• Transactions of the Korean Society of Mechanical Engineers B
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• v.26 no.1
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• pp.133-140
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• 2002

This article presents an application of a large-scale structural mixing model(Broadwell et at. 1984) to the blowout of turbulent reacting cross flow jets. Experimental observations, therefore, aim to identify the existence of large-scale vortical structure exerting an important effect upon the flame stabilization. In the analysis of common stability curve, it is seen that the phenomenon of blowout are only related to the mixing time scale of the two flows. The most notable observation is that the blowout distance is traced at a fixed positions according to the velocity ratio at all times. Measurements of the lower blowout limits in the liftable flame are qualitatively in agreement with the blowout parameter $\xi$, proposed by Broadwell et al. Good agrement between the results calculated by a modified blowout parameter $\xi$'and the present experimental results confirms the important effect of large-scale structure in the stabilization feature of blowout.

• Proceedings of the KIEE Conference
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• 2005.07c
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• pp.2046-2048
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• 2005

This paper deals with ground potential rise of structure grounding electrode when a test current flows through grounding electrode. In order to analyze the potential gradient of ground surface on structure grounding electrode, the reduced scale model has been used. The structures were designed through reducing real buildings and fabricated with four types on a scale of one-one hundred sixty. The supporter was made to put up with weight of structure and could move into vertical, horizontal, rotary direction. When a test current flowed through structure grounding electrodes, ground potential rise was the lowest value at electric cage type(type B). According to resistivity and absorption percentage in concrete attached to structure, the potential distribution of ground surface appeared differently.

• Journal of Radiation Industry
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• v.7 no.2_3
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• pp.201-207
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• 2013

Soil liquefaction by tsunami or wave induced currents can cause serious damages to coastlines and coastal infrastructures. Although liquefaction caused by regular waves over sea beds has been extensively investigated, studies of tsunami-induced liquefaction near coastal area have been relatively rare. In this work, the hydraulic scale model has been designed and constructed to investigate the variations of wave height and sediment transport by tsunami. The distorted hydraulic scale model based on the Froude similarity was adopted to represent hydrodynamics and sediment transport in a coastal area. The scale model was composed of control box, screw axis, wave paddle and rotating coastal structure.

• Magazine of the Korea Concrete Institute
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• v.4 no.3
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• pp.123-134
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• 1992

본연구는 실물크기의 프리캐스트 콘크리트 판구조물의 부분구조체를 모형화하여 실험한 결과를 분석한 것이다. 구조물의 역학적 특성과 파괴성상을 파악하기 위한 구조실험은 실물크기의 구조물과 부재로써 실시하는 것이 가장 좋은 방법이지만, 이것은 치수가 크므로 공간적으로 제한을 받고 많은 시간과 비용을 필요로 하기 때문에 모형실험을 이용하게 된다. 이러한 모형실험을 최소한의 오차범위내에서 원형실험과 같은 재현하고 예측하도록 실험을 준비하는 데에는 상사법칙이 필요하게 된다. 모형은 무엇보다도 원형과의 응력-변형도 관계 등 구성재료에 대한 상사요구조건을 만족시키는 것이 중요하지만, 본 연구의 대상은 1/3축척으로써 기하학적인 요소와 사용재료에 대한 강도의 상사성만을 고려한 모형이다. 본 연구에서는 이러한 모형구조물의 거동을 원형실험결과와 비교하여 상사성 확보의 문제와 가능성을 조사하였다.

• Structural Engineering and Mechanics
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• v.54 no.2
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• pp.239-256
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• 2015

An adaptive-scale damage detection strategy based on a wavelet finite element model (WFEM) for thin plate structures is established in this study. Equations of motion and corresponding lifting schemes for thin plate structures are derived with the tensor products of cubic Hermite multi-wavelets as the elemental interpolation functions. Sub-element damages are localized by using of the change ratio of modal strain energy. Subsequently, such damages are adaptively quantified by a damage quantification equation deduced from differential equations of plate structure motion. WFEM scales vary spatially and change dynamically according to actual needs. Numerical examples clearly demonstrate that the proposed strategy can progressively locate and quantify plate damages. The strategy can operate efficiently in terms of the degrees-of-freedom in WFEM and sensors in the vibration test.

