• Title, Summary, Keyword: Finite strip method

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Free vibration analysis of sandwich FGM shells using isogeometric B-spline finite strip method

  • Shahmohammadi, Mohammad Amin;Azhari, Mojtaba;Saadatpour, Mohammad Mehdi
    • Steel and Composite Structures
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    • v.34 no.3
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    • pp.361-376
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    • 2020
  • This paper presents a free vibration analysis of shell panels made of functionally graded material (FGM) in the form of the ordinary and sandwich FGM and laminated shells using the isogeometric B3-spline finite strip method (IG-SFSM). B3-spline and Lagrangian interpolation are employed along the longitudinal and transverse directions respectively in this type of finite strip. The introduced finite strip formulation is based on the degenerated shell method, which provides variable thickness, arbitrary geometries, and analysis of thin or thick shells. Validity of the obtained natural frequencies by IG-SFSM is checked by comparison with results extracted from references for similar cases in different examples. These examples incorporate several geometries, materials, boundary conditions, and continuous thickness variation. A comparison of these two kinds of results and their proximity showed that the introduced IG-SFSM is a reliable tool which can be used in analysis of shells with the aforementioned properties.

Finite strip method in probabilistic fatigue analysis of steel bridges

  • Li, W.C.;Cheung, M.S.
    • Steel and Composite Structures
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    • v.2 no.6
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    • pp.429-440
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    • 2002
  • A finite strip method is developed for fatigue reliability analysis of steel highway bridges. Flat shell strips are employed to model concrete slab and steel girders, while a connection strip is formed using penalty function method to take into account eccentricity of girder top flange. At each sampling point with given slab thickness and modulus ratio, a finite strip analysis of the bridge under fatigue truck is performed to calculate stress ranges at fatigue-prone detail, and fatigue failure probability is evaluated following the AASHTO approach or the LEFM approach. After the failure probability is integrated over all sampling points, fatigue reliability of the bridge is determined.

A non-symmetric non-periodic B3-spline finite strip method

  • Kim, Kyeong-Ho;Choi, Chang-Koon
    • Structural Engineering and Mechanics
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    • v.18 no.2
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    • pp.247-262
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    • 2004
  • In the earlier application of the spline finite strip method(FSM), the uniform B3-spline functions were used in the longitudinal direction while the conventional interpolation functions were used in the transverse direction to construct the displacement filed in a strip. To overcome the shortcoming of the uniform B3-spline, non-periodic B-spline was developed as the displacement function. The use of non-periodic B3-spline function requires no tangential vectors at both ends to interpolate the geometry of shell and the Kronecker delta property is also satisfied at the end boundaries. Recently, non-periodic spline FSM which was modified to have a multiple knots at the boundary was developed for the shell analysis and applied to the analysis of bridges. In the formulation of a non-symmetric spline finite strip method, the concepts of non-periodic B3-spline and a stress-resultant finite strip with drilling degrees of freedom for a shell are used. The introduction of non-symmetrically spaced knots in the longitudinal direction allows the selective local refinement to improve the accuracy of solution at the connections or at the location of concentrated load. A number of numerical tests were performed to prove the accuracy and efficiency of the present study.

Vibration and stability analyses of thick anisotropic composite plates by finite strip method

  • Akhras, G.;Cheung, M.S.;Li, W.
    • Structural Engineering and Mechanics
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    • v.3 no.1
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    • pp.49-60
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    • 1995
  • In the present study, a finite strip method for the vibration and stability analyses of anisotropic laminated composite plates is developed according to the higher-order shear deformation theory. This theory accounts for the parabolic distribution of the transverse shear strains through the thickness of the plate and for zero transverse shear stresses on the plate surfaces. In comparison with the finite strip method based on the first-order shear deformation theory, the present method gives improved results for very thick plates while using approximately the same number of degrees of freedom. It also eliminates the need for shear correction factors in calculating the transverse shear stiffness. A number of numerical examples are presented to show the effect of aspect ratio, length-to-thickness ratio, number of plies, fibre orientation and stacking sequence on the natural frequencies and critical buckling loads of simply supported rectangular cross-ply and arbitrary angle-ply composite laminates.

Assumed strain finite strip method using the non-periodic B-spline

  • Hong, Hyun-Seok;Kim, Kyeong-Ho;Choi, Chang-Koon
    • Structural Engineering and Mechanics
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    • v.18 no.5
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    • pp.671-690
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    • 2004
  • An assumed strain finite strip method(FSM) using the non-periodic B-spline for a shell is presented. In the present method, the shape function based on the non-periodic B-splines satisfies the Kronecker delta properties at the boundaries and allows to introduce interior supports in much the same way as in a conventional finite element formulation. In the formulation for a shell, the geometry of the shell is defined by non-periodic B3-splines without any tangential vectors at the ends and the penalty function method is used to incorporate the drilling degrees of freedom. In this study, new assumed strain fields using the non-periodic B-spline function are proposed to overcome the locking problems. The strip formulated in this way does not posses any spurious zero energy modes. The versatility and accuracy of the new approach are demonstrated through a series of numerical examples.

