The Experts below are selected from a list of 19242 Experts worldwide ranked by ideXlab platform
G. R. Liu - One of the best experts on this subject based on the ideXlab platform.
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Smoothing Technique based crystal plasticity finite element modeling of crystalline materials
International Journal of Plasticity, 2015Co-Authors: W Zeng, J. M. Larsen, G. R. LiuAbstract:The smoothed finite element method (S-FEM) is known for its outstanding performance for solid mechanics problems, and working effectively with triangular or tetrahedral mesh that can be generated automatically for complicated geometries. In this work, a framework of S-FEM for modeling anisotropic crystalline plasticity is presented to simulate the mechanical behavior with rate-independence. The strain Smoothing Technique is extended to deal with finite strains in a nonlinear incremental integration procedure based on the Newton–Raphson scheme. The constitutive model utilizes a hyperelastic-based multiplicative plasticity method, which involves a local multiplicative decomposition of the deformation gradient into an elastic and a plastic part. The stress updates for a planar double-slip model exploit the return-mapping method with exponential map algorithm. The capability of the simulations to capture the strain localization and to handle plastic incompressibility of single crystal are demonstrated in representative examples. The proposed formulations and algorithms are also implemented to explore the mesoscopic and macroscopic elasto-plastic behavior of polycrystalline aggregates through modeling the synthetic microstructure constructed by Voronoi tessellation Technique.
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a generalized gradient Smoothing Technique and the smoothed bilinear form for galerkin formulation of a wide class of computational methods
International Journal of Computational Methods, 2008Co-Authors: G. R. LiuAbstract:This paper presents a generalized gradient Smoothing Technique, the corresponding smoothed bilinear forms, and the smoothed Galerkin weakform that is applicable to create a wide class of efficient numerical methods with special properties including the upper bound properties. A generalized gradient Smoothing Technique is first presented for computing the smoothed strain fields of displacement functions with discontinuous line segments, by "rudely" enforcing the Green's theorem over the Smoothing domain containing these discontinuous segments. A smoothed bilinear form is then introduced for Galerkin formulation using the generalized gradient Smoothing Technique and Smoothing domains constructed in various ways. The numerical methods developed based on this smoothed bilinear form will be spatially stable and convergent and possess three major important properties: (1) it is variationally consistent, if the solution is sought in a Hilbert space; (2) the stiffness of the discretized model will be reduced comp...
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A GENERALIZED GRADIENT Smoothing Technique AND THE SMOOTHED BILINEAR FORM FOR GALERKIN FORMULATION OF A WIDE CLASS OF COMPUTATIONAL METHODS
International Journal of Computational Methods, 2008Co-Authors: G. R. LiuAbstract:This paper presents a generalized gradient Smoothing Technique, the corresponding smoothed bilinear forms, and the smoothed Galerkin weakform that is applicable to create a wide class of efficient numerical methods with special properties including the upper bound properties. A generalized gradient Smoothing Technique is first presented for computing the smoothed strain fields of displacement functions with discontinuous line segments, by "rudely" enforcing the Green's theorem over the Smoothing domain containing these discontinuous segments. A smoothed bilinear form is then introduced for Galerkin formulation using the generalized gradient Smoothing Technique and Smoothing domains constructed in various ways. The numerical methods developed based on this smoothed bilinear form will be spatially stable and convergent and possess three major important properties: (1) it is variationally consistent, if the solution is sought in a Hilbert space; (2) the stiffness of the discretized model will be reduced compared to the model of the finite element method (FEM) and often the exact model, which allows us to obtain upper bound solutions with respect to both the FEM solution and the exact solution; (3) the solution of the numerical method developed using the smoothed bilinear form is less insensitive to the quality of the mesh, and triangular meshes can be used perfectly without any problems. These properties have been proved, examined, and confirmed by the numerical examples. The smoothed bilinear form establishes a unified theoretical foundation for a class of smoothed Galerkin methods to analyze solid mechanics problems for solutions of special and unique properties: the node-based smoothed point interpolation method (NS-PIM), smoothed finite element method (SFEM), node-based smoothed finite element method (N-SFEM), edge-based smoothed finite element method (E-SFEM), cell-based smoothed point interpolation method (CS-PIM), etc.
Y W Zhang - One of the best experts on this subject based on the ideXlab platform.
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extended finite element method coupled with face based strain Smoothing Technique for three dimensional fracture problems
International Journal for Numerical Methods in Engineering, 2015Co-Authors: Yong Jiang, Lei Chen, Y W ZhangAbstract:SUMMARY In this work, the extended finite element method (XFEM) is for the first time coupled with face-based strain-Smoothing Technique to solve three-dimensional fracture problems. This proposed method, which is called face-based smoothed XFEM here, is expected to combine both the advantages of XFEM and strain-Smoothing Technique. In XFEM, arbitrary crack geometry can be modeled and crack advance can be simulated without remeshing. Strain-Smoothing Technique can eliminate the integration of singular term over the volume around the crack front, thanks to the transformation of volume integration into area integration. Special Smoothing scheme is implemented in the crack front Smoothing domain. Three examples are presented to test the accuracy, efficiency, and convergence rate of the face-based smoothed XFEM. From the results, it is clear that Smoothing Technique can improve the performance of XFEM for three-dimensional fracture problems. Copyright © 2015 John Wiley & Sons, Ltd.
