• Title/Summary/Keyword: Finite Region

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Adaptive Analysis of Multilayered Composite and Sandwich Plates (적층복합재료 및 샌드위치 판의 적응해석)

  • 박진우;김용협
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2001.05a
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    • pp.224-227
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    • 2001
  • Adaptive analysis of multilayered composite and sandwich plates is carried out. The adaptive analysis is based on a finite element error form, which measures the difference between the through-the-thickness distribution of finite element displacement and the actual displacement. The region where the error-measure exceeds the prescribed admitted error value, the finite element mesh locally refined in the thickness direction using the mesh superposition technique. Several numerical tests are conducted to validate the effectiveness of the current approach for adaptive analysis of laminated plates.

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Computer Simulation of the Electric Potential Distribution of Human Cross Section (심장 횡단면의 전위분포 컴퓨터 시뮬레이션)

  • 고용훈;박상희
    • Journal of Biomedical Engineering Research
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    • v.3 no.2
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    • pp.65-70
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    • 1982
  • This paper presents a new method of solving the electric potential distribution using the finite element method. The thoracic region surrounded by the body surface and the heart is discretized into finite elements and the Continuous Laplace-equation is transformed into one of the finite degrees of freedom. The current source density, the conductivity, and the excitable range is obtained by the references. From the result of simulation, it was revealed that the potential pattern of in homogeneity was much different from that of homogeneity.

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An Integral Equation of Various Cracks for Safety in Finite Plane Bodies (유한영역에서 안전을 위한 여러 형태의 균열 해석용 적분방정식 적용연구)

  • 서욱환
    • Journal of the Korean Society of Safety
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    • v.14 no.1
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    • pp.10-18
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    • 1999
  • An integral equation representation of cracks was presented, which differs from well-known "dislocation layer" representation. In this new representation, the integral equation representation of cracks was developed and coupled to the direct boundary-element method for treatment of cracks in finite plane bodies. The method was developed for in-plane(mode I and II) loadings only. In this paper, the method is formulated and applied to various crack problems involving multiple and branch cracks in finite region. The results are compared to exact solutions where available and the method is shown to be very accurate despite of its simplicity.implicity.

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A Study on the T-branch Forming with 3-D Finite Element Method (3차원 유한요소법을 이용한 T형 가지관의 용접자리 성형 방법에 관한 연구)

  • 홍대훈;황두순;신동필;홍성인
    • Transactions of Materials Processing
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    • v.10 no.1
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    • pp.23-29
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    • 2001
  • In this study, the optimized initial hole shape for T-branch forming was proposed to obtain effective welding region. Design variables were determined by approximation analysis using volume constant condition. We performed 3D elastic-plastic FEM(Finite Element Method) analysis to simulate T-branch forming process. The variation of height and thickness of T-branch with various hole shapes was investigated. The optimized initial hole shape equation was obtained by using results for the numerical analysis.

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Splitting of reinforced concrete panels under concentrated loads

  • Foster, Stephen J.;Rogowsky, David M.
    • Structural Engineering and Mechanics
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    • v.5 no.6
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    • pp.803-815
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    • 1997
  • It is well understood that concentrated forces applied in the plane of a beam or panel (such as a wall or slab) lead to splitting forces developing within a disturbed region forming beyond the bearing zone. In a linearly elastic material the length of the disturbed region is approximately equal to the depth of the member. In concrete structures, however, the length of the disturbed region is a function of the orthotropic properties of the concrete-steel composite. In the detailing of steel reinforcement within the disturbed regions two limit states must be satisfied; strength and serviceability (in this case the serviceability requirement being acceptable crack widths). If the design requires large redistribution of stresses, the member may perform poorly at service and/or overload. In this paper the results of a plane stress finite element investigation of concentrated loads on reinforced concrete panels are presented. Two cases are examined (i) panels loaded concentrically, and (ii) panels loaded eccentrically. The numerical investigation suggests that the bursting force distribution is substantially different from that calculated using elastic design methods currently used in some codes of practice. The optimum solution for a uniformly reinforced bursting region was found to be with the reinforcement distributed from approximately 0.2 times the effective depth of the member ($0.2D_e$) to between $1.2D_e$ and $1.6D_e$. Strut and tie models based on the finite element analyses are proposed herein.

