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Goal-oriented error estimation applied to direct solution of steady-state analysis with frequency-domain finite element method
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作者 林治家 由小川 庄茁 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2012年第5期539-552,共14页
Based on the concept of the constitutive relation error along with the residuals of both the origin and the dual problems, a goal-oriented error estimation method with extended degrees of freedom is developed. It lead... Based on the concept of the constitutive relation error along with the residuals of both the origin and the dual problems, a goal-oriented error estimation method with extended degrees of freedom is developed. It leads to the high quality locM error bounds in the problem of the direct-solution steady-state dynamic analysis with a frequency-domain finite element, which involves the enrichments with plural variable basis functions. The solution of the steady-state dynamic procedure calculates the harmonic response directly in terms of the physical degrees of freedom in the model, which uses the mass, damping, and stiffness matrices of the system. A three-dimensional finite element example is carried out to illustrate the computational procedures. 展开更多
关键词 goal-oriented error estimation finite element method (FEM) direct-solutionsteady-state analysis frequency domain
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Distributed Lagrange Multiplier/Fictitious Domain Finite Element Method for a Transient Stokes Interface Problem with Jump Coefficients 被引量:2
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作者 Andrew Lundberg Pengtao Sun +1 位作者 Cheng Wang Chen-song Zhang 《Computer Modeling in Engineering & Sciences》 SCIE EI 2019年第4期35-62,共28页
The distributed Lagrange multiplier/fictitious domain(DLM/FD)-mixed finite element method is developed and analyzed in this paper for a transient Stokes interface problem with jump coefficients.The semi-and fully disc... The distributed Lagrange multiplier/fictitious domain(DLM/FD)-mixed finite element method is developed and analyzed in this paper for a transient Stokes interface problem with jump coefficients.The semi-and fully discrete DLM/FD-mixed finite element scheme are developed for the first time for this problem with a moving interface,where the arbitrary Lagrangian-Eulerian(ALE)technique is employed to deal with the moving and immersed subdomain.Stability and optimal convergence properties are obtained for both schemes.Numerical experiments are carried out for different scenarios of jump coefficients,and all theoretical results are validated. 展开更多
关键词 TRANSIENT STOKES interface problem JUMP COEFFICIENTS DISTRIBUTED LAGRANGE multiplier fictitious domain method mixed finite element an optimal error estimate stability
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INFINITE ELEMENT METHOD FOR PROBLEMS ON UNBOUNDED AND MULTIPLY CONNECTED DOMAINS 被引量:1
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作者 应隆安 《Acta Mathematica Scientia》 SCIE CSCD 2001年第4期440-452,共13页
The author studies the infinite element method for the boundary value problems of second order elliptic equations on unbounded and multiply connected domains. The author makes a partition of the domain into infinite n... The author studies the infinite element method for the boundary value problems of second order elliptic equations on unbounded and multiply connected domains. The author makes a partition of the domain into infinite number of elements. Without dividing the domain, as usual, into a bounded one and an exterior one, he derives an initial value problem of an ordinary differential equation for the combined stiffness matrix, then obtains the approximate solution with a small amount of computer work. Numerical examples are given. 展开更多
关键词 finite element method infinite element method unbounded domain multiply connected domain
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Three-dimensional Simulation of Reverberation Chamber Using Finite-element Time-domain Method 被引量:1
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作者 DU Lei WANG Song +2 位作者 CUI Yaozhong WANG Qingguo PAN Yun 《高电压技术》 EI CAS CSCD 北大核心 2013年第12期2889-2893,共5页
关键词 三维模拟 时域法 有限元 混响室 几何建模 标准偏差 雷达散射截面 低频响应
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Acoustic viscoelastic modeling by frequency-domain boundary element method 被引量:1
