• Title/Summary/Keyword: building dynamic characteristics

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Recent Progress in Air-Conditioning and Refrigeration Research: A Review of Papers Published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 2014 (설비공학 분야의 최근 연구 동향: 2014년 학회지 논문에 대한 종합적 고찰)

  • Lee, Dae-Young;Kim, Sa Ryang;Kim, Hyun-Jung;Kim, Dong-Seon;Park, Jun-Seok;Ihm, Pyeong Chan
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.27 no.7
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    • pp.380-394
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    • 2015
  • This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2014. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) The research works on the thermal and fluid engineering have been reviewed as groups of heat and mass transfer, cooling and heating, and air-conditioning, the flow inside building rooms, and smoke control on fire. Research issues dealing with duct and pipe were reduced, but flows inside building rooms, and smoke controls were newly added in thermal and fluid engineering research area. (2) Research works on heat transfer area have been reviewed in the categories of heat transfer characteristics, pool boiling and condensing heat transfer and industrial heat exchangers. Researches on heat transfer characteristics included the results for thermal contact resistance measurement of metal interface, a fan coil with an oval-type heat exchanger, fouling characteristics of plate heat exchangers, effect of rib pitch in a two wall divergent channel, semi-empirical analysis in vertical mesoscale tubes, an integrated drying machine, microscale surface wrinkles, brazed plate heat exchangers, numerical analysis in printed circuit heat exchanger. In the area of pool boiling and condensing, non-uniform air flow, PCM applied thermal storage wall system, a new wavy cylindrical shape capsule, and HFC32/HFC152a mixtures on enhanced tubes, were actively studied. In the area of industrial heat exchangers, researches on solar water storage tank, effective design on the inserting part of refrigerator door gasket, impact of different boundary conditions in generating g-function, various construction of SCW type ground heat exchanger and a heat pump for closed cooling water heat recovery were performed. (3) In the field of refrigeration, various studies were carried out in the categories of refrigeration cycle, alternative refrigeration and modelling and controls including energy recoveries from industrial boilers and vehicles, improvement of dehumidification systems, novel defrost systems, fault diagnosis and optimum controls for heat pump systems. It is particularly notable that a substantial number of studies were dedicated for the development of air-conditioning and power recovery systems for electric vehicles in this year. (4) In building mechanical system research fields, seventeen studies were reported for achieving effective design of the mechanical systems, and also for maximizing the energy efficiency of buildings. The topics of the studies included energy performance, HVAC system, ventilation, and renewable energies, piping in the buildings. Proposed designs, performance performance tests using numerical methods and experiments provide useful information and key data which can improve the energy efficiency of the buildings. (5) The field of architectural environment was mostly focused on indoor environment and building energy. The main researches of indoor environment were related to the evaluation of work noise in tunnel construction and the simulation and development of a light-shelf system. The subjects of building energy were worked on the energy saving of office building applied with window blind and phase change material(PCM), a method of existing building energy simulation using energy audit data, the estimation of thermal consumption unit of apartment building and its case studies, dynamic window performance, a writing method of energy consumption report and energy estimation of apartment building using district heating system. The remained studies were related to the improvement of architectural engineering education system for plant engineering industry, estimating cooling and heating degree days for variable base temperature, a prediction method of underground temperature, the comfort control algorithm of car air conditioner, the smoke control performance evaluation of high-rise building, evaluation of thermal energy systems of bio safety laboratory and a development of measuring device of solar heat gain coefficient of fenestration system.

A Study on the Seismic Response of a Non-earthquake Resistant RC Frame Using Inelastic Dynamic Analyses (비선형 동적 해석을 이용한 비내진 상세 RC 골조의 지진거동 특성 분석)

  • Jeong, Seong-Hoon;Lee, Kwang-Ho;Lee, Soo-Kueon
    • Journal of the Korea Concrete Institute
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    • v.22 no.3
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    • pp.381-388
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    • 2010
  • In this study, characteristics of the seismic response of the non-earthquake resistant reinforced concrete (RC) frame were identified. The test building is designed to withstand only gravity loads and not in compliance with modern seismic codes. Smooth bars were utilized for the reinforcement. Members are provided with minimal amount of stirrups to withstand low levels of shear forces and the core concrete is virtually not confined. Columns are slender and more flexible than beams, and beam-column connections were built without stirrups. Through the modeling of an example RC frame, the feasibility of the fiber elementbased 3D nonlinear analysis method was investigated. Since the torsion is governed by the fundamental mode shape of the structure under dynamic loading, pushover analysis cannot predict torsional response accurately. Hence, dynamic response history analysis is a more appropriate analysis method to estimate the response of an asymmetric building. The latter method was shown to be accurate in representing global responses by the comparison of the analytical and experimental results. Analytical models without rigid links provided a good estimation of reduced stiffness and strength of the test structure due to bond-slip, by forming plastic hinges closer to the column ends. However, the absence of a proper model to represent the bond-slip poased the limitations on the current inelastic analysis schemes for the seismic analysis of buildings especially for those with round steel reinforcements. Thus, development of the appropriate bond-slip model is in need to achieve more accurate analysis.