• The Journal of Society for e-Business Studies
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• v.6 no.1
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• pp.55-67
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• 2001

Over the past decade, the topic of work breakdown structure (WBS) has gained an increasing amount of attention from information technology Professionals as an effective tool for managing the complexity of a large-scale information system development project. It is a method for planning and controlling a large-scale information system development. A WBS provides the basis for project organization, cost estimation, task scheduling, and contract management. Based on the authors' practical experience, this paper discusses how to establish a specific WBS and some considerations for developing a well-defined WBS. The model of WBS suggested in this study will provide useful insight and guidelines for establishing the spec-ific WBS for a large-scale information systems development.

• Proceedings of the Korea Concrete Institute Conference
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• 1995.10a
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• pp.193-197
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• 1995

Computer-based methods have often been used in the structural analysis. But, regardless of the progress in the technique of structural analysis, there are inevitable limitations in consideration of the material and eometric nonlinearity and prediction of failure loads. Model analysis of concrete structure can supplement this kind of limitations to reasonably predict behavior of the structure. Similitude requirement in the reinforced concrete structure is often hard to be secured because of peculiar uncertainty of concrete. In this study, small scale model of subway box structure was constructed using strength model and results of model of subway box structure was constructed using strength model and results of model test and computer-based analysis were compared.

• 한국전산유체공학회:학술대회논문집
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• 2006.10a
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• pp.26-27
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• 2006

Characteristics of spatial structure of particle clusters are investigated by using the flow field data obtained from three-dimensional numerical simulations. Eulerian/Lagrangian approach with two-way coupling is applied and individual particle-particle collisions are taken into account by using the hard-sphere model. More than 16 million particles are traced in the maximum case. The results show that the cluster is consisted from the multiple-spatial scale components while the low wave-number, hence the large-scale structure, is dominant. Three-dimensional structure reconstructed from the low-pass filtered data enables us to investigate the essential dynamics of particle clusters in detail.

• Journal of the Earthquake Engineering Society of Korea
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• v.10 no.6 s.52
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• pp.103-114
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• 2006

Forced vibration testing is important for correlating the mathematical model of a structure with the real one and for evaluating the performance of the real structure. There exist various techniques available for evaluating the seismic performance using dynamic and static measurements. In this paper, full scale forced vibration tests simulating earthquake response are implemented by using a hybrid mass damper. The finite element (FE) model of the structure was analytically constructed using ANSYS and the model was updated using the results experimentally measured by the forced vibration test. Pseudo-earthquake excitation tests showed that HMD induced floor responses coincided with the earthquake induced ones which were numerically calculated based on the updated FE model.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.40 no.3
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• pp.92-98
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• 2017

The rapid growth of engineering technology and the emergence of systemized and large-scale engineering systems have resulted in complexity and uncertainty throughout the lifecycle activities of engineering systems. This complex and large-scale engineering system consists of numerous components, but system failure can be caused by failure of any one of a number of components. There is a real difficulty in managing such a complex and large-scale system as a part. In order to efficiently manage the system and have high reliability, it is necessary to structure a system with a complex structure as a sub-system. Also, in the case of a system in which cause of failures exist at the same time, it is required to identify the correlation of the components lifetime and utilize it for the design policy or maintenance activities of the system. Competitive risk theory has been used as a theory based on this concept. In this study, we apply the competitive risk theory to the models with combined structure of series and parallel which is the basic structure of most complex engineering systems. We construct a competing risks model and propose a mathematical model of net lifetime and crude lifetime for each cause of failure, assuming that the components consisting a parallel system are mutually dependent. In addition, based on the constructed model, the correlation of cause of failure is mathematically analyzed and the hazard function is derived by dividing into net lifetime and crude lifetime.