A Study on Hybrid Finite Element Method for Solving Electromagnetic Wave Scattering (전자파 산란문제를 해결하기 위한 혼합 유한요소법에 관한 연구)

  • 박동희;강찬석;안정수
    • The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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    • v.4 no.1
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    • pp.38-43
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    • 1993
  • A Hybrid Finite Element Method(HFEM) is applied to solve the electrormagnetic scattering from multi-layered dielectric cylinders. An unbounde region is divided into local boundary regions where a practical differential equation solution is obtained, with the remaining unbounded region represented by a boundary integral equation. If sources, media inhomogeneities, and anisotropies are local, a surgace may be defined to enclose them. Therefore the integral region so defined is bounded, and differential techniques may be used there. Also, in the re- maining unbounded region a boundary integral equation may be formulated using only a simple free - space green's function. Therefore, The local boundary is represented by a boundary - value problem with boundary conditions and solved by the finite element method. The advantage of the proposed method is simple and efficient in the work of electromagnetic scattering. The validity of the results have been verified by comparing results of other method(boundary element method). Examples has been presented to calculate the scattered fields of lossy dielectric cylinders of arbitray cross section.

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Consideration on Frictional Laws and their Effect on Finite Element Solutions in Bulk Metal Forming (체적소성가공에서 마찰법칙이 유한요소해석 결과에 미치는 영향에 관한 고찰)

  • Joun, M.S.;Moon, H.K.;Hwang, S.M.
    • Journal of the Korean Society for Precision Engineering
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    • v.13 no.2
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    • pp.102-109
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    • 1996
  • Effects of frictional laws on finite element solutions in metal forming were investigated in this paper. A rigid-viscoplastic finite element formulation was given with emphasis on the frictional laws. The Coulomb friction and the constant shear friction laws were compared through finite element analyses of compression of rings and cylinders with different aspect ratios, ring-gear forging, multi-stage cold extrusion and hot strip rolling under the isothermal condition. It has been shown that two laws may yield quite different results when the aspect ratio of a process and the fractional contact region are large.

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Finite Element Analysis Using an Analytical Solution (해석해를 이용한 유한 요소 해석법)

  • Huh, Young-Woo;Lim, Jang-Keun
    • Proceedings of the KSME Conference
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    • 2000.11a
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    • pp.458-463
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    • 2000
  • The mechanical structures generally have discontinuous parts such as the cracks, notches and holes owing to various reasons. In this paper, in order to analyze effectively these singularity problems using the finite element method, a mixed analysis method which an analytical solution and finite element solutions are simultaneously used is newly proposed. As the analytical solution is used in the singularity region and the finite element solutions are used in the remaining regions except this singular zone, this analysis method reasonably provides for the numerical solution of a singularity problem. Through various numerical examples, it is shown that the proposed analysis method is very convenient and gives comparatively accurate solution.

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Influence of Crown Margin Design on the Stress Distribution in Maxillary Canine Restored by All-Ceramic Crown: A Finite Element Analysis

  • Ozer, Zafer;Kurtoglu, Cem;Mamedov, Amirullah M.;Ozbay, Ekmel
    • Journal of Korean Dental Science
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    • v.8 no.1
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    • pp.28-35
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    • 2015
  • Purpose: To investigate the influence of crown margin design on the stress distribution and to localize critical sites in maxillary canine under functional loading by using three dimensional finite element analysis. Materials and Methods: The bite force of 100 N, 150 N, and 200 N was applied with an angulation of $45^{\circ}$ to the longitudinal axis of tooth. Six models were restored with IPS e.max (Ivoclar Vivadent, Schaan, Liechtenstein) with a different margin design. With lingual ledge and various thicknesses, three different core ceramics were designed in each model. Result: In the core ceramic, the maximum tensile stresses were found at the labiocervical region. In the veneering ceramic the maximum tensile stresses were found at the area where the force was applied in all models. Conclusion: Shoulder and chamfer margin types are acceptable for all-ceramic rehabilitations. A ledge on the core ceramic at cervical region may affect the strength of all-ceramic crowns.

Stress Analysis of Fir-Tree Root in Turbine Rotor Using Photoelastic Technique (광탄성기법을 이용한 터빈로터 퍼-트리부의 응력해석)

  • Sin, Gwang-Bok;Gyeong, U-Min;Hong, Chang-Seon
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.20 no.6
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    • pp.1784-1797
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    • 1996
  • The disk/blade assembly of a turbine engine is made in the shape of a dovetail type or a fir-tree type. Since disk fillet regions or contact surfaces undergo high stress comcentration, fatigue cracks frequentrly occur in the disk/blade assembly. Therefore, it is necessary to analyze the stress distributions in the fir-tree type disk/balde assembly and predict the region of fatigue failure. The stress distributions of the disk/blade assembly were investigated by using the photoelastic method and the finite element method. Two dimensional photoelastic techniques were used to investigate the stress distributions of contact surfaces and fillet regions. TH stress distributions were obtained by the shear-difference method and were compared to the finite element results. It was found that maximum tensile stresses were higher in the fillet region thatn in the contact surfaces of the fir-tree models. The finite element results showed good agreement with the experimental results.