• 한국연소학회:학술대회논문집
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• 2006.04a
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• pp.39-45
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• 2006

Analysis of the internal state of the blast furnace is needed to predict and control the operating condition. Especially, it is important to develop modeling of blast furnace for predicting cohesive zone because shape of cohesive zone influences overall operating condition of blast furnace such as gas flow, chemical reactions and temperature. because many previous blast furnace models assumed cohesive zone to be fixed, they can't evaluate change of cohesive zone shape by operation condition such as PCR, blast condition, and production rate. In this study, an axi-symmetric 2-dimensional steady state model is proposed to simulate blast furnace process. In this model, cohesive zone is changed by solid temperature range, FVM is used for numerical simulation. To find location of cohesive zone whole calculation procedure is iterated Until cohesive zone is converged. Through this approach, shape of cohesive zone, velocity, composition and temperature within the furnace are predicted by model.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.23 no.9
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• pp.1129-1138
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• 1999

This paper presents a systematic two-zone modeling for reliable performance prediction of centrifugal compressors. In order to improve the predictive capability, a modified jet slip factor is developed and new corrections for the wake flow deviation and mass fraction are suggested based on the comprehensive experimental data of the three Eckardt impellers. The proposed two-zone modeling is tested against nine sets of measured data of centrifugal compressors. The results are also compared with those obtained by the mean streamline analysis. It was found that the predictions by the present two-zone modeling agree fairly well with experimental data for a variety of centrifugal compressors over the wide operating conditions.

• Fire Science and Engineering
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• v.18 no.1
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• pp.42-48
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• 2004

The deterministic modeling techniques like Zone model and Field model are mainly used for thermal distribution and smoke flow at fire case in multi use facilities. While Zone model analyse fire simulation by dividing spaces by 2 section, the Field model dividing many cells. However, the difficultly follows to prove efficiency between the two models when it applys. Therefore new modeling development is required which in closes to real situation by verify number algorithm and related data for fire modeling. The paper analyses the efficiency of two different fire modeling at interior spaces of multiplex cinema theater. It is found that the zone model for average distribution and the field model for detail space phenomenon are relevant to apply. Also, Filed model is useful to the result that fire analysis and position of detector and review for smoke control system.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.05a
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• pp.531-536
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• 2002

The design of anchorage zone in prestressed concrete cable stayed bridges is very important area due to the more accurate analysis is needed to estimate the behavior. In the study, since the cable anchorage zone in the prestressed concrete cable-stayed bridge is subject to a large amount of concentrated tendon forces, it shows very complicated stress distributions and causes a serious local cracks. Accordingly, It is necessary to investigate the parameters of affecting the stress distribution, such as the cable inclination, the position of anchor plate, the modeling method and the three dimensional effect. The tensile stress distribution of anchorage zone is compared to the actual design condition by varing the stiffness of spring element in the local modeling and an appropriate position of anchor plate is determined. These results would be elementary data to the stress state of anchorage zone and more efficient design.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1997.04a
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• pp.53-60
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• 1997

The strain localization of concrete is a phenomenon such that the deformation of concrete is localized in finite region along with softening behavior. The objective of this paper is to develope a consistent algorithm for the finite element modeling of localized zone in the analysis of the strain-localization in concrete. For modeling of the localized zone in concrete under strain localization, a general Drucker-Prager failure criterion which can consider nonlinear strain softening behavior of concrete after peak-stress is introduce. The return-mapping algorithm is used for the integration of the elasto-plastic rate equation and the consistent tangent modulus is derived. Using finite element program implemented with the developed algorithms, strain localization behaviors for the different sizes of concrete specimen under compression are simulated.

• International conference on construction engineering and project management
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• 2015.10a
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• pp.294-298
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• 2015

In the United States, the completion of Construction Work Zone (CWZ) impact assessments for all federally-funded highway infrastructure improvement projects is mandated, yet it is regarded as a daunting task for state transportation agencies, due to a lack of standardized analytical methods for developing sounder Transportation Management Plans (TMPs). To circumvent these issues, this study aims to create a spatiotemporal modeling framework, dubbed "SWAT" (Spatiotemporal Work zone Assessment for TMPs). This study drew a total of 43,795 traffic sensor reading data collected from heavily trafficked highways in U.S. metropolitan areas. A multilevel-cluster-driven analysis characterized traffic patterns, while being verified using a measurement system analysis. An artificial neural networks model was created to predict potential 24/7 traffic demand automatically, and its predictive power was statistically validated. It is proposed that the predicted traffic patterns will be then incorporated into a what-if scenario analysis that evaluates the impact of numerous alternative construction plans. This study will yield a breakthrough in automating CWZ impact assessments with the first view of a systematic estimation method.

