检索结果-南通市图书馆

The Numerical Accuracy Analysis of Asymptotic Homogenization Method and Multiscale Finite Element Method for Periodic Composite Materials

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Computer Modeling in Engineering & Sciences 2016年第5期111卷 395-419页

作者： Hao Dong Yufeng Nie zihao yang yang Zhang YataoWu Department of Applied Mathematics School of ScienceNorthwestern Polytechnical UniversityXi’an 710129PR China Research Center for Computational Science Northwestern Polytechnical UniversityXi’an 710129PR China

In this paper,we discuss the numerical accuracy of asymptotic homogenization method(AHM)and multiscale finite element method(MsFEM)for periodic composite *** numerical calculation of the model problems for four kinds of typical periodic composite materials,the main factors to determine the accuracy of first-order AHM and second-order AHM are found,and the physical interpretation of these factors is ***,the way to recover multiscale solutions of first-order AHM and MsFEM is theoretically analyzed,and it is found that first-order AHM and MsFEM provide similar multiscale solutions under some ***,numerical experiments verify that MsFEM is essentially a first-order multiscale method for periodic composite materials.

关键词： Asymptotic homogenization method Multiscale finite element method First-order AHM Slight fluctuations Second-order AHM Severe fluctuations

Multiscale analysis-based peridynamic simulation of fracture in porous media

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Structural and Civil Engineering 2024年第1期18卷 1-13页

作者： zihao yang Shangkun SHEN Xiaofei GUAN Xindang HE Junzhi CUI School of Mathematics and Statistics Northwestern Polytechnical UniversityXi’an 710072China School of Mathematical Sciences Tongji UniversityShanghai 200092China School of Mechanics Civil Engineering and ArchitectureNorthwestern Polytechnical UniversityXi’an 710072China LSEC ICMSECAcademy of Mathematics and Systems ScienceCASBeijing 100190China

The simulation of fracture in large-scale structures made of porous media remains a challenging *** techniques either assume a homogeneous model,disregarding the microstructure characteristics,or adopt a micro-mechanical model,which incurs an intractable computational cost due to its complex stochastic geometry and physical properties,as well as its nonlinear and multiscale *** this study,we propose a multiscale analysis-based dual-variable-horizon peridynamics(PD)model to efficiently simulate macroscopic structural *** influence of microstructures in porous media on macroscopic structural failure is represented by two PD parameters:the equivalent critical stretch and *** equivalent critical stretch is calculated using the microscale PD model,while the equivalent micro-modulus is obtained through the homogenization method and energy density equivalence between classical continuum mechanics and PD *** examples of porous media with various microstructures demonstrate the validity,accuracy,and efficiency of the proposed method.

关键词： porous media multiscale variable-horizon peridynamic equivalent critical stretch equivalent micro-modulus

Multi-Modes Multiscale Approach of Heat Transfer Problems in Heterogeneous Solids with Uncertain Thermal Conductivity

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Advances in Applied Mathematics and Mechanics 2023年第1期15卷 69-93页

作者： Shan Zhang zihao yang Xiaofei Guan College of Mathematics and Physics Shanghai University of Electric PowerShanghai 200090China School of Mathematics and Statistics Northwestern Polytechnical UniversityXi’anShanxi 710072China School of Mathematical Sciences Tongji UniversityShanghai 200092China

Stochastic temperature distribution should be carefully inspected in the thermal-failure design of heterogeneous solids with unexpected random energy *** multiscale modeling for these problems involve multiscale and highdimensional uncertain thermal parameters,which remains limitation of prohibitive *** this paper,we propose a multi-modes based constrained energy minimization generalized multiscale finite element method(MCEM-GMsFEM),which can transform the original stochastic multiscale model into a series of recursive multiscale models sharing the same deterministic material parameters by multiscale ***,MCEM-GMsFEM reveals an inherent low-dimensional representation in random space,and is designed to effectively reduce the complexity of repeated computation of discretized multiscale *** addition,the convergence analysis is established,and the optimal error estimates are ***,several typical random fluctuations on multiscale thermal conductivity are considered to validate the theoretical results in the numerical *** numerical results indicate that the multi-modes multiscale approach is a robust integrated method with the excellent performance.