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Extended finite element method coupled with face‐based strain Smoothing Technique for three‐dimensional fracture problems
International Journal for Numerical Methods in Engineering, 2015Co-Authors: Yong Jiang, Lei Chen, Tong Earn Tay, Y W ZhangAbstract:SUMMARY In this work, the extended finite element method (XFEM) is for the first time coupled with face-based strain-Smoothing Technique to solve three-dimensional fracture problems. This proposed method, which is called face-based smoothed XFEM here, is expected to combine both the advantages of XFEM and strain-Smoothing Technique. In XFEM, arbitrary crack geometry can be modeled and crack advance can be simulated without remeshing. Strain-Smoothing Technique can eliminate the integration of singular term over the volume around the crack front, thanks to the transformation of volume integration into area integration. Special Smoothing scheme is implemented in the crack front Smoothing domain. Three examples are presented to test the accuracy, efficiency, and convergence rate of the face-based smoothed XFEM. From the results, it is clear that Smoothing Technique can improve the performance of XFEM for three-dimensional fracture problems. Copyright © 2015 John Wiley & Sons, Ltd.
Byung Chai Lee - One of the best experts on this subject based on the ideXlab platform.
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a four node c 0 tetrahedral element based on the node based Smoothing Technique for the modified couple stress theory
Computational Mechanics, 2020Co-Authors: Jaehoon Choi, Gidong Sim, Byung Chai LeeAbstract:In this paper, a four-node $$C^{0}$$ tetrahedral element for the modified couple stress theory is proposed. Since the governing equations are the fourth-order differential equations, the first-order derivative of displacement or rotation should be approximated by a continuous function. In the proposed element, nodal rotations are defined using the node-based Smoothing Technique. Continuous rotation fields are defined with the shape functions and nodal rotations. Both the displacement field and the rotation field are expressed solely in terms of the displacement degrees of freedom. The element stiffness matrix is calculated using the newly defined rotation field. To prevent the increase of calculation cost due to increase of the bandwidth of the stiffness matrix, the preconditioned conjugate gradient method is introduced. The performance of the proposed element is evaluated through various numerical examples.
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A four-node C$$^{0}$$0 tetrahedral element based on the node-based Smoothing Technique for the modified couple stress theory
Computational Mechanics, 2020Co-Authors: Jaehoon Choi, Gidong Sim, Byung Chai LeeAbstract:In this paper, a four-node $$C^{0}$$ C 0 tetrahedral element for the modified couple stress theory is proposed. Since the governing equations are the fourth-order differential equations, the first-order derivative of displacement or rotation should be approximated by a continuous function. In the proposed element, nodal rotations are defined using the node-based Smoothing Technique. Continuous rotation fields are defined with the shape functions and nodal rotations. Both the displacement field and the rotation field are expressed solely in terms of the displacement degrees of freedom. The element stiffness matrix is calculated using the newly defined rotation field. To prevent the increase of calculation cost due to increase of the bandwidth of the stiffness matrix, the preconditioned conjugate gradient method is introduced. The performance of the proposed element is evaluated through various numerical examples.
Yong Jiang - One of the best experts on this subject based on the ideXlab platform.
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XFEM with Smoothing Technique for Static Fracture Mechanics in Three-Dimension
International Journal of Computational Methods, 2016Co-Authors: Yong JiangAbstract:In this work, the advantages of face-based Smoothing Technique and extended finite element method (XFEM) are combined to develop a face-based smoothed extended finite element method (FS-XFEM). By this new method, arbitrary crack geometry can be modeled and crack advance can be simulated without remeshing. At the same time, the integration of singular term over the volume around the crack front can be eliminated induced by the transformation of volume integration into area integration. Numerical examples are presented to test the accuracy and convergence rate of the FS-XFEM. From the results, it is clear that Smoothing Technique can improve the performance of XFEM for three-dimensional fracture problems.
