• Title, Summary, Keyword: Element

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Formulation Method for Solid-to-Beam Transition Finite Elements

  • Im, Jang-Gwon;Song, Dae-Han;Song, Byeong-Ho
    • Journal of Mechanical Science and Technology
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    • v.15 no.11
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    • pp.1499-1506
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    • 2001
  • Various transition elements are used in general for the effective finite element analysis of complicated mechanical structures. In this paper, a solid-to-beam transition finite element, which can b e used for connecting a C1-continuity beam element to a continuum solid element, is proposed. The shape functions of the transition finite element are derived to meet the compatibility condition, and a transition element equation is formulated by the conventional finite element procedure. In order to show the effectiveness and convergence characteristics of the proposed transition element, numerical tests are performed for various examples. As a result of this study, following conclusions are obtained. (1) The proposed transition element, which meets the compatibility of the primary variables, exhibits excellent accuracy. (2) In case of using the proposed transition element, the number of nodes in the finite element model may be considerably reduced and the model construction becomes more convenient. (3) This formulation method can be applied to the usage of higher order elements.

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An assumed-stress hybrid element for static and free vibration analysis of folded plates

  • Darilmaz, Kutlu
    • Structural Engineering and Mechanics
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    • v.25 no.4
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    • pp.405-421
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    • 2007
  • A four-node hybrid stress element for analysing orthotropic folded plate structures is presented. The formulation is based on Hellinger-Reissner variational principle. The element is developed by combining a hybrid plane stress element and a hybrid plate element. The proposed element has six degree of freedom per node and permits an easy connection to other type of elements. An equilibrated stress field in each element and inter element compatible boundary displacement field are assumed independently. Static and free vibration analyses of folded plates are carried out on numerical examples to show that the validity and efficiency of the present element.

A new 3D interface element for three dimensional finite element analysis of FRP strengthened RC beams

  • Kohnehpooshi, O.;Noorzaei, J.;Jaafar, M.S.;Saifulnaz, M.R.R.
    • Interaction and multiscale mechanics
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    • v.4 no.4
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    • pp.257-271
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    • 2011
  • The analysis of interfacial stresses in structural component has been the subject of several investigations but it still requires more effort and studies. In this study a general three-dimensional interface element has been formulated for stress and displacement analyses in the interfacial area between two adjacent plate bending element and brick element. Interface element has 16 nodes with 5 degrees of freedom (DOF) in each node adjacent to plate bending element and 3 DOF in each node adjacent to brick element. The interface element has ability to transfer three translations from each side of interface element and two rotations in the side adjacent to the plate element. Stiffness matrix of this element was formulated and implemented in three-dimensional finite element code. Application of this element to the reinforced concrete (RC) beam strengthened with fiber reinforced polymer (FRP) including variation of deflection, slip between plate and concrete, normal and shear stresses distributions in FRP plates have been verified using experimental and numerical work of strengthened RC beams carried out by some researchers. The results show that this interface element is effective and can be used for structural component with these types of interface elements.

A hybrid 8-node hexahedral element for static and free vibration analysis

  • Darilmaz, Kutlu
    • Structural Engineering and Mechanics
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    • v.21 no.5
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    • pp.571-590
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    • 2005
  • An 8 node assumed stress hexahedral element with rotational degrees of freedom is proposed for static and free vibration analyses. The element formulation is based directly on an 8-node element. This direct formulation requires fewer computations than a similar element that is derived from an internal 20-node element in which the midside degrees of freedom are eliminated by expressing them in terms of displacements and rotations at corner nodes. The formulation is based on Hellinger-Reissner variational principle. Numerical examples are presented to show the validity and efficiency of the present element for static and free vibration analysis.

Development of a flat shell element by using the hybrid Trefftz plane element with drilling D.O.F. and the DKMQ element (면내 회전 자유도가 추가된 hybrid Trefftz 평면 요소와 DKMQ 요소를 이용한 4 절점 평면 셸 요소의 개발)

  • 최누리;추연석;이승규;이병채
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.855-859
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    • 2004
  • We develop a new four-node flat shell element which is accurate, efficient, and suitable to be used on general purpose. The new element has a hybrid Trefftz element with drilling degrees of freedom as a membrane part. We define the two independent displacement field: the internal displacement field that satisfies governing equations in the domain a priori and the boundary displacement field that is usually used as a conventional finite element method. The hybrid Trefftz variational formulation connects these two displacement fields on the boundary of the domain. To add drilling degrees of freedom, we introduce the Allman's quadratic displacement field to the boundary displacement field. As a result, our flat shell element has 6 degrees of freedom per a node. We also use the well-known DKMQ plate bending element for the plate part of the proposed element. The DKMQ element satisfies Mindlin-Reissner‘s plate theory along the edge of the element and gives proper behavior regardless of the thickness. A series of numerical experiments shows that the performance of the new element such as accuracy, rate of convergence, robustness to mesh quality, and so on.