关键词： Stochastic multiscale heat transfer problems uncertainty quantification MCEMGMsFEM multimodes expansion

Dynamic thermo-mechanical coupled simulation of statistically inhomogeneous materials by statistical second-order two-scale method

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Mechanica Sinica 2015年第5期31卷 762-776页

作者： zihao yang Junzhi Cui Yufeng Nie Zhiqiang Huang Meizhen Xiang Department of Applied Mathematics Northwestern Polytechnical University LSEC ICMSECAcademy of Mathematics and Systems ScienceChinese Academy of Sciences Institution of Applied Physics and Computational Mathematics

In this paper,a statistical second-order twoscale（SSOTS） method is developed to simulate the dynamic thcrmo-mechanical performances of the statistically inhomogeneous *** this kind of composite material,the random distribution characteristics of particles,including the shape,size,orientation,spatial location,and volume fractions,are all ***,the *** for the microscopic configuration of the statistically inhomogeneous materials is ***,the SSOTS formulation for the dynamic thermo-mechanical coupled problem is proposed in a constructive way,including the cell problems,effective thermal and mechanical parameters,homogenized problems,and the SSOTS formulas of the temperatures,displacements,heat flux densities and *** then the algorithm procedure corresponding to the SSOTS method is brought *** numerical results obtained by using the SSOTS algorithm are compared with those by classical *** addition,the thermo-mechanical coupling effect is studied by comparing the results of coupled case with those of uncoupled *** demonstrates that the coupling effect on the temperatures,heat flux densities,displacements,and stresses is very *** results show that the SSOTS method is valid to predict the dynamic thermo-mechanical coupled performances of statistically inhomogeneous materials.

关键词： Statistically inhomogeneous materials Dynamic thermo-mechanical coupled performances The SSOTS method The thermo-mechanical coupling effect

Statistical Multiscale Analysis of Transient Conduction and Radiation Heat Transfer Problem in Random Inhomogeneous Porous Materials

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Computer Modeling in Engineering & Sciences 2018年第4期115卷 1-24页

作者： Yiqiang Li Liang Ma Zhiqiang yang Xiaofei Guan Yufeng Nie zihao yang Department of Applied Mathematics Northwestern Polytechnical UniversityXi’an 710072China State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi’an 710072China School of Astronautics Harbin Institute of TechnologyHarbin 150001China School of Mathematics Sciences Tongji UniversityShanghai 200092China

This paper is devoted to the homogenization and statistical multiscale analysis of a transient heat conduction problem in random porous materials with a nonlinear radiation boundary condition.A novel statistical multiscale analysis method based on the two-scale asymptotic expansion is *** the statistical multiscale formulations,a unified linear homogenization procedure is established and the second-order correctors are introduced for modeling the nonlinear radiative heat transfer in random perforations,which are our main ***,a numerical algorithm based on the statistical multiscale method is given in *** results prove the accuracy and efficiency of our method for multiscale simulation of transient nonlinear conduction and radiation heat transfer problem in random porous materials.

关键词： Statistical multiscale analysis method transient heat conduction problem nonlinear radiation boundary condition random porous materials

Mapping the magnetic field in the solar corona through magnetoseismology

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2020年第11期63卷 2357-2368页

作者： yang zihao TIAN Hui TOMCZYK Steven MORTON Richard BAI XianYong SAMANTA Tanmoy CHEN YaJie School of Earth and Space Sciences Peking UniversityBeijing 100871China Key Laboratory of Solar Activity National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100012China High Altitude Observatory National Center for Atmospheric ResearchBoulderCO 80307USA Department of Mathematics Physics and Electrical EngineeringNorthumbria UniversityNewcastle Upon Tyne NE18STUK Department of Physics and Astronomy George Mason UniversityFairfaxVA 22030USA Johns Hopkins University Applied Physics Laboratory LaurelMD 20723USA Max Planck Institute for Solar System Research 37077 G¨ottingenGermany

Magnetoseismology,a technique of magnetic field diagnostics based on observations of magnetohydrodynamic(MHD)waves,has been widely used to estimate the field strengths of oscillating structures in the solar ***,previously magnetoseismology was mostly applied to occasionally occurring oscillation events,providing an estimate of only the average field strength or one-dimensional distribution of field strength along an oscillating *** restriction could be eliminated if we apply magnetoseismology to the pervasive propagating transverse MHD waves discovered with the Coronal Multi-channel Polarimeter(CoMP).Using several CoMP observations of the Fe xiii 1074.7 nm and 1079.8 nm spectral lines,we obtained maps of the plasma density and wave phase speed in the corona,which allow us to map both the strength and direction of the coronal magnetic field in the plane of *** also examined distributions of the electron density and magnetic field strength,and compared their variations with height in the quiet Sun and active *** measurements could provide critical information to advance our understanding of the Sun's magnetism and the magnetic coupling of the whole solar atmosphere.

关键词： solar corona solar magnetic field waves magnetoseismology

An Improved Peridynamic Model with Energy-Based Micromodulus Correction Method for Fracture in Particle Reinforced Composites

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Communications in Computational Physics 2022年第7期32卷 424-449页

作者： zihao yang Shaoqi Zheng Fei Han Shangkun Shen Xiaofei Guan School of Mathematics and Statistics Northwestern Polytechnical UniversityXi’an 710072China Department of Engineering Mechanics Dalian University of TechnologyDalian 116023China School of Mathematical Sciences Tongji UniversityShanghai 200092China

