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이병하(Byungha Lee),조미희(Mihui Jo) 한국자동차공학회 2007 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
In the engines of automobiles, knowledge on the thermo-elasticity a priori is very informative in the design stage. Especially, increasing demands on engine performance and fuel economy have resulted in progressively higher loadings on internal components of combustion engines. Therefore the durability assessment should be requested in the cylinder head and block design. In this study, an efficient and reliable analysis technique for the cylinder head, gasket and block compound by using computer modeling and numerical method was described. Commercial software GT Power<SUP>TM</SUP> and Fluent<SUP>TM</SUP> were used to find the gas side and coolant side thermal loading condition. ABAQUS<SUP>TM</SUP> software was followed to predict the temperature and stress of the engine with utilization of estimated coefficients. FE-Fatigue<SUP>TM</SUP> was used for fatigue safety factor.
A computational procedure on predicting temperature field in automotive friction clutches
Byungha Lee(이병하) 한국자동차공학회 2006 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
In the design stage of friction clutches of automobiles, knowledge on the thermo-elasticity, especially the precise prediction technique of maximum temperature and stress, a priori is very informative, In this study, an efficient and reliable thermal analysis technique for the mechanical clutches by using computer modeling and numerical method was developed. A commercial software STAR-CD™ was used to find the convective heat-transfer coefficients. MSC/NASTRAN™ was followed to predict the temperature of clutch with utilization of estimated coefficients. Some experiments were also performed with a dynamometer to verify the procedure and calibrate the thermal load. As conclusion, a design procedure, including numerical steps and experimental techniques for calibration, was proposed.
에너지저장 커패시터의 최적 충전을 위한 직렬공진형 컨버터의 운용 모드 비교
이병하(Byungha Lee),강태섭(Taesub Kang),차한주(Hanju Cha) 대한전기학회 2012 전기학회논문지 Vol.61 No.3
In this paper, charging modes of series resonant converter for a high voltage energy storage capacitor are compared in terms of charging time, peak resonant current, normalized peak resonant current and voltage in each operation mode. Operating principles of the full bridge series resonant converter with capacitor load are explained and analyzed in discontinuous and continuous operation mode. Based on the analysis and simulation result, 0.6ω<sub>r</sub><ω<sub>s</sub><0.75ω<sub>r</sub> and 1.3ω<sub>r</sub><ω<sub>s</sub><1.4ω<sub>r</sub> are evaluated to the best range of switching frequency for charging of an high voltage energy storage capacitor. 1.8 kJ/s SRC prototype is assembled with TI 28335 DSP controller and 40 kJ, 7 kV energy storage capacitor. Design rules based on the comparative analysis are verified by experiment.
3상 직렬공진형 고전압 커패시터 충전기의 해석 및 설계
이병하(Byungha Lee),박상은(Sangeun Park),차한주(Hanju Cha) 대한전기학회 2013 전기학회논문지 Vol.62 No.4
This paper suggests a 3-phase series-resonant type high voltage capacitor charger for an EML pulsed power system. The operating principle on the charger is explained by an equivalent circuit. Additionally, we analyze the charging characteristic in one discontinuous conduction mode and three continuous conduction modes. The analysis shows that the resonant current per phase is two thirds of the 3-phase charger’s average charging current and one third of the single-phase charger’s average charging current with the same capacity. We suggest a design method of the 3-phase capacitor charger in each operational mode and present an example of 3.5 kW capacitor charger at ωs=0.33ωr. The 3.5 kW 3-phase capacitor charger prototype is assembled with a TI28335 controller and a 40 kJ, 7 kV capacitor. The design rules based on the analysis are verified by experiment.
고온 산화소성 철적유에 나타나는 Whitlockite계 결정과 Magnesioferrite의 관계
박원숙,이병하,Park, Wonsook,Lee, Byungha 한국세라믹학회 2005 한국세라믹학회지 Vol.42 No.6
In the hard oxidizing fire iron red glaze which colorated red exposed magnesioferrite and whitlockite-type crystals. And whitlockite-type crystals has formed before magnesioferrite forming in the step of sintering. This study tries to identify the coloration mechanism of hard oxidizing fire iron red glaze by the experiment of substitution of whitlockite-like crystals and to confirm such substitution be able to farm magnesioferrite. As the results of experiment, magnesioferrite was appeared during substitution of two kinds of whitlockite-type. It can be considered that the magnesioferrite colors the iron glaze to red with covering the glaze surface.
이진아(Jina Lee),이병하(Byungha Lee),김시환(Sihwan Kim),정종화(Chonghwa Chung) 한국자동차공학회 2012 한국자동차공학회 학술대회 및 전시회 Vol.2012 No.11
The objective of this research is essential to optimize produced crankshaft pin shoulder design for cost reduction. This paper describes how to evaluate and improve strength of crankshaft with mass reduction. DFSS method was used for analyzing which design parameters dominantly affected on pin journal fillet strength of crankshaft. This study focused on reducing mass of crankshaft and stress level at pin journal fillet area. There should be many factors affecting the strength of crankshaft, however in this investigation only height and width of crankshaft pin shoulder were chosen as control factors. After determining optimized crankshaft design through DFSS, crankshaft fatigue analysis was performed under engine running condition using EXCITE to assess the crankshaft fatigue safety factor of current and optimized model.