• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.8
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• pp.945-951
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• 2012

In this study, we analyze the static and dynamic characteristics of a bulk-cement trailer with a simpler structure that carries powders. The commercial software ANSYS is used to prepare a detailed three-dimensional model of the chassis frame and tank body that bear most of the load of a bulk-cement trailer for the finite element analysis. Modal analysis is conducted to examine the dynamic characteristics of the trailer body, and static analysis shows weak links in the structure. Finally, we propose a method to increase the strength of vulnerable areas and to reduce the weight of the trailer by applying the Taguchi method.

• Journal of the Korean Society for Marine Environment & Energy
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• v.10 no.4
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• pp.218-226
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• 2007

In modern naval ships, the design of submarines has continually evolved to improve survivability and it is also important to design ship against shock response. Exiting underwater ship design has been peformed due to results of static analysis considering shock acceleration by simple method. However, it can not be anticipated good assesment. The present study applied the Arbitrary Lagrangian-Eulerian (ALE) technique, a fluid-structure interaction approach, to simulate an underwater explosion and investigate the survival capability of a damaged submarine liquefied oxygen tank. The Lagrangian-Eulerian coupling algorithm and the equations of state for explosives and seawater were also reviewed. It is shown that underwater explosion analysis using the ALE technique can accurately evaluate structural damage after attack. This procedure could be applied quantitatively to real structural design.

• Journal of the Korean Society for Railway
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• v.15 no.6
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• pp.588-596
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• 2012

This paper presents a new semi-analytical annular Mindlin plate element with which out-of-plane natural vibration of thick disks can be analyzed simply, efficiently, and accurately through FEM by including effects of rotary inertia and transverse shear deformation. Using static deformation modes which are exact solutions of equilibrium equations of annular Mindlin plate, the element interpolation functions, stiffness and mass matrices corresponding to each number of nodal diameters are derived. The element is capable of representing out-of-plane rigid-body motions exactly and free from shear locking. Natural frequencies of uniform and multi-step disks with or without concentric ring support are analyzed by applying the presented element. Such results are compared with theoretical predictions of previous works or FEA results obtained by using two-dimensional shell element to investigate the convergence and accuracy of the presented element.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.10
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• pp.22-28
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• 1998

Signal transmission and crosstalk of coupled bondwires buried in plastic packages are analyzed using the Method of Moments and the Fourier Transform algorithm. It is also shown that the quasi-static crosstalk model of SPICE is inappropriate for designing the high-speed plastic packages. Plastic packaging material, increasing the self and mutual capacitances, is found to be helpful for the signal transmission integrity due to the dielectric compensation effect. However, it is also observed that the plastic material increases the crosstalk due to the radiation-enhanced mutual coupling effect. By investigating the geometrical and material dependence of the pulse transmission and crosstalk, it is found that the radiation-enhanced coupling effect is significant for most of typical bondwire geometries and plastic package materials. These calculation results can be effectively used for designing plastic packages of high-speed digital IC's and monolithic RFIC's.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2002.05a
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• pp.44-47
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• 2002

A liner static and dynamic analysis for a golf shaft, which is made of carbon fiber reinforced composite materials, is presented in this study. Major mechanical parameters of golf shafts such as deflection, torsional angel, frequency of vibration(CPM), and kick point are analyzed by finite element method. The effects of major parameters on the performance of golf shafts are also discussed. The results show that the major parameters of golf shafts are strongly dependent on the material properties of fibers and design pattern of golf shafts. The present results will be useful to design sheet-rolled golf shafts.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2016.11a
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• pp.201.1-201.1
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• 2016

