• Title/Summary/Keyword: 가속모사모드

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방염도료의 신뢰성 평가법 개발

  • Choe, Jeong-Jin;Park, Yun-Mi
    • Proceedings of the Korea Institute of Fire Science and Engineering Conference
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    • 2013.04a
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    • pp.84-85
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    • 2013
  • 방염제품의 내구신뢰성은 국민의 화재 안전성 확보를 위한 필수 불가결의 요소로 이들 제품의 내구성능 예측은 방염성능의 지속적 유지를 위한 방염시설물 유지 관리 측면에서도 상당히 중요하다. 본 논문에서는 방염도료의 내구신뢰성 예측 및 확보를 위한 방염도료 가속수명법에 관한 연구로써, 방염도료의 고장 원인분석을 진행하였으며, 현장시험 및 현장 모사 실내 가속촉진시험을 진행하였다. 실내 가속촉진시험은 방염도료의 현장 주고장모드인 온 습도 사이클 시험으로 진행하였으며, 시험 척도로서 화학발광을 분석하여 적용하였으며 현장 데이터와 실내 촉진데이터와의 상관성 규명을 위하여 Mitab 등의 통계적 기법을 이용하여 고장유형 및 상관성을 규명하였다.

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Damage Detection of a Steel Member Using Modal Testing (강부재의 손상발견을 위한 모달실험 기법)

  • Jang, Jeong Hwan;Lee, Jung Whee;Kim, Sung Kon;Chang, Sung Pil
    • Journal of Korean Society of Steel Construction
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    • v.9 no.4 s.33
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    • pp.467-477
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    • 1997
  • A series of experimental tests have been performed on a tube beam in which artificial damage is applied in order to address damage detectability using modal analysis. Modal parameters considered are frequency, displacement mode shape and strain mode shape CoMAC(Coordinate Modal Assurance Criterion) and Modal Vector Error have been adopted for presenting the change of displacement mode shape and strain mode shape. It is revealed strain mode shape is the most sensitive to damage.

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Comparision in Emission Inspection System of a Gasoline Vehicle in Service (운행 휘발유 자동차의 배출가스검사 시스템 비교)

  • Oh, Sangyeob;Park, Wondeok
    • Transactions of the Korean Society of Automotive Engineers
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    • v.22 no.1
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    • pp.1-7
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    • 2014
  • In the most of a nation, the safety and emission gas inspection system of a vehicle in service have been conducted with the most compatible inspection system according to its real environmental situation. Especially, the state of vehicle emission gas is measured by advanced emission gas inspection equipment. It has the problem that the decrease effect of an environmental pollution matter is not calculated by weight percent measurement type equipment. Therefore, in this study, the correlations for the results of emission gas measurement are analyzed by comparing a weight percent measurement type (IDLE+ASM2525 mode) and an advanced mass measurement type (IM240 mode). As the result, the selectivity of an emission gas by IM240 mode is higher than that by IDLE+ASM2525 mode. In the future, therefore, the introduction of IM240 mode and a mass measurement type equipment are necessary. Also, we need to prepare a vehicle emission gas inspection system for introducing IM240 mode.

Vibration Mode Measurement Test of External Fuel Tank for Aircraft (항공기용 외부연료탱크 진동모드 측정시험)

  • Kim, Hyun-gi;Choi, Hyun Kyung;Kim, Sungchan;Park, Hyung Bae;An, Su Hong;Kim, Young Shin
    • Journal of Aerospace System Engineering
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    • v.16 no.4
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    • pp.88-94
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    • 2022
  • The vibration mode measurement test measures the natural vibration characteristics of the target specimen. The measured natural mode characteristics are compared with the numerical analysis result to verify the reliability of the numerical analysis. If necessary, it is used to supplement the numerical analysis model of the specimen used for the dynamic characteristic analysis. In this paper, the natural frequency and natural mode of the external fuel tank are respectively obtained through the vibration mode measurement test and the numerical analysis, using the finite element model. The results are compared to verify the reliability of the numerical analysis model of the external fuel tank to apply to the entire aircraft model. To measure the vibration mode of the test specimen, a bungee cord was used, to simulate the free boundary condition for the test specimen. And, 3-axis accelerometers were installed on the test specimen. The response characteristics of the test specimen were measured, by excitation with an impact hammer. As a result of the test, after performing the frequency response analysis on the response acceleration, the natural frequency of the test specimen and its vibration mode were confirmed. The reliability of the numerical analysis model was verified by comparing the frequency and vibration mode, obtained through the test and the numerical analysis.