A Study on the Expression of a Trance Aesthetic Consciousness of Continuity in Contemporary Fashion (현대 패션에 나타난 연속성의 트랜스 미의식에 관한 연구)

  • Yang, Hee-Young;Lee, Kyung-Hee
    • Journal of the Korean Society of Costume
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    • v.58 no.8
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    • pp.74-90
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    • 2008
  • Since the late of 20th Century, philosophy, art, and aesthetics have attention to the movement of object that persue the dynamics and qualitative change, not existing fixed and quantitative object. Qualitative continuity, including discontinuity of specific spot and surface that occurs sudden change, is distinct characteristics considered in contemporary logo civilization, which combines and disperses according as various purpose among the different elements and objects. Therefore, I studied about the characteristics of qualitative continuity that creates the change and the differentiation continuously through the "formative characteristics of the continuity expressed in contemporary fashion" of my preceding paper. This paper is the following study of above mentioned paper, and Investigates about aesthetic consciousness leading to the various change. This is intends to consider the trans-aesthetic consciousness that accepts dynamic movement and change the different object and reforms new relationship continuously. This studies' conclusion is as follows; 1) sublimity-Infinity, de-constructive, excessive 2) jouissance - functional, structural 3) paradox-perceptual, spatial. A study about the trans-aesthetic consciousness would help to offer philosophical basis, and make a change building aesthetic foundation in explaining various relationship like as phenomenon of the retro, neo, post, fusion expressed since the late of 20th Century.

Equivalent damping ratio based on earthquake characteristics of a SDOF structure with an MR damper (지진특성에 따른 MR 감쇠기가 설치된 단자유도 구조물의 등가감쇠비)

  • Moon, Byoung-Wook;Park, Ji-Hun;Lee, Sung-Kyung;Min, Kyung-Won
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2007.11a
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    • pp.459-464
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    • 2007
  • Seismic control performance of MR dampers, which have severe nonlinearity, differs with respect to the dynamic characteristics of an earthquake such as magnitude, frequency and duration. In this study, the effects of excitation characteristics on the equivalent linear system of a building structure with the MR damper are investigated through numerical analysis for artificial ground motions generated from different response spectrums. The equivalent damping ratio of the structure with the MR damper is calculated using Newmark and Hall's equations for ground motion amplification factors. It is found that the equivalent damping ratio of the structure with the MR damper is dependent on the ratio of the maximum friction force of the MR damper over excitation magnitude. Frequency contents of the earthquake ground motion affects the equivalent damping ratio of long-period structures considerably. Also, additional damping effect caused by interaction between the viscousity and friction of the MR damper is observed. Finally, response reduction factors for equivalent linear systems are proposed in order to improve accuracy in the prediction of the actual nonlinear response.

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Impact Collapse Characteristics of CF/Epoxy Composite Tubes for Light-Weights

  • Kim, Young-Nam;Hwang, Jae-Jung;Baek, Kyung-Yun;Cha, Cheon-Seok;Yang, In-Young
    • Journal of Mechanical Science and Technology
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    • v.17 no.1
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    • pp.48-56
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    • 2003
  • This paper investigates the collapse characteristics of CF/Epoxy composite tubes subjected to axial loads as changing interlaminar number and outer ply orientation angle. The tubes are aften used for automobiles, aerospace vehicles, trains, ships, and elevators. We have performed static and dynamic impact collapse tests by a way of building impact test machine with vertical air compression. It is fanad that CF/Epoxy tube of the 6 interlaminar number (C-type) with 90$^{\circ}$ outer orientation angle and trigger absorbed more energy than the other tubes (A. B and D-types). Also collapse mode depended upon outer orientation angle of CF/Epoxy tubes and loading type as well; typical collapse modes of CF/Epoxy tubes are wedged, splayed and fragmentcl.

Equivalent Damping Ratio Based on Earthquake Characteristics of a SDOF Structure with an MR Damper (지진특성에 따른 MR감쇠기가 설치된 단자유도 구조물의 등가감쇠비)

  • Moon, Byoung-Wook;Park, Ji-Hun;Lee, Sung-Kyung;Min, Kyung-Won
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.18 no.1
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    • pp.87-93
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    • 2008
  • Seismic control performance of MR dampers, which have severe nonlinearity, varies with respect to the dynamic characteristics of an earthquake such as magnitude, frequency and duration. In this study, the effects of excitation characteristics on the equivalent linear system of a building structure with the MR damper are investigated through numerical analysis for artificial ground motions generated from different response spectrums. The equivalent damping ratio of the structure with the MR damper is calculated using Newmark and Hall's equations for ground motion amplification factors. It is found that the equivalent damping ratio of the structure with the MR damper is dependent on the ratio of the maximum friction force of the MR damper over excitation magnitude. Frequency contents of the earthquake ground motion affects the equivalent damping ratio of long-period structures considerably. Also, additional damping effect caused by interaction between the viscousity and friction of the MR damper is observed. Finally. response reduction factors for equivalent linear systems are proposed in order to improve accuracy in the prediction of the actual nonlinear response.

