• Title/Summary/Keyword: boundary element method

### The Prediction Modelling on the Stress Intensity Factor of Two Dimensional Elastic Crack Emanating from the Hole Using Neural Network and Boundary element Method (신경회로망과 경계요소법을 이용한 원공에서 파생하는 2차원 탄성균열의 응력세기계수 예측 모델링)

• Yun, In-Sik;Yi, Won
• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.3
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• pp.353-361
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• 2001
• Recently the boundary element method has been developed swiftly. The boundary element method is an efficient and accurate means for analysis of two dimensional elastic crack problems. This paper is concerned with the evaluation and the prediction of the stress intensity factor(SIF) for the crack emanating from the circular hole using boundary element method-neural network. The SIF of the crack emanating from the hole was calculated by using boundary element method. Neural network is used to evaluate and to predict SIF from the results of boundary element method. The organized neural network system (structure of four processing element) was learned with the accuracy 99%. The learned neural network system could be evaluated and predicted with the accuracy of 83.3% and 71.4% (in cases of SIF and virtual SIF). Thus the proposed boundary element method-neural network is very useful to estimate the SIF.

### Wave Force Analysis Acting on a Vertical Circular Cylinder by Boundary Element Method (경계요소법에 의한 수직원주에 작용하는 파력해석)

• Kim, Nam-Hyeong;Park, Min-Su
• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.1910-1913
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• 2006
• To solve the interaction of incident monochromatic waves with a bottom-fixed vertical circular cylinder, a numerical analysis by boundary element method is developed using three-dimensional linear potential theory. A numerical analysis by boundary element method is based on Green's theorem and introduce to an integral equation for the fluid velocity potential around the vertical circular cylinder. These numerical results are compared with those of ManCamy and Fuchs(1954) and Williams and Mansour(2002), and it has shown good relationship with their results. This numerical analysis developed by boundary element method will be applied for various offshore structures to be constructed in coastal zones in the future.

### THE BOUNDARY ELEMENT METHOD FOR POTENTIAL PROBLEMS WITH SINGULARITIES

• YUN, BEONG IN
• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.3 no.2
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• pp.17-28
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• 1999
• A new procedure of the boundary element method(BEM),say, singular BEM for the potential problems with singularities is presented. To obtain the numerical solution of which asymptotic behavior near the singularities is close to that of the analytic solution, we use particular elements on the boundary segments containing singularities. The Motz problem and the crack problem are taken as the typical examples, and numerical results of these cases show the efficiency of the present method.

### Analysis of Three Dimensional Crack Growth by Using the Symmetric Galerkin Boundary Element Method

• Kim, Tae-Soon;Park, Jai-Hak
• International Journal of Safety
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• v.2 no.1
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• pp.17-22
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• 2003
• In order to analyze general three dimensional cracks in an infinite body, the symmetric Galerkin boundary element method formulated by Li and Mear is used. A crack is modelled as distribution of displacement discontinuities, and the governing equation is formulated as singularity-reduced integral equations. With the proposed method several example problems for three dimensional cracks in an infinite solid, as well as their growth under fatigue, are solved and the accuracy and efficiency of the method are demonstrated.

### On boundary discretization and integration in frequency-domain boundary element method

• Fu, Tia Ming;Nogami, Toyoaki
• Structural Engineering and Mechanics
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• v.6 no.3
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• pp.339-345
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• 1998
• The computation size and accuracy in the boundary element method are mutually coupled and strongly influenced by the formulations in boundary discretization and integration. This aspect is studied numerically for two-dimensional elastodynamic problems in the frequency-domain. The localized nature of error is observed in the computed results. A boundary discretization criterion is examined. The number of integration points in the boundary integration is studied to find the optimum number for accuracy. Useful information is obtained concerning the optimization in boundary discretization and integration.

