Vol.124, No.1, 2020-Table of Contents
  • Web of Science search for CMES: Specify the source (journal title) as “CMES*”. For example, to search for topic “deep learning” in CMES, use “ts=(deep learning) and so=(CMES*)”. More details are given in this page.

  • Study on a Dual Embedded Discrete Fracture Model for Fluid Flow in Fractured Porous Media
  • Abstract Simulation of fluid flow in the fractured porous media is very important and challenging. Researchers have developed some models for fractured porous media. With the development of related research in recent years, the prospect of embedded discrete fracture model (EDFM) is more and more bright. However, since the size of the fractures in the actual reservoir varies greatly, a very fine grid should be used which leads to a huge burden to the computing resources. To address this challenge, in the present paper, an upscaling based model is proposed. In this model, the flow in large-scale fractures is directly described… More
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  • Comparison of Thermal Performance for Two Types of ETFP System under Various Operation Schemes
  • Abstract The earth to fluid pipe (ETFP) system has been widely applied to various energy engineering. The numerical model of the heat transfer process in the ETFP system with a shallow-buried horizontal or a deep-buried vertical U-shape pipe adopted in practical engineering was established and the model distinctions were pointed out. The comparison of the thermal performance between the two types of ETFP system under various schemes was conducted on the basis of numerical prediction. The results showed that the thermal parameters of the ETFP system with a shallow-buried horizontal pipe were influenced by the inlet velocity and ground temperature obviously.… More
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  • Partition of Unity Finite Element Analysis of Nonlinear Transient Diffusion Problems Using p-Version Refinement
  • Abstract We propose a high-order enriched partition of unity finite element method for linear and nonlinear time-dependent diffusion problems. The solution of this class of problems often exhibits non-smooth features such as steep gradients and boundary layers which can be very challenging to recover using the conventional low-order finite element methods. A class of steady-state exponential functions has been widely used for enrichment and its performance to numerically solve these challenges has been demonstrated. However, these enrichment functions have been used only in context of the standard h-version refinement or the so-called q-version refinement. In this paper we demonstrate that the… More
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  • An Adaptive Substructure-Based Model Order Reduction Method for Nonlinear Seismic Analysis in OpenSees
  • Abstract Structural components may enter an initial-elastic state, a plastic-hardening state and a residual-elastic state during strong seismic excitations. In the residual-elastic state, structural components keep in an unloading/reloading stage that is dominated by a tangent stiffness, thus structural components remain residual deformations but behave in an elastic manner. It has a great potential to make model order reduction for such structural components using the tangent-stiffness-based vibration modes as a reduced order basis. In this paper, an adaptive substructure-based model order reduction method is developed to perform nonlinear seismic analysis for structures that have a priori unknown damage distribution. This method… More
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  • BDF Schemes in Stable Generalized Finite Element Methods for Parabolic Interface Problems with Moving Interfaces
  • Abstract There are several difficulties in generalized/extended finite element methods (GFEM/XFEM) for moving interface problems. First, the GFEM/XFEM may be unstable in a sense that condition numbers of system matrices could be much bigger than those of standard FEM. Second, they may not be robust in that the condition numbers increase rapidly as interface curves approach edges of meshes. Furthermore, time stepping schemes need carrying out carefully since both enrichment functions and enriched nodes in the GFEM/XFEM vary in time. This paper is devoted to proposing the stable and robust GFEM/XFEM with effi- cient time stepping schemes for the parabolic interface… More
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  • An Improved Non-Parametric Method for Multiple Moving Objects Detection in the Markov Random Field
  • Abstract Detecting moving objects in the stationary background is an important problem in visual surveillance systems. However, the traditional background subtraction method fails when the background is not completely stationary and involves certain dynamic changes. In this paper, according to the basic steps of the background subtraction method, a novel non-parametric moving object detection method is proposed based on an improved ant colony algorithm by using the Markov random field. Concretely, the contributions are as follows: 1) A new nonparametric strategy is utilized to model the background, based on an improved kernel density estimation; this approach uses an adaptive bandwidth, and… More
