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学者姓名:郑宏
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Abstract :
The numerical solution of the hydro-mechanical-chemical (HMC) fully coupled equations in porous media faces significant challenges due to spurious oscillation in pore pressure and concentration caused by locking and convection dominance. This study proposes a combination of two different discretization schemes: (1) the Galerkin discretization on the primal mesh for the soil skeleton deformation, and (2) the finite volume method (FVM) on the dual mesh for solute transport and fluid flow, named G-FVM, where the approximations of skeleton displacement (u), pore pressure (p), and concentration(c) are established by NMM, to reflect compressible and incompressible deformation. Typical examples of chemo-osmotic and chemo-mechanical consolidation are simulated to verify the accuracy of the G-FVM. Through the numerical tests of 1D and 2D chemo-mechanical consolidation problems, it is evident that when convection-dominated solute transport is associated with Biot's consolidation law, two different numerical oscillations are observed in both pore pressure and concentration if only the Galerkin method is applied. Nevertheless, the G-FVM did not produce oscillations in either pore pressure or concentration and is free of locking and convection dominance, accurately predicting the response of low-permeability porous media.
Keyword :
Galerkin 's discretization Galerkin 's discretization Porous media Porous media Hydro-mechanical-chemical coupling Hydro-mechanical-chemical coupling Numerical manifold method Numerical manifold method Finite volume method Finite volume method
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GB/T 7714 | Wang, Shu-Qing , Zheng, Hong , Zhang, Zhi-Hong . Associative approximation of Galerkin and FVM for the HMC fully coupled model under the NMM framework [J]. | ENGINEERING ANALYSIS WITH BOUNDARY ELEMENTS , 2024 , 166 . |
MLA | Wang, Shu-Qing 等. "Associative approximation of Galerkin and FVM for the HMC fully coupled model under the NMM framework" . | ENGINEERING ANALYSIS WITH BOUNDARY ELEMENTS 166 (2024) . |
APA | Wang, Shu-Qing , Zheng, Hong , Zhang, Zhi-Hong . Associative approximation of Galerkin and FVM for the HMC fully coupled model under the NMM framework . | ENGINEERING ANALYSIS WITH BOUNDARY ELEMENTS , 2024 , 166 . |
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Abstract :
The helical anchor foundation is driven into the soil under the combined action of torque and vertical pressure. The installation process involves a significant deformation of the soil, which is difficult to simulate numerically using the traditional finite element method. As a meshless method, Smoothed Particle Hydrodynamics (SPH) is very suitable for simulating large deformation problems. In this paper, the SPH meshless method and traditional finite element method are used to simulate the installation and pulling process of helical anchor foundations in sandy soil. The variations in installation force, installation torque, ultimate uplift capacity, and torque correlation factor under different advancement ratios were studied. The research results indicate that using a low advancement ratio for installation can significantly reduce the installation force and torque of the helical anchor and positively affect the ultimate uplift capacity. Moreover, the torque correlation factor is also influenced by the advancement ratio. Using the torque correlation factor value obtained from the "pitch matching" installation to predict the ultimate uplift capacity at other advancement ratios may result in an overestimation.
Keyword :
ultimate uplift capacity ultimate uplift capacity smoothed particle hydrodynamics smoothed particle hydrodynamics helical anchor helical anchor finite element method finite element method advancement ratio advancement ratio
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GB/T 7714 | Hu, Haiyang , Yuan, Chi , Zheng, Hong . Simulation Study on the Installation of Helical Anchors in Sandy Soil Using SPH-FEM [J]. | APPLIED SCIENCES-BASEL , 2024 , 14 (17) . |
MLA | Hu, Haiyang 等. "Simulation Study on the Installation of Helical Anchors in Sandy Soil Using SPH-FEM" . | APPLIED SCIENCES-BASEL 14 . 17 (2024) . |
APA | Hu, Haiyang , Yuan, Chi , Zheng, Hong . Simulation Study on the Installation of Helical Anchors in Sandy Soil Using SPH-FEM . | APPLIED SCIENCES-BASEL , 2024 , 14 (17) . |
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This paper aims to predict the damage and fracture behavior of thermoplastic fiber-reinforced metal laminates (TFMLs) under ballistic impact loadings. A dynamic metal constitutive model has been employed and implemented in Abaqus/Explicit through a vectorized user material subroutine (VUMAT). The effects of the Lode angle, temperature, and strain rate are considered in the strength model, while the effects of stress triaxiality, Lode angle, temperature, and strain rate are taken into account in the failure criteria. To assess the validity and superiority of the proposed model, the numerically predicted responses of polypropylene fiber-reinforced metal laminates subjected to varying impact energies were systematically compared with corresponding experimental results. Additionally, a comparative analysis was performed between the numerical simulation results predicted by the present model and those obtained using other constitutive models, such as the Johnson-Cook (JC) constitutive model and the elastoplastic constitutive model. Furthermore, the effect of projectile types on the ballistic performance of TFMLs have been systematically investigated. The findings demonstrate that the failure pattern predicted by the current model closely aligns with the experimental observations, while both the Johnson-Cook (JC) constitutive model and the elastoplastic constitutive model were unable to accurately replicate the experimentally observed failure behavior. This study also reveals that the projectile's nose shape plays a significant role in influencing the perforation behavior of TFMLs, affecting both the residual velocity and damage.