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作者 Xizhu Guan Li-Yun Fu Weijia Sun 《Earthquake Science》 CSCD 2017年第2期97-105,共9页
Earth medium is not completely elastic, with its viscosity resulting in attenuation and dispersion of seismic waves. Most viscoelastic numerical simulations are based on the finite-difference and finite-element method... Earth medium is not completely elastic, with its viscosity resulting in attenuation and dispersion of seismic waves. Most viscoelastic numerical simulations are based on the finite-difference and finite-element methods. Targeted at viscoelastic numerical modeling for multilayered media, the constant-Q acoustic wave equation is transformed into the corresponding wave integral representation with its Green's function accounting for viscoelastic coefficients. An efficient alternative for full-waveform solution to the integral equation is proposed in this article by extending conventional frequency-domain boundary element methods to viscoelastic media. The viscoelastic boundary element method enjoys a distinct characteristic of the explicit use of boundary continuity conditions of displacement and traction, leading to a semi-analytical solution with sufficient accuracy for simulating the viscoelastic effect across irregular interfaces. Numerical experiments to study the viscoelastic absorption of different Q values demonstrate the accuracy and applicability of the method. 展开更多
关键词 Viscoelastic media Viscoelastic boundary element method frequency-domain implementation Viscoelastic numerical modeling
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DIRECT SOLUTION BY 2-D AND 3-D FINITE ELEMENT METHOD ON FORWARD PROBLEM OF LOW FREQUENCY CURRENT FIELDS IN INHOMOGENEOUS MEDIA
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作者 Chen Xiaoguang Nie Zaiping(University of Electronic Science and Technology of China, Chengdu 610054) 《Journal of Electronics(China)》 1998年第2期158-167,共10页
The paper adopts finite element method to analyze the forward problem of low-frequency current fields in inhomogeneous media. Firstly, the direct solution of 2-D and 3-D scalar potential is given. Secondly, the techni... The paper adopts finite element method to analyze the forward problem of low-frequency current fields in inhomogeneous media. Firstly, the direct solution of 2-D and 3-D scalar potential is given. Secondly, the technique of covering finite elements for problems with movement has been presented; namely, when the place of testing point moved, the meshing data will be produced automatically to avoid re-meshing and distortion of the mesh. Thirdly the free and prescribed potential method is used to make the finite element coefficient matrices. Then this paper provides the result of a validity test obtained by simulating the laterolog-3 logging, compared with the numerical model-matching method. Finally, the MLL response is calculated. 展开更多
关键词 finite element method LOW-frequency current FIELDS The technique of COVERinG finite elements Electrical LOGGinG
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Aerodynamic Design of Airfoils Based on Variable-Domain Variational Finite Element Method
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作者 陈池 刘高联 《Journal of Shanghai University(English Edition)》 CAS 2005年第3期210-215,共6页
Designing airfoils according to given pressure (or velocity) distribution is one kind of free boundary problems. Free boundary condition can be coupled with the flow governing equations by variable-domain variational ... Designing airfoils according to given pressure (or velocity) distribution is one kind of free boundary problems. Free boundary condition can be coupled with the flow governing equations by variable-domain variational calculus, which makes it possible to calculate simultaneously the flow field and the free boundary. An accurate deduction of the variable-domain variational principles is taken herein to design airfoils in compressible and incompressible flows. Furthermore, two grid types (H and O) are used in the calculation with better results for the O-type grid. It is shown that convergence is accelerated and good results can be obtained even if the initial guessed airfoil shape is a triangle, demonstrating the strong adaptability of this method. 展开更多
关键词 inverse design finite element method variable-domain variational principle.