전주된 Invar (Fe-35%Ni) 박판 위에 증착된 Cu 박막은 스퍼터 전력량이 증가할수록 증착속도가 증가하였다. Cu/Invar 박판이 Invar 박판보다 면저항 값이 34%로 작았다. Invar 박판 위에 Cu가 증착되면 최대자화와 투자율은 각각 40.3, 65.0 [%] 감소하였다. Cu 박막의 탄성하강강성도, 마찰계수, 피로한계는 각각 45, 0.130, 0.093 이었다. 동적 나노 압침법으로 얻은 Invaar/Cu 박막의 하중-시간-변위 곡선의 가장 큰 차이는 탄성하강강성도(elastic stiffness) 이었다. 미세경도와 나노경도의 실험적 관계식은 $Y[GPa]=9.18{\times}10^{-3}X[Hv]$ 이었다. 나노압침선단의 하중분포를 이차원 선형 및 비선형 유한요소해석을 통하여 1.0 [mN] 의 정적하중을 가한 Cu 박막은 486 [mN] 으로 예측되었다. 이는 표면탐침현미경으로 관찰한 압흔의 변형정도와 유사한 경향을 보였다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.32 no.10
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• pp.890-896
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• 2008

Sheet metal forming is one of the most useful and important method in manufacturing of the autobody panels because of the excellent production rate. The objectives of sheet metal forming processes are getting a desired geometrical shape of products with good quality, low cost and reasonable lead time. In this paper, we examined the validity of finite element method analysis on the automobile FRT-PLR-L/R stamping process by using the lancing engineering method. Lancing is a press operation in which a single-line cut or slit is made on part way across the strip stock, without removing any metal. As a result, it has shown that the proper lancing engineering method could prevent fracturing by improving sheet metal flow.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.10a
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• pp.398-401
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• 2005

The characteristic of sheet metal process is the few loss of material during process, the short processing time and the excellent price and strength. Such press-forming process are the used machine ability and the characteristic, used material, the accuracy of the part which becomes processing and side condition of a process are considered and the designed. The purpose of this study is apply efficiently sheet metal forming processing by 3D formation-analyzed program simulations in the site. By a study, forming process was simulation to drawing and trimming and cam process using static-implicit method software. By making apply this to an industrial site the productivity improvement and cost reduction etc. effect able was predicted.

• Proceedings of the Korean Information Science Society Conference
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• 2005.11b
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• pp.619-621
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• 2005

햅틱 장치를 이용한 변형체의 실시간 시뮬레이션은 가상현실을 구축하기 위한 중요한 기술의 하나로서 최근에 크게 각광받고 있다. 본 연구에서는 햅틱 장비와 변형체의 정확한 인터페이스를 구축하기 위하여 변형체의 물리적 특성을 고려한 연속체적 모델인 유한요소법을 통한 선행해석을 수행한다. 변형체와 햅틱 장치의 상호작용 과정에서 발생하는 변형과 반력을 사용자에게 실시간으로 제공하기 위하여 선행해석 결과를 이용한 변형체의 정적 시뮬레이션을 구현한다. 이와 함께 햅틱 장치와 접촉이 이루어지는 부분의 변형을 보다 자연스럽게 표현하기 위하여 적응적 유한요소법인 s-adaptive 방법을 적용하였으며 햅틱 장치와 접촉이 끝난 후의 변형체가 평형 상태로 돌아가는 과정을 모사하기 위하여 Newmark scheme을 통한 동적 시뮬레이션을 구현한다. 또한 최적화 행렬 연산 함수인 BLAS와 LAPACK을 이용하여 행렬 연산을 빠르게 수행하고 효율적인 메모리 사용 추구한다.

• Bulletin of the Society of Naval Architects of Korea
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• v.26 no.3
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• pp.51-61
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• 1989

Recently, the growth in the propulsion power and propeller size of typical energy saving ships has resulted in severe damages of the oil-lubricated stern tube bearing. Consequently, a more rational analytical method for the design of the shafting system is required. In this paper an analytical method applicable to the design of the oil-lubricated stern tube bearing and shafting system is presented. The method consists of the finite element analysis of the shafting system and the oil film hydrodynamics. The shafting system is modeled as a three-dimensional problem using beam elements taking account for the steady components of thrust, lateral forces and moments of the propeller as well as the elastic foundation effects. The oil film hydrodynamics is modeled as a two-dimensional problem. Equal and retangular elements employing hourglass control method are used for the construction of the oil film fluidity matrix. To search the quasi-static equilibrium position between the propeller shaft and the oil film, an optimization technique is employed. Some numerical results based on the proposed method are compared with some measured and numerical data available. They show acceptable agreements with the data.