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Xiangyang Cui - One of the best experts on this subject based on the ideXlab platform.

  • stochastic Stable Node based smoothed finite element method for uncertainty and reliability analysis of thermo mechanical problems
    Engineering Analysis With Boundary Elements, 2020
    Co-Authors: Bing Wang, Yong Cai, Chensen Ding, Tianjuan Yang, Xiangyang Cui
    Abstract:

    Abstract This thesis herein proposes a stochastic Stable Node-based smoothed finite element method for uncertainty and reliability analysis of thermo-mechanical problems. First, the deterministic ingredient of the thermo-mechanical solution is accurately solved by our proposed Stable Node-based smoothed finite element method (SNS-FEM); and the stochastic ingredient including the fourth-order moment and probability density functions (PDFs) is obtained via stochastic response analysis. Furthermore, we extend the work to the reliability field by innovatively exploring several mathematical models for reliability analysis, such as structural failure probability (Pf) of thermal stress. At last, several thermo-mechanical related examples, including 2D and 3D, are hereby demonstrated to verify the accuracy and efficiency of the proposed stochastic Stable Node-based smoothed finite element method, by comparing with the direct classic Monte Carlo simulation (MCS). In addition, the effects of different uncertain parameters on the solution to the stochastic response and reliability analysis are illustrated and discussed.

  • a Stable Node based smoothed finite element method for metal forming analysis
    Computational Mechanics, 2019
    Co-Authors: H Yang, Xiangyang Cui, Y H Bie
    Abstract:

    In this paper, a Stable Node-based smoothed finite element method (SNS-FEM) is presented for analyzing metal forming problems using linear triangular or tetrahedral elements. In present method, the numerical integration domains are approximately circular or spherical regions of the Node-based smoothing domains generated by the Node-based smoothed finite element method (NS-FEM). Four or six supplementary integration points, which are symmetrically located at the crossover points of the region and the coordinate axis, are employed for each Node to form the stabilization items associated with the variance of smoothed shape function gradient. Through this operation without the introducing of any uncertain parameter, the SNS-FEM not only significantly cures the temporal instability of NS-FEM but also performs better in effectiveness and efficiency than FEM, which is well validated by several numerical examples containing benchmark cases. Additionally, a simple but effective contact algorithm including contact searching and contact force computation is presented.

  • the Stable Node based smoothed finite element method for analyzing acoustic radiation problems
    Engineering Analysis With Boundary Elements, 2017
    Co-Authors: Xiangyang Cui, Qunyi Zhang, G Wang
    Abstract:

    Abstract In this paper, the Stable Node-based smoothed finite element method (SNS-FEM) and the well-known Dirichlet-to-Neumann (DtN) boundary condition are coupled together to reduce the dispersion error in analyzing acoustic radiation problems. An artificial boundary is introduced to truncate the infinite domain and the DtN boundary condition is imposed on the artificial boundary to guarantee the uniqueness of the solution. In the SNS-FEM formulation, a Stable item which contains the gradient variance items is constructed without any uncertain parameter to strengthen the system stiffness. Through this operation, a perfect balance between the stiffness and mass matrices is established and the dispersion error is reduced significantly. Two benchmark cases and two practical engineering problems are employed to investigate the performance of the SNS-FEM. The results demonstrate that the SNS-FEM achieves super accuracy and super convergence. Additionally, the SNS-FEM is less sensitive to the wave number and high-efficiency.

  • stochastic analysis using the generalized perturbation Stable Node based smoothed finite element method
    Engineering Analysis With Boundary Elements, 2016
    Co-Authors: Xiangyang Cui, H Feng
    Abstract:

    Abstract The traditional stochastic finite element method based on the finite element method fails to give the fine solution in precise determination of reliable problems when the computer power consumption is limited. To cure this fatal defect, the generalized n th order stochastic perturbation technique based on a Stable Node-based smoothed finite element method (GS_SNS-FEM) is presented. The framework intends to essentially improve the accuracy, lower the mesh limitation and occupy much less computational consumption for stochastic problems, especially when its second order realization is ineffective for large variations of input random fields. Besides, the n th orders expansion makes it possible to get the prefect accuracy for expected values and variances. Numerical examples including the static and dynamic problems are completed and compared with the solution of Monte Carlo simulation. It is found that the SNS-FEM applied in the stochastic problem can improve the accuracy of static and dynamic results, largely decrease the time cost, and lower the requirement of mesh.