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Propagations of Rayleigh and Love waves in ZnO films/glass substrates analyzed by three-dimensional finite element method 被引量:3
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作者 王艳 谢英才 +1 位作者 张淑仪 兰晓东 《Chinese Physics B》 SCIE EI CAS CSCD 2017年第8期468-473,共6页
Propagation characteristics of surface acoustic waves(SAWs) in ZnO films/glass substrates are theoretically investigated by the three-dimensional(3D) finite element method. At first, for(11ˉ20) ZnO films/glass ... Propagation characteristics of surface acoustic waves(SAWs) in ZnO films/glass substrates are theoretically investigated by the three-dimensional(3D) finite element method. At first, for(11ˉ20) ZnO films/glass substrates, the simulation results confirm that the Rayleigh waves along the [0001] direction and Love waves along the [1ˉ100] direction are successfully excited in the multilayered structures. Next, the crystal orientations of the ZnO films are rotated, and the influences of ZnO films with different crystal orientations on SAW characterizations, including the phase velocity, electromechanical coupling coefficient, and temperature coefficient of frequency, are investigated. The results show that at appropriate h/λ, Rayleigh wave has a maximum k^2 of 2.4% in(90°, 56.5°, 0°) ZnO film/glass substrate structure; Love wave has a maximum k^2 of 3.81% in(56°, 90°, 0°) ZnO film/glass substrate structure. Meantime, for Rayleigh wave and Love wave devices, zero temperature coefficient of frequency(TCF) can be achieved at appropriate ratio of film thickness to SAW wavelength. These results show that SAW devices with higher k^2 or lower TCF can be fabricated by flexibly selecting the crystal orientations of ZnO films on glass substrates. 展开更多
关键词 surface acoustic wave ZnO films electromechanical coupling coefficient temperature coefficientof frequency 3D finite element method
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Finite difference time domain method forward simulation of complex geoelectricity ground penetrating radar model 被引量:5
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作者 戴前伟 冯德山 何继善 《Journal of Central South University of Technology》 EI 2005年第4期478-482,共5页
The ground penetrating radar(GPR) forward simulation all aims at the singular and regular models, such as sandwich model, round cavity, square cavity, and so on, which are comparably simple. But as to the forward of c... The ground penetrating radar(GPR) forward simulation all aims at the singular and regular models, such as sandwich model, round cavity, square cavity, and so on, which are comparably simple. But as to the forward of curl interface underground or “v” figure complex model, it is difficult to realize. So it is important to forward the complex geoelectricity model. This paper takes two Maxwell’s vorticity equations as departure point, makes use of the principles of Yee’s space grid model theory and the basic principle finite difference time domain method, and deduces a GPR forward system of equation of two dimensional spaces. The Mur super absorbed boundary condition is adopted to solve the super strong reflection on the interceptive boundary when there is the forward simulation. And a self-made program is used to process forward simulation to two typical geoelectricity model. 展开更多
关键词 ground penetrating radar finite difference time domain method forward simulation ideal frequency dispersion relationship
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Geotechnical particle finite element method for modeling of soilstructure interaction under large deformation conditions 被引量:1
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作者 Josep Maria Carbonell Lluís Monforte +2 位作者 Matteo O.Ciantia Marcos Arroyo Antonio Gens 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2022年第3期967-983,共17页
The possibilities of the particle finite element method(PFEM)for modeling geotechnical problems are increasingly evident.PFEM is a numerical approach to solve large displacement and large strain continuum problems tha... The possibilities of the particle finite element method(PFEM)for modeling geotechnical problems are increasingly evident.PFEM is a numerical approach to solve large displacement and large strain continuum problems that are beyond the capabilities of classical finite element method(FEM).In PFEM,the computational domain is reconfigured for optimal solution by frequent remeshing and boundary updating.PFEM inherits many concepts,such as a Lagrangian description of continuum,from classic geomechanical FEM.This familiarity with more popular numerical methods facilitates learning and application.This work focuses on G-PFEM,a code specifically developed for the use of PFEM in geotechnical problems.The article has two purposes.The first is to give the reader an overview of the capabilities and main features of the current version of the G-PFEM and the second is to illustrate some of the newer developments of the code.G-PFEM can solve coupled hydro-mechanical static and dynamic problems involving the interaction of solid and/or deformable bodies.Realistic constitutive models for geomaterials are available,including features,such as structure and destructuration,which result in brittle response.The solutions are robust,solidly underpinned by numerical technology including mixedfield formulations,robust and mesh-independent integration of elastoplastic constitutive models and a rigorous and flexible treatment of contact interactions.The novel features presented in this work include the contact domain technique,a natural way to capture contact interactions and impose contact constraints between different continuum bodies,as well as a new simplified formulation for dynamic impact problems.The code performance is showcased by the simulation of several soil-structure interaction problems selected to highlight the novel code features:a rigid footing insertion in soft rock,pipeline insertion and subsequent lateral displacement on over-consolidated clay,screw-pile pull-out and the dynamic impact of a free-falling spherical penetrometer into clay. 展开更多
