Open Access

EDITORIAL

Jingfa Li¹, Liang Gong², Yongtu Liang³, Zhiguo Qu⁴, Bo Yu^1,*
CMES-Computer Modeling in Engineering & Sciences, Vol.124, No.1, pp. 1-4, 2020, DOI:10.32604/cmes.2020.011924
（This article belongs to this Special Issue: Advances in Modeling and Simulation of Complex Heat Transfer and Fluid Flow)
Abstract This article has no abstract. More >

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ARTICLE

Heng Zhang¹, Tingyu Li², Dongxu Han^{1, *}, Daobing Wang¹, Dongliang Sun¹, Bo Yu¹
CMES-Computer Modeling in Engineering & Sciences, Vol.124, No.1, pp. 5-21, 2020, DOI:10.32604/cmes.2020.09290
（This article belongs to this Special Issue: Advances in Modeling and Simulation of Complex Heat Transfer and Fluid Flow)
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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ARTICLE

Lingtong Li¹, Zaiguo Fu^{1, *}, Benxiang Li², Qunzhi Zhu¹
CMES-Computer Modeling in Engineering & Sciences, Vol.124, No.1, pp. 23-44, 2020, DOI:10.32604/cmes.2020.09299
（This article belongs to this Special Issue: Advances in Modeling and Simulation of Complex Heat Transfer and Fluid Flow)
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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ARTICLE

Shihao Fan, Mingliang Chang^*, Shouxi Wang, Qing Quan, Yong Wang, Dan Li
CMES-Computer Modeling in Engineering & Sciences, Vol.124, No.1, pp. 45-59, 2020, DOI:10.32604/cmes.2020.08973
（This article belongs to this Special Issue: Advances in Modeling and Simulation of Complex Heat Transfer and Fluid Flow)
Abstract It is important to determine the insulation thickness in the design of the buried hot oil pipelines. The economic thickness of the insulation layer not only meets the needs of the project but also maximizes the investment and environmental benefits. However, as a significant evaluation, the environmental factors haven’t been considered in the previous study. Considering this factor, the mathematical model of economic insulation thickness of the buried hot oil pipelines is built in this paper, which is solved by the golden section method while considering the costs of investment, operation, environment, the time value of money. The environmental cost… More >

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ARTICLE

Abdelkarim El Kahoui¹, Mustapha Malek¹, Nouh Izem¹, M. Shadi Mohamed², Mohammed Seaid^3,4,*
CMES-Computer Modeling in Engineering & Sciences, Vol.124, No.1, pp. 61-78, 2020, DOI:10.32604/cmes.2020.010874
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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ARTICLE

Jian Wang^{1, 2}, Ming Fang^{3, *}, Hui Li^{1, 2}
CMES-Computer Modeling in Engineering & Sciences, Vol.124, No.1, pp. 79-106, 2020, DOI:10.32604/cmes.2020.09470
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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ARTICLE

Pengfei Zhu¹, Qinghui Zhang^2,*
CMES-Computer Modeling in Engineering & Sciences, Vol.124, No.1, pp. 107-127, 2020, DOI:10.32604/cmes.2020.09831
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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ARTICLE

Qin Wan^1,2,*, Xiaolin Zhu¹, Yueping Xiao¹, Jine Yan¹, Guoquan Chen¹, Mingui Sun³
CMES-Computer Modeling in Engineering & Sciences, Vol.124, No.1, pp. 129-149, 2020, DOI:10.32604/cmes.2020.09397
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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ARTICLE

Bufan Chu^1,2, Qiwen Liu^1,2, Lisheng Liu^1,2,3,*, Xin Lai^1,2, Hai Mei^1,2
CMES-Computer Modeling in Engineering & Sciences, Vol.124, No.1, pp. 151-178, 2020, DOI:10.32604/cmes.2020.010115
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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2148