Seismic Fragility Analysis of Container Crane Considering Far-Fault and Near-Fault Ground Motion Characteristics (원거리와 근거리 지진파의 특성을 고려한 항만 컨테이너 크레인의 지진취약도 분석)

  • Park, Ju-Hyun;Min, Jiyoung;Lee, Jong-Han
    • Journal of the Earthquake Engineering Society of Korea
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    • v.27 no.2
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    • pp.83-90
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    • 2023
  • The recent increase in earthquake activities has highlighted the importance of seismic performance evaluation for civil infrastructures. In particular, the container crane essential to maintaining the national logistics system with port operation requires an exact evaluation of its seismic response. Thus, this study aims to assess the seismic vulnerability of container cranes considering their seismic characteristics. The seismic response of the container crane should account for the structural members' yielding and buckling, as well as the crane wheel's uplifting derailment in operation. The crane's yielding and buckling limit states were defined using the stress of crane members based on the load and displacement curve obtained from nonlinear static analysis. The derailment limit state was based on the height of the rail, and nonlinear dynamic analysis was performed to obtain the seismic fragility curves considering defined limit states and seismic characteristics. The yield and derailment probabilities of the crane in the near-fault ground motion were approximately 1.5 to 4.7 and 2.8 to 6.8 times higher, respectively, than those in the far-fault ground motion.

Improvement Effect and Field Application of Dynamic Replacement Using Crushed Rock (암버력 매립층의 동치환공법 현장 적용성 및 개량효과에 관한 연구)

  • Lee, In-Hwan;Lee, Chul-Hee;Shin, Eun Chul
    • Journal of the Korean Geosynthetics Society
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    • v.18 no.4
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    • pp.1-13
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    • 2019
  • The purpose of this study is to examine the effect of soft ground improvement by dynamic replacement with utilizing crushed rock. In order to understand the ground improvement effect when applying dynamic replacement method with crushed rock, the laboratory test and field test were performed. The internal friction angle and apparent cohesion were derived through direct shear test. The dynamic replacement characteristics were identified by analyzing the weight, drop, and number of blows needed for dynamic replacement. Through the field plate bearing test and density test, the bearing capacity and settlement of the improved ground were measured, and the numerical analysis were conducted to analyze the behavior of the improved ground. In this study, it proposes modified soil experimental coefficient(CDR) to 0.3~0.5 in the dynamic replacement method with crushed rock. Also when applying the dynamic replacement method using crushed rock, the particle size range is less than 100 mm, D90 is less than 80 mm and D15 is more than 30 mm.

Simnlation of a Thermal Behavior in Solar Heating and Cooling System with respect to Demand Room Temperature (실내 설정온도에 따른 태양열 냉난방 시스템의 동적 거동 해석)

  • Jang, H.Y.;Lee, S.B.;Chung, K.T.;Suh, J.S.
    • Proceedings of the KSME Conference
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    • 2007.05b
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    • pp.3446-3451
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    • 2007
  • The thermal behavior of a building in response to heat input from an active solar space heating system is analysed to determine the effect of the variable storage tank temperature on the cycling rate, on and off temperature of a heating cycle and on the comfort characteristics of room air temperature. A computer simulation of the system behavior has been performed and verified by comparisons with various parameters. Especially, this study is focused on the effect of the system's performance when subjected to dynamic cooling loads. The heat input to the absorption system is provided by an array of solar collectors that coupled to a thermal storage tank.

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Study on the feasibility test of Renewable Energy Systems for Schools (교육시설의 신재생에너지 시스템 적용성 평가 방법론에 관한 연구)

  • Park, Eun-Mi;Jang, Ji-Hyun;Nam, Hyun-Jin;Pae, Min-Ho;Park, Hyo-Soon;Kim, Jae-Min
    • 한국신재생에너지학회:학술대회논문집
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    • 2008.05a
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    • pp.99-102
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    • 2008
  • In terms of operation profiles and building characteristics, Schools, as public facilities, are one of the most suitable buildings for small scale Renewable energy systems since they have its energy demand on daytime mostly and large open area, roof surface available for the installation of Renewable energy systems such as solar collectors or Photovoltaic pannels. This paper presents a methodology of the feasibility test for Renewable energy systems to be intalled at schools. The methodology is based on the analysis of the demand/supply profiles dynamic matching. a case study is also presented to test the applicability of the proposed assessment methodology.

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