• Tunnel and Underground Space
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• v.15 no.2 s.55
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• pp.111-118
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• 2005

The area of investigation belongs to Okchon metamorphic zone and the fault fractured zone runs parallel to the tunnel direction. It causes the independent decline of tunnel face and the slackness of the tunnel surrounding base so, after all, the severe displacement has occurred within the tunnel. Accordingly, the TSP(Tunnel Seismic Prediction) survey has been performed to investigate the extent of fault fractured zone and to analize its characteristics. Also, we have analized the behavior causes by performing the tunnel face mapping and drilling investigation, and confirmed the position and scale of geological anomaly area and front fractured zone which influences tunnel excavation and supporting. Collected data analyzed ground layer condition through 3 dimensional modeling. Several variables included in the modeling were analyzed by geostastistics. The analysis of the modeling data shows that the belt of weathering by fault fractured zone is developing on the basis of the right side of tunnel and that is decreasing to the left side. The fault fractured zone was confirmed that it has strike, $N0\~5^{\circ}E$ dip NW, and it is consisted of large-scale fractured zone including several anomalies. The severe displacement in tunnel is probably caused by asymmetrical load that n generated by the crossing of discontinuity and the rock strength imbalance of tunnel's both side by fault fractured zone, and judge that need tunnel reinforcement method of grouting etc.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.10
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• pp.1195-1203
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• 2012

Welding is a well-developed, widely used process for permanently joining metal components. However, the mechanical reliability of welded parts still offers room for improvement. A weld region consists of a fusion zone, a partially melted zone, and a heat-affected zone, and each zone has different material properties. In addition, the geometrical shape of a weld bead or fillet influences the mechanical reliability. A precise structural analysis must consider how a local welded region influences the mechanical behavior of the entire structure. This study focuses on an effective modeling scheme for the weld region. It relies on experimental and numerical methods to determine the proper correlation based on experimental results and to propose a modeling scheme for welded parts.

• International Journal of Highway Engineering
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• v.14 no.6
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• pp.93-101
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• 2012

PURPOSES : This study is to develop ISM for potential risk factor in School Zone. METHODS : Based on the literature review, the Analytic Hierarchy Process (AHP) has been used most widely. However, it is difficult to apply in practice because the AHP results have the characteristics of the independence between each element and the interlayer can not explain the interrelationship. The Network Analysis Process (ANP) is possible to analyze the relationship between the elements and the network through the feedback. But, the reliability of the analysis fall because of complicated pair of comparison, also it is difficult to solve the super matrix. In this study, the complicated relationship between each element is inquired through the Interpretive Structural Modeling (ISM). RESULTS : The methodology of ISM is developed to remove the children's potential risk factors in school zone. CONCLUSIONS : It is possible to remove the children's potential risk factors from low level to high level step by step and improve safety. Through this, risk factors can be removed from the low-level, and upper-level will automatically improve.

• The Journal of Engineering Geology
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• v.26 no.3
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• pp.325-330
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• 2016

The second phase of low- and intermediate-level waste (LILW) disposal facility is under planned on the sedimentary rock in unsaturated zone. In this study, we created two meshes which were a matrix continuum mesh and a fracture continuum mesh to carry out 2 dimensional numerical modeling for groundwater flow in the unsaturated zone containing fractures focused on the second phase of LILW disposal facility. Two continuum meshes were developed using MINC in meshmaker module of TOUGH2 code. A fracture continuum mesh was included the k-field distribution of the permeability derived from the Discrete Fractured Network (DFN) modeling. To apply the unsaturated zone for the modeling, the gridding steps to generate mesh were developed. Each step to generate a mesh consisted of definition of materials, setting the initial conditions and creating grids using MINC. The methodology development of meshes in this study will be applied for more precise modeling of groundwater flow and mass transport.