• Steel and Composite Structures
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• v.20 no.4
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• pp.913-930
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• 2016

It is common practice to use Reduced Web Beam Sections (RWBS) in steel moment resisting frames. Perforation of beam web in these members may cause stress and strain concentration around the opening area and facilitate ductile fracture under cyclic loading. This paper presents a numerical study on the cyclic fracture of these structural components. The considered connections are configured as T-shaped assemblies with beams of elongated circular perforations. The failure of specimens under Ultra Low Cycle Fatigue (ULCF) condition is simulated using Cyclic Void Growth Model (CVGM) which is a micromechanics based fracture model. In each model, CVGM fracture index is calculated based on the stress and strain time histories and then models with different opening configurations are compared based on the calculated fracture index. In addition to the global models, sub-models with refined mesh are used to evaluate fracture index around the beam to column weldment. Modeling techniques are validated using data from previous experiments. Results show that as the perforation size increases, opening corners experience greater fracture index. This is while as the opening size increases the maximum observed fracture index at the connection welds decreases. However, the initiation of fracture at connection welds occurs at lower drift angles compared to opening corners. Finally, a probabilistic framework is applied to CVGM in order to account for the uncertainties existing in the prediction of ductile fracture and results are discussed.

• Special Issue of the Society of Naval Architects of Korea
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• 2009.09a
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• pp.93-96
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• 2009

Foundation structure for the main engine heavy spare parts in the engine room is susceptible to resonance problem due to outfitting weight. In addition the deck floor has a large opening for the main engine installation and maintenance, which further weakens the foundation structure. To reinforce the weak structure, two types of approaches have been used; 1) insert an H-pillar below or above the floor and 2) increase the stiffener size. In this paper, the H-pillar approach is used to solve the vibration problem of the foundation structure in the engine room opening area. A commercial program is used to analyze the vibration problem ad to find the location and the size of the H-pillar. Modal test at the quay and on-board vibration measurement during the sea trial have confirmed the validity of inserting an H-pillar below the floor.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.85-86
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• 2010

This study is aimed to investigate on the structural properties (like as strength, failure mode, ductility) of beams with web openings reinforced with steel tube of square. The main parameters are follows; 1) with and without web opening 2) the number of opening, 3) location of openings. In the quasi-static tests, structural properties of PFBS1A and PFBS2A were most superior. When the locations of opening are respectively maximal moment zone (M), shear (S), co-existence area of moment and shear (M+S), the specimen with web opening at maximal moment zone is not less than that without web opening in terms of strength and ductility.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.18 no.3
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• pp.395-405
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• 2020

Compartment fire tests were performed using kerosene and Jet A-1 as fire sources to evaluate the relationship between flame temperature and opening size. The tests were performed for a fire caused by the release of kerosene owing to vehicle impact, and for a fire caused by the release of Jet-A-1 owing to airplane collision. The compartment fire tests were performed using a 1/3-scale model of a metal storage cask when the flame temperature was deemed to be the highest. We found the combustion time of Jet-A-1 to be shorter than that of kerosene, and consequently, the flame temperature of Jet-A-1 was measured to be higher than that of kerosene. When the opening was installed on the compartment roof, even though the area of the opening was small, the ventilation factor was large, resulting in a high flame temperature and long combustion. Therefore, the position of the opening is a crucial factor that affects the flame temperature. When the metal storage cask was stored in the compartment, the flame temperature decreased proportionally with the energy that the metal storage cask received from the flame.

• 유체기계공업학회:학술대회논문집
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• 2004.12a
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• pp.315-320
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• 2004

Swing check valves are the most common type of check valve in nuclear power plant and need to be operated property to perform their functions and to keep the valve internals stable. However, for a swing check valve disc to remain stable, the opening characteristics should be identified and the upstream flow velocity should be enough to hold the disc fully open and without motion. Thus it is necessary to develop a model for predicting the flow velocity for a given disc opening. In the present study, the disc positions with mean flow velocity were measured for 3 inch and 6 inch swing check valves. Comparison of the measurements with the existing models showed that the models underestimate the mean flow velocity for a given disc position. Therefore, the existing model for predicting swing check valve disc position was improved with the realistic disc impingement area perpendicular to the flow stream and the experimental data. The result showed that the improved model with the best estimate of kb = 0.04 predicts well the disc openings of 6 inch swing check valve, especially in the low velocity region. For better prediction of the disc opening at high flow velocity, however, it is recommended to develop a kb correlation with the disc angle.

• Journal of Korean Port Research
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• v.11 no.2
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• pp.157-172
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• 1997

To develop the port productivity and effictiveness, the introduction of the On Dock Operating System in Pusan Container Terminals has to be considered and the present Off Dock CY be closed step by step. This work aims to evaluate the needed CY area in Pusan Port under the On Dock Operating System. This researching flow is as follows. Firstly, estimate total sea-borne container cargo volumes in Korea and distribute them to all container terminals according to the past trends and the planned port development. Secondly, estimate the average period and the average tiers stored at On Dock CY in case of On Dock Operating System. Thirdly caculate the needed CY Area to handle the distributed container cargo volume under the On Dock Operating System. Finally, the following results are obtained. (1) In 1998, opening the Gamman Terminal, 827 thousands cubic meters are insufficient. (2) In $2001\sim2004$, the insufficiency of needed CY Area will be maximized and estimated to be 936 thousands cubic meters in 2001. (3) In $2005\sim2011$, opening the Gadu Terminal, the insufficiency of needed CY Area will be decreased and estimated to be 240 thousands cubic meters in 2011.