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extended finite element method coupled with face based strain Smoothing Technique for three dimensional fracture problems
International Journal for Numerical Methods in Engineering, 2015Co-Authors: Yong Jiang, Lei Chen, Y W ZhangAbstract:SUMMARY In this work, the extended finite element method (XFEM) is for the first time coupled with face-based strain-Smoothing Technique to solve three-dimensional fracture problems. This proposed method, which is called face-based smoothed XFEM here, is expected to combine both the advantages of XFEM and strain-Smoothing Technique. In XFEM, arbitrary crack geometry can be modeled and crack advance can be simulated without remeshing. Strain-Smoothing Technique can eliminate the integration of singular term over the volume around the crack front, thanks to the transformation of volume integration into area integration. Special Smoothing scheme is implemented in the crack front Smoothing domain. Three examples are presented to test the accuracy, efficiency, and convergence rate of the face-based smoothed XFEM. From the results, it is clear that Smoothing Technique can improve the performance of XFEM for three-dimensional fracture problems. Copyright © 2015 John Wiley & Sons, Ltd.
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Extended finite element method coupled with face‐based strain Smoothing Technique for three‐dimensional fracture problems
International Journal for Numerical Methods in Engineering, 2015Co-Authors: Yong Jiang, Lei Chen, Tong Earn Tay, Y W ZhangAbstract:SUMMARY In this work, the extended finite element method (XFEM) is for the first time coupled with face-based strain-Smoothing Technique to solve three-dimensional fracture problems. This proposed method, which is called face-based smoothed XFEM here, is expected to combine both the advantages of XFEM and strain-Smoothing Technique. In XFEM, arbitrary crack geometry can be modeled and crack advance can be simulated without remeshing. Strain-Smoothing Technique can eliminate the integration of singular term over the volume around the crack front, thanks to the transformation of volume integration into area integration. Special Smoothing scheme is implemented in the crack front Smoothing domain. Three examples are presented to test the accuracy, efficiency, and convergence rate of the face-based smoothed XFEM. From the results, it is clear that Smoothing Technique can improve the performance of XFEM for three-dimensional fracture problems. Copyright © 2015 John Wiley & Sons, Ltd.
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invited a face based smoothed xfem for three dimensional fracture problems
The 5th International Conference on Computational Methods (ICCM2014), 2014Co-Authors: Yong JiangAbstract:800x600 In this work, a face-based smoothed extended finite element method (FS-XFEM) is developed for three-dimensional fracture problems. This method combines the extended finite element method (XFEM) and Smoothing Technique together. With XFEM, arbitrary crack geometry can be modeled and crack advance can be simulated without remeshing. Smoothing Technique can eliminate the integration of singular term over the volume around the crack front, thanks to the transformation of volume integration into area integration. Special Smoothing scheme is implemented in the crack front Smoothing domain. Three examples are presented to test the accuracy and convergence rate of the FS-XFEM. From the results, it is clear Smoothing Technique can improve the performance of XFEM for three-dimensional fracture problems.
W Zeng - One of the best experts on this subject based on the ideXlab platform.
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A Smoothing Technique based beta finite element method (βFEM) for crystal plasticity modeling
Computers & Structures, 2015Co-Authors: W Zeng, Di Li, Xiaohu DongAbstract:A novel Smoothing Technique based beta finite element method (βFEM) is proposed.The method can produce super-accurate solution and treat volumetric locking issue.A framework for large strain rate-independent crystal plasticity model is introduced.Plastic incompressibility and large mesh distortion during strain localization are tackled.The approach is further developed for modeling bi-crystal and polycrystalline plasticity. This paper presents a novel class of Smoothing Techniques based beta finite element method (βFEM) for modeling of crystalline materials. The method is first examined by a simple standard patch test and applied in elastic problems. It is then implemented to model the anisotropic plastic deformation of rate-independent single crystals and bi-crystal. Several representative examples are studied to demonstrate the capability of proposed method with the integration algorithm for capturing the strain localization and dealing with plastic incompressibility. It is also performed to simulate the mechanical behavior of polycrystalline aggregates through modeling the synthetic microstructure constructed by Voronoi tessellation Technique.
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Smoothing Technique based crystal plasticity finite element modeling of crystalline materials
International Journal of Plasticity, 2015Co-Authors: W Zeng, J. M. Larsen, G. R. LiuAbstract:The smoothed finite element method (S-FEM) is known for its outstanding performance for solid mechanics problems, and working effectively with triangular or tetrahedral mesh that can be generated automatically for complicated geometries. In this work, a framework of S-FEM for modeling anisotropic crystalline plasticity is presented to simulate the mechanical behavior with rate-independence. The strain Smoothing Technique is extended to deal with finite strains in a nonlinear incremental integration procedure based on the Newton–Raphson scheme. The constitutive model utilizes a hyperelastic-based multiplicative plasticity method, which involves a local multiplicative decomposition of the deformation gradient into an elastic and a plastic part. The stress updates for a planar double-slip model exploit the return-mapping method with exponential map algorithm. The capability of the simulations to capture the strain localization and to handle plastic incompressibility of single crystal are demonstrated in representative examples. The proposed formulations and algorithms are also implemented to explore the mesoscopic and macroscopic elasto-plastic behavior of polycrystalline aggregates through modeling the synthetic microstructure constructed by Voronoi tessellation Technique.
