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Start/Stop 차량의 NVH 예측을 위한 하중 생성에 관한 연구
이한걸(Hangeol Lee),조미희(Mihui Jo),민선기(Sunki Min) 한국자동차공학회 2010 한국자동차공학회 학술대회 및 전시회 Vol.2010 No.11
Although engine start-stop system has many advantages in terms of fuel economic and the reduction of emission., it can cause undesired vibration to the occupant of the vehicle, In this paper, an investigation of the engine start-stop vibration issues has been presented. The investigation concludes that engine start-stop NVH issues are caused by crankshaft reaction torque coming from the combustion pressure and the inertia torque. To minimize force inputs from the powertrain to the vehicle, torsional vibration analysis method is used to provide recommendations. It is found that increased cranking speed and improving starter motor performance are effective to reduce vibration level due to PT roll mode.
Torsional Vibration Model을 이용한 Powertrain 거동 연구
이한걸(Hangeol Lee),송재은(Jaeeun Song),이정근(Jungkeun Rhee) 한국자동차공학회 2009 한국자동차공학회 학술대회 및 전시회 Vol.2009 No.11
Recently the research of powertrain torsional vibration behavior due to engine torque fluctuation has been widely studied. Shudder and Clunk are typical torsional phenomenon , which take places low frequency range from 10 ㎐ to 30㎐. This vibration is transmitted from many different locations towards indoor in vehicle and typically contributes to booming noise. In this paper, torsional vibration analysis model is developed in order to expect the torsional behavior of powertrain . At first, driveline torsional vibration model using AMESim is built. Then torsional vibration analysis is carried out under engine maneuver condition. It is found that clutch damper design is one of the main effective counter-measures to reduce torsional vibration.
Residual Vector를 이용한 시간이력해석의 잔여모드 응답 고려 방법
변창호,이한걸,김정용 한국압력기기공학회 2021 한국압력기기공학회 논문집 Vol.17 No.2
The mode superposition time history analysis method is commonly used in a seismic analysis. The maximum response in the time history analysis can be derived by combining the responses of individual modes. The residual mode response is the response of the modes which are not considered in the time history analysis. In this paper, the residual vector method to consider the residual mode response in the time history analysis is introduced and evaluated. Seismic analyses for a sample structure model and a reactor vessel model are performed to evaluate the residual vector method. The analysis results show that residual mode response is well calculated when the residual vector method is used. It is confirmed that the residual vector method is useful and acceptable to consider the residual mode response in a seismic analysis of the nuclear power plant equipment.
잎들깨 품종에 따른 추출물의 항산화 활성 및 생리활성 평가
김현영,이한걸,서혜영,서우덕,이미자,송승엽,김정인,최준열 한국식품영양학회 2022 韓國食品營養學會誌 Vol.35 No.6
This study aimed to investigate the biological activities, including polyphenolic content, flavonoid content, and antioxidant activities, of various cultivars of Korean perilla leaves. The results indicated that among nine cultivars (Namcheon dlggae, Saedora, Nulbora, Donggel 1, Donggell 2, Soim, Sangyeop, Somirang, and Saebom) of perilla leaves, the total polyphenolic content (gallic acid equivalent mg/g, GAE) was the highest in “Nulbora,” while it was lowest in Namcheon dlggae. Moreover, flavonoid content in the extracts of nine cultivars leaves was in the range of 132.93~268.50 mg catechin equivalent/g sample. The antioxidant effects of the perilla leaves were determined using two different in vitro bioassays measuring DPPH and ABTS radical-scavenging activities. The results revealed that antioxidant activity was also higher in “Nulbora” compared with other cultivars. Xanthin-oxidase-inhibition activity ranged from 65.65% to 80.58%, with “Nulbora” exhibiting the highest activity, although the difference with other cultivars was not significant. “Nulbora” extracts reduced the expression of pro-inflammatory genes and several cytokines, including IL-6 activation induced by LPS in macrophages in the range of 100–50 μg/mL. These results suggest that extracts from perilla leaves can be used as bioactive and functional materials that could be important in industrial applications in the future.
김승현,김연정,이한걸,강선예 한국압력기기공학회 2022 한국압력기기공학회 논문집 Vol.18 No.1
Nuclear Power Plants (NPP) should be designed to have sufficient safety margins and to ensure seismic safety against earthquake that may occur during the plant life time. After the 9.12 Gyeongju earthquake accident, the structural integrity of nuclear power plants due to the beyond design basis earthquake is one of key safety issues. Accordingly, it is necessary to conduct structural integrity evaluations for domestic NPPs under beyond design basis earthquake. In this study, the Level 3 LBB (Leak Before Break) evaluation was performed by considering the beyond design basis earthquake for the surge line of a OPR1000 plant of which design basis earthquake was set to be 0.2g. The beyond design basis earthquake corresponding to peak ground acceleration 0.4g at the maximum stress point of the surge line was considered. It was confirmed that the moment behaviors of the hot leg and pressurized surge nozzle were lower than the maximum allowable loading in moment-rotation curve. It was also confirmed that the LBB margin could be secured by comparing the LBB margin through the Level 2 method. It was judged that the margin was secured by reducing the load generated through the compliance of the pipe.
APR1400 원자로냉각재계통 스너버의 비구속기능 상실의 영향 평가
황병천(Byung Chun Hwang),이한걸(Han Gul Lee),전장환(Jang Hwan Jheon),성기광(Ki Kwang Sung),김현민(Hyun Min Kim) 대한기계학회 2016 대한기계학회 춘추학술대회 Vol.2016 No.12
This study assesses the effects of a failure of snubber installed on two Steam Generators(SGs) and four Reactor Coolant Pumps(RCPs) in the APR1400 Reactor Coolant System(RCS) under normal operation(NOP) conditions. The analysis results show that the single snubber failure i.e., lockup, during the normal operation conditions has somewhat severe effects especially on the inlet nozzle of the SG and the outlet nozzle of the RCP. However, the resultant load increases on the RCS will be limited to a certain level since the failed snubber does not act as a restraint any more beyond the snubber load rate, and a stress evaluation reveals that the resultant stress intensities remain below the allowable. Additionally, the analysis results also show that the single snubber failure effects are confined to the component having the failed snubber. Accordingly, the single snubber failure in the RCS will not degrade the structural integrity of the RCS.