• 대한기계학회논문집
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• 제7권3호
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• pp.278-285
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• 1983

The momentum transfer in axisymmetric turbulent boundary layer over a rotating cone submerged in a free stream was studied by experiments and numerical analysis. In numerical analysis the velocity profiles were calculated by finite difference method using Prandtl mixing length concept, and the results were compared with experimental results. The agreement was good. By the numerical analysis the wall fircition coefficient was increased as the Reynolds number increased when the rotational speed is large, but the wall friction coefficient was decreased as the rotational speed increased.

• International Journal of Precision Engineering and Manufacturing
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• 제1권2호
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• pp.14-23
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• 2000

A numerical scheme is proposed to obtain the individual stress intensity factors in an axisymmetric crack and in a three dimensional mixed mode crack. The method is based on the path independence of J and M integral and mutual or two-state conservation integral , which involves two elastic fields. Some numerical example are presented to investigate the effectiveness and applicability of the method for and axisymmetric crack and a three dimensional penny shaped crack problem under mixed mode.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 춘계학술대회논문집A
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• pp.854-859
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• 2000

When the round bar with step is twisted and bent, stress concentration is occurred in the irregular geometric parts. Two dimensional axisymmetric stress analysis is carried out according to the geometric change of the stress-concentrated part of round bar with step. Three dimensional cases are also investigated.

• 천문학논총
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• 제17권1호
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• pp.7-10
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• 2002

In the earlier papers we analyzed the axisymmetric, nonstationary electrodynamics of the central black hole and a surrounding thin accretion disk in an active galactic nucleus. Based on those papers we analyze the axisymmetric, nonstationary force-free black hole magnetosphere and the motion of the plasma. We concentrate on deriving the relations between the velocity components of the plasma and those of the accreting magnetic field lines. We conclude that the former are given by the sum of the latter and the magnetic field terms.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1998년도 봄 학술발표회 논문집
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• pp.357-364
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• 1998

In this paper, ground vibration analysis methods for train transit on bridges are studied. Train loads acting on the piers are evaluated considering the interactions between the trains and the bridge. The 2D in-plane wave propagation method and the axisymmetric wave propagation method are used in the ground vibration analysis, and then the results of the ground vibration are compared. A modified axisymmetric method is presented, which can consider the effect of the train loadings on a series of piers as the train moves.

• 한국농공학회:학술대회논문집
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• 한국농공학회 1999년도 Proceedings of the 1999 Annual Conference The Korean Society of Agricutural Engineers
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• pp.200-205
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• 1999

In this study, a computer program considering iniial imperfectiionof axiymmetric reinforced concrete shell which show plastic deformation by large external loading was developed . Initial imperfection of wall was assumed as 'sine curve' which can be expressed as Wi =W0 sin(n$\pi$/1y). The developed model was applied to the analysis of dynamic response of axisymmetric reinforced concrete shell when it has initial imperfection . The initial imperfection of 0.0, -5.0 and 5 cm and steel ration 0 , 3 and 5% were tested for numerical examples.

• 대한전기학회논문지
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• 제43권7호
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• pp.1061-1066
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• 1994

The eddy currents of 3-dimensional conductin medium are calculated using vectorial Boundary element Method with vector variables E and H. Boundary edge basis vectors are used to expand the tangential components of E and H fields. Especially for axisymmetric conductor the computer storage and the computation time are greatly saved with the help of block-circulant boundary meshes. to verify this method eddy currents of conducting sphere are computed and show good agreements with the analytic solutions.

• 소성∙가공
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• 제5권2호
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• pp.156-164
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• 1996

To investigate the behavior of plastic deformation in axisymmetric extrusion through square dies, experimental works with the plasticine as a model material are carried out at the room temperature. Some mechanical properties of the model material are determined by compression and ring compression tests. Visioplasticity method using expermental grid distortion in extrusion is introduced to analyze the plastic flow strain rate and strain distribution. In spite of severe deformation during the extrusion through square die the visioplasticity method shows good results for the distribution of effective strain rate and effective strain.

• Journal of applied mathematics & informatics
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• 제41권1호
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• pp.155-165
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• 2023

We consider circular Rayleigh problem of hydrodynamic stability which deals with linear stability of axial flows of an incompressible iniviscid homogeneous fluid to axisymmetric disturbances. For this problem, we obtained two parabolic instability regions which intersect with Batchelor and Gill semi-circle under some condition. This has been illustrated with examples. Also, we derived upper bound for the amplification factor.

• 한국전산구조공학회논문집
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• 제16권2호
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• pp.165-172
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• 2003

본 연구에서는 축대칭 쉘구조물의 정동적해석을 효과적으로 수행할 수 있는 새로운 유한요소를 제안하였다. 본 유한요소는 축대칭 쉘의 전단변형률을 고려하였으며, 쉘의 경계에서 기술할 수 있는 변수들만으로 표현되는 효율적인 형태의 수정된 혼합 변분이론에 바탕하여 유한요소정식화를 수행하였다. 또한, 변위장에 대해 무절점 자유도를 추가적으로 도입하여 요소의 수치적 성능을 크게 향상시켰다 계산의 효율성을 위해, 요소정식화의 최종단계에서 정치조건으로부터 응력매개변수들을 제거하고, 동적축약을 통하여 무절점 자유도 성분들 또한 최종적인 유한요소방정식에서 제거되어짐으로써, 일반적인 변위기저 요소와 같은 크기의 유한요소방정식을 얻을 수 있다. 몇 가지 수치예제들에 대한 해석을 통하여, 무절점 자유도와 변위장에 일치하는 적절한 응력매개변수를 가지는 제안된 혼합 축대칭 쉘요소가 정동적해석에서 대단히 정확하고 효율적임을 확인할 수 있었다