• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.10a
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• pp.171-177
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• 2011

In this paper, a square simply supported panel flutter have been considered at high supersonic flow by using coupled fluid-structure (FSI) analysis that based on time domain method. The Reynolds-Average Navier Stokes (RANS) equation with Spalart-Allmaras turbulent model were applied for unsteady flow problems of panel flutter. A fully implicit time marching schemed based on the Newmark direct integration method is used for calculating the coupled aeroelastic governing equations of it. In addition, the SOL 145 solver of MSC.NASTRAN was used to investigate flutter velocity based on PK-method of Piston theory. Our numerical results indicated that there is a good agreement result between Piston Theory in MSC.NASTRAN and coupled fluid-structure analysis.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.05a
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• pp.64-64
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• 2004

최근 복합재료, 신소재 등 다양한 방법을 통해 빔(beam), 바(bar), 패널(panel) 등 초경량 구조재료가 개발되고 있다. 이중 금속 내부구조재를 가진 접합판재(Inner Structured and Bonded panel, ISB panel)은 3차원 형상의 내부구조재가 강성 및 강도를 증가시키는 반면, 부피의 대부분이 비어있어 비강도 및 비강성을 크게 개선시킨다 일반적으로 다양한 트러스 형태의 금속 내부구조물은 허니컴 형상의 내부구조와 유사한 정도로 기계적 특성이 우수하다.(중략)

• Computers and Concrete
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• v.13 no.6
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• pp.749-764
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• 2014

Structural safety has always been a key preoccupation for engineers responsible for the design of civil engineering projects. One of the mechanisms of structural failure, which has gathered increasing attention over the past few decades, is referred to as 'progressive collapse' which happens when one or several structural members suddenly fail, whatever the cause (accident, attack, seismic loading(.Any weakness in design or construction of structural elements can induce the progressive collapse in structures, during seismic loading. Masonry infill panels have significant influence on structure response against the lateral load. Therefore in this paper, seismic performance and shear strength of R.C frames with brick infill panel under various lateral loading patterns are investigated. This evaluation is performed by nonlinear static analysis. The results provided important information for additional design guidance on seismic safety of RC frames with brick infill panel under progressive collapse.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1993.10a
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• pp.149-156
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• 1993

Precast concrete (P.C.) large panel structures have usually weaker stiffness at joints than that of monolithic in-situ reinforced concrete structures. But structural designers do not in general take into account this characteristics of P. C. large panel structures and use the same analytical models as for the monolithic structure. Therefore, the results of analysis obtained by using these models may be quite different from those actually occuring in real P.C. structure. In this study, the change in force and stress distribution and deflections of structure caused by applying lower shear stiffness at vertical joints are investigated through trying several finite element modeling schemes specific for P.C. structures. Finally, for engineers in practice. a simplified model, which takes account of the effect of lower shear stiffness at vertical joints, is proposed with the understanding on possible amount of errors.

• Journal of the Korean Society of Safety
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• v.16 no.2
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• pp.91-96
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• 2001

Theoretical definitions of mixed behavior of PE panel and connote should have preceded to cause a mixed behavior of connote and polyethylene which have different elastic module, one-line expansion coefficients, poison ratios, compressive strengths and tensile strengths. Consequently, changes are analyzed through experiment process to identify the effects on interpretation of mixed behavior on the basis of temperature change of structures, temperature rise of concrete other than PE panel due to hydration heat temperature rise of concrete other than PE panel due to drying and contraction, working of hydrostatic pressure by storage and temperature gradient From the results of interpretation of the analysis, it is concluded that PE panel have slight influences on the change of guess of structures and maintains structural stability compared with concrete structures without PE panel.

• Steel and Composite Structures
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• v.19 no.5
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• pp.1167-1184
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• 2015