关键词 Particle finite element method(PFEM) Structured soils Nonlocal elastoplasticity Contact domain method Soil penetration problems
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A DOMAIN DECOMPOSITION ALGORITHM WITH FINITE ELEMENT-BOUNDARY ELEMENT COUPLING
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作者 严波 杜娟 +1 位作者 胡宁 关根英树 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2006年第4期519-525,共7页
A domain decomposition algorithm coupling the finite element and the boundary element was presented. It essentially involves subdivision of the analyzed domain into sub-regions being independently modeled by two metho... A domain decomposition algorithm coupling the finite element and the boundary element was presented. It essentially involves subdivision of the analyzed domain into sub-regions being independently modeled by two methods, i.e., the finite element method (FEM) and the boundary element method (BEM). The original problem was restored with continuity and equilibrium conditions being satisfied on the interface of the two sub-regions using an iterative algorithm. To speed up the convergence rate of the iterative algorithm, a dynamically changing relaxation parameter during iteration was introduced. An advantage of the proposed algorithm is that the locations of the nodes on the interface of the two sub-domains can be inconsistent. The validity of the algorithm is demonstrated by the consistence of the results of a numerical example obtained by the proposed method and those by the FEM, the BEM and a present finite element-boundary element (FE-BE) coupling method. 展开更多
关键词 finite element method boundary element method finite element-boundary element coupling domain decomposition
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A parallel two-level finite element method for the Navier-Stokes equations
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作者 尚月强 罗振东 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2010年第11期1429-1438,共10页
Based on domain decomposition, a parallel two-level finite element method for the stationary Navier-Stokes equations is proposed and analyzed. The basic idea of the method is first to solve the Navier-Stokes equations... Based on domain decomposition, a parallel two-level finite element method for the stationary Navier-Stokes equations is proposed and analyzed. The basic idea of the method is first to solve the Navier-Stokes equations on a coarse grid, then to solve the resulted residual equations in parallel on a fine grid. This method has low communication complexity. It can be implemented easily. By local a priori error estimate for finite element discretizations, error bounds of the approximate solution are derived. Numerical results are also given to illustrate the high efficiency of the method. 展开更多
关键词 Navier-Stokes equations finite element two-level method overlapping domain decomposition parallel algorithm
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An Adaptive Finite Element Method Based on Optimal Error Estimates for Linear Elliptic Problems
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作者 汤雁 《Transactions of Tianjin University》 EI CAS 2004年第3期225-228,共4页
The subject of the work is to propose a series of papers about adaptive finite element methods based on optimal error control estimate. This paper is the third part in a series of papers on adaptive finite element met... The subject of the work is to propose a series of papers about adaptive finite element methods based on optimal error control estimate. This paper is the third part in a series of papers on adaptive finite element methods based on optimal error estimates for linear elliptic problems on the concave corner domains. In the preceding two papers (part 1:Adaptive finite element method based on optimal error estimate for linear elliptic problems on concave corner domain; part 2:Adaptive finite element method based on optimal error estimate for linear elliptic problems on nonconvex polygonal domains), we presented adaptive finite element methods based on the energy norm and the maximum norm. In this paper, an important result is presented and analyzed. The algorithm for error control in the energy norm and maximum norm in part 1 and part 2 in this series of papers is based on this result. 展开更多
关键词 adaptive finite element method concave corner domain elliptic problems
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2.5-D modeling of cross-hole electromagnetic measurement by nite element method 被引量:3
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作者 Shen Jinsong Sun Wenbo 《Petroleum Science》 SCIE CAS CSCD 2008年第2期126-134,共9页
