• Title, Summary, Keyword: Finite Region

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EVALUATION OF THE FINITE ELEMENT MODELING OF A SPOT WELDED REGION FOR CRASH ANALYSIS

  • Song, J.H.;Huh, H.;Kim, H.G.;Park, S.H.
    • International Journal of Automotive Technology
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    • v.7 no.3
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    • pp.329-336
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    • 2006
  • The resistance spot-welded region in most current finite element crash models is characterized as a rigid beam at the location of the welded spot. The region is modeled to fail with a failure criterion which is a function of the axial and shear load at the rigid beam. The calculation of the load acting on the rigid beam is important to evaluate the failure of the spot-weld. In this paper, numerical simulation is carried out to evaluate the calculation of the load at the rigid beam. At first, the load on the spot-welded region is calculated with the precise finite element model considering the residual stress due to the thermal history during the spot welding procedure. And then, the load is compared with the one obtained from the model used in the crash analysis with respect to the element size, the element shape and the number of imposed constraints. Analysis results demonstrate that the load acting on the spot-welded element is correctly calculated by the change of the element shape around the welded region and the location of welded constrains. The results provide a guideline for an accurate finite element modeling of the spot-welded region in the crash analysis of vehicles.

A Composite Method of Finite Element and of Boundary Integral Methods for the Magnetic Field Problems with Open Boundary (유한요소법 및 경계적분법의 혼합법에 의한 개 영역 자장문제 해석)

  • 정현교;함송엽
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.36 no.6
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    • pp.396-402
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    • 1987
  • A Composite method of finite element and boundary integral methods is introduced to solve the magnetostatic field problems with open boundary. Only the region of prime interest is taken as the compution region where the finite element method is applied. The boundary conditions of the region are dealt with using boundary integral method. The boundary integration in the boundary integral method is done by numerical and analytical techniques repectively. The proposed method is applied to a simple linear problem, and the results are compared with those of the finite element method and the analytic solutions. It is concluded that the proposed method gives more accurate results than the finite element method under the same computing efforts.

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Finite Element Analysis of Mechanical Behavior of Bolt Tightened in Plastic Region (소성역 체결 볼트의 기계적 거동 유한요소해석)

  • Cho, Sung-San;Shin, Chun-Se
    • Transactions of the Korean Society of Automotive Engineers
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    • v.18 no.3
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    • pp.37-42
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    • 2010
  • Plastic region tightening is widely used in critical bolted joints in internal combustion engines in order to reduce the engine weight by maximizing the use of load-carrying capacity of bolt. Mechanical behavior of bolt tightened in plastic region under external axial tensile load is investigated for various friction conditions using three dimensional finite element analysis. The behavior of bolt tightened in elastic region as well as that in tensile test are investigated for comparison. Tightening process is simulated by rotating the bolt in order to examine the friction effect realistically. It is revealed that the bolt tightened in plastic region can carry more external load until the joint is opened, and yields at lower bolt load than the bolt tightened in elastic region. The friction coefficient has effect on the yield load, but not on the load-carrying capacity. Moreover, the scatter in the bolt preload due to friction begins with plastic deformation of bolt in the angle tightening control, whereas it begins with the onset of tightening in the torque tightening control. The observations are interpreted with the residual torsional stress in the bolt generated during the tightening.

Multi-Region Structural-Acoustic Coupling Analysis on Noise Reduction of Layered Structures using Finite Element and Boundary Element Technique (경계요소법과 유한요소법에 의한 흡음판의 소음저감에 관한 다영역 연성해석)

  • Ju, Hyun-Don;Seo, Won-Jin;Lee, Shi-Bok
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.309-313
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    • 2000
  • A structural-acoustic coupling problem involving fluid in a cavity divided with flexible walls and porous materials is investigated in this paper. In many practical problems, the use of finite elements to discretize the fluid region leads to large stiffness and mass matrices. But, since the acoustic boundary element discretization requires to put elements only on the surface of structure, the size of matrices is reduced considerably. Here, we developed a numerical analysis program for the structural-acoustic coupling problems of the multi-region cavity, using boundary elements for the fluid regions and finite elements for the structure. By considering sound transmission through layered systems placed in a cavity, the accuracy of the coupled acoustical-structural finite element model has been verified by comparing its transmission loss predictions with analytical sloutions. Example problems are included to investigate the characteristics of the multi-region structural-acoustic coupling system with porous material.

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Evaluation of the Finite Element Modeling of Spot-Welded Region for Crash Analysis (충돌해석에서의 점용접부 모델링에 따른 하중특성 평가)

  • Song, Jung-Han;Huh, Hoon;Kim, Hong-Gee;Kim, Sung-Ho
    • Transactions of the Korean Society of Automotive Engineers
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    • v.14 no.2
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    • pp.174-183
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    • 2006
  • The resistance spot-welded region in most current finite element crash models is characterized as a rigid beam at the location of the welded spot. The region is modeled to fail with a failure criterion which is a function of the axial and shear load at the rigid beam. The role of this rigid beam is simply to transfer the load across the welded components. The calculation of the load acting on the rigid beam is important to evaluate the failure of the spot-weld. In this paper, numerical simulation is carried out to evaluate the calculation of the load at the rigid beam. The load calculated from the precise finite element model of the spot-welded region considering the residual stress due to the thermal history during the spot welding procedure is regarded as the reference value and the value of the load is compared with the one obtained from the spot-welded model using the rigid beam with respect to the element size, the element shape and the number of imposed constraints. Analysis results demonstrate that the load acting on the spot-welded element is correctly calculated by the change of the element shape around the welded region and the location of welded constrains. The results provide a guideline for an accurate finite element modeling of the spot-welded region in the crash analysis of vehicles.