Keyword :
fracture fracture FE model FE model damage damage thermoplastic FMLs thermoplastic FMLs ballistic impact ballistic impact
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GB/T 7714 | Zeng, Yan , Li, Chunguang , Zheng, Hong et al. Ballistic Performance of Thermoplastic Fiber-Reinforced Metal Laminates Subjected to Impact Loadings [J]. | APPLIED SCIENCES-BASEL , 2024 , 14 (20) . |
MLA | Zeng, Yan et al. "Ballistic Performance of Thermoplastic Fiber-Reinforced Metal Laminates Subjected to Impact Loadings" . | APPLIED SCIENCES-BASEL 14 . 20 (2024) . |
APA | Zeng, Yan , Li, Chunguang , Zheng, Hong , Liu, Yijun . Ballistic Performance of Thermoplastic Fiber-Reinforced Metal Laminates Subjected to Impact Loadings . | APPLIED SCIENCES-BASEL , 2024 , 14 (20) . |
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Abstract :
This study presents a simple approach and its associated MATLAB toolbox for 3D block cutting and mesh cutting. The approach is suitable for the meshes of numerical methods including the Key Block Theory (KBT), the Discontinuous Deformation Analysis (DDA), the Numerical Manifold Method (NMM), and the cut Finite Element Method (Cut-FEM). The strategy is based on calculations on convex bodies. It uses two different forms of representation: the geometric representation which includes vertices and faces, and the algebraic representation which consists of inequalities. The cutting was implemented on the algebraic representation, and the resulting inequalities were converted into a geometric representation. The above strategy turned out to be robust and straightforward to execute, at the cost of a general body being regarded as a combination of convex bodies. The efficiency guarantee was considered through pre-checking algorithms. The source code was provided, as well as some simple examples.
Keyword :
Convex body Convex body Joints Joints Mesh Mesh Three-dimensional cutting Three-dimensional cutting
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GB/T 7714 | Zhang, Ning , Zheng, Hong , Yang, Miao et al. An open-source MATLAB toolbox for 3D block cutting and 3D mesh cutting in geotechnical engineering [J]. | ADVANCES IN ENGINEERING SOFTWARE , 2024 , 197 . |
MLA | Zhang, Ning et al. "An open-source MATLAB toolbox for 3D block cutting and 3D mesh cutting in geotechnical engineering" . | ADVANCES IN ENGINEERING SOFTWARE 197 (2024) . |
APA | Zhang, Ning , Zheng, Hong , Yang, Miao , Wang, Ningbo . An open-source MATLAB toolbox for 3D block cutting and 3D mesh cutting in geotechnical engineering . | ADVANCES IN ENGINEERING SOFTWARE , 2024 , 197 . |
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Abstract :
Soil and rock mixture (SRM) is ubiquitous in nature and also an excellent engineering fill material. Accurate evaluation of mechanical characteristics of SRM is of vital importance in the analysis of stability and deformation. Unfortunately, the presence of mega blocks in SRM makes it impossible to grasp the real attributes of full graded SRM using indoor or in-situ experiments. Consequently, numerical methods, especially those threedimensional methods, become crucial to the objective evaluation of SRM mechanical properties. However, even the most powerful and sophisticated mesh generators become too weak to produce even low-quality meshes of real SRM samples. Accordingly, the numerical manifold method (NMM) is an excellent tool for this purpose since it successfully throws off shackles of mesh generation. In this study, we first produce an SRM sample according to the given size distribution and content of rock blocks. Then, we employ a tetrahedron mesh to act as the mathematical cover of the SRM sample; the mesh does not match the SRM sample domain. Next, we utilize Boolean operations in Ansys to generate the physical cover of the SRM sample and the robustness of the program is hence ensured to the greatest extent. As a preliminary application, finally we demonstrate the permeability evaluation of SRM, indicating that even for those SRM samples that cannot be meshed with the most powerful mesh generator, the proposed procedure can easily arrive at their solutions.
