• Title/Summary/Keyword: spline function

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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.

A spline finite element method on mapping

  • Ding, Hanshan;Shao, Rongguang;Ding, Dajun
    • Structural Engineering and Mechanics
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    • v.4 no.4
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    • pp.415-424
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    • 1996
  • This paper presents a newly suggested calculation method in which an arbitrary quadrilateral element with curved sides is transformed to a normal rectangular one by mapping of coordinates, then the two-dimensional spline is adopted to approach the displacement function of this element. Finally the solution can be obtained by the least-energy principle. Thereby, the application field of Spline Finite Element Method will be extended.

Analysis for computing heat conduction and fluid problems using cubic B-spline function (3차 B-spline 함수를 이용한 열전도 및 유체문제의 해석)

  • Kim, Eun-Pil
    • Journal of computational fluids engineering
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    • v.3 no.2
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    • pp.1-8
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    • 1998
  • We make use of cubic B-spline interpolation function in two cases: heat conduction and fluid flow problems. Cubic B-spline test function is employed because it is superior to approximation of linear and non-linear problems. We investigated the accuracy of the numerical formulation and focused on the position of the breakpoints within the computational domain. When the domain is divided by partitions of equal space, the results show poor accuracy. For the case of a heat conduction problem this partition can not reflect the temperature gradient which is rapidly changed near the wall. To correct the problem, we have more grid points near the wall or the region which has a rapid change of variables. When we applied the unequally spaced breakpoints, the results show high accuracy. Based on the comparison of the linear problem, we extended to the highly non-linear fluid flow problems.

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Synthesis of Optimum CAM Curve by Cubic Spline (Cubic Spline을 사용한 최적 캠곡선의 합성)

  • 손태영;양민양
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.19 no.5
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    • pp.1168-1175
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    • 1995
  • The application of cubic spline is presented for basic curve (DRD motion) of cam motion. The purpose of this paper is to achieve better dynamic characteristics than general cam curves. A cubic spline is a piecewise function that is continuous in displacement, velocity and acceleration. The best cam curve is obtained by changing the weights of the object function. So the method can be used to any machine system case by case. For the proposed object function, the result has improved all characteristics such as velocity, acceleration and jerk compared with that of the modified sine curve.

A mesh-free analysis method of structural elements of engineering structures based on B-spline wavelet basis function

  • Chen, Jianping;Tang, Wenyong;Huang, Pengju;Xu, Li
    • Structural Engineering and Mechanics
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    • v.57 no.2
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    • pp.281-294
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    • 2016
  • The paper is devoted to study a mesh-free analysis method of structural elements of engineering structures based on B-spline Wavelet Basis Function. First, by employing the moving-least square method and the weighted residual method to solve the structural displacement field, the control equations and the stiffness equations are obtained. And then constructs the displacement field of the structure by using the m-order B-spline wavelet basis function as a weight function. In the end, the paper selects the plane beam structure and the structure with opening hole to carry out numerical analysis of deformation and stress. The Finite Element Method calculation results are compared with the results of the method proposed, and the calculation results of the relative error norm is compared with Gauss weight function as weight function. Therefore, the clarification verified the validity and accuracy of the proposed method.

$-bicubic spline interpolant on an irregular mesh

  • Shin, Byeong-Chun
    • Communications of the Korean Mathematical Society
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    • v.11 no.2
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    • pp.525-538
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    • 1996
  • In the course of working on the preconditioning of $C^1$-bicubic collocation method, one has to deal with the $C^1$-bicubic splines. In this paper we are concerned with $C^1$-bicubic spline interpolant for a given function. We construct a basis for the space of $C^1$-bicubic splines for a given partition and find the $C^1$-bicubic spline interpolant for a given function defined on a set.

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Spline function solution for the ultimate strength of member structures

  • Zhang, Qi-Lin;Shen, Zu-Yan
    • Structural Engineering and Mechanics
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    • v.2 no.2
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    • pp.185-196
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    • 1994
  • In this paper a spline function solution for the ultimate strength of steel members and member structures is derived based on total Lagrangian formulation. The displacements of members along longitudinal and transverse directions are interpolated by one-order B spline functions and three-order hybrid spline functions respectively. Equilibrium equations are established according to the principle of virtual work. All initial imperfections of members and effects of loading, unloading and reloading of material are taken into account. The influence of the instability of members on structural behavior can be included in analyses. Numerical examples show that the method of this paper can satisfactorily analyze the elasto-plastic large deflection problems of planar steel member and member structures.

$L_2$-Norm Based Optimal Nonuniform Resampling (유클리드 norm에 기반한 최적 비정규 리사이징 알고리즘)

  • 신건식;엄지윤;이학무;강문기
    • Journal of Broadcast Engineering
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    • v.8 no.1
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    • pp.37-44
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    • 2003
  • The standard approach to signal resampling is to fit the original image to a continuous model and resample the function at a desired rate. We used the compact B-spline function as the continuous model which produces less oscillatory behavior than other tails functions. In the case of nonuniform resampling based on a B-spline model, the digital signal is fitted to a spline model, and then the fitted signal is resampled at a space varying rate determined by the transformation function. It is simple to implement but may suffer from artifacts due to data loss. The main purpose of this paper is the derivation of optimal nonuniform resampling algorithm. For the optimal nonuniform formulation, the resampled signal is represented by a combination of shift varying splines determined by the transformation function. This optimal nonuniform resampling algorithm can be verified from the experiments that It produces less errors.

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.