• Title, Summary, Keyword: 3D Finite Element

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MLS-Based Finite Elements and a Proposal for Their Applications (MLS기반 유한요소와 그 응용에 관한 제언)

  • Cho, Young-Sam
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.22 no.4
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    • pp.335-341
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    • 2009
  • In this paper, review of developed MLS-based finite elements and a proposal for their applications are described. The shape functions and their derivatives of MLS-based finite elements are constructed using Moving-Least Square approximation. In MLS-based finite element, using the adequate influence domain of weight function used in MLS approximation, kronecker delta condition could be satisfied at the element boundary. Moreover, because of the characteristics of MLS approximation, we could easily add extra nodes at an arbitrary position in MLS-based finite elements. For these reasons, until now, several variable-node elements(2D variable element for linear case and quadratic case and 3D variable-node elements) and finite crack elements are developed using MLS-based finite elements concept. MLS-based finite elements could be extended to 2D variable-node triangle element, 2D finite crack triangle element, variable-node shell element, finite crack shell element, and 3D polyhedron element. In this paper, we showed the feasibility of 3D polyhedron element at the case of femur meshing.

Direct Finite Element Model Generation using 3 Dimensional Scan Data (3D SCAN DATA 를 이용한 직접유한요소모델 생성)

  • Lee Su-Young;Kim Sung-Jin;Jeong Jae-Young;Park Jong-Sik;Lee Seong-Beom
    • Journal of the Korean Society for Precision Engineering
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    • v.23 no.5
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    • pp.143-148
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    • 2006
  • It is still very difficult to generate a geometry model and finite element model, which has complex and many free surface, even though 3D CAD solutions are applied. Furthermore, in the medical field, which is a big growth area of recent years, there is no drawing. For these reasons, making a geometry model, which is used in finite element analysis, is very difficult. To resolve these problems and satisfy the requests of the need to create a 3D digital file for an object where none had existed before, new technologies are appeared recently. Among the recent technologies, there is a growing interest in the availability of fast, affordable optical range laser scanning. The development of 3D laser scan technology to obtain 3D point cloud data, made it possible to generate 3D model of complex object. To generate CAD and finite element model using point cloud data from 3D scanning, surface reconstruction applications have widely used. In the early stage, these applications have many difficulties, such as data handling, model creation time and so on. Recently developed point-based surface generation applications partly resolve these difficulties. However there are still many problems. In case of large and complex object scanning, generation of CAD and finite element model has a significant amount of working time and effort. Hence, we concerned developing a good direct finite element model generation method using point cloud's location coordinate value to save working time and obtain accurate finite element model.

Analysis of PSC Box Girder Anchorage Zone using FEM and 2D SUB-3D STM Approach (유한요소법 및 유사 3 차원 스트릿-타이 모델 방법을 이용한 PSC 박스거더 정착부의 해석)

  • Yun, Young-Mook;Kim, Seung-Eock;Oh, Jin-Woo;Park, Jung-Woong
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.4 no.2
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    • pp.113-129
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    • 2000
  • This study evaluates the behavior and strength of an anchorage zone of the prestressed concrete box girder bridge on the Kyungboo highway railroad using the 2D SUB-3D STM approach and a linear elastic finite element analysis. The 2D SUB-3D STM approach utilizes several two-dimensional sub strut-tie models that represent the compressive and tensile stress flows of each projected plane of the three-dimensional structural concrete in the selection of a three dimensional strut-tie model, evaluation of the effective strengths of the concrete struts, and verification of the geometric compatibility condition and bearing capacity of the critical nodal zones in the selected three-dimensional strut-tie model. The finite element analysis uses an 8-node brick element and the longitudinal prestressing force is considered as the equivalent nodal force. Analysis results show that the 2D SUB-3D STM approach and linear elastic finite element method can be effectively applied to the analysis and design of three-dimensional structural concrete including a prestressed concrete box girder anchorage zone.

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A 2-D four-noded finite element containing a singularity of order λ

  • Abdel Wahab, M.M.;de Roeck, G.
    • Structural Engineering and Mechanics
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    • v.3 no.4
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    • pp.383-390
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    • 1995
  • A 2-D four-noded finite element which contains a ${\lambda}$ singularity is developed. The new element is compatible with quadratic standard isoparametric elements. The element is tested on two different examples. In the first example, an edge crack problem is analyzed using two different meshes and different integration orders. The second example is a crack perpendicular to the interface problem which is solved for different material properties and in turn different singularity order ${\lambda}$. The results of those examples illustrate the efficiency of the proposed element.

Finite Element Analysis and Experiment Study of Motorcycle Helmet (모터 싸이클 헬멧의 유한 요소 해석 및 실험 연구)

  • Thai, Huu-Tai;Kim, Seung-Eock
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • pp.451-456
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    • 2007
  • A finite element analysis and experiment study of a motorcycle helmet are presented in this paper. The finite element LS-DYNA3D code is used to analyze the helmet. The test specimen, instruments, and setup procedures are described. Since the displacements and Von-Mises stresses obtained by numerical analysis and experiment agree well, the numerical simulation is proved to be valid.

