Hao Hu^1,2, Jian He^1,*, Lian Song¹, Zhifeng Zhan¹, Zhengliang Li³

CMES-Computer Modeling in Engineering & Sciences, Vol.119, No.3, pp. 499-539, 2019, DOI:10.32604/cmes.2019.06266

Abstract This paper investigates Q420 dual-angle cross combined section columns under axial and eccentric compression by conducting experiments. The specimen parameters, experimental setup, and test results are presented. It showed that local buckling occurred apparently for single internode specimens (λ<35) under axial compression, while overall bending buckling appeared for others, and no torsional buckling occurred. The theoretical formulas on stability factor were derived by the energy approach. Non-linear finite element models considering residual stress were established using ANSYS which were verified by the corresponding experimental results. The parametric study was to evaluate the effects of slenderness ratio (λ), width to thickness… More >

D. Brunner¹, M. Junge¹, P. Rapp¹, M. Bebendorf², L. Gaul¹

CMES-Computer Modeling in Engineering & Sciences, Vol.58, No.2, pp. 131-160, 2010, DOI:10.3970/cmes.2010.058.131

Abstract The simulation of the hydroacoustic sound radiation of ship-like structures has an ever-growing importance due to legal regulations. Using the boundary element method, the overall dimension of the problem is reduced and only integrals over surfaces have to be considered. Additionally, the Sommerfeld radiation condition is automatically satisfied by proper choice of the fundamental solution. However, the resulting matrices are fully populated and the set-up time and memory consumption scale quadratically with respect to the degrees of freedom. Different fast boundary element methods have been introduced for the Helmholtz equation, resulting in a quasilinear complexity. Two of these methods are… More >

N. Simões^1,2, A. Tadeu²

CMES-Computer Modeling in Engineering & Sciences, Vol.9, No.3, pp. 221-234, 2005, DOI:10.3970/cmes.2005.009.221

Abstract The use of the Boundary Element Method (BEM) to formulate the 3D transient heat transfer through cylindrical structures with irregular cross-sections, bounded by a homogeneous elastic medium, is described in this paper. In this formulation, both the conduction and the convection phenomena are modeled. This system can be subjected to heat emitted by either point or line sources located somewhere in the media. The solution is first obtained in the frequency domain for a wide range of frequencies and axial wavenumbers. Time domain responses are later calculated by means of (fast) inverse Fourier transforms into space-time. The appropriate fundamental solution… More >

Hiroshi Kadowaki¹, Wing Kam Liu²

CMES-Computer Modeling in Engineering & Sciences, Vol.7, No.3, pp. 269-282, 2005, DOI:10.3970/cmes.2005.007.269

Abstract A method to derive governing equations and elastic-plastic constitutive relations for the micropolar continuum model is proposed. Averaging procedures are operated over a surrounding sub-domain for each material point to bridge a discrete microstructure to a macro continuum model. Material parameters are determined by these procedures. The size of the sub-domain represents the material intrinsic length scale, and it is passed into the macroscopic governing equation so that the numerical solution can be regularized for analyses of failure phenomena. An application to a simple granular material model is presented. More >

D.L. Young^1,2, J.W. Ruan²

CMES-Computer Modeling in Engineering & Sciences, Vol.7, No.2, pp. 223-232, 2005, DOI:10.3970/cmes.2005.007.223

Abstract The applications of the method of fundamental solutions (MFS) for modeling the scattering of time-harmonic electromagnetic fields, which are governed by vector Helmholtz equations with coupled boundary conditions, are described. Various perfectly electric conductors are considered as the scatterers to investigate the accuracy of the numerical performance of the proposed procedure by comparing with the available analytical solutions. It is also the intention of this study to reveal the characteristics of the algorithms by comparisons with other numerical methods. The model is first validated to the exact solutions of the electromagnetic wave propagation problems for the scatterers of a circular… More >