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  • A Rate-Dependent Peridynamic Model for the Dynamic Behavior of Ceramic Materials
  • Abstract In this study, a new bond-based peridynamic model is proposed to describe the dynamic properties of ceramics under impact loading. Ceramic materials show pseudo-plastic behavior under certain compressive loadings with high strain-rate, while the characteristic brittleness of the material dominates when it is subjected to tensile loading. In this model, brittle response under tension, softening plasticity under compression and strain-rate effect of ceramics are considered, which makes it possible to accurately capture the overall dynamic process of ceramics. This enables the investigation of the fracture mechanism for ceramic materials, during ballistic impact, in more detail. Furthermore, a bond-force updating algorithm… More
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  • IGA Based Bi-Layer Fiber Angle Optimization Method for Variable Stiffness Composites
  • Abstract This paper presents a topology optimization method for variable stiffness composite panels with varying fiber orientation and curvilinear fiber path. Non-uniform rational B-Splines (NURBS) based Isogeometric analysis (IGA) is utilized for the numerical computation of the general minimum compliance problem. The sensitivity analysis of the structure compliance function for the density and bi-layer orientation is conducted. The bi-layer fiber paths in the design domain are generated using streamline method and updated by divided pieces reselection method after the optimization process. Several common examples are tested to demonstrate the effectiveness of the method. The results show that the proposed method can… More
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  • Parametric Structural Optimization of 2D Complex Shape Based on Isogeometric Analysis
  • Abstract The geometric model and the analysis model can be unified together through the isogeometric analysis method, which has potential to achieve seamless integration of CAD and CAE. Parametric design is a mainstream and successful method in CAD field. This method is not continued in simulation and optimization stage because of the model conversion in conventional optimization method based on the finite element analysis. So integration of the parametric modeling and the structural optimization by using isogeometric analysis is a natural and interesting issue. This paper proposed a method to realize a structural optimization of parametric complex shapes by using isogeometric… More
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  • Numerical Simulation of Multi-Layer Penetration Process of Binder Droplet in 3DP Technique
  • Abstract This paper studies the binder droplet injection process in the 3DP technique. The mathematical model of the binder penetration process for multi-nozzle and multi-layer in 3DP technique is established, by using the conservation Level set method. According to the two-dimensional plane model of three-dimensional spatial structure of sand bed, the construction method of an equivalent cylindrical mapping infiltration model is proposed to represent the porosity of the model in the two-dimensional plane, which is exactly the same as that in the three-dimensional space, as well as closer to the arrangement of the three-dimensional space, and to realize the differentiation between… More
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  • Investigation into Spatter Particles and Their Effect on the Formation Quality During Selective Laser Melting Processes
  • Abstract During the selective laser melting process, a high-energy laser beam acts on the powder, a molten pool is rapidly generated and the characteristic parameters are constantly changing. Among them, temperature is one of the important parameters in the forming process. Due to the generation of splash particles, there will be defects in the microstructure, which will seriously affect the formation quality of the prepared parts. Therefore, it is necessary to study the relationships between the splash behavior, molten pool characteristics and product quality. The finite element simulation of the transient temperature field was performed by ANSYS software. Time-series images at… More
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  • Constructive Texture Steganography Based on Compression Mapping of Secret Messages
  • Abstract This paper proposes a new constructive texture synthesis steganographic scheme by compressing original secret messages. First, we divide the original message into multiple bit blocks, which are transferred to decimal values and compressed into small decimal values by recording their interval sign characters. Then, a candidate pattern is generated by combining the given source pattern and boundary extension algorithm. Furthermore, we segment the candidate pattern into multiple candidate patches and use affine transformation algorithm to locate secret positions on a blank canvas, which are used to hide the sign characters by mapping the candidate patches. Finally, we select the candidate… More
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