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Large displacement geometrically nonlinear finite element analysis of 3D Timoshenko fiber beam element

  • Hu, Zhengzhou;Wu, Minger
    • Structural Engineering and Mechanics
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    • v.51 no.4
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    • pp.601-625
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    • 2014
  • Based on continuum mechanics and the principle of virtual displacements, incremental total Lagrangian formulation (T.L.) and incremental updated Lagrangian formulation (U.L.) were presented. Both T.L. and U.L. considered the large displacement stiffness matrix, which was modified to be symmetrical matrix. According to the incremental updated Lagrangian formulation, small strain, large displacement, finite rotation of three dimensional Timoshenko fiber beam element tangent stiffness matrix was developed. Considering large displacement and finite rotation, a new type of tangent stiffness matrix of the beam element was developed. According to the basic assumption of plane section, the displacement field of an arbitrary fiber was presented in terms of nodal displacement of centroid of cross-area. In addition, shear deformation effect was taken account. Furthermore, a nonlinear finite element method program has been developed and several examples were tested to demonstrate the accuracy and generality of the three dimensional beam element.

A new numerical modelling for evaluating the stress intensity factors in 3-D fracture analysis

  • Cao, Zongjie;Liu, Yongyu
    • Structural Engineering and Mechanics
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    • v.43 no.3
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    • pp.321-336
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    • 2012
  • As an improvement on the isoparametric element method, the derivation presented in this paper is close to that done by Wang (1990) for the 2-D finite element. We extend this idea to solve 3-D crack problems in this paper. A new displacement modelling is constructed with local solutions of three-dimensional cracks and a quasi-compatible isoparametric element for three-dimensional fracture mechanics analysis is presented. The stress intensity factors can be solved directly by means of the present method without any post-processing. A new method for calculating the stress intensity factors of three-dimensional cracks with complex geometries and loads is obtained. Numerical examples are given to demonstrate the validity of the present method. The accuracy of the results obtained by the proposed element is demonstrated by solving several crack problems. The results illustrate that this method not only saves much calculating time but also increases the accuracy of solutions. Because this quasi-compatible finite element of 3-D cracks contains any singularities and easily meets the requirement of compatibility, it can be easily implemented and incorporated into existing finite element codes.

A Study on Orbital Forming Analysis of Automotive Hub Bearing using the Explicit Finite Element Method (외연적 유한요소법을 이용한 자동차 Hub Bearing의 Orbital Forming해석에 관한 연구)

  • Cho, Hyun-Jik;Koo, Jeong-Seo;Bae, Won-Rak;Lim, Jong-Soon
    • Transactions of the Korean Society of Automotive Engineers
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    • v.16 no.1
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    • pp.29-36
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    • 2008
  • In this paper, the orbital forming analysis of an automotive hub bearing was studied to predict forming performances using the explicit finite element method. To find an efficient solution technique for the orbital forming, axisymmetric finite element models and 3D solid element models were solved and numerically compared. The time scaling and mass scaling techniques were introduced to reduce the excessive computational time caused by small element size in case of the explicit finite element method. It was found from the numerical simulations on the orbital forming that the axisymmetric element models showed the similar results to the 3D solid element models in forming loads whereas the deformations at the inner race of bearing were quite different. Finally the strains at the inner race of bearing and the forming forces to the peen were measured for the same product of the numerical model by test, and were compared with the 3D solid element results. It was founded that the test results were in good agreements with the numerical ones.

A continuum mechanics based 3-D beam finite element with warping displacements and its modeling capabilities

  • Yoon, Kyungho;Lee, Youngyu;Lee, Phill-Seung
    • Structural Engineering and Mechanics
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    • v.43 no.4
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    • pp.411-437
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    • 2012
  • In this paper, we propose a continuum mechanics based 3-D beam finite element with cross-sectional discretization allowing for warping displacements. The beam element is directly derived from the assemblage of 3-D solid elements, and this approach results in inherently advanced modeling capabilities of the beam element. In the beam formulation, warping is fully coupled with bending, shearing, and stretching. Consequently, the proposed beam elements can consider free and constrained warping conditions, eccentricities, curved geometries, varying sections, as well as arbitrary cross-sections (including thin/thick-walled, open/closed, and single/multi-cell cross-sections). We then study the modeling and predictive capabilities of the beam elements in twisting beam problems according to geometries, boundary conditions, and cross-sectional meshes. The results are compared with reference solutions obtained by analytical methods and solid and shell finite element models. Excellent modeling capabilities and solution accuracy of the proposed beam element are observed.

Prediction of Roll Force Profile in Cold Rolling - Part II : Application and Validation (냉간 압연에서 압하력 분포 예측 - Part II : 적용 및 검증)

  • Nam, S.Y.;Hwang, S.M.
    • Transactions of Materials Processing
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    • v.28 no.4
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    • pp.197-202
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    • 2019
  • This paper proposes a precise mathematical model for the prediction of the variation of the roll force across a strip in cold rolling. It further describes the deformation characteristics of the strip using a 3-D finite element method. The different features of hot rolling and cold rolling through a 3-D finite element method are shown. The predicted roll force profile and tension profile are verified through comparison with the prediction from a 3-D finite element method.