Hybrid Two-Dimensional Finite Element Model of Tires (타이어의 복합 이차원 유한 요소 모델)

  • Kim, Yong-Joe;Bolton, J.Stuart
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.62-67
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    • 2002
  • It has been shown that the vibrational response of a tire can be represented by a set of decaying waves, each associated with a particular cross-sectional mode shape in the region near the contact patch. Thus, it can be concluded that tires can be effectively modeled as lossy waveguides. It has also been shown that the sound radiation from tires is mainly from the region close to the contact patch. In consequence, it may be computationally efficient to analyze tire vibration and sound radiation in the region close to the contact patch by using a hybrid finite element model in which the cross-section of a tire is approximated by 2-D finite elements while an analytical wave solution is assumed in the circumferential direction of the tire. In this article. a hybrid finite element was formulated based on a composite shell model. The dispersion relations for sample structures obtained by using the hybrid FE model were then compared with those obtained by using a full, three-dimensional FE model. It has been shown that the FE analysis made using the hybrid 2-D finite elements yields results in close agreement with the three-dimensional model.

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Determination of strut efficiency factor for concrete deep beams with and without fibre

  • Sandeep, M.S.;Nagarajan, Praveen;Shashikala, A.P.;Habeeb, Shehin A.
    • Advances in Computational Design
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    • v.1 no.3
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    • pp.253-264
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    • 2016
  • Based on the variation of strain along the cross section, any region in a structural member can be classified into two regions namely, Bernoulli's region (B-region) and Disturbed region (D-region). Since the variation of strain along the cross section for a B-region is linear, well-developed theories are available for their analysis and design. On the other hand, the design of D-region is carried out based on thumb rules and past experience due to the presence of nonlinear strain distribution. Strut-and-Tie method is a novel approach that can be used for the analysis and design of both B-region as well as D-region with equal importance. The strut efficiency factor (${\beta}_s$) is needed for the design and analysis of concrete members using Strut and Tie method. In this paper, equations for finding ${\beta}_s$ for bottle shaped struts in concrete deep beams (a D-region) with and without steel fibres are developed. The effects of transverse reinforcement on ${\beta}_s$ are also considered. Numerical studies using commercially available finite element software along with limited amount of experimental studies were used to find ${\beta}_s$.

A Finite Element Model for Impact Assessment of Dike Construction (방파제 축조 영향해석에서의 유한요소모형)

  • 서승원
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.6 no.2
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    • pp.196-204
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    • 1994
  • Studied was impact assessment of sea dike construction in Saemankeum. To represent complexity of the geometry and topography of the region a flexible finite grid system are adopted. Combined fine and coarse meshes based on automatic mesh generator were applied in pre-processing. A nonlinear periodic finite element model. TEANL, was implied in this analysis, which gave good results compared to the observed data. It was predicted that the front region of dike connecting Shinsi-Karyeok-Daehang-Pyunsan will behave as a closed rectangular bay with wide width, which may affect significantly to the circulation and dispersion mechanism in the region.

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Finite Element Analysis for Free Vibration of Laminated Plates Containing Multi-Delamination (다층 층간분리된 적층 판의 유한요소 자유진동해석)

  • Taehyo Park;Seokoh Ma
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • pp.37-44
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    • 2003
  • In this proposed work, computational, finite element model far multi-delaminated plates will be developed. In the current analysis procedures of multi-delaminated plates, different elements are used at delaminated and undelaminated region separately. In the undelaminated region, plate element based on Mindlin plate theory is used in order to obtain accurate results of out-of-plane displacement of thick plate. And for delaminated region, plate element based on Kirchhoff plate theory is considered. To satisfy the displacement continuity conditions, displacement vector based on Kirchhoff theory is transformed to displacement of transition element. Element mass and stiffness matrices of each region (delaminated, undelaminated and transition region) will be assembled for global matrix.

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A Study on Design of Linear Induction Motor in Dynamic Tester for Catenary-current Collection (주행 집전계 시험기의 주행 대차용 선형 유도전동기 설계에 관한 연구)

  • Ham, Sang-Hwan;Cho, Su-Yeon;Lee, Ju
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.60 no.4
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    • pp.771-775
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    • 2011
  • This paper presents design process of linear induction motor in dynamic tester for catenary-current collection. To minimize length of rail for dynamic tester for catenary-current collection, accelerating performance of the linear induction motor is very important. So the design process of linear induction motor considered in this paper is different with general design process of linear induction motor, because dynamic tester has three type driving region, as accelerating region, constant speed region, and braking region. Considering accelerating performance of motor, distance and time from starting point to constant speed region were concerned for load condition of motor. Designed linear induction motor was analyzed by 2-dimensional finite element method. Using mechanical dynamics simulation with analysis result of 2-dimensional finite element method and accelerating performance of designed motor was proved.