전단 인장 시험을 이용한 점용접부 파단모델 구성

하지웅(Jiwoong Ha),김유종(Yujong Kim),허훈(Hoon Huh),임지호(Jiho Lim) 한국자동차공학회 2009 한국자동차공학회 학술대회 및 전시회 Vol.2009 No.11

This paper propose an alternative methodology to construct the dynamic failure model of a spot weld under combined loading conditions for auto-body crash analyses using cross-tension and lap-shear tests. In order to construct the failure model proposed by Song and Huh, failure tests of spot welds should be carried out at intervals of 15˚ from 0˚ to 90˚ or cross-tension and pure-shear tests. But this methodology is not practical because of too difficult and a large number of experiments. In order to substitute lap-shear tests for pure-shear tests, correlation equation between failure loads of pure-shear and lap-shear tests is derived from stress distribution that was assumed around a nugget at failure of a spot weld. Using failure loads of lap-shear and cross-tension tests and β-norm 1.45, Song and Huh’s dynamic failure model of a spot weld is constructed simply. With the failure model which is constructed by the alternative methodology, FE analyses in which are failure loads and failure behaviors of the spot weld are investigated carried out.

개량박막 유한요소법에 의한 두가지 블랭크로부터의 사각컵 딥드로잉 성형해석

허훈,한수식,Huh, Hoon,Han, Soo-Sik 대한기계학회 1994 대한기계학회논문집 Vol.18 No.10

The design of sheet metal working processes is based on the knowledge about the deformation mechanism and the influence of the process parameters. The typical geometric process parameters are the die geometry, the initial sheet thickness, the initial blank shape, and so on. The initial blank shape is of vital importance in the most sheet metal forming operations, especially in the deep drawing process, since the forming load and the strain distribution are significantly affected by the shape of an initial blank. The influence of the initial blank shape on a square cup deep drawing process is investigated by the numerical simulation and the experiment. The numerical simulation is carried out by a modified membrane finite element method which takes bending deformation into account. The numerical and experi-mental results show that the initial blank shape have strong influence on the forming load and the strain distribution. The numerical results are compared with the experimental results and other numerical results which are calculated with the membrane theory.

원형평판의 붕괴문제에 관한 유한차분 완전 하계해

허훈,Huh, Hoon 대한기계학회 1990 대한기계학회논문집 Vol.14 No.6

본 연구에서는 Yang의 이론을 바탕으로 여러가지 원형집중하중을 받는 원형평 판에 관한 최대하계해를 구하고자 한다.앞서 열거한 문헌에서는 여러가지 해석법이 제시되었으나, 문제의 성격에 비하여 그 해법이 매우 복잡하였다. 본 논문에서는 원 형평판에 관한 해법으로서 전산기를 응용하여 가능한 한 단순한 해법으로 최대화기법 에 의한 완전한 해를 얻기 위한 시도를 제시하고자 한다. Accurate load-carrying capacities and moment distributions of thin circular plates are obtained for clamped or simply-supported boundary condition under various concentrated circular loadings. The material is regarded as perfectly-plastic based on an arbitrary yield function such as the Tresca yield function, the Johansen yield function, and the farmily of .betha.-norms which possesses the von Mises yield function and the Frobenius norm. To obtain the lower bound solutions, a maximization formulation is derived and implemented for efficient numerical calculation with a finite difference method and the modified Newton's method. The numerical results demonstrate plastic collapse behavior of circular plates and provide their design criteria.

초소형재료의 펀치성형에 관한 유한요소해석

허훈,이기석,최영준,Huh, Hoon,Lee, Ki-Seok,Choi, Yeong-Jun 대한기계학회 1996 大韓機械學會論文集A Vol.20 No.2

Superplastic punch forming of sheets is simulated by a finite element method to obtain the optimal punch speed and the related deformed shapes. The punch forming has an advantage of guaranteeing the desired accuracy inside a product and controlling the thichness of a deformed sheet more accurately than blow forming. The finit element code developed is associated with the contact algorithm and the control algorithm of punch speed for the optimum forming. The simulation demonstrates that the variation of the thichness in a blank sheet affects the punch speed and the final distribution of the thichness in a product. The analysis proposes that a ring-typed thichness controller is very effective in controlling the thichness of a deformed sheet appropriately.

유도결합 플라즈마 화학기상증착법을 이용한 Ni/SiO₂/Si 기판에서 그라핀 제조

박영수,허훈회,김의태,Park, Young-Soo,Huh, Hoon-Hoe,Kim, Eui-Tae 한국재료학회 2009 한국재료학회지 Vol.19 No.10

Graphene has been effectively synthesized on Ni/SiO$_2$/Si substrates with CH$_4$ (1 SCCM) diluted in Ar/H$_2$(10%) (99 SCCM) by using an inductively-coupled plasma-enhanced chemical vapor deposition. Graphene was formed on the entire surface of the 500 nm thick Ni substrate even at 700 $^{\circ}C$, although CH$_4$ and Ar/H$_2$ gas were supplied under plasma of 600 W for 1 second. The Raman spectrum showed typical graphene features with D, G, and 2D peaks at 1356, 1584, and 2710 cm$^{-1}$, respectively. With increase of growth temperature to 900 $^{\circ}C$, the ratios of the D band intensity to the G band intensity and the 2D band intensity to the G band intensity were increased and decreased, respectively. The results were strongly correlated to a rougher and coarser Ni surface due to the enhanced recrystallization process at higher temperatures. In contrast, highquality graphene was synthesized at 1000 $^{\circ}C$ on smooth and large Ni grains, which were formed by decreasing Ni deposition thickness to 300 nm.