Derivation of Dynamic Characteristic Values for Multi-degree-of-freedom Frame Structures based on Frequency Response Function(FRF) (주파수응답함수 기반 다자유도 골조 구조물의 동특성치 도출 및 구조모델링 적용 )

  • So-Yeon Kim;Min-Young Kim;Seung-Jae Lee;Kyoung-Kyu Choi
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.27 no.4
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    • pp.1-10
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    • 2023
  • In the seismic design of structures, seismic forces are calculated based on structural models and analysis. In order to accurately address the dynamic characteristics of the actual structure in the structural model, calibration based on actual measurements is required. In this study, a 4-story frame test specimen was manufactured to simulate frame building, accelerometers were attached at each floor, and 1-axis shaking table test was performed. The natural period of the specimen was similar to that of the actual 4 story frame building, and the columns were designed to behave with double-curvature having the infinite stiffness of the horizontal members. To investigate the effects seismic waves characteristics, historical and artificial excitations with various frequencies and acceleration magnitudes were applied. The natural frequencies, damping ratios, and mode shapes were obtained using frequency response functions obtained from dynamic response signals, and the mode vector deviations according to the input seismic waves were verified using the Mode assurance criterion (MAC). In addition, the damping ratios obtained from the vibration tests were applied to the structural model, and the method with refined dynamic characteristics was validated by comparing the analysis results with the experimental data.

Emission Factor and Fuel Economy Calculation Using Vehicle Inspection and Maintenance Program (자동차 환경검사에 의한 대기오염물질 배출계수 및 연비 산출)

  • Lee, Tae-Woo;Keel, Ji-Hoon;Park, Jun-Hong;Eom, Myoung-Do;Kim, Jong-Choon;Lee, Dae-Yup
    • Transactions of the Korean Society of Automotive Engineers
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    • v.17 no.5
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    • pp.97-106
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    • 2009
  • An objective of this study is to give practical information that could be used for calculating pollutant emission factors and fuel economy from Korean Inspection & Maintenance program, which has been using steady state acceleration simulation mode. Concentration results from I/M test is adequately converted to mass emission factors and fuel efficiency data, which have unit of g/km and km/L, respectively. Exhaust volume flow(EVF), which is for converting emission result from concentration to mass, is measured by tracer method in various vehicle speed - power condition. It is found that there is an apparent second order relationship between EVF and vehicle inertia weight. EVF is expressed in function of vehicle inertia weight in order to estimate EVF in I/M site without measuring device. Converted mass emission results from measured EVF and raw emission analyzer show a satisfactory agreement with those from conventional CVS-bag type measurement system. Mass emission factors and fuel efficiency from measured EVF and estimated EVF also show good agreement to each other. Considering that an I/M program has great advantages to recruit-based emission test in terms of the number of test vehicle, the information in this study can be used for developing an alternative procedure to collect more various data to establish national database of mobile emission factors and fuel economy, even though the driving cycle in I/M program is steady state cycle rather than transient cycle.

Vibration Estimation of Synchrotron Light Source Building Using Experimental Modal Analysis (실험적 모드해석을 이용한 방사광 가속기 건물의 진동평가)

  • 박상규;이홍기;권형오
    • Journal of KSNVE
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    • v.5 no.3
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    • pp.413-421
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    • 1995
  • Synchrotron light source building of the accelerator has stringent vibration limits since the performance of the optical devices and electronic equipments in the laboratory is strongly influenced by the vibrations of the building. In this study, vibrations of the synchrotron light source building are estimated using experimental modal analysis and force response simulation technique. Dynamic properties of the building are identified from the modal parameters and vibration responses are predicted from the force response simulation. A double anti vibration system is designed and applied to the HVAC equipments and it has been shown that the measured vibrations of the building with the double anti vibration system satisfy the vibration criteria.