Despite considerable life casualty and financial loss resulting from past earthquakes, many existing steel buildings are still seismically vulnerable as they have no lateral resistance or at least need some sort of retrofitting. Passive control methods with decreasing seismic demand and increasing ductility reduce rate of vulnerability of structures against earthquakes. One of the most effective and practical passive control methods is to use a shear panel system working as a ductile fuse in the structure. The shear Panel System, SPS, is located vertically between apex of two chevron braces and the flange of the floor beam. Seismic energy is highly dissipated through shear yielding of shear panel web while other elements of the structure remain almost elastic. In this paper, lateral behavior and related benefits of this system with narrow-flange link beams is experimentally investigated in chevron braced simple steel frames. For this purpose, five specimens with IPE (narrow-flange I section) shear panels were examined. All of the specimens showed high ductility and dissipated almost all input energy imposed to the structure. For example, maximum SPS shear distortion of 0.128-0.156 rad, overall ductility of 5.3-7.2, response modification factor of 7.1-11.2, and finally maximum equivalent viscous damping ratio of 35.5-40.2% in the last loading cycle corresponding to an average damping ratio of 26.7-30.6% were obtained. It was also shown that the beam, columns and braces remained elastic as expected. Considering this fact, by just changing the probably damaged shear panel pieces after earthquake, the structure can still be continuously used as another benefit of this proposed retrofitting system without the need to change the floor beam.

• Journal of Welding and Joining
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• v.26 no.3
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• pp.23-29
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• 2008

The purpose of this study is to propose the proper fillet welding process for preventing the buckling distortion in thin panel welded structure. In order to do it, a heat input model for laser hybrid welding process was developed using FEA and experiment. The principal factors controlling the angular distortion and longitudinal shrinkage force caused by FCA and laser hybrid welding were identified as the welding heat input and weld rigidity using FEA. The predictive equations of angular distortion and longitudinal shrinkage force for each welding process were formulated as a function of the principal factors proposed. With the predictive equations, the buckling distortion at the thin panel welded structure with welding process was evaluated and compared using nonlinear buckling analysis and STEM(simplified thermo elastic method). Based on the results, the best way to prevent the buckling distortion at the given welded panel structures was identified as an intermittent FCA welding.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.806-811
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• 2007

In this study, we propose a more systematic design process for the structure-borne noise. The proposed way consists of 4 steps: Problem definition, Cause analysis, Development of counter-measure and Validation. Especially, we improved the second step: Cause analysis. According to the PCA(Panel Contribution Analysis), a reduction in vibration of the panels of which panel contribution is positive and larger, results in a reduction in structure-borne noise. We have, however, met the case in which the concept of PCA is no valid in a few vehicle tests. In order to understand this phenomenon, we compared the major panels selected by PCA with the one chosen by DSA(Design Sensitivity Analysis). After investigating the difference between the two results, a more improved process is suggested. The proposed one for the second step in the design process consists of not only the previous way: PCA with deformation analysis results but also DSA. It is finally validated that the proposed design process decreases the sound pressure of the concerned noise transfer function more than 3.5 dB.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.35 no.6
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• pp.121-128
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• 2019

There is a big move to build zero-energy buildings in the form of passive houses that reduce energy waste worldwide. Korea has set a goal of reducing its greenhouse gas emissions by 37% by 2030 through the activation of green buildings, such as strengthening the energy levels of new buildings and improving the energy efficiency of existing buildings. The use of insulation with high insulation performance is one of the key technologies to realize this, and vacuum insulation is the next generation insulation that blocks the energy flow of the building. In this study, we measured the bonding structure of dry and wet processing glass fiber core materials and compared the insulation performance of vacuum insulation panel. In addition, the insulation performance of vacuum insulation panel was measured according to the thickness of the laminated core. It can be confirmed that the lamination structure of the core and the lamination thickness are important factors for the heat insulating performance of the vacuum insulating panel.

• Asia-Pacific Journal of Business
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• v.13 no.1
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• pp.277-288
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• 2022

Purpose - This study analyzed the determinants of local unemployment rate in Korea using panel data from 16 metropolitan cities and provinces from 2000 to 2018. Design/methodology/approach - We use a dynamic spatial panel model that considers characteristics of the regional unemployment rate such as the common factors effect, spatial dependence, and serial correlations. Findings - The local unemployment rate is affected by the past and present values of the national unemployment rate. And it is significantly affected by the past local unemployment rate and the past neighboring unemployment rate because spatial dependence and serial correlations are clearly present. In addition, when the industrial structure diversity and labor productivity were high, the regional unemployment rate decreased, and when the education level was high, the regional unemployment rate increased. Research implications or Originality - In order to reduce regional unemployment rate, it is necessary to plan and establish regional customized industrial structure policies under the stance of diversification rather than specializing the regional industrial structure and accompany improvement of the quality of education with the number of years of education. In addition, the redistribution of labor from low labor productivity sectors to high labor productivity sectors through technology development will help to reduce the local unemployment rate.