### Permeable Breakwaters Analysis by Using Boundary Element Method (경계요색법(境界要索法)에 의한 투과잠제(透過潛堤)의 해석기법(解析技法))

• Kim, Nam Hyeong;Takikawa, Kiyoshi;Choi, Han Kuv
• Journal of Industrial Technology
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• v.10
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• pp.69-72
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• 1990
• In this paper the numerical method for the study of wave reflection from and transmission through submerged permeable breakwaters using the boundary element method is developed. The numerical analysis technique is based on the wave pressure function instead of velocity potential because it is difficult to define the velocity potential in the each region arising the energy dissipation. Also, the non-linear energy dissipation within the submerged porous structure is simulated by introducing the linear dissipation coefficient and the tag mass coefficient equivalent to the non-linear energy dissipation. For the validity of this analysis technique, the numerical results obtained by the present boundary element method are compared with those obtained by the other computation method. Good agreements are obtained and so the validity of the present numerical analysis technique is proved.

### Development of the Direct Boundary Element Method for Thin Bodies with General bBundary Conditions (일반 경계 조건을 가진 얇은 물체에 대한 직접 경계 요소법의 개발)

• 이강덕;이덕주
• Journal of KSNVE
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• v.7 no.6
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• pp.975-984
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• 1997
• A direct boundary element method (DBEM) is developed for thin bodies whose surfaces are rigid or compliant. The Helmholtz integral equation and its normal derivative integral equation are adoped simultaneously to calculate the pressure on both sides of the thin body, instead of the jump values across it, to account for the different surface conditions of each side. Unlike the usual assumption, the normal velocity is assumed to be discontinuous across the thin body. In this approach, only the neutral surface of the thin body has to be discretized. The method is validated by comparison with analytic and/or numerical results for acoustic scattering and radiation from several surface conditions of the thin body; the surfaces are rigid when stationary or vibrating, and part of the interior surface is lined with a sound-absoring material.

### The Boundary Element Analysis of Wave Force acting on Multiple Cylinders

• Kim, Nam-Hyeong;Cao, Tan Ngooc Than;Yang, Soon-Bo
• Journal of Navigation and Port Research
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• v.36 no.7
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• pp.561-569
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• 2012
• In this paper, the boundary element method is applied to solve the diffraction of waves by multiple vertical cylinders under the assumption of linear wave theory. A numerical analysis by boundary element method is based on Green's theorem and introduced to an integral equation for the fluid velocity potential around the cylinders. The numerical results obtained in this study are compared with the experimental data and the results of the theory using multiple scattering techniques. The comparisons show strong agreement. This numerical analysis method developed by using boundary element method could be used broadly for the design of various offshore structures to be constructed in coastal zones in the future.

### Treatment of Numerical Integration for Boundary Element Method (경계요소법에 있어서 수치적분에 관한 고찰)

• Park, Sung-Oan;Kwak, Chang-Sup;Koo, Young-Duk
• Journal of the Korean Society for Precision Engineering
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• v.13 no.2
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• pp.185-193
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• 1996
• Errors included in solutions obtained by the boundary element method are generally larger than those by the finite element method in the case that the number of discreted elements is small. One of the reasons is supposed to be attributed to the error which will be produced in the numerical integration of the singular functions in two dimensional elastic problem. Then, treatment of analytical integration to reduce computing time and to decrease errors of boundary element method are proposed.

### Prediction of Crack Propagation Path Using Boundary Element Method in IC Packages (반도체 패키지의 경계요소법에 의한 균열진전경로의 예측)

• Chung, Nam-Yong
• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.3
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• pp.15-22
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• 2008
• Applications of bonded dissimilar materials such as integrated circuit(IC) packages, ceramics/metal and resin/metal bonded joints, are very increasing in various industry fields. It is very important to analyze the thermal stress and stress singularity at interface edge in bonded joints of dissimilar materials. In order to investigate the IC package crack propagating from the edge of die pad and resin, the fracture parameters of bonded dissimilar materials and material properties are obtained. In this paper, the thermal stress and its singularity index for the IC package were analyzed using 2-dimensional elastic boundary element method(BEM). From these results, crack propagation direction and path by thermal stress in the IC package were numerically simulated with boundary element method.