http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
다꾸찌방법을 사용한 여러변수들이 패키지균열에 미치는 신뢰도 평가
권용수,박상선,박재완,채영석,최성렬,Kwon, Yong-Su,Park, Sang-Sun,Park, Jae-Wan,Chai, Young-Suck,Choi, Sung-Ryul 대한기계학회 1997 大韓機械學會論文集A Vol.21 No.6
Package crack caused by the soldering process in the surface mounting plastic package is evaluated by applying the maximum energy release rate criterion. It could be shown that the crack propagation from the lower edge of the ie pad is easily occurred at the maximum temperature during the soldering process, where the pressure acting on the crack surface is assumed by the saturated vapor pressure at maximum temperature. The package crack formation depends on various parameters such as chip size, relative thickness, material properties, the moisture content and soldering temperature etc. The quantitative measure of the effects of the parameters could be easily obtained by using the taguchi's method which requires only a few kinds of combinations with such parameters. From the results, it could be obtained that the more significant parameters to effect the package reliability are the orders of Young's modulus, die pad size, down set, chip thickness and maximum soldering temperature.
인코넬 합금의 미세조직과 기계적 특성에 미치는 냉각속도 영향
박노경,이호성,채영석,Park, No-Kyeong,Lee, Ho-Seong,Chai, Young-Suck 한국재료학회 2007 한국재료학회지 Vol.17 No.10
The mechanical properties and microstructure of Inconel 690 and 600 alloys with various cooling rates were investigated. Optical microscopy and scanning electron microscopy observations indicated that in case of the cooling rate of $0.5^{\circ}C/min$, discontinuous carbides along the grain boundaries were formed and when the cooling rate was $10^{\circ}C/min$, continuous carbides were formed in Inconel 690 and 600 alloys. For the annealed Inconel 690 alloy with high Cr content, a lot of annealing twins, which led the preferential growth of (111) planes, were observed. However, the annealed Inconel 600 alloy with low Cr content showed a few annealing twins and the preferential growth of (200) planes. Inconel 600 alloy had a larger value of ultimate tensile strength (UTS) than Inconel 690 alloy.
설일찬,이춘열,채영석,Seol, Il-Chan,Lee, Choon-Yeol,Chai, Young-Suck 대한기계학회 2002 大韓機械學會論文集A Vol.26 No.7
Single fiber pull-out technique has been commonly used to characterize the mechanical behavior of interface in fiber reinforced composite materials. An improved analysis considering the effects of transversely isotropic properties of fiber and the effects of thermal residual stresses in both radial and axial directions along the fiber/matrix interface is developed for the single fiber pull-out test. Although the stress transfer properties across the interface is not much affected by considering the transversely isotropic properties of fiber, interfacial debonding is notably encouraged by the effect. The interfacial shear stress that plays an important role in interfacial debonding is very much affected by the component of axial thermal residual stress in the bonded region, which can induce a two-way debonding mechanism.
서응수(Eung Soo Seo),김용식(Yongsik Kim),황중국(Joong Kook Hwang),채영석(Young Suck Chai),심재술(Jaesool Shim) 대한기계학회 2015 大韓機械學會論文集A Vol.39 No.9
염료감응형 태양전지용 플렉시블 필름에 도포된 코팅물질의 균질한 코팅은 제품의 성능과 내구성과 매우 밀접한 관계가 있고, 균질한 코팅은 열풍건조로 노즐에서의 균일한 온도분포와 질량유량에 의해 얻어질 수 있다. 본 연구에서 열풍건조로의 성능향상에 영향을 주는 다양한 인자들에 대한 수치해석을 수행함으로써 열풍건조로 출구의 균일한 온도분포와 질량유량을 얻고자 하였다. 수치해석 모델은 유동방정식과 에너지방정식으로 구성되었고, 수치해석을 모델의 검증을 위해 수치해석 결과값과 실험결과를 비교하였다. 연구결과로서 열풍건조로의 타공판이 균일한 온도분포 및 질량유량에 큰 영향을 미친다는 것을 알 수 있었다. The homogeneous coating of a flexible film that is applied to dye-sensitized solar cells is related to the performance and durability of the product. The applied coating is obtained from the uniform temperature distribution and the mass flow rate in the nozzle of the hot air dryer. In this study, we determine the uniform temperature distribution and mass flow rate of each nozzle by performing numerical simulations to understand how various factors affect the performance of the hot air dryer. The numerical model is composed of the momentum equation for flow motion and the energy equation for temperature. In addition, we compare the numerical results to the experimental results to validate the model. Based on the results, the round-hole plate inside the hot air dryer significantly affects the uniform temperature and the mass flow rate.