  • a Stable Node based smoothed finite element method for acoustic problems
    Computer Methods in Applied Mechanics and Engineering, 2015
    Co-Authors: G Wang, Xiangyang Cui, H Feng
    Abstract:

    Abstract It is well-known that the classical “overly-soft” Node-based smoothed finite element method (NS-FEM) fails to provide reliable results to the Helmholtz equation due to the “temporal instability”. To cure the fatal drawback of NS-FEM and reduce the dispersion error in computational acoustics, this paper proposed a Stable Node-based smoothed finite element method (SNS-FEM) for analyzing acoustic problems using linear triangular (for 2D space) and tetrahedral (for 3D space) elements that can be generated automatically for any complicated configurations. In the present formulation, the system stiffness matrix is computed using the smoothed acoustic pressure gradients together with the gradient variance items over the smoothing domains associated with Nodes of element mesh. It turns out the addition of stabilization term makes the SNS-FEM possess an ideal stiffness, thus successfully cures the temporal instability and significantly reduces the dispersion error in acoustic problems. Numerical examples, including both benchmark cases and practical engineering problems, demonstrate that the SNS-FEM possesses the following important properties: (1) temporal stability; (2) super accuracy and super convergence; (3) higher computational efficiency; (4) insensitive to mesh distortion.

H Feng - One of the best experts on this subject based on the ideXlab platform.

  • stochastic analysis using the generalized perturbation Stable Node based smoothed finite element method
    Engineering Analysis With Boundary Elements, 2016
    Co-Authors: Xiangyang Cui, H Feng
    Abstract:

    Abstract The traditional stochastic finite element method based on the finite element method fails to give the fine solution in precise determination of reliable problems when the computer power consumption is limited. To cure this fatal defect, the generalized n th order stochastic perturbation technique based on a Stable Node-based smoothed finite element method (GS_SNS-FEM) is presented. The framework intends to essentially improve the accuracy, lower the mesh limitation and occupy much less computational consumption for stochastic problems, especially when its second order realization is ineffective for large variations of input random fields. Besides, the n th orders expansion makes it possible to get the prefect accuracy for expected values and variances. Numerical examples including the static and dynamic problems are completed and compared with the solution of Monte Carlo simulation. It is found that the SNS-FEM applied in the stochastic problem can improve the accuracy of static and dynamic results, largely decrease the time cost, and lower the requirement of mesh.

  • a Stable Node based smoothed finite element method for acoustic problems
    Computer Methods in Applied Mechanics and Engineering, 2015
    Co-Authors: G Wang, Xiangyang Cui, H Feng
    Abstract:

    Abstract It is well-known that the classical “overly-soft” Node-based smoothed finite element method (NS-FEM) fails to provide reliable results to the Helmholtz equation due to the “temporal instability”. To cure the fatal drawback of NS-FEM and reduce the dispersion error in computational acoustics, this paper proposed a Stable Node-based smoothed finite element method (SNS-FEM) for analyzing acoustic problems using linear triangular (for 2D space) and tetrahedral (for 3D space) elements that can be generated automatically for any complicated configurations. In the present formulation, the system stiffness matrix is computed using the smoothed acoustic pressure gradients together with the gradient variance items over the smoothing domains associated with Nodes of element mesh. It turns out the addition of stabilization term makes the SNS-FEM possess an ideal stiffness, thus successfully cures the temporal instability and significantly reduces the dispersion error in acoustic problems. Numerical examples, including both benchmark cases and practical engineering problems, demonstrate that the SNS-FEM possesses the following important properties: (1) temporal stability; (2) super accuracy and super convergence; (3) higher computational efficiency; (4) insensitive to mesh distortion.