• Journal of the Korean Geosynthetics Society
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• v.12 no.2
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• pp.55-66
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• 2013

The experiment of model soil structures has been executed for the soil retaining wall in various conditions of excavation, in this study, to analyze the behavior of the corner of opening. The ground for experiment has been constituted with the sandy soil of relatively loose density, the construction condition has been divided into the opening length of corner, embedded depth, existence of strut, etc., and the excavation has been carried out for 4 stages in total. The behavior characteristics at the corner of opening area has been verified by concentrate analysis of the displacement of wall and the subsidence of ground surface, for each construction and excavation condition, using the measuring instrument mounted inside the model soil structure. In the result of experiment, it has been analyzed that the opening area of corner is unstable structurally compared to the linear area, as it shows that the wall displacement and subsidence of ground surface have been increased when the opening length of corner gets longer. The longer the embedded depth, ground surface settlement of coner was decreased 40%. To apply deeper embedded depth than designed estimate was an advantage in the safety. As a result of the analysis of coner behavior with added struts, maximum surface settlement and maximum horizontal displacement was evaluated 40% and 30%, respectively. Hence increased embedded depth with the added struts in coner edge was effective in the safety.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.11
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• pp.2796-2803
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• 2000

For traditional Leak-Before-Break(LBB) analyses, symmetric conditions were assumed for a pipe-nozzle interface to simplify the analysis in calculating J-integral. However. this assumption could result in an overly conservative design criteria for a pipe-nozzle interface, Since the pipe-nozzle interface is asymmetric due to the difference of stiffness between pipe and nozzle, it is required to develop a new methodology considering the nozzle effect. The objective of this paper is to evaluate the effect of nozzle no the development of LBB design criteria for nuclear pipings. For this purpose, extensive finite element analysis were performed to evaluate the effect of nozzle on Crack Opening Area(COA), Detectable Leakage Crack(DLC) length and J-integral values. In conclusion, it was proven that the application of LBB concept could be extended for more nuclear piping system by considering the nozzle.

• Journal of the Korean Institute of Educational Facilities
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• v.16 no.1
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• pp.59-68
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• 2009

In the knowledge-base 21st century, schools are required functions as a place of education for student as well as a place of life-long education for community. Therefore schools are needed to be open and to be multiple. The purpose of this study is to analysis of open-facilities to community of twenty elementary schools in Busan and to suggest a design guideline for open -facilities of school plan at the base of this analysis. The main contents of this study are as follows: 1) Study for general ideals and necessity of opening school facilities to community. 2) Establish the study objects of the opening facilities by existing studies and a questionnaire. 3) Focused on twenty elementary schools in Busan, analysis of the characteristics of opening facilities in terms of the using efficiency, that is, the approachability, the recognition and the territoriality. 4) At the base of 1) 2) 3), results are as follows: $\circ$ In consideration of approachability, the block plan of the open-facilities should be designed at making a circulation system without interruption of the student's educational area. $\circ$ In consideration of recognition, the form and detail of external and internal of the open-facilities should be designed at making distinction with the student's educational area. $\circ$ In consideration of territoriality, the zone of the open-facilities should be designed at composing exclusive hall, staircase and sanitation.

• YAKHAK HOEJI
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• v.42 no.2
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• pp.196-204
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• 1998

The blood-brain barrier (BBB) of rats was modificated opening reversibly by infusing a hyperosmotic solution of arabinose (1.6 molal) into the right external carotid artery. Pre vious studies demonstrated that permeability was increased maxmmally in the first 15 min and remained slightly elevated at 1 hr. As control reference, saline was used. In the present study, to evaluate the effects of osmotic BBB opening on the BBB trasport according to hydrophilic or hydrophobic characteristics of drugs. And the differences of the uptakes of these compounds to right (treated osmotic opening) and left (untreated) hemispheres in same rats were compared each other following injection of 8 mCi per rat of $^{99m}Tc$-ethylene triamine pentaacetic acid (DTPA) as hydrophilic drug or 5mg/kg of phenytoin as hydrophobic drug mto the right external carotid artery of rats between two groups (1.6 molal arabinose vs saline). The uptakes of $^{99m}Tc$-DTPA and phenytoin in the right cerebral hemispheres were increased to about thirty three times and twice rather than those in the left cerebral heimspheres, respectively. And PAs (permeability X capillary surface area) were also increased from a control mean of 2.11${\times}10^{-4}$ (Untreated) to 6.98${\times}10^{-3}\;sec^{-1}$ (treated osmotic opening for $^{99m}Tc$-DTPA and 0.29 to 0.17 $sec^{-1}$ for phenytoin, respectively. From the results of present study, it is noted that osmotic opening of BBB is more effective in the brain delivery of hydrophilic drugs rather than that of hydrophobic drugs.