The Experts below are selected from a list of 39 Experts worldwide ranked by ideXlab platform

G R Liu - One of the best experts on this subject based on the ideXlab platform.

  • Highly accurate smoothed finite element methods based on simplified eight-noded hexahedron elements
    Engineering Analysis with Boundary Elements, 2019
    Co-Authors: R.p. Niu, G R Liu
    Abstract:

    Abstract Compared with the tetrahedron elements, hexahedron elements are preferred for their high accuracy. However, coordinate mapping required in the hexahedron elements of FEM formulation costs huge running time, leading to poor performance. Besides, the high quality of Jacobian matrix and mesh is required, which affects the accuracy of the strain results greatly. In order to solve these problems, we propose a novel simplified Integration technique based on the smoothed finite element method (S-FEM) for the eight-noded hexahedron elements, where coordinate mapping is not demanded. The proposed new S-FEM-H8 models include simplified NS-FEM-H8 (using node-based smoothing domains) and simplified FS-FEM-H8 (using face-based smoothing domains). In the work, we divide a quadrilateral surface segment of a smoothing domain into two triangular sub-segments, so that the strain-displacement matrix can be calculated using a simple summation in the S-FEM theory instead of the Integration in FEM. Then we conduct the Gauss Integration Scheme in each triangular surface sub-segment in order to avoid the coordinate mapping required in quadrilateral surface segments. The rest solving algorithm is the same as the standard S-FEM. Intensive numerical examples demonstrate that the simplified S-FEM-H8 possess the following features: (1) The strain energy of simplified NS-FEM-H8 is an upper bound of the exact solutions; (2) The simplified NS-FEM-H8 can overcome the volume locking problems for incompressible materials; (3) The method of dividing boundary surface into two triangular surfaces in smoothing domain keeps nearly the same accuracy as the standard S-FEM-H8.

  • a nodal Integration technique for meshfree radial point interpolation method ni rpim
    International Journal of Solids and Structures, 2007
    Co-Authors: G R Liu, Guiyong Zhang, Y Y Wang, Z H Zhong, Xu Han
    Abstract:

    A novel nodal Integration technique for the meshfree radial point interpolation method (NI-RPIM) is presented for solid mechanics problems. In the NI-RPIM, radial basis functions (RBFs) augmented with polynomials are used to construct shape functions that possess the Delta function property. Galerkin weak form is adopted for creating discretized system equations, in which nodal Integration is used to compute system matrices. A stable and simple nodal Integration Scheme is proposed to perform the nodal Integration numerically. The NI-RPIM is examined using a number of example problems including stress analysis of an automobile mechanical component. The effect of shape parameters and dimension of local support domain on the results of the NI-RPIM is investigated in detail through these examples. The numerical solutions show that the present method is a robust, reliable, stable meshfree method and possesses better computational properties compared with traditional linear FEM and original RPIM using Gauss Integration Scheme.

S. C. Han - One of the best experts on this subject based on the ideXlab platform.

  • A resultant 8-node solid-shell element for geometrically nonlinear analysis
    Computational Mechanics, 2005
    Co-Authors: K. D. Kim, G. Z. Liu, S. C. Han
    Abstract:

    A new resultant force formulation of 8-node solid element is presented for the linear and nonlinear analysis of thin-walled structures. The global, local and natural coordinate systems were used to accurately model the shell geometry. The assumed natural strain methods with plane stress concept were implemented to remove the various locking problems appearing in thin plates and shells. The correct warping behavior in the very thin twisted beam test was obtained by using an improved Jacobian transformation matrix. The 2 × 2 Gauss Integration Scheme was used for the calculation of the element stiffness matrix. From the computational viewpoint, the present solid element is very efficient for a large scale of nonlinear modeling. A lot of numerical tests were carried out for the validation of the present 8-node solid-shell element and the results are in good agreement with references.

Xu Han - One of the best experts on this subject based on the ideXlab platform.

  • a nodal Integration technique for meshfree radial point interpolation method ni rpim
    International Journal of Solids and Structures, 2007
    Co-Authors: G R Liu, Guiyong Zhang, Y Y Wang, Z H Zhong, Xu Han
    Abstract:

    A novel nodal Integration technique for the meshfree radial point interpolation method (NI-RPIM) is presented for solid mechanics problems. In the NI-RPIM, radial basis functions (RBFs) augmented with polynomials are used to construct shape functions that possess the Delta function property. Galerkin weak form is adopted for creating discretized system equations, in which nodal Integration is used to compute system matrices. A stable and simple nodal Integration Scheme is proposed to perform the nodal Integration numerically. The NI-RPIM is examined using a number of example problems including stress analysis of an automobile mechanical component. The effect of shape parameters and dimension of local support domain on the results of the NI-RPIM is investigated in detail through these examples. The numerical solutions show that the present method is a robust, reliable, stable meshfree method and possesses better computational properties compared with traditional linear FEM and original RPIM using Gauss Integration Scheme.

K. D. Kim - One of the best experts on this subject based on the ideXlab platform.

  • A resultant 8-node solid-shell element for geometrically nonlinear analysis
    Computational Mechanics, 2005
    Co-Authors: K. D. Kim, G. Z. Liu, S. C. Han
    Abstract:

    A new resultant force formulation of 8-node solid element is presented for the linear and nonlinear analysis of thin-walled structures. The global, local and natural coordinate systems were used to accurately model the shell geometry. The assumed natural strain methods with plane stress concept were implemented to remove the various locking problems appearing in thin plates and shells. The correct warping behavior in the very thin twisted beam test was obtained by using an improved Jacobian transformation matrix. The 2 × 2 Gauss Integration Scheme was used for the calculation of the element stiffness matrix. From the computational viewpoint, the present solid element is very efficient for a large scale of nonlinear modeling. A lot of numerical tests were carried out for the validation of the present 8-node solid-shell element and the results are in good agreement with references.

G. Z. Liu - One of the best experts on this subject based on the ideXlab platform.

  • A resultant 8-node solid-shell element for geometrically nonlinear analysis
    Computational Mechanics, 2005
    Co-Authors: K. D. Kim, G. Z. Liu, S. C. Han
    Abstract:

    A new resultant force formulation of 8-node solid element is presented for the linear and nonlinear analysis of thin-walled structures. The global, local and natural coordinate systems were used to accurately model the shell geometry. The assumed natural strain methods with plane stress concept were implemented to remove the various locking problems appearing in thin plates and shells. The correct warping behavior in the very thin twisted beam test was obtained by using an improved Jacobian transformation matrix. The 2 × 2 Gauss Integration Scheme was used for the calculation of the element stiffness matrix. From the computational viewpoint, the present solid element is very efficient for a large scale of nonlinear modeling. A lot of numerical tests were carried out for the validation of the present 8-node solid-shell element and the results are in good agreement with references.