A finite element method is developed for simulating frequency domain electromagnetic responses due to a dipole source in the 2-D conductive structures. Computing costs are considerably minimized by reducing the full t... A finite element method is developed for simulating frequency domain electromagnetic responses due to a dipole source in the 2-D conductive structures. Computing costs are considerably minimized by reducing the full three-dimensional problem to a series of two-dimensional problems. This is accomplished by transforming the problem into y-wave number (Ky) domain using Fourier transform and the y-axis is parallel to the structural strike. In the Ky domain, two coupled partial differential equations for magnetic field Hy and electric field Ey are derived. For a specific value of Ky, the coupled equations are solved by the finite element method with isoparametric elements in the x-z plane. Application of the inverse Fourier transform to the Ky, domain provides the electric and magnetic fields in real space. The equations derived can be applied to general complex two-dimensional structures containing either electric or magnetic dipole source in any direction. In the modeling of the electromagnetic measurement, we adopted a pseudo-delta function to distribute the dipole source current and circumvent the problem of singularity at the source point. Moreover, the suggested method used isoparametric finite elements to accommodate the complex subsurface formation. For the large scale linear system derived from the discretization of the Maxwell's equations, several iterative solvers were used and compared to select the optimal one. A quantitative test of accuracy was presented which compared the finite element results with analytic solutions for a dipole source in homogeneous space for different ranges and different wave numbers Ky. to validate the addressed the effects of the distribution range τ of the homogeneous medium. code and check its effectiveness. In addition, we pseudo-delta function on the numerical results in 展开更多
关键词 2.5-D electromagnetic modeling frequency domain isoparametric finite element pseudo-delta function
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Analysis of the electromechanical behavior of ferroelectric ceramics based on a nonlinear finite element model 被引量:3
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作者 Daining Fang Faxin Li +1 位作者 A. K. Soh Tieqi Liu 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2005年第3期294-304,共11页
A nonlinear finite element (FE) model based on domain switching was proposed to study the electromechanical behavior of ferroelectric ceramics. The incremental FE formulation was improved to avoid any calculation in... A nonlinear finite element (FE) model based on domain switching was proposed to study the electromechanical behavior of ferroelectric ceramics. The incremental FE formulation was improved to avoid any calculation instability. The problems of mesh sensitivity and convergence, and the efficiency of the proposed nonlinear FE technique have been assessed to illustrate the versatility and potential accuracy of the said technique. The nonlinear electromechanical behavior, such as the hysteresis loops and butterfly curves, of ferroelectric ceramics subjected to both a uniform electric field and a point electric potential has been studied numerically. The results obtained are in good agreement with those of the corresponding theoretical and experimental analyses. Furthermore, the electromechanical coupling fields near (a) the boundary of a circular hole, (b) the boundary of an elliptic hole and (c) the tip of a crack, have been analyzed using the proposed nonlinear finite element method (FEM). The proposed nonlinear electromechanically coupled FEM is useful for the analysis of domain switching, deformation and fracture of ferroelectric ceramics. 展开更多
关键词 Ferroelectric material domain switching finite element method Nonlinear electromechanical coupling Crack and fracture
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Second-Order Invariant Domain Preserving ALE Approximation of Euler Equations
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作者 Jean-Luc Guermond Bojan Popov Laura Saavedra 《Communications on Applied Mathematics and Computation》 2023年第2期923-945,共23页
An invariant domain preserving arbitrary Lagrangian-Eulerian method for solving non-linear hyperbolic systems is developed.The numerical scheme is explicit in time and the approximation in space is done with continuou... An invariant domain preserving arbitrary Lagrangian-Eulerian method for solving non-linear hyperbolic systems is developed.The numerical scheme is explicit in time and the approximation in space is done with continuous finite elements.The method is made invar-iant domain preserving for the Euler equations using convex limiting and is tested on vari-ous benchmarks. 展开更多
关键词 Conservation equations Hyperbolic systems Arbitrary Lagrangian-Eulerian Moving meshes invariant domains High-order method Convex limiting finite element method
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Modelling of Wideband Concentric Ring Frequency Selective Surface for 5G Devices
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作者 Ankush Kapoor Pradeep Kumar Ranjan Mishra 《Computers, Materials & Continua》 SCIE EI 2023年第1期341-361,共21页
