• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2019.11a
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• pp.252-253
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• 2019

선박의 안정성에서 복원성은 매우 밀접한 관계를 가진다. 선박의 복원성을 알기위해서는 GM을 알아야 한다. GM을 구하는 방법은 출항 후 횡요주기로 구하는 방법, 경사시험에 의한 방법, 배수량 등곡선도를 이용하여 계산하여 구할 수 있다. 본 연구에서는 GM을 구하는 방법들 중 출항 후 횡요주기로 구하는 방법과 경사시험에 의한 방법 간의 오차범위를 확인하며 설계된 데이터와 비교하여 정확도를 분석하고자 한다. 시험에 사용되는 모형선박은 KVLCC2이며, 모형선박의 무게, 무게중심과 관성모멘트를 변경하면서 정확도를 분석하였다.

• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.4
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• pp.380-388
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• 2023

This study estimates the metacentric height (GM) of a model ship by varying the transverse weight distribution, considering the effects of the roll period and moment of inertia, and compares it with the GM values measured by the inclining test. In the process, the relationship between the values is analyzed. Three types of ships-a 7-ton fishing vessel, 20-ton fishing vessel, and KRISO Very Large Crude-oil Carrier (KVLCC)-were used for the experiment and comparison. The roll period and moment of inertia were measured using the free roll decay and swing frame tests, and the GM was measured using inclining test. The estimated GM from the roll period and moment of inertia showed the same trend as the GM measured using the inclining test in the change of the weight distribution. However, the GM values measured using the inclining test were lower. Therefore, additional correction factors or parameters other than the roll period and moment of inertia are necessary for estimating GM. In the future, the relationship between the weight center and the estimated GM will be analyzed to derive the correction factors.

• Journal of the Korean Geotechnical Society
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• v.39 no.11
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• pp.41-51
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• 2023

This study employs three-dimensional simulation through FLAC3D to investigate the impact of installation angles on the dynamic characteristics of Triaxial Micropiles. The numerical model is validated against centrifuge test results to ensure accuracy. The findings reveal significant influences of the installation angle on the dynamic behavior of Triaxial Micropiles. Specifically, under seismic conditions such as the Capetown and San Fernando earthquakes, the lowest recorded values for peak bending moment and settlement occurred at an installation angle of 15 degrees. In contrast, when subjected to an artificial earthquake with a frequency of 2 Hz (Sine 2 Hz), Micropiles installed at 0 degrees exhibited the lowest peak bending moment, maximum axial load, and settlement values.

• Journal of Navigation and Port Research
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• v.26 no.1
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• pp.1-7
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• 2002

A coastwise chemical tanker sailing at full speed has capsized in calm water and while turing. We investigate reasons of the accident and demonstrate that a proper correction for the free surface effect of the liquid cargo has not been practiced in the initial design stage and that the bow-sinkage induced in sailing has weakened the form stability of the ship. It is also shown that the liquid cargo shift occurring in turning generated a significant outward heel moment.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.20 no.4
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• pp.485-492
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• 2007

In this study, based on the temperature distribution and the spalling histories those obtained in the companion paper, the thermal stress and moments of underground box structure were estimated. Additionally, the ultimate sectional moment considering with the thermal nonlinearities of material were estimated and the load carrying capacity of underground box structure was also obtained. As results, the load carrying capacity of negative moment part was dominated by thermal moment that come from thermal gradient of the section. However, the load carrying capacity of the positive moment part was rules by the yield stress of rebar that exposed to the high temperature induced spalling phenomena.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.11 no.3
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• pp.165-172
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• 1999

A probability density function of reliability function is derived in this paper, by which the stability of armor units on the rubble-mound breakwater can be studied on the probabilistic approach. To obtain the distribution, each random variable of the reliability function is assumed to follow Gaussian distribution. The distribution function of reliability function is in agreement with the histogram simulated by the Monte-Carlo method. In addition, the failure probability of armor units on the rubble-mound breakwater evaluated by the derived probability density function is shown to have the same order of magnitude as those calculated by FMA and AFDA of moment method. In particular, it is important to note that random variables of the reliability function may be considered to be statistically independent in the reliability analysis of armor units on the rubble-mound breakwater. Therefore, the present approach may be straightforwardly applicable to all of the cases that any random variables in the reliability function are controlled by other distribution functions as well as normal distribution.