  • A temporal Stable Node-based smoothed finite element method for three-dimensional elasticity problems
    Computational Mechanics, 2013
    Co-Authors: H Feng, X.y. Cui, S Z Feng
    Abstract:

    A stabilized Node-based smoothed finite element method (sNS-FEM) is formulated for three-dimensional (3-D) elastic-static analysis and free vibration analysis. In this method, shape functions are generated using finite element method by adopting four-Node tetrahedron element. The smoothed Galerkin weak form is employed to create discretized system equations, and the Node-based smoothing domains are used to perform the smoothing operation and the numerical integration. The stabilization term for 3-D problems is worked out, and then propose a strain energy based empirical rule to confirm the stabilization parameter in the formula. The accuracy and stability of the sNS-FEM solution are studied through detailed analyses of benchmark cases and actual elastic problems. In elastic-static analysis, it is found that sNS-FEM can provide higher accuracy in displacement and reach smoother stress results than the reference approaches do. And in free vibration analysis, the spurious non-zero energy modes can be eliminated effectively owing to the fact that sNS-FEM solution strengths the original relatively soft Node-based smoothed finite element method (NS-FEM), and the natural frequency values provided by sNS-FEM are confirmed to be far more accurate than results given by traditional methods. Thus, the feasibility, accuracy and stability of sNS-FEM applied on 3-D solid are well represented and clarified.

S Z Feng - One of the best experts on this subject based on the ideXlab platform.

  • Stable Node based smoothed extended finite element method for fracture analysis of structures
    Computers & Structures, 2020
    Co-Authors: J W Zhao, S Z Feng, Yourui Tao
    Abstract:

    Abstract Based on low-order elements, a Stable Node-based smoothed extended finite element method (SNS-XFEM) is proposed for fracture analysis of structures in this study. For the proposed method, the problem domain is discretized using low-order elements, which can be easily generated for structures with complex shapes. The Node-based smoothing domains are then generated to perform the strain smoothing technique, which can effectively avoid singular integration. The discontinuity caused by crack is modeled using enrichment functions and a stabilization term based on strain gradient is also taken into account to further improve the accuracy. Finally, some numerical cases are studied to fully investigate the performance of present method. The obtained results show that the proposed SNS-XFEM can perform much better than standard XFEM and NS-XFEM.

  • steady and transient heat transfer analysis using a Stable Node based smoothed finite element method
    International Journal of Thermal Sciences, 2016
    Co-Authors: Z C Li, S Z Feng
    Abstract:

    Abstract In order to cure the instability of NS-FEM and further improve the accuracy, a Stable Node-based smoothed finite element method (SNS-FEM) is formulated for steady and transient heat transfer problems using linear triangular and tetrahedron element. In present method, both smoothed temperature gradient and variance of temperature gradient in smoothing domains are considered. The accuracy, computational efficiency and stability of SNS-FEM are examined through several numerical examples with different kinds of boundary conditions. It is found that present method is more accurate and efficient than traditional finite element method (FEM) and NS-FEM. Most importantly, compared with NS-FEM, present SNS-FEM can be very Stable when dealing with transient heat transfer problems.

  • A temporal Stable Node-based smoothed finite element method for three-dimensional elasticity problems
    Computational Mechanics, 2013
    Co-Authors: H Feng, X.y. Cui, S Z Feng
    Abstract:

    A stabilized Node-based smoothed finite element method (sNS-FEM) is formulated for three-dimensional (3-D) elastic-static analysis and free vibration analysis. In this method, shape functions are generated using finite element method by adopting four-Node tetrahedron element. The smoothed Galerkin weak form is employed to create discretized system equations, and the Node-based smoothing domains are used to perform the smoothing operation and the numerical integration. The stabilization term for 3-D problems is worked out, and then propose a strain energy based empirical rule to confirm the stabilization parameter in the formula. The accuracy and stability of the sNS-FEM solution are studied through detailed analyses of benchmark cases and actual elastic problems. In elastic-static analysis, it is found that sNS-FEM can provide higher accuracy in displacement and reach smoother stress results than the reference approaches do. And in free vibration analysis, the spurious non-zero energy modes can be eliminated effectively owing to the fact that sNS-FEM solution strengths the original relatively soft Node-based smoothed finite element method (NS-FEM), and the natural frequency values provided by sNS-FEM are confirmed to be far more accurate than results given by traditional methods. Thus, the feasibility, accuracy and stability of sNS-FEM applied on 3-D solid are well represented and clarified.

