of full-scale measurements points are different from those of the wind tunnel tests taps, the weighted proper orthogonal decomposition technique is applied to the wind pressure data obtained from the wind tunnel tests to generate a time history of wind load vector, then loads acted on all the internal nodes are obtained by interpolation technique. The nodal mean wind pressure coefficients, root-mean-square of wind pressure coefficients and wind pressure power spectrum are also calculated. The time and frequency domain characteristics of full-scale measurements wind load are analyzed based on filtered data-acquisitions. In the analysis, special attention is paid to the distributions of the mean wind pressure coefficients of center part of Shenzhen Citizen Center long-span roof spatial latticed structure. Furthermore, a brief discussion about difference between the wind pressure power spectrum from the wind tunnel experiments and that from the full-scale in-site measurements is compared. The result is important fundament of wind-induced dynamic response of long-span spatial latticed structures.

• Journal of the Korean Geotechnical Society
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• v.18 no.4
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• pp.21-32
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• 2002

Small and full scale model tests were performed to obtain the transient responses of shafts subjected to elastic impact by impact-echo test. Four end conditions of drilled shafts were considered: (1) free, (2) fixed, (3) rock-socketed, and (4) soft bottom. In small scale model tests, mock-up shafts were fabricated to simulate these four drilled shafts using poly-urethane and plastic material. Additionally, skin frictions between shaft and rock were changed to find out the effect of side contact on dynamic responses. All impact responses were tested in the air. Subsequently, full scale model tests were also carried out on concrete shafts that were in free and rock-socketed condition. The end conditions of the drilled shafts could be identified with good reliability by the waveforms from both small and full scale model tests. The results obtained in this study will provide an improved understanding of the impact responses for end conditions, especially for rock-socketed drilled shafts that are frequently designed and built in Korea.

• Proceedings of the KSR Conference
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• 2002.10a
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• pp.54-59
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• 2002

In general, the aluminum extrusions are used to the light construction of the high speed rail vehicle structures. However, the research works ok the crashworthy design of the high speed rail vehicle structures are not published sufficiently because the crash test of high speed rail vehicle structures costs high and is complicated. So, a method that can predict crash characteristics of a large size structure like a high speed tail vehicle should be suggested. In this study, the scale model studies are performed to predict the impact energy absorption characteristics of full scale model. In the first place, we verified the theory of scale law using FE-simulation from the crashworthiness point of view. Secondly, we performed the crush test using scale model, made of aluminum sub structure. As a result, we could predict the crash characteristics using scale model by 10∼20% error.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.42 no.3
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• pp.148-157
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• 2006

A model experiment, simulation test using personal computer and real sea trial fishing were carried out to investigate the basic efficiency of bottom trawl net which can be used in the sea mount of North West Pacific, and experimental values were analyzed as the values of full-scale bottom trawl net. Hydrodynamic resistance for the full-scale trawl net according to the Koyama equation was 2.1 times higher than that of simulation and 2.4 times higher than that of model experiment at the average towing velocity. At the 3.5kt's of towing speed, net width of the full-scale trawl net was 2.5% smaller than that of simulation and 8.2% larger than that of model experiment. On the fishing experiment of the full-scale trawl net for the 3.5kt's of average towing speed, average net height of A group(same direction with external force) was 423.5% higher than that of model experiment and 457.1% higher than that of simulation and that of B group(opposite direction with external force) were 283.8% and 306.3% higher than in case of model experiment and Simulation respectively. Net mouth of the full-scale trawl net was 338.1-504.6% higher than those of model experiment and simulation in A group, and 525.2-745.3% higher in B group.

• Journal of the Society of Naval Architects of Korea
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• v.47 no.2
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• pp.178-187
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• 2010

The performance of the waterjet system of a patrol boat has been experimentally studied. A waterjet propulsion system has many advantages comparing with a conventional screw propeller especially for high speed craft because of its good cavitation performance. This paper describes experimental procedure and analysis method of self-propulsion tests with a 1/12-scale model. Experimental results were analyzed according to ITTC 96 standard method. The full-scale effective power and delivered power of the ship were also analyzed and the full-scale speed predicted from the model test compares reasonably with the measured full-scale results of the sea trial.

• Journal of the Society of Naval Architects of Korea
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• v.46 no.2
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• pp.127-135
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• 2009

The performance of the waterjet system of 180 ton class fishing guard ship has been experimentally studied. A waterjet propulsion system has many advantages in comparison with a conventional screw propeller especially for high speed craft because of its good cavitation performance. Recently waterjet system has been applied to fishing boats and fishing guard ship because of avoiding a net problem although their speeds are not so high. This paper describes experimental procedure and analysis method of resistance and self-propulsion tests with a 1/14.46-scale model. Experimental results were analyzed according to ITTC 96 standard method. The full-scale effective power and delivered power of the ship were also analyzed and the full-scale speed predicted from the model test results shows a good agreement with the full-scale result from the sea trial tests.

• Journal of the Society of Naval Architects of Korea
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• v.61 no.3
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• pp.161-169
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• 2024

In order to investigate cavitation performance for the azimuth thruster in Large Cavitation Tunnel (LCT), the cavitation test apparatus was designed and manufactured. Generally the model scale is determined by the pod dynamometer with about 70mm diameter. Recently as ships with azimuth thruster have become bigger, the problem of the model ship installation was occurred. The model ship with pod dynamometer couldn't be installed in the LCT test section. The cavitation test apparatus and technique which can conduct the cavitation test without pod dynamometer were developed. The cavitation tests were conducted in torque identity method instead of thrust identity method. The target ship with azimuth thruster is 18K LNG bunkering vessel. As the full-scale ship test was conducted, the model cavitation tests were conducted at the same operating conditions. The fluctuating pressure levels of the full-scale ship were compared to those of the model tests. Another model cavitation test was conducted in the foreign institute and the cavitation observation results were compared to those of LCT. Through the comparison with the existing results, it is thought that the cavitation test for the azimuth thruster can be conducted in torque identity method.