복합하중조건에서 AHSS 점용접부의 준정적 파단특성 연구

하지웅(Jiwoong Ha),허훈(Hoon Huh),이홍우(Hongwoo Lee),김교성(Kyo-seong Kim) 한국자동차공학회 2010 한국자동차공학회 학술대회 및 전시회 Vol.2010 No.11

This paper is concerned with the failure characteristic and the failure load of spot welds of AHSS under combined axial and shear loading conditions. The testing fixture and the specimen are newly designed to impose the pure-shear load on a spot weld. The testing fixture and the specimen proposed Song and Huh1 are used to impose the combined axial and shear load from 0° to 75° on spot welds. Using those testing fixture and specimens, failure tests of the spot weld of 590TRIP 1.2t, 780DP 1.0t, and 980DP 1.2t are conducted with seven different combined loading conditions. Based on the experimental results, failure loads and failure behaviors of the spot weld are investigated with respect to different loading angles. Failure loads of the spot weld obtained from failure tests are interpolated to construct Song and Huh’s failure model1, which facilitates the failure description of spot welds in the macroscopic finite element analysis of auto-body structure.

CdSe/ZnS 나노결정 양자점 Pyrolysis 제조와 발광다이오드 소자로의 응용

강승희,키란쿠마르,손기철,허훈회,김경현,허철,김의태,Kang, Seung-Hee,Kumar, Kiran,Son, Kee-Chul,Huh, Hoon-Hoe,Kim, Kyung-Hyun,Huh, Chul,Kim, Eui-Tae 한국재료학회 2008 한국재료학회지 Vol.18 No.7

We report on the light-emitting diode (LED) characteristics of core-shell CdSe/ZnS nanocrystal quantum dots (QDs) embedded in $TiO_2$thin films on a Si substrate. A simple p-n junction could be formed when nanocrystal QDs on a p-type Si substrate were embedded in ${\sim}5\;nm$ thick $TiO_2$ thin film, which is inherently an n-type semiconductor. The $TiO_2$ thin film was deposited over QDs at $200^{\circ}C$ using plasma-enhanced metallorganic chemical vapor deposition. The LED structure of $TiO_2$/QDs/Si showed typical p-n diode currentvoltage and electroluminescence characteristics. The colloidal core-shell CdSe/ZnS QDs were synthesized via pyrolysis in the range of $220-280^{\circ}C$. Pyrolysis conditions were optimized through systematic studies as functions of synthesis temperature, reaction time, and surfactant amount.

온라인 쇼핑몰의 고객 상호작용이 재구매의도에 미치는 영향에 관한 연구 -지각된 품질과 구매단계별 서비스요인을 중심으로

허훈 ( Hoon Huh ),한만억 ( Man Eok Han ),문달주 ( Dal Ju Mun ) 한국고객만족경영학회 2013 고객만족경영연구 Vol.15 No.3