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A study on the effect of Octane-Number on combustion characteristics and vehicle performance (옥탄가 차이가 연소특성 및 차량 성능에 미치는 영향 연구)

  • Noh, Kyeong-ha;Kim, Jung-hwan;Lee, Min-ho;Kim, Ki-ho
    • Journal of Energy Engineering
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    • v.25 no.3
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    • pp.41-50
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    • 2016
  • This study examined the combustion characteristics and emissions, fuel economy, acceleration by selecting the two fuel with octane number difference to investigate the effect on the combustion characteristics and performance of the vehicle according to the octane number. First, a single-cylinder engine was used for the combustion characteristic experiment, Of the fuel, which is distributed on the market by the selection of two different octane fuel it is performed experiments. Single cylinder experiment examined the combustion characteristics that appear when you gradually advancing the ignition timing by the ignition timing and air-fuel ratio control for each fuel and through an output, emissions, pressure, hence examined the correlation between by octane number. In addition through the actual vehicle compared the changes in the fuel octane number difference, through acceleration tests examined the impact of the octane number requirements for high-performance segment. As a result, fuel of high octane number in accordance with the ignition timing the advancing showed a slightly stable combustion characteristics, a slight increase occurred in the acceleration test and power. However, both fuel does not significantly differ from the current mode, simulating the urban and highway fuel efficiency. Therefore, the operating conditions of the vehicle currently being sold on the Effects of high-octane fuel. fuel efficiency was found insufficient.

Flexible Body Dynamics Analysis of Agricultural Tractor Using 4-Post Road Simulator (4-Post Road Simulator 를 이용한 농용 트랙터의 유연 다물체 동역학 해석)

  • Park, Ji Soo;Lee, Kang Wook;Cho, Chong Youn;Yoon, Ji Won;Shin, Jai Yoon
    • Transactions of the KSME C: Technology and Education
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    • v.3 no.2
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    • pp.83-88
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    • 2015
  • Agricultural tractors are utilized on rough road such as rice paddy field. Therefore, static and dynamic load should be considered when simulating structural analysis with finite element analysis (FEA). But it consumes a lot of time and effort to measure dynamic load because of difficulty and complexity in modeling various field working load conditions and kinematics of machinery. In this paper, to reduce the efforts, 4-post road simulator is developed for agricultural tractor like modeling commercial vehicle. In proving ground test in our facility, I measured acceleration of front/rare axle and strain of body frame to validate input loads. The acceleration is used for defining input loads. And strain is validated with dynamics analysis including mode superposition method. As a result, I was able to calculate 4-post input road profiles, which represent similar proving ground profile with good reliability.

Seismic Safety Assessment of Long Period Structures Base on Elastic/Inelastic Response Characteristics (장주기구조물의 탄소성응답특성을 고려한 지진안전성 평가)

  • Bang, Myung-Seok
    • Journal of the Korean Society of Safety
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    • v.26 no.3
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    • pp.52-58
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    • 2011
  • The earthquake characteristic assessment of social overhead facilities would be an important examination issue for seismic capacity enhancement. This study is intended to reasonably evaluate the structural behavior of longperiod frame structures considering near-fault and far-fault earthquake characteristics. Elastic/inelastic time history analyses were performd by selecting the objective structure which can precisely reflect the effect of input ground motion. Based on the result of numerical analysis, we have investigated response aspects of shear force, moment, acceleration and displacement according to earthquake characteristics. Moreover, in order to understand the inelastic behavior of the objective structure, we have analyzed and compared collapse modes by considering the occurrence process of plastic hinges. The outcome of this research is expected to provide the basic information for the seismic safety assessment of long-period frame structures.