We introduce an improved bond-based peridynamic(BPD)model for simulating brittle fracture in particle reinforced composites based on a micromodulus correction *** the peridynamic(PD)constitutive model of particle reinforced composites,three kinds of interactive bond forces are considered,and precise definition of mechanical properties for PD bonds is essential for the fracture analysis in particle reinforced composites.A new micromodulus model of PD bonds for particle reinforced composites is proposed based on the equivalence between the elastic strain energy density of classical continuum mechanics and peridynamic model and the harmonic average *** damage of particle reinforced composites is defined locally at the level of pairwise bond,and the critical stretch criterion is described as a function of fracture energy based on the composite failure *** algorithm procedure for the improved BPD model based on the finite element/discontinuous Galerkin finite element method is brought forward in *** numerical examples are performed to test the feasibility and effectiveness of the proposed model and algorithm in analysis of elastic deformation,crack nucleation and propagation in particle reinforced ***,the impact of distribution,shape and size of particles on the fractures of composite materials are also *** results demonstrate that the improved BPD model can effectively be used to analyze the fracture in particle reinforced composites.

关键词： Particle reinforced composite peridynamics bonds micromodulus correction fracture crack growth path

Learning Invariant Representation of Multiscale Hyperelastic Constitutive Law from Sparse Experimental Data

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Communications in Computational Physics 2023年第7期34卷 392-417页

作者： Rui He Junzhi Cui zihao yang Jieqiong Zhang Xiaofei Guan School of Mathematics and Statistics Northwestern Polytechnical UniversityXi’an 710072China LSEC ICMSECAcademy of Mathematics and Systems ScienceCASBeijing 100190China Innovation Center NPU Chongqing Northwestern Polytechnical UniversityChongqing 400000China School of Mathematics Northwest UniversityXi’an 710127China School of Mathematical Sciences Tongji UniversityShanghai 200092China

Constitutive modeling of heterogeneous hyperelastic materials is still a challenge due to their complex and variable *** propose a multiscale datadriven approach with a hierarchical learning strategy for the discovery of a generic physics-constrained anisotropic constitutive model for the heterogeneous hyperelastic *** on the sparse multiscale experimental data,the constitutive artificial neural networks for hyperelastic component phases containing composite interfaces are established by the particle swarm optimization algorithm.A microscopic finite element coupled constitutive artificial neural networks solver is introduced to obtain the homogenized stress-stretch relation of heterogeneous materials with different *** a dense stress-stretch relation dataset is generated by training a neural network through the FE ***,a generic invariant representation of strain energy function(SEF)is proposed with a parameter set being implicitly expressed by artificial neural networks(SANN),which describes the hyperelastic properties of heterogeneous materials with different microstructures.A convexity constraint is imposed on the SEF to ensure that the multiscale constitutive model is physically relevant,and the ℓ_(1) regularization combined with thresholding is introduced to the loss function of SANN to improve the interpretability of this ***,the multiscale model is hierarchically trained,cross-validated and tested using the experimental data of cord-rubber composite materials with different *** proposed multiscale model provides a convenient and general methodology for constitutive modeling of heterogeneous hyperelastic materials.

关键词： Heterogeneous hyperelastic materials data-driven approach multiscale generic constitutive model physics-constrained

A Normalizing Field Flow Induced Two-Stage Stochastic Homogenization Method for Random Composite Materials

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Communications in Computational Physics 2023年第8期34卷 787-812页

作者： zihao yang Xintong Wang Xiaofei Guan Jizu Huang Xixin Wu School of Mathematics and Statistics Northwestern Polytechnical UniversityXi’an 710072China Institute of Mathematics Henan Academy of SciencesZhengzhou 450046China MOE Key Laboratory for Complexity Science in Aerospace Northwestern Polytechnical UniversityXi’an 710072China School of Mathematical Sciences Tongji UniversityShanghai 200092China LSEC Academy of Mathematics and Systems ScienceChinese Academy of SciencesBeijing 100190China School of Mathematical Sciences University of Chinese Academy of SciencesBeijing 100049China

The traditional stochastic homogenization method can obtain homogenized solutions of elliptic problems with stationary random ***,many random composite materials in scientific and engineering computing do not satisfy the stationary *** overcome the difficulty,we propose a normalizing field flow induced two-stage stochastic homogenization method to efficiently solve the random elliptic problem with non-stationary *** applying the two-stage stochastic homogenization method,the original elliptic equation with random and fast oscillatory coefficients is approximated as an equivalent elliptic equation,where the equivalent coefficients are obtained by solving a set of cell *** the stationary assumption,the number of cell problems is large and the corresponding computational cost is *** improve the efficiency,we apply the normalizing field flow model to learn a reference Gaussian field for the random equivalent coefficients based on a small amount of data,which is obtained by solving the cell problems with the finite element *** results demonstrate that the newly proposed method is efficient and accurate in tackling high dimensional partial differential equations in composite materials with complex random microstructures.

关键词： Two-stage stochastic homogenization normalizing field flows multi-modes Monte Carlo method random composite materials non-stationary random