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자전연소합성법에 의한 ZrB<sub>2</sub> 세라믹분말합성 및 NaCl의 영향
김진성,원창환,Kim, Jinsung,Nersisyan, Hayk,Won, Changwhan 한국재료학회 2014 한국재료학회지 Vol.24 No.5
Zirconium boride is an artificial or which is rarely found in the nature. $ZrB_2$ is popular in the hard material industry because it has a high melting point, excellent mechanical properties and chemical stability. There are two known methods to synthesize $ZrB_2$. The first involves direct reaction between Zr and B, and the second is by reduction of the metal halogen. However, these two methods are known to be unsuitable for mass production. SHS(Self-propagating High-temperature Synthesis) is an efficient and economic method for synthesizing hard materials because it uses exothermic reactions. In this study, $ZrB_2$ was successfully synthesized by subjecting $ZrO_2$, Mg and $B_2O_3$ to SHS. Because of the high combustion temperature and rapid combustion, in conjunction with the stoichiometric ratio of $ZrO_2$, Mg and $B_2O_3$; single phase $ZrB_2$ was not synthesized. In order to solve the temperature problem, Mg and NaCl additives were investigated as diluents. From the experiments it was found that both diluents effectively stabilized the reaction and combustion regime. The final product, made under optimum conditions, was single-phase $ZrB_2$ of $0.1-0.9{\mu}m$ particle size.
비대칭 모자형 단면 사각관의 정적 붕괴 실험 및 결과의 임의성
김진성(Jinsung Kim),임지호(Jiho Lim),허훈(Hoon Huh),이문용(Munyoung Lee),정병훈(Byunghun Jung) 한국자동차공학회 2003 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
In this paper, we discuss the result of the static collapse test of the asymmetric top hatted rectangular tube. The result includes collapse mode, maximum load, and absorbed energy. Five types of asymmetric top hatted rectangular tube were used. Two types of tube with laser welded are different in their flange length. Three types of tube with spot welded have different distances between the spot welding points. From the experimental results, we investigate the characteristics of energy absorption and collapse mode of each specimen type. And we discuss the uncertainty of energy absorption following the irregular collapse mode. Finally, in designing the asymmetric top hatted rectangular tube, we discuss how to consider the uncertainties of the collapse modes and absorbed energy during the Static collapse.
김진성(Jinsung Kim),허훈(Hoon Huh),이강욱(Kangwook Kang),하대율(Daeyul Ha),여태정(Taejung Yeo),박순조(Soonjo Park) 한국자동차공학회 2006 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
This paper deals with dynamic tensile characteristics for the polypropylene composite used in an IP(lnstrument Panel). This polypropylene composite is adopted in the dash board of a car, especially PAB(Passenger Air Bag) module. The dynamic tensile characteristics are important because the PAB module undergoes high speed deformation during the airbag expansion. The operating temperature of a car varies from -30캜 to 110캜 according to the specification. The dynamic tensile tests are performed at the low temperature(-30캜), room temperature(21캜) and high temperature(85캜). The tensile tests are carried out at strain rates of nine intervals ranged from 0.001/sec to 200/sec. The flow stress increases as the strain rate becomes higher. The flow stress decreases at the high temperature while the strain rate sensitivity increases. Finite element analysis of the tensile test with the special specimen was carried out with unmodified stress-strain curve obtained from the ASTM IV specimen directly. The analysis result shows that the load response is almost same with the experimental result but the strain is rather larger than the experimental result. The stress-strain curves were modified on the basis of the gage length change rate, that is the change of gage length divided by the crosshead stroke. The analysis result with the modified stress-strain curves showed good agreement with the experimental result. The material properties obtained from this research will be useful to estimate the airbag expansion accurately in engineering sense.