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ARTICLE

Chao Mei, Qifu Wang^*, Chen Yu, Zhaohui Xia
CMES-Computer Modeling in Engineering & Sciences, Vol.124, No.1, pp. 179-202, 2020, DOI:10.32604/cmes.2020.09948
（This article belongs to this Special Issue: Recent Developments of Isogeometric Analysis and its Applications in Structural Optimization)
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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2060

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ARTICLE

Long Chen¹, Li Xu¹, Kai Wang¹, Baotong Li^2,*, Jun Hong²
CMES-Computer Modeling in Engineering & Sciences, Vol.124, No.1, pp. 203-225, 2020, DOI:10.32604/cmes.2020.09896
（This article belongs to this Special Issue: Recent Developments of Isogeometric Analysis and its Applications in Structural Optimization)
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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1898

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ARTICLE

Xiangyu Gao, Weidong Yang^*, Hongxuan Xian, Xiyuan Tu, Yuanyuang Wang^*
CMES-Computer Modeling in Engineering & Sciences, Vol.124, No.1, pp. 227-241, 2020, DOI:10.32604/cmes.2020.09923
（This article belongs to this Special Issue: Design & simulation in Additive Manufacturing)
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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2217

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ARTICLE

Zhiqiang Wang¹, Xuede Wang¹, Xin Zhou^1,*, Guangzhao Ye², Xing Cheng^1,3, Peiyu Zhang¹
CMES-Computer Modeling in Engineering & Sciences, Vol.124, No.1, pp. 243-263, 2020, DOI:10.32604/cmes.2020.09934
（This article belongs to this Special Issue: Design & simulation in Additive Manufacturing)
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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ARTICLE

Dongsheng Du^1,*, Sheng Shi¹, Weizhi Xu¹, Chen Kong², Shuguang Wang¹, Weiwei Li¹
CMES-Computer Modeling in Engineering & Sciences, Vol.124, No.1, pp. 265-285, 2020, DOI:10.32604/cmes.2020.09151
（This article belongs to this Special Issue: Numerical Modeling and Simulation for Structural Safety and Disaster Mitigation)
Abstract The intensity non-stationarity is one of the most important features of earthquake records. Modeling of this feature is significant to the generation of arti- ficial earthquake waves. Based on the theory of phase difference spectrum, an intensity non-stationary envelope function with log-normal form is proposed. Through a tremendous amount of earthquake records downloaded on Kik-net, a parameter fitting procedure using the genetic algorithm is conducted to obtain the value of model parameters under different magnitudes, epicenter distances and site conditions. A numerical example is presented to describe the procedure of generating fully non-stationary ground motions via spectral representation, and the… More >

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2142

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ARTICLE

Qigang Sun¹, Jian Wu¹, Dahai Wang^2,*, Yue Xiang², Haitao Liu¹, Xiaobin Sun³
CMES-Computer Modeling in Engineering & Sciences, Vol.124, No.1, pp. 287-302, 2020, DOI:10.32604/cmes.2020.09118
（This article belongs to this Special Issue: Numerical Modeling and Simulation for Structural Safety and Disaster Mitigation)
Abstract Downburst event is identified as a major cause to failure of transmission lines in non-coastal regions. In this paper, a novel nonlinear analytical frame for quasi-static buffeting responses of hinged and multi-span insulator-line systems are derived based on the theory of cable structure. The closed-form solutions are presented and applied to predict nonlinear response including displacements and other reactions of the system subjected to a moving downburst wind in a case study. Accuracy and efficiency of the derived analytical frame are validated via comparisons with results from finite element method. More >