• Journal of Convergence for Information Technology
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• v.10 no.4
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• pp.160-167
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• 2020

This study analyzes the effects of changes in running velocity and slope on the biomechanical factors of the lower limb joints. For this purpose, 15 adult males in their 20s ran according to changes in running speed (2.7, 3.3 m/s) and slope ( -9°, -6°, 0°, 6°, 9°) on the treadmill, and their running characteristics (stride length, stride frequency). The range of motion of the lower limb joint and the vertical ground reaction force were greater in UR (p <.05), and the moment of the lower limb joint, braking force, thrust and load factor was large in DR (p <.05). In joint power, the ankle joint was greater in DR, and hip joint was greater in the UR (p <.05). These results show that the injuries of the ankle joint will be greater than other cases when running DR at a speed of 3.3 m/s.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.10
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• pp.967-974
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• 2017

In this paper, a differential-braking-based yaw moment control system was developed to guarantee robust performance against road bank angle. A new target yaw rate model was established by combining the signal from a lateral acceleration sensor and 2-DOF single track model. In addition, a disturbance observer was utilized to take into account parameter uncertainties in yaw dynamics and to improve robust performance of the controller. CARSIM, which is a multi-DOF vehicle dynamic simulation tool, was used to verify the performance of the proposed controller in various driving scenarios. The simulation results indicate that the stability of the vehicle was robustly maintained by the controller, which is characterized by the reflection of the signal of a lateral acceleration sensor signal and by the compensation of the errors in the model parameters via the disturbance observer.

• Journal of the Korea Concrete Institute
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• v.24 no.2
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• pp.147-156
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• 2012

In recent years, many high-rise buildings have been constructed in irregular structural system with inclined columns, which may have effect on the structural behavior of beam-column joints. Since the external load leads to shear and flexural forces on the inclined columns in different way from those on the conventional vertical columns, failure mode, resistant strength, and ductility capacity of the inclined column-beam joints may be different than those of the perpendicular beam-column joints. In this study, six RC inclined beam-column joint specimens were tested. The main parameter of the specimens was the angle between axes of the column and beam (90, 67.5, and 45 degree). Test results indicated that the structural behavior of conventional perpendicular beam-column joint was different to that of the inclined beam-column joints, due to different loading conditions between inclined and perpendicular beam-column joints. Both upper and lower columns of perpendicular beam-column joints were subjected to compressive force, while the upper and lower columns of the inclined beam-column joints were subjected to tensile and compressive forces, respectively.

• Proceedings of the KIEE Conference
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• 2006.07e
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• pp.5-6
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• 2006

본 시험의 목적은 수직주 및 $80^{\circ}$경사주에 대한 강도시험을 통하여 보통지선이 없는 수평지선주의 시설가능 범위를 파악하고, 전선장력에 대한 지선장력과 전주저항모멘트간의 상관관계를 실증시험을 통하여 지선 강도계산시 전주저항모멘트 적용의 타당성 여부를 조사하는 것이다. 시험결과 $2^{\circ}$이상 휘어진 전주는 지선 보강이 필요하며, 설계시 하중 작용점에 따른 전주저항모멘트는 일정한 값을 적용하여도 됨을 확인하였다. 그리고 지선강도계산식에서 전주의 저항모멘트를 고려하지 않는 것이, Y지선보다는 각 하중 작용점에 해당 불평균장력에 견디는 1조 지선을 시설하는 것이 바람직하다. 또한 보통지선이 없는 수평지선주는 지선에 작용하는 하중, 전주의 설계하중, 전주길이 및 지선의 설치위치를 고려하여 선정하여야 하여야 함을 도출하였다.