비대칭 모자형 사각관의 정적 및 동적 압궤실험을 통한 충돌성능 평가
김진성(Jinsung Kim),임지호(Jiho Lim),허훈(Hoon Huh),김종섭(Jongseub Kim),정태현(Taehyun Jung) 한국자동차공학회 2004 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
The axial crush of channeled members is important in estimation of the energy absorption during the car frontal crash. In order to improve the energy absorption capacity and the velocity deceleration factor of an auto-body, the front-side members are mounted at the side of the engine room and made undergo the axial crush at the beginning of the car crash. There have been so many studies about square or rectangular boxes and hat-type specimens for the axial crush both experimentally and analytically while there are few studies about asymmetric hat¬type specimens that are used for designated deformation. The axial crush of asymmetric hat-type specimens is, however, difficult to describe analytically with the kinematic crush mechanism. In this paper, asymmetric hat-type specimens are fabricated by spot welding or laser welding with different spacing between two welded spots. The specimens are then deformed for the axial crush at the various crush velocity. The experimental result shows that the specimens are not deformed in a consistent manner, but arbitrarily. In this type of axial crush, the length of the flange region is an important parameter as well as the spacing between welded spots. Experimental results also show the difference in the crush mode between the spot-welded specimens and the laser-welded ones. The difference in the first peak and average load is also demonstrated as well as the energy absorption capacity.
하중 조건의 미세한 변화에 따른 비대칭 모자형 사각관의 붕괴 거동
김진성(Jinsung Kim),임지호(Jiho Lim),허훈(Hoon Huh),김종섭(Jongseub Kim),정태현(Taehyun Jung) 한국자동차공학회 2004 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
Hat-type rectangular tube is a common structural member of an auto body, usually a front side member. The front side member is an important part in absorbing the crash energy of frontal car crash. In frontal car crash the front side member should absorb the crash energy as much as possible to minimize the deformation of the passenger room. The front side member usually has a so-called hat shaped cross-section which is known to show better energy absorption efficiency than the square tube with same cross sectional area. Crash worthiness of the front side member is studied with hat-type specimens that are idealized shape of the front side member. In this research, asymmetric hat-type specimens were studied. Static and dynamic crush tests were performed with five types' of asymmetric hat-type specimen. The collapse modes show very arbitrary collapse profile even if the final energy absorptions are not so much dispersed. In this paper, finite element analysis of asymmetric hat-type specimen was performed with the small error of loading condition, describing errors in specimen specification, loading angle and experimental process. Slight error in the loading angle was considered in the finite element analysis of asymmetric hat-type specimen. The result of finite element analysis shows arbitrary collapse mode also. And this result is suggestive in estimating the efficiency of crash energy absorption during the car crash.
김진성(Jinsung Kim),정현승(Hyunseung Jung),권태수(Taesoo Kwon),이덕희(Duckhee Lee),정세환(Sehwan Jeong) 한국자동차공학회 2011 한국자동차공학회 학술대회 및 전시회 Vol.2011 No.11
This paper reports standard uncertainties of full-scale crash testing facilities for a train. KRRI(Korea Railroad Research Institute) has established full-scale crash testing facilities which is the first testing facilities among Asian countries. The testing facilities enabled single item test, crash module test and full structure test including dummies for a occupant injury evaluation. Full-scale crash testing facilities consist of a crash barrier, dynamic load cell, high speed DAS(Data Acquisition System), a laser displacement sensor, dummies, a motor car and etc. The items for evaluation of standard uncertainties are impact load, displacement during impact, energy absorption and acceleration. Six dynamic load cells with a capacity of 3,000 kN each are used to measure the impact load and the data acquisition system records the converted voltage signal. Displacement during impact is measured with a laser displacement sensor which has high sampling capacity. Acceleration data are measured with several accelerometers attached to the specimen and moving car. Standard uncertainties of measurement devices were evaluated on the basis of the ISO guide(GUM: Guide to the expression of Uncertainty in Measurement)
가상 하이브리드 차량 모델을 위한 구동계 핵심부품 모델링
김진성(Jinsung Kim),이재훈(Jaehoon Lee),박기홍(Kihong Park),허승진(Seung-Jin Heo) 한국자동차공학회 2011 한국자동차공학회 부문종합 학술대회 Vol.2011 No.5
In this paper, a virtual simulation model to analyze performance of hybrid electric vehicle is presented. Simulation model consist of dynamic models of HEV powertrain. In order to estimate the performance of HEV: Power Split type HEV, a HEV simulator is developed using MATLAB/SIMULINK. Using driving mode simulation (UDDS: Urban Dynamometer Driving Schedule) performance of HEV were calculated. In order to consider each model of accuracy , the simulation has compared with PSAT.