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Open Access

ARTICLE

Yan Li^1,2, Dayou Liu^1,2, Yungang Zhu^1,2, Jie Liu^1,2,*
CMES-Computer Modeling in Engineering & Sciences, Vol.124, No.1, pp. 303-313, 2020, DOI:10.32604/cmes.2020.09353
（This article belongs to this Special Issue: Data Science and Modeling in Biology, Health, and Medicine)
Abstract Under different conditions, gene regulatory networks (GRNs) of the same gene set could be similar but different. The differential analysis of GRNs under different conditions is important for understanding condition-specific gene regulatory relationships. In a naive approach, existing GRN inference algorithms can be used to separately estimate two GRNs under different conditions and identify the differences between them. However, in this way, the similarities between the pairwise GRNs are not taken into account. Several joint differential analysis algorithms have been proposed recently, which were proved to outperform the naive approach apparently. In this paper, we model the GRNs under different… More >

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2279

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ARTICLE

Xinshuai Shi¹, Hongwen Jing^{1, *}, Jianguo Ning², Zhenlong Zhao¹, Junfu Zhu¹
CMES-Computer Modeling in Engineering & Sciences, Vol.124, No.1, pp. 315-343, 2020, DOI:10.32604/cmes.2020.07955
（This article belongs to this Special Issue: Modeling and Simulation of Fluid flows in Fractured Porous Media: Current Trends and Prospects)
Abstract The stability control of gob-side entry retaining in fully mechanized caving face is a typical challenge in many coal mines in China. The rotation and subsidence of the lateral cantilever play a critical role in a coal mine, possibly leading to instability in a coal seam wall or a gob-side wall due to its excessive rotation subsidence. Hence, the presplitting blasting measures in the roof was implemented to cut down the lower main roof and convert it to caved immediate roof strata, which can significantly reduce the rotation space for the lateral cantilever and effectively control its rotation. Firstly, the… More >

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ARTICLE

Qian Yin^1,2, Xiaojing Li^3,*, Liyuan Yu¹, Ming He¹, Richeng Liu^1,2
CMES-Computer Modeling in Engineering & Sciences, Vol.124, No.1, pp. 345-373, 2020, DOI:10.32604/cmes.2020.08204
（This article belongs to this Special Issue: Modeling and Simulation of Fluid flows in Fractured Porous Media: Current Trends and Prospects)
Abstract An experimental and numerical study was carried out to investigate the solute removal process through a large-scale fracture plane considering different flow paths and hydraulic head differences. The visualization techniques were utilized in the experiment to capture the removal process images, which were then transferred to binary images. The variations in dimensionless concentration, which is defined as saturation of solute phase, were analyzed. With increasing hydraulic head difference, the speed of solute removal increases and the dimensionless concentration decreases. The flow paths result in different solute distribution patterns and different mechanisms for solute removal such as advection and diffusion, thus… More >

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ARTICLE

Hongtao Wang^1,2,*, Ping Liu^1,2, Lige Wang^3,4,*, Chi Liu⁵, Xin Zhang^1,2, Luyao Liu^1,2
CMES-Computer Modeling in Engineering & Sciences, Vol.124, No.1, pp. 375-391, 2020, DOI:10.32604/cmes.2020.08270
（This article belongs to this Special Issue: Modeling and Simulation of Fluid flows in Fractured Porous Media: Current Trends and Prospects)
Abstract Layered rock strata are observed to be common during the excavation of tunnels or cavities, and may significantly affect the deformation and failure characteristics of surrounding rock masses due to various complex forms and mechanical properties. In this paper, we propose a three-dimensional axisymmetric velocity field for roof collapse of shallow cavities in multi rock layers, by considering the influences of roof cross-section shapes, supporting pressure, ground overload, etc. The internal energy dissipation rate and work rates of external forces corresponding to the velocity field are computed by employing the Hoek-Brown strength criterion and its associated flow rule. Further, the… More >

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ARTICLE

Fengyong Li^{1, *}, Zongliang Yu¹, Chuan Qin²
CMES-Computer Modeling in Engineering & Sciences, Vol.124, No.1, pp. 393-410, 2020, DOI:10.32604/cmes.2020.09452
（This article belongs to this Special Issue: Information Hiding and Multimedia Security)
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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