Keyword :
3-dimensional numerical manifold method 3-dimensional numerical manifold method Seepage permeability Seepage permeability Block cutting Block cutting Modeling of soil and rock mixtures Modeling of soil and rock mixtures
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GB/T 7714 | Zhang, Yusen , Zheng, Hong , Lin, Shan . Preserved structure modeling of soil-rock mixtures and physical cover generation based on finite element meshes [J]. | ENGINEERING GEOLOGY , 2023 , 323 . |
MLA | Zhang, Yusen et al. "Preserved structure modeling of soil-rock mixtures and physical cover generation based on finite element meshes" . | ENGINEERING GEOLOGY 323 (2023) . |
APA | Zhang, Yusen , Zheng, Hong , Lin, Shan . Preserved structure modeling of soil-rock mixtures and physical cover generation based on finite element meshes . | ENGINEERING GEOLOGY , 2023 , 323 . |
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Abstract :
Liquidity index is used to measure the relative consistency of natural soils, making it possible to evaluate the stiffness degree and strength of clays. However, a systematic understanding of the relationship between the undrained shear strength and the liquidity index remains unclear. While some studies are being conducted on this putative relationship, the theoretical foundation is still lacking. This study proposes a new undrained shear strength prediction model based on the Mohr-Coulomb failure criterion and the critical state theory. A database of 103 soil samples from 18 research is utilised to validate the model's applicability. The results reflect a consistent level of accuracy. The proposed model has an obvious advantage and has potential for predicting the undrained shear strength of clays.
Keyword :
Prediction model Prediction model Undrained shear strength Undrained shear strength Liquidity index Liquidity index Atterberg limits Atterberg limits Clays Clays
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GB/T 7714 | Wang, Qiusheng , Qiu, Songnan , Zheng, Hong et al. Undrained shear strength prediction of clays using liquidity index [J]. | ACTA GEOTECHNICA , 2023 , 19 (7) : 4325-4342 . |
MLA | Wang, Qiusheng et al. "Undrained shear strength prediction of clays using liquidity index" . | ACTA GEOTECHNICA 19 . 7 (2023) : 4325-4342 . |
APA | Wang, Qiusheng , Qiu, Songnan , Zheng, Hong , Zhang, Ruitao . Undrained shear strength prediction of clays using liquidity index . | ACTA GEOTECHNICA , 2023 , 19 (7) , 4325-4342 . |
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The main challenge in the analysis of unconfined seepage flow is that the position of free surfaces is unknown a priori, which needs to be determined through a series of iterative processes. The numerical manifold method (NMM) is a promising method which uses a dual cover system consisting of both mathematical and physical covers. Compared with those traditional methods, NMM is characterized by meshing convenience, approximation accuracy, and being capable of coping with free boundary value problems. Unlike the traditional NMM where the material interface participates in cutting the mathematical cover while forming the physical cover, the physical patches in this study can contain the material interface. The new weight functions for such physical patches are constructed using the refraction law, followed by the application to the analysis of unconfined seepage flow problems. By comparing with analytical or reference solutions of some classic examples, it is validated that the proposed method can accurately locate the free surface, demonstrating its accuracy and convenience in solving unconfined seepage problems.
Keyword :
Refraction law Refraction law Weight functions Weight functions Unconfined seepage problems Unconfined seepage problems Free surfaces Free surfaces Numerical manifold method Numerical manifold method
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GB/T 7714 | Jia, Zhen , Zheng, Hong . A new procedure for locating free surfaces of complex unconfined seepage problems using fixed meshes [J]. | COMPUTERS AND GEOTECHNICS , 2023 , 166 . |
MLA | Jia, Zhen et al. "A new procedure for locating free surfaces of complex unconfined seepage problems using fixed meshes" . | COMPUTERS AND GEOTECHNICS 166 (2023) . |
APA | Jia, Zhen , Zheng, Hong . A new procedure for locating free surfaces of complex unconfined seepage problems using fixed meshes . | COMPUTERS AND GEOTECHNICS , 2023 , 166 . |
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Due to the salient feature of cutting operation, the numerical manifold method (NMM) can deal with an any-shaped problem domain by the simplest regular grid. However, this usually creates many irregularly shaped lower-order manifold elements. As a result, the NMM not only needs lots of integration points, but also encounters severe locking issues on nearly incompressible or bending-dominated conditions. This study shows a robust single-point integration rule to handle the above issue in the two-dimensional NMM. The essential idea is to separate the virtual work of an element in terms of moments to the center, so that a zero-order main term and higher-order stabilizing terms are obtained. Further, the volumetric locking and the shearing locking are avoided by modifications to the spherical part and shearing part of the stabilizing terms, and hourglass deformation is overcome since stabilizing terms are always non-zero. Consequently, in addition to fewer integration points, the rule improves accuracy since it is free from locking or hourglass issues. Numerical examples verify the robustness and accuracy improvement of the new rule.