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

  • the Stable Node based smoothed finite element method for analyzing acoustic radiation problems
    Engineering Analysis With Boundary Elements, 2017
    Co-Authors: Xiangyang Cui, Qunyi Zhang, G Wang
    Abstract:

    Abstract In this paper, the Stable Node-based smoothed finite element method (SNS-FEM) and the well-known Dirichlet-to-Neumann (DtN) boundary condition are coupled together to reduce the dispersion error in analyzing acoustic radiation problems. An artificial boundary is introduced to truncate the infinite domain and the DtN boundary condition is imposed on the artificial boundary to guarantee the uniqueness of the solution. In the SNS-FEM formulation, a Stable item which contains the gradient variance items is constructed without any uncertain parameter to strengthen the system stiffness. Through this operation, a perfect balance between the stiffness and mass matrices is established and the dispersion error is reduced significantly. Two benchmark cases and two practical engineering problems are employed to investigate the performance of the SNS-FEM. The results demonstrate that the SNS-FEM achieves super accuracy and super convergence. Additionally, the SNS-FEM is less sensitive to the wave number and high-efficiency.

  • a Stable Node based smoothed finite element method for acoustic problems
    Computer Methods in Applied Mechanics and Engineering, 2015
    Co-Authors: G Wang, Xiangyang Cui, H Feng
    Abstract:

    Abstract It is well-known that the classical “overly-soft” Node-based smoothed finite element method (NS-FEM) fails to provide reliable results to the Helmholtz equation due to the “temporal instability”. To cure the fatal drawback of NS-FEM and reduce the dispersion error in computational acoustics, this paper proposed a Stable Node-based smoothed finite element method (SNS-FEM) for analyzing acoustic problems using linear triangular (for 2D space) and tetrahedral (for 3D space) elements that can be generated automatically for any complicated configurations. In the present formulation, the system stiffness matrix is computed using the smoothed acoustic pressure gradients together with the gradient variance items over the smoothing domains associated with Nodes of element mesh. It turns out the addition of stabilization term makes the SNS-FEM possess an ideal stiffness, thus successfully cures the temporal instability and significantly reduces the dispersion error in acoustic problems. Numerical examples, including both benchmark cases and practical engineering problems, demonstrate that the SNS-FEM possesses the following important properties: (1) temporal stability; (2) super accuracy and super convergence; (3) higher computational efficiency; (4) insensitive to mesh distortion.

Y H Bie - One of the best experts on this subject based on the ideXlab platform.

  • a Stable Node based smoothed finite element method for metal forming analysis
    Computational Mechanics, 2019
    Co-Authors: H Yang, Xiangyang Cui, Y H Bie
    Abstract:

    In this paper, a Stable Node-based smoothed finite element method (SNS-FEM) is presented for analyzing metal forming problems using linear triangular or tetrahedral elements. In present method, the numerical integration domains are approximately circular or spherical regions of the Node-based smoothing domains generated by the Node-based smoothed finite element method (NS-FEM). Four or six supplementary integration points, which are symmetrically located at the crossover points of the region and the coordinate axis, are employed for each Node to form the stabilization items associated with the variance of smoothed shape function gradient. Through this operation without the introducing of any uncertain parameter, the SNS-FEM not only significantly cures the temporal instability of NS-FEM but also performs better in effectiveness and efficiency than FEM, which is well validated by several numerical examples containing benchmark cases. Additionally, a simple but effective contact algorithm including contact searching and contact force computation is presented.