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Comparisons of Elasto-Fiber and Fiber & Bernoulli-Euler reinforced concrete beam-column elements

  • Karaton, Muhammet
    • Structural Engineering and Mechanics
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    • v.51 no.1
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    • pp.89-110
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    • 2014
  • In this study, two beam-column elements based on the Elasto-Fiber element theory for reinforced concrete (RC) element have been developed and compared with each other. The first element is based on Elasto Fiber Approach (EFA) was initially developed for steel structures and this theory was applied for RC element in there and the second element is called as Fiber & Bernoulli-Euler element approach (FBEA). In this element, Cubic Hermitian polynomials are used for obtaining stiffness matrix. The beams or columns element in both approaches are divided into a sub-element called the segment for obtaining element stiffness matrix. The internal freedoms of this segment are dynamically condensed to the external freedoms at the ends of the element by using a dynamic substructure technique. Thus, nonlinear dynamic analysis of high RC building can be obtained within short times. In addition to, external loads of the segment are assumed to be distributed along to element. Therefore, damages can be taken account of along to element and redistributions of the loading for solutions. Bossak-${\alpha}$ integration with predicted-corrected method is used for the nonlinear seismic analysis of RC frames. For numerical application, seismic damage analyses for a 4-story frame and an 8-story RC frame with soft-story are obtained to comparisons of RC element according to both approaches. Damages evaluation and propagation in the frame elements are studied and response quantities from obtained both approaches are investigated in the detail.

Finite Element Analysis of Sheet Metal Forming Process Using Shell Element (쉘 요소를 이용한 박판성형공정의 유한요소해석)

  • Jung Dong-Won;Ko Hyung-Hoon;Lee Chan-Ho;You Ho-Young
    • Journal of the Korean Society for Precision Engineering
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    • v.23 no.1
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    • pp.152-158
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    • 2006
  • The AutoForm previously used the membrane element and it accomplished sheet metal forming analysis. The membrane analysis has been widely applied to various sheet metal forming processes because of its time effectiveness. However, it is well-known that the membrane analysis can not provide correct information for the processes which have considerable bending effects. In this research experimental results were compared with the analysis results obtained by using the shell element which is applied newly in the AutoForm commercial software. The shell element is a compromise element between continuum element and membrane element. The Finite element method by using shell element is the most efficient numerical method. From this research, it is known that FEA by using shell element can predict accurately the problems happened in actual experimental auto-body panel.

A Study on the Criterion for Membrane/Shell Mixed Element and Application to the Rigid-Plastic/Elastic-Plastic Finite Element Analysis (박막/쉘 혼합요소의 판별조건과 강소성/탄소성 유한요소해석 적용에 관한 연구)

  • Jung, Dong-Won;Yang, Kyoung-Boo
    • Journal of Ocean Engineering and Technology
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    • v.13 no.2
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    • pp.1-10
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    • 1999
  • This study is concerned with the application of new criterion for membrane/shell mixed element in the rigid-plastic finite element analysis and elastic-plastic finite element analysis. The membrane/shell mixed element can be selctively adapted to the pure stretching condition by using membrane or a shell element in the bending effect areas. Thus, membrane/shell mixed element requires a efficient criterion for a distinction between membrane and shell element. In the present study introduce the criterion using the angle of between two element and confirm a generality of criterion from appling the theory to a rigid-plastic and elastic-plastic problems.

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Development of 8-node Flat Shell Element for the Analysis of Folded Plate Structures (절판 구조물의 해석을 위한 8절점 평면 첼 요소의 개발)

  • 최창근;한인선
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • pp.234-241
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    • 1999
  • In this study, an improved 8-node flat shell element is presented for the analysis of shell structure, by combining 8-node membrane element with drilling degree-of-freedom and 8-node plate bending element based on the recently presented technique. Firstly, 8-node membrane element designated as CLM8 is presented in this paper. The element has drilling degree-of.freedom in addition to transitional degree-of-freedom. Therefore the element possesses 3 degrees-of-freedom per each node which as well as the improvement of the element behavior, permits an easy connection to other element with rotational degree-of -freedom. Secondly. 8-node flat shell element was composed by adding 8-node Mindlin plate bending element to the membrane element. The behavior of the introduced plate bending element is further improved by combined use of nonconforming displacement modes, selectively reduced integration scheme and assumed shear strain fields. The element passes in the patch test, doesn't show spurious mechanism and doesn't produce shear locking phenomena. Finally, Numerical examples are presented to show the performance of flat shell element developed in the present study.

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Formulation Method of a Solid-To-Beam Transitional Finite Element (연속체-보 천이 유한요소의 구성)

  • Park, Woo-Jin;Lim, Jang-Keun
    • Proceedings of the KSME Conference
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    • pp.351-356
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    • 2000
  • Various transition elements are generally used for the effective analysis of a complicated mechanical structure. In this paper, a solid-to-beam transition finite element which connects a continuum element and a $c^1-continuity$ beam element each other is proposed. The shape functions of the transition finite elements, which a 8-noded hexahedral solid element fur 3D analysis and a 4-noded quadrilateral plane element fur 2D analysis are connected to a Euler's beam element, are explicitely formulated. In order to show the effectiveness and convergence characteristics of the proposed transition elements. numerical tests are performed for various examples and their results are compared with those obtained by other methods. As the result of this study. following conclusions are obtained: (1)The proposed transition finite elements show the monotonic convergence characteristics because of having used the compatible displacement folds. (2)As being used the transition element in the finite element analysis, the finite element modelings are more convenient and the analysis results are more accurate because of the formulation characteristies of the Euler's beam element.

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