Keyword :
Single point integration Single point integration Locking Locking Hourglass control Hourglass control Numerical manifold method Numerical manifold method
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GB/T 7714 | Zhang, Ning , Zheng, Hong , Yang, Liang et al. A single point integration rule for numerical manifold method without locking and hourglass issues [J]. | ACTA MECHANICA SINICA , 2023 , 39 (9) . |
MLA | Zhang, Ning et al. "A single point integration rule for numerical manifold method without locking and hourglass issues" . | ACTA MECHANICA SINICA 39 . 9 (2023) . |
APA | Zhang, Ning , Zheng, Hong , Yang, Liang , Wang, Yichen , Wu, Wenan . A single point integration rule for numerical manifold method without locking and hourglass issues . | ACTA MECHANICA SINICA , 2023 , 39 (9) . |
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Abstract :
PurposeThis article aims to present a direct solution to handle linear constraints in finite element (FE) analysis without penalties or the Lagrange multipliers introduced.Design/methodology/approachFirst, the system of linear equations corresponding to the linear constraints is solved for the leading variables in terms of the free variables and the constants. Then, the reduced system of equilibrium equations with respect to the free variables is derived from the finite-dimensional virtual work equation. Finally, the algorithm is designed.FindingsThe proposed procedure is promising in three typical cases: (1) to enforce displacement constraints in any direction; (2) to implement local refinements by allowing hanging nodes from element subdivision and (3) to treat non-matching grids of distinct parts of the problem domain. The procedure is general and suitable for 3D non-linear analyses.Research limitations/implicationsThe algorithm is fitted only to the Galerkin-based numerical methods.Originality/valueThe proposed procedure does not need Lagrange multipliers or penalties. The tangential stiffness matrix of the reduced system of equilibrium equations reserves positive definiteness and symmetry. Besides, many contemporary Galerkin-based numerical methods need to tackle the enforcement of the essential conditions, whose weak forms reduce to linear constraints. As a result, the proposed procedure is quite promising.
Keyword :
Non-matching grid Non-matching grid Finite element method Finite element method Adaptive refinement Adaptive refinement Constraint condition Constraint condition
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GB/T 7714 | Zhang, Ning , Zheng, Hong , Yuan, Chi et al. A direct solution to linear constraints in the finite element analysis and its application illustrations [J]. | ENGINEERING COMPUTATIONS , 2023 , 40 (9/10) : 2328-2347 . |
MLA | Zhang, Ning et al. "A direct solution to linear constraints in the finite element analysis and its application illustrations" . | ENGINEERING COMPUTATIONS 40 . 9/10 (2023) : 2328-2347 . |
APA | Zhang, Ning , Zheng, Hong , Yuan, Chi , Wu, Wenan . A direct solution to linear constraints in the finite element analysis and its application illustrations . | ENGINEERING COMPUTATIONS , 2023 , 40 (9/10) , 2328-2347 . |
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Abstract :
In solving the system of Stokes and Navier-Stokes equations, lack of mass conservation has been viewed as the critical drawback of the finite element methods based on the least-squares (LS) principle. Although many modifications have been proposed, there is a need for a global approach that improves both mass conservation and momentum conservation. The key to such a global method is to control local conservation, which is weaker than to control the residual everywhere. Accordingly, a new method named conservation-prioritized Moment Least-Squares (CMLS) is developed. The CMLS method emerges from the moment conditions. Among these moment conditions, the zero-order moment, which exactly expresses the local conservation condition on the element, is prioritized over the others; thereby, good local conservation can be achieved. The advantages of the CMLS method over the LS method are demonstrated by conservation errors, convergence studies, and numerical accuracy in nonlinear Navier-Stokes tests. Besides, the CMLS method retains the merits of the LS method: it has a symmetric positive-definite global matrix and the same interpolation for both velocity and pressure.(c) 2022 Elsevier B.V. All rights reserved.
Keyword :
Mass conservation Mass conservation Finite element method Finite element method Navier-Stokes Navier-Stokes Momentum conservation Momentum conservation Least -squares Least -squares
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GB/T 7714 | Zhang, Ning , Zheng, Hong , Yuan, Chi et al. A conservation-prioritized approach simultaneously enhancing mass and momentum conservation of least-squares method for Stokes/Navier-Stokes problems [J]. | COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING , 2022 , 398 . |
MLA | Zhang, Ning et al. "A conservation-prioritized approach simultaneously enhancing mass and momentum conservation of least-squares method for Stokes/Navier-Stokes problems" . | COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING 398 (2022) . |
APA | Zhang, Ning , Zheng, Hong , Yuan, Chi , Wu, Wenan . A conservation-prioritized approach simultaneously enhancing mass and momentum conservation of least-squares method for Stokes/Navier-Stokes problems . | COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING , 2022 , 398 . |
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