• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2002년도 가을 학술발표회 논문집
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• pp.483-490
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• 2002

This paper presents the results of a comparative study between FEM and LEM on slope stability analysis. For validation, factors of safety were compared between FEM and LEM. The results from the two methods were in good agreement suggesting that the FEM with the shear strength reduction method can be effectively used on slope stability analyses. A series of analysis were then performed using the FEM for various constitutive laws, slope angles, flow rules, and the finite element discretizations. Among the findings, the finite element method in conjunction with the shear strength reduction method can provide reasonable results in terms of factor of safety. Also revealed is that the results of FEM can be significantly affected by the way in which the type of constitutive law and flow rule are selected.

• 대한조선학회지
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• 제19권4호
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• pp.19-29
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• 1982

Galerkin's finite element method is applied to a two-dimensional heat convection-diffusion problem arising in the hydrodynamic lubrication of thrust bearings used in naval vessels. A parabolized thermal energy equation for the lubricant, and thermal diffusion equations for both bearing pad and the collar are treated together, with proper juncture conditions on the interface boundaries. it has been known that a numerical instability arises when the classical Galerkin's method, which is equivalent to a centered difference approximation, is applied to a parabolic-type partial differential equation. Probably the simplest remedy for this instability is to use a one-sided finite difference formula for the first derivative term in the finite difference method. However, in the present coupled heat convection-diffusion problem in which the governing equation is parabolized in a subdomain(Lubricant), uniformly stable numerical solutions for a wide range of the Peclet number are obtained in the numerical test based on Galerkin's classical finite element method. In the present numerical convergence errors in several error norms are presented in the first model problem. Additional numerical results for a more realistic bearing lubrication problem are presented for a second numerical model.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1994년도 추계학술대회 논문집
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• pp.133-140
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• 1994

In this paper, we have proposed a new method to determine the initial billet for the forged products using a function approximation in neural networks. the architecture of neural network is a three-layer neural network and the back propagation algorithm is employed to train the network. By utilizing the ability of function approximation of neural network, an optimal billet is determined by applying nonlinear mathematical relationship between shape ratio in the initial billet and the final products. A volume of incomplete filling in the die is measured by the rigid-plastic finite element method. The neural network is trained with the initial billet shape ratio and that of the un-filled volume. After learning, the system is able to predict the filling region which are exactly the same or slightly different to results of finite element method. It is found that the prediction of the filling shape ratio region can be made successfully and the finite element method results are represented better by the neural network.

• Journal of the Korean Wood Science and Technology
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• 제23권3호
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• pp.8-15
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• 1995

This analytical study was carried out to make quality and productivity up in designing the frame-type furniture with semi-rigid joint by understanding the mechanical and structural behavior of the joint and by evaluating the validity of application of the time-saving Finite Element Method to its structural analysis. Slope deflection equation for rigid joint was modified to describe the moment-rotation behavior of semi-rigid joint and the joint stiffness factor(Z) could be calculated to lessen the experimental expense. It was proved that Finite Element Analysis with imaginary elements having equivalent MOE to the semi-rigid joint could be the alternative method for the structural analysis of the frame-type furniture, comparing the internal rotation of the 2-dimensional beam-to-column model with two-pin(wooden dowel) from the finite element method with other available theoretical and experimental rotation value.

• 한국해양공학회지
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• 제16권1호
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• pp.22-26
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• 2002

In this paper, a finite element method is applied to the numerical calculation of the harbor calmness. The mild stop equation as the basic equation is used. The key of this model is that the bottom friction and boundary absorption are imposed. A numerical result is presented and compared with the results obtained from the other numerical analysis. These results are in very well agreement. This method calculating the calmness can be broadly utilized making the new design of harbor and fishing port in the future.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1996년도 추계학술대회논문집
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• pp.93-98
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• 1996

Process design is one of the most important fields in metal forming, where the finite element method has appeared a useful method for industrial applications. In this study. A finite element method has been applied for iso-thermal forging design in turbine disk. This kind of approach is good for minimize actual redesign of die. which can reduce die production cost. - vital importance in current industrial environment.

• 소성∙가공
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• 제9권2호
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• pp.159-164
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• 2000

In this paper, a computer simulation technique for the forging process having a floating die is presented. The penalty rigid-plastic finite element method is employed together with an iteratively force-balancing method, in which the convergence is achieved when the floating die part is in force equilibrium within the user-specified tolerance. The force balance is controled by adjusting the velocity of the floating die in an automatic manner. An application example of a three-stage cold forging process is given.

• 대한기계학회논문집A
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• 제29권9호
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• pp.1225-1234
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• 2005

Mode I stress intensity factor $(K_I)$ of Notched Ring Test(NRT) specimen for measuring slow crack growth resistance was found using finite-element method. The theoretical $K_I$ value of NRT was not available in any references and could not be solved analytically. At first, in order to verify the accuracy of the finite-element approach, published $K_I$ values of several cracks were calculated and compared with finite-element results. The results were in good agreement within inherent errors of theoretical $K_I$. Finally the mode I stress intensity factor of NRT was found using 2- and 3-dimensional finite-element methods and expressed as a function of the applied load. This enabled direct comparison of resistance to slow crack growth between NRT and Notched Pipe Test(NPT), which employ different loading regime.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1991년도 추계학술발표회 논문집 지반공학에서의 컴퓨터 활용 COMPUTER UTILIZATION IN GEOTECHNICAL ENGINEERING
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• pp.195-215
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• 1991

This report deals with the process of the finite element computation and the design of the particular example tunnel (the double track section tunnel for Line 5, 7, 8 of Seoul Subway). The finite element calculations are performed with the program MISES 3 was developed from Austria which have been used in Eroupe. The principles of mechanic and mathematic analysis for the program MISES 3 are based on "The Finite Element Method -3rd Edition" by O.C zienkiewicz. The calculations are approximate analysis method divide continuum into quadrilateral element and calculate deformation and stress, according to the force equations at the node of the element. On the calculation of under excavation, this is a very convenient method and able to calculate compounded structure with tunnel lining and surrounding materials. Although calculated under the same factor and conditions, the result is not same solution, according to the shape of mesh. Therefore , it is important that we collect the construction results of NATM on the spot and by comparing the results of the finite element method with the surveying results review the validity of analysis model.sis model.

• 대한기계학회논문집A
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• 제20권5호
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• pp.1383-1391
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• 1996

The steady-state response for a coupled structure-acoustic-cavity systme has been investigated by numerical technique using a directly coupled finite element method(FEM) and Boundary Element Method(BEM) model. The Laplace tranformed matrix equations for the structure and the acoustic cavity are coupled directly satisfying the necessary equilibrium and compatibility conditions. The coupled FEM-BEM code is verified by comparing its prediction for an example with known analytical, numerical and experimental results. The example involves a coupled structure-acoustic-cavity system which is a box-type cavity with one end as experimentally excited pinned-pinned plate.