S.Aoki¹, K.Amaya², M.Urago³, A.Nakayama⁴

CMES-Computer Modeling in Engineering & Sciences, Vol.6, No.2, pp. 123-132, 2004, DOI:10.3970/cmes.2004.006.123

Abstract The Fast Multipole Boundary Element Method(FMBEM) which is suitable for a large scale computation is applied to corrosion analysis. Many techniques of the FMBEM on the potential problems can be usefully employed. Additionally, some procedures are developed for corrosion analysis. To cope with the non-linearity due to the polarization curve, the Bi-CGSTAB iterative method which is commonly used in the FMBEM is modified. To solve infinite domain problems, the M₀⁰ which is obtained naturally in the multipole expansion is conveniently used. A pipe element for the FMBEM is developed. A couple of example problems are solved to show the… More >

Wan-Sul Lee, Kie-Chan Kwon, Bong-Kyu Kim, Ji-Hyon Cho, Sung-Kie Youn¹

CMES-Computer Modeling in Engineering & Sciences, Vol.5, No.3, pp. 279-286, 2004, DOI:10.3970/cmes.2004.005.279

Abstract A numerical approach for eigenvalue analysis of the electrostatically tunable micro-mechanical actuators is presented. An efficient algorithm for calculating the natural frequency shifting in the micro-mechanical actuators due to applied DC turning voltage is proposed. In the calculations of the coupled field problem, the three-dimensional FEM/BEM approaches and iterative staggered algorithm are employed. The numerical examples for actually fabricated actuators are presented and the numerical analysis results are compared with experimental data. More >

P. Raghavan¹, S. Ghosh²

CMES-Computer Modeling in Engineering & Sciences, Vol.5, No.2, pp. 151-170, 2004, DOI:10.3970/cmes.2004.005.151

Abstract This paper presents an adaptive multi-level computational model that combines a conventional displacement based finite element model with a microstructural Voronoi cell finite element model for multi-scale analysis of composite structures with non-uniform microstructural heterogeneities as obtained from optical or scanning electron micrographs. Three levels of hierarchy, with different resolutions, are introduced in this model to overcome shortcomings posed by modeling and discretization errors. Among the three levels are: (a) level-0 of pure macroscopic analysis; (b) level-1 of macro-micro coupled modeling, used for signaling the switch over from macroscopic analyses to pure microscopic analyses; and (c) level-2 regions of pure… More >

Youping Chen¹, James D Lee², Azim Esk,arian¹

CMES-Computer Modeling in Engineering & Sciences, Vol.5, No.1, pp. 35-44, 2004, DOI:10.3970/cmes.2004.005.035

Abstract This paper addresses the need of theories and simulations for material body of mesoscopic and microscopic sizes. An overview of polar theories is presented. The micropolar theory proposed by Eringen is introduced and compared with other polar theories. Constitutive equations of micropolar thermo-visco-elastic solid are derived. Finite element analyses have been performed for a few sample problems with wide range of length scales. Based on the discussion, comparison and computer simulations, the unique feature and applicability of micropolar theory are demonstrated. More >

Yong Xie¹, Zui Tao^2,*, Wen Shao³, John J. Qu⁴, Hai Huan³, Chuanyang Tian³

Journal on Internet of Things, Vol.1, No.1, pp. 9-16, 2019, DOI:10.32604/jiot.2019.05859

Abstract Radiation cross-calibration is an effective method to check and verify the accuracy and stability of sensor measurements. Satellites with high radiation accuracy are used to calibrate satellites with low radiation accuracy. In order to ensure the reliability of the radiation cross-calibration method, we propose to obtain the gain and offset of the GaoFen-1 satellite by linear regression after the radiation cross-calibration of the satellite with low precision and compare with the official coefficient. Finally, we get the relationship between the error in radiation cross-calibration results and side swing angle. The linear correction coefficients of each band are: 0.618, 0.625, 0.512… More >