Prediction and Design of Edge Shape of Initial Strip for Thick Tube Roll Forming using Finite Element Method (유한요소해석을 이용한 후육관 롤포밍에서의 초기소재 에지 형상 예측과 설계)

  • Kim, Nak-Su;Lee, Seung-Yun
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.26 no.4
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    • pp.644-652
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    • 2002
  • Increasing demands for Electric Resistance Welded pipes of high quality with thick wall require c lose investigations in edge deformation by slitting, strip deformation during break down farming, and difference of circumferential length. In order to obtain good quality of a welding zone, it is necessary to predict the edge shape of the initial strip. The modeling of the multi-pass thick tube roll forming process with rigid plastic finite element method ultra the edge shape prediction of an initial strip with 2nd-degree polynomial regression method are presented. Edge shapes of initial strip have been analyzed by the finite element method and designed by the regression method to satisfy the requirements in target fin pass. It is concluded that the proposed edge design method results in optimal edge shapes sat string the design requirements.

FINITE STRIP ANALYSIS OF FOLDED LAMINATED COMPOSITE PLATES (유한대판법에 의한 복합적층절판의 해석)

  • Yoon, Seok Ho;Han, Sung Cheon;Chang, Suk Yoon
    • Journal of Korean Society of Steel Construction
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    • v.13 no.1
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    • pp.41-52
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    • 2001
  • In this paper the analysis of laminate composite folded plates with arbitrary angle connection like box girder is studied by finite strip method Total stiffness of laminated plate is obtained by integration of the stiffness in each layer or lamina through laminate thickness and total stiffness in each layer or lamina through laminate thickness and total tiffness matrix is obtained by substitutionto equilibrium equation derived from the minimum total potential energy theorem. The assumed displacement functions for a finite strip method in plate or box girder analysis are combinations of one-way polynomial functions in the transverse direction and harmonic functions in the span-wise direction. Finite strip method with the merits of the simplification in modeling and the reduction of analytical time is accurate in the analysis of laminate composite folded plates shaped like box firders.

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Finite Element Analysis of Strip Drawing Including the Evolution of Material Damage (재료결함의 성장을 포함하는 스트립 드로잉 공정의 유한요소해석)

  • Hahm, Seung-Yeun;Lee, Yong-Shin
    • Transactions of Materials Processing
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    • v.3 no.1
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    • pp.120-132
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    • 1994
  • Strip drawing of strain-hardening, viscoplastic materials with damage is analyzed by a rigid plastic finite element method. A process model is formulated using two state variables, one for strain hardening from slip dominated plastic distortion and the other for damage from growth of microvoids. Application of the model to aluminum strip drawing is given via implementation in a consistent penalty finite element formulation. The predicted density changes as a result of void growth are compared to those from experiments reported in the literature. The effects of drawing conditions such as drawing speed and die angle on the mechanical property chages are studied.

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Assessment of transient vibrations of graphene oxide reinforced plates under pulse loads using finite strip method

  • Mirjavadi, Seyed Sajad;Forsat, Masoud;Barati, Mohammad Reza;Hamouda, A.M.S.
    • Computers and Concrete
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    • v.25 no.6
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    • pp.575-585
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    • 2020
  • Based on a refined shear deformation finite strip, transient vibrations of graphene oxide powder (GOP) reinforced plates due to external pulse loads have been investigated. The plate has uniformly and linearly distributed GOPs inside material structure. Applied pulse loads have been selected as sinusoidal, linear and blast types. Such pulse loads result in transient vibrations of the GOP-reinforced plates which are not explored before. Finite strip method (FSM) has been performed for solving the equations of motion and then inverse Laplace transform technique has been employed to derive transient responses due to pulse loading. It is reported in this study that the transient responses of GOP-reinforced plates are dependent on GOP dispersions, GOP volume fraction, type of pulse loading, loading time and load locations.

AN INTEGRATED FINITE ELEMENT COMPUTER SIMULATOR FOR THE PREDICTION OF ROLL AND STRIP PROFILE IN HOT STRIP ROLLING (열연중 판 및 롤 프로파일 예측 시뮬레이터 개발)

  • 류성룡;김태효;황상무
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • pp.301-307
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    • 1999
  • A three dimensional finite element-based computer simulator is presented for the analysis of the thermomechanical behaviors of rolls and strip during hot strip rolling. The simulator is capable of predicting the strip profiles in a 4 high mill stand, and in particular, can account for the effect of bender forces and pair cross angles. The structure of the simulator as well as various numerical schemes employed are described. The capability of the simulator is demonstrated through applications to some selected set of process conditions.

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