Frequency selective surfaces(FSSs)play an important role in wireless systems as these can be used as filters,in isolating the unwanted radiation,in microstrip patch antennas for improving the performance of these ante... Frequency selective surfaces(FSSs)play an important role in wireless systems as these can be used as filters,in isolating the unwanted radiation,in microstrip patch antennas for improving the performance of these antennas and in other 5G applications.The analysis and design of the double concentric ring frequency selective surface(DCRFSS)is presented in this research.In the sub-6 GHz 5G FR1 spectrum,a computational synthesis technique for creating DCRFSS based spatial filters is proposed.The analytical tools presented in this study can be used to gain a better understanding of filtering processes and for constructing the spatial filters.Variation of the loop sizes,angles of incidence,and polarization of the concentric rings are the factors which influence the transmission coefficient as per the thorough investigation performed in this paper.A novel synthesis approach based on mathematical equations that may be used to determine the physical parameters ofDCRFSSbased spatial filters is presented.The proposed synthesis technique is validated by comparing results from high frequency structure simulator(HFSS),Ansys electronic desktop circuit editor,and an experimental setup.Furthermore,the findings acquired from a unit cell are expanded to a 2×2 array,which shows identical performance and therefore proves its stability. 展开更多
关键词 Spatial filters double concentric ring frequency selective surface(DCRFSS) angle of incidence finite element method(FEM) polarization angles
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Finite Element Modeling and Design of Rectangular Patch Antenna with Different Feeding Techniques 被引量:1
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作者 Rajat Arora Ajay Kumar +1 位作者 Saleem Khan Sandeep Arya 《Open Journal of Antennas and Propagation》 2013年第2期11-17,共7页
The finite element modeling of three dimensional structures is important for researchers especially in the field of antennas and other domains of electromagnetic waves. This paper presents a finite element calculation... The finite element modeling of three dimensional structures is important for researchers especially in the field of antennas and other domains of electromagnetic waves. This paper presents a finite element calculations and numerical analysis for the microstrip patch antennas. In this paper, two different designs have been modelled and analyzed and both designs are based on the rectangular patches. The feeding point of one design is inside the patch while the other design contains feeding point outside the patch is T shaped. The computational analysis showed some interesting results for radiation pattern and far field domain. For these designs, the characteristic impedance taken is 50 Ω and the operating frequency domain is 1.4 to 1.7 GHz. The microstrip patch antennas are encapsulated in the inert spherical atmosphere of 20 mm thickness containing air inside it. 展开更多
关键词 MICROSTRIP PATCH Antenna finite element method T SHAPED FEEDinG Point FAR Field domain
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Finite Element Method for Transient Electric Field by Using Indirect Laplace Transform with High Accuracy
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作者 Teng Wen Xiang Cui +2 位作者 Xuebao Li Sijia Liu Zhibin Zhao 《CSEE Journal of Power and Energy Systems》 SCIE EI CSCD 2024年第1期401-411,共11页
This paper focuses on the finite element method in the complex frequency domain(CFD-FEM)for the transient electric field.First,the initial value and boundary value problem of the transient electric field under the ele... This paper focuses on the finite element method in the complex frequency domain(CFD-FEM)for the transient electric field.First,the initial value and boundary value problem of the transient electric field under the electroquasistatic field in the complex frequency domain is given.In addition,the finite element equation and the constrained electric field equation on the boundary are derived.Secondly,the indirect algorithm of the numerical inverse Laplace transform is introduced.Based on it,the calculation procedures of the CFD-FEM are illustrated in detail.Thirdly,the step response,zero-state response under the positive periodic square waveform(PPSW)voltage,and the zero-input response by the CFD-FEM with direct algorithm and indirect algorithm are compared.Finally,the reason for the numerical oscillations of the zero-state response under the PPSW voltage is analyzed,and the method to reduce oscillations is proposed.The results show that the numerical accuracy of the indirect algorithm of the CFD-FEM is more than an order of magnitude higher than that of the direct algorithm when calculating the step response of the transient electric field.The proposed method can significantly reduce the numerical oscillations of the zero-state response under the PPSW voltage.The proposed method is helpful for the calculation of the transient electric field,especially in the case of frequency-dependent parameters. 展开更多
关键词 Electroquasistatic field transient electric field finite element method complex frequency domain numerical Laplace transform
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Finite Element Modeling of Unbounded Grounding System Considering Soil Ionization Characteristic 被引量:1
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作者 CHEN Lin LI Jingli +2 位作者 YANG Qing SIMA Wenxia SUN Caixin 《高电压技术》 EI CAS CSCD 北大核心 2012年第8期2104-2111,共8页
关键词 局部放电 射频信号 放电量 高电压技术
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