The Experts below are selected from a list of 1869 Experts worldwide ranked by ideXlab platform
Jian Shan - One of the best experts on this subject based on the ideXlab platform.
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The Finite Element Model Study of the Pre-Twisted Euler Beam
Advanced Materials Research, 2012Co-Authors: Ying Huang, Chang Hong Chen, Jian ShanAbstract:Based on the traditional mechanical model of straight beam, the paper makes a systematic analysis and research on the pre-twisted Euler beam finite element numerical model. The paper uses two-node model of 12 degrees of freedom, axial displacement Interpolation Function using 2-node Lagrange Interpolation Function, beam transverse bending displacements (u and υ) still use the cubic displacement, bending with torsion angle displacement Function using cubic polynomial displacement Function. Firstly, based on the author previous literature on the flexure strain relationship, the paper deduces the element stiffness matrix of the pre-twisted beam. Finally, by calculating the pre-twisted rectangle section beam example, and contrasting three-dimensional solid finite element using ANSYS, the comparative analysis results show that pre-twisted Euler beam element stiffness matrix has good accuracy.
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The Finite Element Model Research of the Pre-Twisted Beam
Applied Mechanics and Materials, 2012Co-Authors: Chang Hong Chen, Ying Huang, Jian ShanAbstract:Based on the traditional mechanical model of straight beam element, the paper makes a systematic analysis and research on the pre-twisted beam finite element numerical model. Firstly, the paper proposed the pre-twisted Euler beam element mode, the mode uses 2 node and 12 freedom degrees, the element axial and torsion displacements use 2 nodes Lagrange Interpolation Function, bending displacement still use the cubic displacement. Secondly, the paper studies a new pre-twisted Timoshenko beam element mode, the proposed new Timoshenko beam element takes separate Interpolation polynomial Functions both flexure bending and rotation displacement. According to the relationship between bending moment and shear, the relationship between of bending displacement and angle displacement is derived, which is more accurate to consider the effects of shear deformation. Finally, by calculating the pre-twisted rectangle cantilever beam example, and contrasting three-dimensional solid finite element using ANSYS, the comparative analysis results show that pre-twisted Timoshenko beam element mode has good accuracy.
Chun’guang You - One of the best experts on this subject based on the ideXlab platform.
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Explicit bound for quadratic Lagrange Interpolation constant on triangular finite elements
Applied Mathematics and Computation, 2018Co-Authors: Xuefeng Liu, Chun’guang YouAbstract:For the quadratic Lagrange Interpolation Function, an algorithm is proposed to provide explicit and verified bound for the Interpolation error constant that appears in the Interpolation error estimation. The upper bound for the Interpolation constant is obtained by solving an eigenvalue problem along with explicit lower bound for its eigenvalues. The lower bound for Interpolation constant can be easily obtained by applying the Rayleigh–Ritz method. Numerical computation is performed to demonstrate the sharpness of lower and upper bounds of the Interpolation constants over triangles of different shapes. An online computing demo is available at http://www.xfliu.org/onlinelab/.
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Explicit Bound for Quadratic Lagrange Interpolation Constant on Triangular Finite Elements
arXiv: Numerical Analysis, 2016Co-Authors: Xuefeng Liu, Chun’guang YouAbstract:For the quadratic Lagrange Interpolation Function, an algorithm is proposed to provide explicit and verified bound for the Interpolation error constant that appears in the Interpolation error estimation. The upper bound for the Interpolation constant is obtained by solving an eigenvalue problem along with explicit lower bound for its eigenvalues. The lower bound for Interpolation constant can be easily obtained by applying the Rayleigh-Ritz method. Numerical computation is performed to demonstrate the sharpness of lower and upper bounds of the Interpolation constants over triangles of different shapes. An online computing demo is available at this http URL
Yaolin Shi - One of the best experts on this subject based on the ideXlab platform.