이미 경쟁자들로 포화상태가 된 온라인 쇼핑은 잠재적인 구매자를 실질적인 구매 고객으로 유도 하고, 이미 구매한 고객을 충성도가 높은 고객으로 유지하는 것은 기업의 생존과 직결되는 문제가 되었다. 이러한 현실에 비추어 볼 때, 본 연구가 제시하고 있는 인터넷 쇼핑몰의 상호작용성, 지각된 즐거움, 구매단계별 서비스에 대한 논의는 온라인 쇼핑의 고객 유치와 유지라는 측면에서 의의가 있다고 할 수 있다. 본 연구의 실증적 의의는 다음 네 가지로 요약해 볼 수 있겠다. 첫째, 고객신뢰와 지각된 즐거움은 재구매의도에 많은 영향을 미치고 있는 것으로 입증되었다. 특히 이 두가지 요인은 인터넷 쇼핑몰에서 판매자와 소비자의 안정적이고 지속적인 관계를 증가시키고 소비자의 재구매 의도를 높일 수 있게 하는 중요한 요소임이 입증되었다. 둘째, 온라인 쇼핑몰의 상호작용성은 고객신뢰에 긍정적이고 강력한 영향을 준다는 것이 본 연구 논문을 통해 다시 한번 밝혀졌다. 본 연구에서 상호작용성은 구매자의 요구에 대한 반응속도, 쇼핑몰 사이트의 비언어적 측면의 지원에 대한 정도, 구매자의 쇼핑몰 사이트에 대한 의사소통 채널의 확보 등의 측정항목을 통해 고찰되었다. 셋째, 본 연구는 온라인 쇼핑에서의 구매가 가지는 특성을 실증분석을 통해 밝혔다. 전통적 상거래에서의 구매 특성과 온라인 쇼핑의 구매 특성은 온라인 쇼핑이 가지는 무점포 거래적 속성으로 인해 차별화 되므로 온라인 쇼핑몰은 특히 이 부분에 주력해야 함을 보여주고 있다. 넷째, 본 연구는 온라인 쇼핑의 서비스 측정에 대한 기존 연구가 온라인 쇼핑경험을 총체적으로 파악하여 그에 대한 고객의 만족요인이나 신뢰요인을 검증하는 것에 비해, 온라인 쇼핑을 상호작용성, 지각된 즐거움, 구매 단계별로 나누고, 각각의 개별 서비스 요인을 파악하여 그에 대한 서비스 요인을 측정했다. 이는 온라인 쇼핑 입장에서 고객이 요구하는 서비스를 제공하기 위해 보다 구체적인 접근을 가능케 했다고 볼 수 있겠다. Due to its potential for interactive communication, the internet is considered a promising tool for relationship marketing. Particularly, the interactivity and global connectivity of the internet offers several interesting opportunities and applications for interactive shopping and internet marketing. The existing researches suggested that the internet is hypothesized to lead to increased efficiency, examples, in customer information search cost and customer complaint recovery cost, and increased effectiveness, through different applications that are designed to support internet shopping customer and assist in building customer loyalty. Although many attention have been paid to internet interactivity, very few attempts have been made to how interactivity type and personalization may develop and enhance customer trust and perceived value about internet shopping mall. This study explored the conceptual model, in which interactivity type(such as perceived participation, telepresence, and online community) and personalization influence the relative effect of customer trust and perceived value in internet shopping. The major findings of this study can be summarized as follows: First, The trust in internet shopping mall is affected by interactivity and personalization. Perceived participation and personalization is very important in the trust in internet shopping mall. But among the variables perceived participation, telepresence, and personalization did not affects perceived value. Second, The perceived value in internet shopping mall is positively affected by trust. This fact means that the perceived value of consumer is affected from strong trust. Third, trust and perceived value are found to be more likely to lead to repurchase intention.

[論文] 일괄 풀림처리된 강판의 예비 변형정도에 따른 소열경화 특성

허훈(Hoon Huh),황필상(P. S. Whang) 한국자동차공학회 1990 오토저널 Vol.12 No.1

Bake hardenability of batch annealed steel sheets is investigated in connection with the amount of tensile deformation and the bake hardening condition. This study associates with the method for producing bake hardening materials by means of batch annealing process and for measuring bake hardenability which is not yet fully established. The experimental result demonstrates the relationship between strain distribution and bake hardening behavior in various bake hardening conditions, which provides an essential information for automobile design and related sheet metal forming in a press shop. The result also shows the bake hardenability ofthe tested material increases as the baking temperature is increased froni 150 ℃. The result assures the bake hardening materials can guarantee reasonably high strength as well as good uniformity in yield strength for the automobile body by sheet metal forming process.

韓國大學生들의 老父母에 對한 家族扶養意識에 關한 調査硏究

Hoon Huh(許勳) 한국노년학회 1988 한국노년학 Vol.8 No.1

The study aims to provide materials for planning school and social education for the aged and the devise the welfare policy for the aged by grasping the Korean college student's attitude toward the aged and the degree of their opinions of supporting the aged parents and by analyzing factors related with it. The data were collected from April 25, 1988 till May 12, 1988 for 470Students consisted of 234male students and 236female students. S-P-S-S was used for data analysis, data were verified by X-test according to each variable. The results are summarized as follows: 1. The opinions about economics supporting the aged parents 1) It is the majority of the opinions that give their aged parents the pocket money. 2) With regard to the method about the pocked money for the aged parents, it have a tendency that male students give through the spouse and female students give personally. And there was a significant difference(p<0.05) according to sex. 3) It shows high priority that the pocket money for the aged parents be needed of a dilettante life, social participation. 4) In case of many matters, it causes complications between students and the aged parents, it have a tendency that male students concede in the parents' favor, the other side female students distinguish between right and wrong. 2. The opinions about emotional supporting the aged parents. 1) With regard to the opinions about live together their parents after marriage, it is 83.3% among male students and 53.4% among female students that they want to live together their parents. And there was a significant difference (p<0.01) according to sex. The reason why female students shows low rates about it is that must support their parents-in-law. 2) It has begun the filial piety, propriety education since when the babyhood and when the matters great and small of the family is decided, it have a tendency to respect the aged parents' wishes. 3) In case of a conflict of opinions, it have a tendency that male students conced in the parent's female students consult withe spouse. 3. The opinions about physical service supporting the aged parents. 1) With regard to the opinions about eating out and journey, it have a high tendency to bear the aged parents company 2) In case of nursing and disease of the aged parents in have a high tendency to care by the family.