• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.18 no.5
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• pp.491-497
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• 2009

Of all of pneumatic components utilized in the make up of pneumatic circuits on either automatic assembly machine or industrial equipment, the pneumatic cylinder is more oriented toward being a structural as well as a pneumatic member. The structural design must be based to a large degree on the end of application of the cylinder on the equipment it is operating. In this paper, design studies of a double-acting pneumatic cushion type cylinder with low-friction and high-speed driving have been developed. Of interest here is to investigate the stress and strain analysis of cylinder tube, piston rod, end cover, and to analyze the buckling of piston rod. A finite element analysis is carried out to compute the distribution of the displacement, stress and safety factors by using ANSYS. As a result, the structural safety factors of each parts in pneumatic cushion cylinder are evaluated and confirmed at the design specifications.

• Journal of Auto-vehicle Safety Association
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• v.6 no.1
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• pp.33-40
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• 2014

In this study the cylinder liner deformation which is one of the most influencing factors in a diesel engine oil consumption was performed by the finite element analysis on the basic designed structure consisting of the cylinder block, head and liners under the conditions of assembly, thermal and gas loads. Compared with a large number of other cylinder blocks showing remarkable harmonic orders of the liner distortion, results are excellent. Namely. the higher harmonic order amplitudes of the radial liner deformation amount to 1 ~ 2㎛ maximally. The main reason lies in the relatively large wall thickness of the liner which amounts to 8.2% of the bore diameter. Besides, a very stiff and symmetrical cylinder block design in combination with a bolt force introduction approximately 1.5mm below the block top deck have a further share on these results. Therefore excellent low oil consumption can be expected.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.22 no.4
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• pp.315-322
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• 2009

This paper presents a novel numerical method based on the extended moving least squares finite difference method(MLS FDM) for solving 1-D Stefan problem. The MLS FDM is employed for easy numerical modelling of the moving boundary and Taylor polynomial is extended using wedge function for accurate capturing of interfacial singularity. Difference equations for the governing equations are constructed by implicit method which makes the numerical method stable. Numerical experiments prove that the extended MLS FDM show high accuracy and efficiency in solving semi-infinite melting, cylindrical solidification problems with moving interfacial boundary.

• The Journal of the Acoustical Society of Korea
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• v.34 no.5
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• pp.360-370
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• 2015

In case that an infinite length waveguide structure is connected with a finite length structure, it is required to combine a wave approach for the waveguide structure and a modal approach for the finite length structure to investigate the dynamic response of the connected target structure. In this study, the wavenumber finite element (WFE) analysis is adopted for the infinite length waveguide substructure and a finite element (FE) method is applied for the finite length substructure and then their results are coupled in terms of the impedance or mobility at the connected points between the substructures. As a structural model, an infinite length cylindrical shell with a rectangular plate inside is regarded. These two substructures are connected at the four corner points of the plate, rigidly or resiliently. From this investigation, it was confirmed that the wave approach (WFE method) and modal approach (FE method) can be combined by the impedance coupling.

• The Journal of the Acoustical Society of Korea
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• v.38 no.5
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• pp.511-521
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• 2019

In this study, we theoretically study the acoustic scattering of an obliquely incident plane wave from a finite elastic cylindrical shell. A heuristic scattering method of Ye [Z. Ye, J. Acoust. Soc. Am. 102, 877-884 (1997)] for a finite fluid cylinder is extended into a finite elastic cylindrical shell since no analytic solutions exist in the finite cylinder. The elastic cylindrical shell is modeled with the 3D elastic wave theory considering internal fluid. Using the derived analytic solution, we observe the effect of the internal fluid on the scattering field, the scattering field for the Rayleigh parameter, and the far-field scattering function for the elastic property of the cylindrical shell.

• Journal of the korean Society of Automotive Engineers
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• v.7 no.1
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• pp.55-62
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• 1985

This study modeled in axisymmetric solid elements and analyzed the neighbourhood of the contact surface zone between liner and block in a diesel engine. The results of finite element analysis show that this model is deformed by bolt jointed load and pressure load and that stresses can vary much due to major dimensional changes in the joint area. Guidelines have been developed for selecting fillet radii and for the width of the contact area between liner and block.

• 한국기계연구소 소보
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• s.14
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• pp.33-43
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• 1985

Thick cylindrical structures, such as assemblies with electrical induction heaters or nuclear fuel element, are sometimes subjected to thermal stresses from internal heating. Such stresses are produced by temperature gradients between the inside and outside surfaces. These problems possess symmetry about either a point or an axis. the objective of this paper is to present the determination of the temperature distribution and thermal stress-strain within a conducting body by finite element method.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1993.04a
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• pp.97-107
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• 1993

프시톤 형상에 관한 연구는 엔진의 열효율을 상승시키는데 중점을 두었으나 캘리포니아주의 환경 관련 법안을 계기로 공해 물질의 배출을 중이는 방향으로 연구가 이루어지고 있다. 즉, 실린더내의 최고 온도와 압력을 적정한 수준에서 조절하여 공해물질의 방출을 극소화시키면서 열효율을 높힐 수 있는 방안에 대한 연구를 많이 진행하고 있다. 본 논문은 유한요소법을 이용하여 저마찰 패드식 피스톤에 대한 트라이볼로지적 해석으로 피스톤의 편심에 따른 압력 분포도 해석, 마찰력과 피스톤의 동특성에 대하여 알아보고자 한다. 이들을 해석하기 위한 가장 중요한 역학적 상태량은 피스톤 표면의 압력 분포와 피스톤의 편심량이며 특히, 압력 분포 해석은 피스톤의 유막 설계시 기본이 된다.

• Proceedings of the Acoustical Society of Korea Conference
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• 1998.06e
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• pp.255-258
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• 1998

본 연구에서는 해석적인 방법을 사용하여 고감도 멘드릴형 광섬유 음향센서를 설계하고자 하였다. 음향감지부의 형상으로 실린더형 멘드릴 및 중공원통형 층상복합체 멘드릴을 선정하고, 음향감도에 대한 이론식을 유도하여 재질변수 및 형상변수 등에 따른 음향감도를 해석하였다. 또한 해석적 방법 및 유한요소법을 이용한 분석결과를 비교하여 해석적인 방법의 타당성을 검증하였다. 그 결과, 멘드릴의 외경변화에 의한 감도변화 경향만이 다소 차이를 보이고 있으나 그 이외의 재질변수 및 형상변수에 의한 음향감도 변화 경향은 서로 잘 일치하는 것으로 분석되었다.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.7 no.2
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• pp.427-435
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• 2017

Most of the domestic city buses are equipped with the pressure vessels subjected to internal pressure applied by compressed natural gas. Pressure vessels subjected to internal pressure are used in various forms and purposes. Fuel is explosive and has flammable high pressure. The damage of the pressure vessel causes many property damage and loss of life. Safe design for pressure vessel is always necessary. Due to these reasons, many studies using finite element analysis have been conducted. In this paper, the stresses of cylindrical vessel and spherical dome were analyzed using ANSYS, a finite element analysis software. In order to verify the validity of the analysis, a model with a perfectly spherical shape of the dome was designed and observed. Based on the ASME standard in used, stress distribution was also analyzed for models designed with compressed natural gas(CNG). The FEM analysis software agreed with the theory when the dome shape was perfectly spherical. The model designed based on the ASME specification theory, stress concentration occurred in the knuckle part.