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Computation of Present Strain Rate Field of Qinghai‐Tibetan Plateau and Its Geodynamic Implications
Chinese Journal of Geophysics, 2005Co-Authors: Shoubiao Zhu, Yongen Cai, Yaolin ShiAbstract:Many researchers calculated strain rate of significant differences from the same GPS measurement data. In this paper, we use the Kriging method in geostatistics to GPS velocity field. Interpolating the scattered GPS velocity data of Qinghai-Tibetan plateau and its adjacent areas to grid point values by Kriging, we calculate the strain rates from these nodal values in each grid cell similar to derivative of shape Functions (essentially Lagrange Interpolation Function) in finite element algorithm, and obtain the stable distribution of strain rate field in Qinghai-Tibetan plateau. The results show that the main part of Qinghai-Tibetan plateau is in the state of compression in north-south direction, and extension in west-east direction. On the contrary, in the eastern part of Tibet, the strain rate is compressive in west-east and extensional in north-south direction. The orientations of principal strain rates are consistent with those of the P axis and T axis in focal mechanism. The high values of maximum compressive principal strain rates are located in the Himalayan main boundary thrust zone (MBT) and the surrounded regions. The maximum extensive principal strain rates are higher than those of the compressive ones in the main part of the interior of Qinghai-Tibetan plateau. Also, the surface dilation strain rate shows that it is in the state of surface compression in Himalayan and its surrounded areas, and in the state of surface extension in the interior of Qinghai-Tibetan plateau. The distribution of maximum shear strain rate clearly displays the outlines of some main active fault zones. The result of the strain rate in this study suggests that the contemporary tectonic strain of Tibet inherits the long term geological deformation.
Carlo Ciulla - One of the best experts on this subject based on the ideXlab platform.
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The Main Innovation Determined By the Sub-Pixel Efficacy Region
Improved Signal and Image Interpolation in Biomedical Applications, 2009Co-Authors: Carlo CiullaAbstract:This chapter introduces the reader to Section V of the book. The chapter opens up with a discussion on the undeniable evidence reported in literature that the magnitude of the Interpolation error is strictly related to the magnitude of the sampling resolution. While reference to the literature on the Lagrange Interpolation Function is reported elsewhere (Ciulla & Deek, 2006), the chapter devotes attention to the literature and the applications related to the Sinc Function. The core of the chapter reports a section that condenses the message to the reader of this book about the main innovation determined through the Sub-pixel Efficacy Region. It is delivered to the reader the realization that combining signal intensity with the curvature of the Interpolation Function, the approximation properties of the model Function can be improved. This message is linked to the bridging concept between classic and SRE-based Interpolation which is that of the curvature of the Interpolation Function.
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Extension of the Sub-pixel Efficacy Region to the Lagrange Interpolation Function
2006Co-Authors: Carlo Ciulla, Fadi P. DeekAbstract:This paper reports on a novel methodology for improving the approximation properties of the cubic form of the Lagrange Interpolation Function through the use of two mathematical formulations: (i) the Intensity- Curvature Functional (∆E) and (ii) its derived Sub-pixel Efficacy Region (SRE). Equations are determined dependent on the local curvature of the Interpolation Function and the pixel intensity at the neighbourhood, thus making it possible to calculate the Lagrange Function with improved approximation properties. Characterizations of Interpolation error and Interpolation error improvement bounds are also presented. Fast Fourier Transform and Root-mean-square-error analyses are used to realize and present the improvements. The significance of the results is discussed within the context of a unifying framework which uses the same methodology for the improvement of the Interpolation error of diverse Functions.
Zhu Shou - One of the best experts on this subject based on the ideXlab platform.
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Computation of the present-day strain rate field of the Qinghai-Tibetan plateau and its geodynamic implications
Chinese Journal of Geophysics, 2005Co-Authors: Zhu ShouAbstract:Many researchers have calculated strain rates from the same GPS measurement data and obtained different results. In this paper, we introduce the Kriging method in geo_statistics to the study of GPS velocity field. Interpolating the scattered GPS velocity data of the Qinghai_Tibetan plateau and its adjacent areas to grid point values by the Kriging method, we calculate the strain rates from these nodal values of all elements similar to derivatives of shape Functions(essential Lagrange Interpolation Function) in the finite element algorithm. and obtain the distribution of the strain rate field in the Qinghai_Tibetan plateau. The results show that the main part of the Qinghai_Tibetan plateau is in the state of compression in north_south direction, and of extension in the orientation of east_west. On the contrary, in the eastern part of Qinghai_Tibet, the strain rate behaves compressively in east_west and extension in north_south trending. The orientations of principal strain rates are consistent with those of the P axis and T axis in focal mechanisms. The high values of maximum compressive principal strain rates are located in the Himalayan main boundary thrust zone (MBT) and its adjacent regions. The maximum extensional principal strain rate is higher than that of the compressive one in some regions of the interior of the Qinghai_Tibetan Plateau, so the region is in the state of extension. Also, the surface dilation strain rate shows that it is in the state of surface compression in the Himalayan and its surrounding areas, and it is in the state of surface extension in the interior of the Qinghai_Tibetan Plateau. The distribution of maximum shear strain rates clearly shows the patterns of some main active fault zones. The result of the strain rate in this study suggests that the contemporary tectonic strain of Tibet inherits the long term geological deformation.