배준우(Joon Woo Bae),이춘열(Choon Yeol Lee),채영석(Young Suck Chai) 대한기계학회 2005 대한기계학회 춘추학술대회 Vol.2005 No.10
Fretting, which is a special type of wear, is defined as small amplitude relative motion along the contacting interface between two materials. The structural integrity of steam generators in nuclear power plants is very much dependent up on the fretting wear characteristics of Inconel 690 U-tubes. A finite element model that can simulate fretting wear was developed in this study in order to investigate the behavior of the phenomenon quantitatively. Two-dimensional and three-dimensional finite element analyses were adopted to investigate the fretting wear problems. Two-dimensional finite element analyses for elastic contact wear problems were performed to demonstrate the feasibility of the finite element method to the fretting wear problems in consideration of frictional contact. A numerical example which has existing solutions was treated. By introducing a control parameter s, which scaled up the wear constant and scaled down the cycle numbers, the algorithm was shown to greatly reduce the time required for the analysis. In the wear model, the work rate model was adopted. The two-dimensional solutions of the study are in good agreement with the previous results by Stromberg. The actual tube-to-tube fretting wear tests in the steam generator were simulated in the three-dimensional finite element analysis. Normal contact pressures and wear depth along the contact surface were plotted under the different values of wear parameters and a number of cycles.
유한요소법을 이용한 조건에 따른 마모 영역별 2차원 프레팅 마모 해석
우종관(Jong Kwan Woo),배준우(Joon Woo Bae),이춘열(Choon Yeol Lee),채영석(Young Suck Chai) 대한기계학회 2006 대한기계학회 춘추학술대회 Vol.2006 No.3
In nuclear power plant, fretting wear, caused by flow induced vibration (FIV), can make a serious problem in a U-tube bundle in steam generator. In this study, finite element analysis of the fretting wear on the secondary side of the steam generator was investigated which arises between U-tubes and their supports or foreign objects. Using finite element method, two-dimensional models with cylindrical or plate supports were adopted to investigate the fretting wear problems. As boundary conditions, various combinations of loads are applied to verify different fretting mechanisms, such as stick only, stick-slip and gross slip wear. For this purpose, four different load conditions are considered and in the finite element analysis, ABAQUS are used with the program which is developed to calculate wear depth and modify input files at each cycle. As a result, regions for each wear mechanism are found and fretting wear map is constructed, which can be used as a reference or criterion for fretting wear experiments.
최병선(Byung-Sun Choi),배원호(Won-Ho Bae),채영석(Young-Suck Chai) 한국산업융합학회 2001 한국산업융합학회 논문집 Vol.4 No.4
The lower toughness or brittle materials for mechanical test lead to the additional requirement that applied displacements be controlled with high resolution. Biaxial tension and shear tester using stepper motor with harmonic driver is shown. The device had to be high resolution so that the crack initiation process of slow extension and steady growth could be examined, Grip plates were connected to a linear bearing and actuator. The actuators consisted of stepper motors with harmonic driver connected to pre-loaded ball screw and nut assemblies. The encoders and motor controllers were connected to a personal computer so that arbitrary displacements histories could he prescribed in normal and tangential directions. The linear bearings were used to react loads perpendicular to their axes while allowing low friction, parallel movement of the attached grips. Load cells measured the reactions normal and tangential. the loads measured the reactions were recorded by the computer.<br/>