Qianxin Wang^1,2,3, Chao Hu^1,2,*, Ya Mao^1,2

CMES-Computer Modeling in Engineering & Sciences, Vol.117, No.3, pp. 509-525, 2018, DOI:10.31614/cmes.2018.04098

Abstract Designing the optimal distribution of Global Navigation Satellite System (GNSS) ground stations is crucial for determining the satellite orbit, satellite clock and Earth Rotation Parameters (ERP) at a desired precision using a limited number of stations. In this work, a new criterion for the optimal GNSS station distribution for orbit and ERP determination is proposed, named the minimum Orbit and ERP Dilution of Precision Factor (OEDOP) criterion. To quickly identify the specific station locations for the optimal station distribution on a map, a method for the rapid determination of the selected station locations is developed,… More >

Yang Yang^{1, *}

CMES-Computer Modeling in Engineering & Sciences, Vol.116, No.3, pp. 365-389, 2018, DOI:10.31614/cmes.2018.03847

Abstract The selection of machining parameters directly affects the production time, quality, cost, and other process performance measures for multi-pass milling. Optimization of machining parameters is of great significance. However, it is a nonlinear constrained optimization problem, which is very difficult to obtain satisfactory solutions by traditional optimization methods. A new optimization technique combined chaotic operator and imperialist competitive algorithm (ICA) is proposed to solve this problem. The ICA simulates the competition between the empires. It is a population-based meta-heuristic algorithm for unconstrained optimization problems. Imperialist development operator based on chaotic sequence is introduced to improve… More >

Jin Li^1,2, De-hao Yu^3,4

CMES-Computer Modeling in Engineering & Sciences, Vol.102, No.2, pp. 103-126, 2014, DOI:10.3970/cmes.2014.102.103

Abstract The generalized composite middle rectangle rule for the computation of Hilbert integral is discussed. The pointwise superconvergence phenomenon is presented, i.e., when the singular point coincides with some a priori known point, the convergence rate of the rectangle rule is higher than what is global possible. We proved that the superconvergence rate of the composite middle rectangle rule occurs at certain local coordinate of each subinterval and the corresponding superconvergence error estimate is obtained. By choosing the superconvergence point as the collocation points, a collocation scheme for solving the relevant Hilbert integral equation is presented More >

De-Shin Liu¹, Chin-Yi Tu¹, Cho-Liang Chung²

CMES-Computer Modeling in Engineering & Sciences, Vol.92, No.6, pp. 573-594, 2013, DOI:10.3970/cmes.2013.092.573

Abstract The Infinite Element Method (IEM) is widely used for the analysis of elastostatic structures containing singularities. In the IEM method, the problem domain is partitioned into multiple element layers, where the stiffness matrix of each layer is similar to that of the other layers in the discretized domain. However, in Mindlin-Reissner plate theory, the stiffness matrix varies through the layers of the plate, and thus the conventional IEM algorithm cannot be applied. Accordingly, the present study proposes a Plate Infinite Element Method (PIEM) in which the element stiffness matrix is separated into two sub-matrices; each… More >

Changsheng Wang¹, Ping Hu^1,2

CMES-Computer Modeling in Engineering & Sciences, Vol.88, No.5, pp. 325-350, 2012, DOI:10.3970/cmes.2012.088.325

Abstract Based on the Reissner-Mindlin plate theory, two 3-node triangular flat shell elements QCS31 and QCS32 are proposed by using Timoshenko's beam function within the framework of quasi-conforming technique. The exact displacement function of the Timoshenko's beam is used as the displacement on the element boundary in the bending part and the interpolated inner field function is also derived by the function. In the shear part the re-constitution technique is adopted. The drilling degrees of freedom are added in the membrane part to improve membrane behavior. The proposed elements can be used for the analysis of More >

Qiang Li, Jie Ouyang¹, Xuejuan Li², Guorong Wu², Binxin Yang²

CMES-Computer Modeling in Engineering & Sciences, Vol.74, No.3&4, pp. 247-268, 2011, DOI:10.3970/cmes.2011.074.247

Abstract A unified mathematical model is proposed to predict the short shot, primary and secondary gas penetration phenomenon in gas-assisted injection molding (GAIM) process, where the Cross-WLF model and two-domain modified Tait equation are employed to simulate the melt viscosity and density in the whole process, respectively. The governing equations of two-phase flows including gas, air and polymer melt are solved using finite volume method with SIMPLEC technology. At first, two kinds of U-shaped gas channels are modeled, where the shape corner and generous corner cases are studied. At last, as a case study, the short More >

E.Y.K. Ng¹, S.T. Poh ²

CMES-Computer Modeling in Engineering & Sciences, Vol.3, No.3, pp. 351-366, 2002, DOI:10.3970/cmes.2002.003.351

Abstract Advances in microfabrication technology have allowed the use of microchannels in ultra compact, very efficient heat exchangers, which capitalize on the channels large surface area to volume ratio, to transport high heat fluxes with small thermal resistances. One example is the cooling of microchips. However, research into microscale flow and heat transfer phenomena conducted by various researchers provided substantial experimental data and considerable evidence that the behaviour of fluid flow and heat transfer in microchannels without phase change may be different than that which normally occurs in larger more conventional sized channels.
This paper describes… More >

J. Sladek¹, V. Sladek¹, P. Stanak¹, P.H. Wen², S.N. Atluri³

CMES-Computer Modeling in Engineering & Sciences, Vol.85, No.6, pp. 543-572, 2012, DOI:10.3970/cmes.2012.085.543

Abstract A meshless local Petrov-Galerkin (MLPG) method is applied to solve laminate piezoelectric plates described by the Reissner-Mindlin theory. The piezoelectric layer can be used as a sensor or actuator. A pure mechanical load or electric potential are prescribed on the top of the laminated plate. Both stationary and transient dynamic loads are analyzed here. The bending moment, the shear force and normal force expressions are obtained by integration through the laminated plate for the considered constitutive equations in each lamina. Then, the original three-dimensional (3-D) thick plate problem is reduced to a two-dimensional (2-D) problem. More >

Ping Hu¹, Yang Xia¹, Limin Tang²

CMES-Computer Modeling in Engineering & Sciences, Vol.73, No.2, pp. 103-136, 2011, DOI:10.3970/cmes.2011.073.103

Abstract In this paper, an assumed displacement quasi-conforming finite element method with truncated polynomial expansions of in-domain displacements and derived expansions of strains is introduced. Based on the method a four-node quadrilateral flat shell element with complete quadratic polynomials for membrane and bending displacement fields is developed. Numerical tests are carried out for validation of the present element. The results show that the present element preserves all the advantages of the quasi-conforming i.e., explicit stiffness matrix, convenient post processing and free from membrane locking and shear locking. The tests also prove that the present element gives More >

Jinling Long^1,2, Bingang Xu^1,3, Xiaoming Tao¹

CMES-Computer Modeling in Engineering & Sciences, Vol.72, No.4, pp. 273-298, 2011, DOI:10.3970/cmes.2011.072.273

Abstract Moving slender threadline structures are widely used in various engineering fields. The dynamics of these systems is sometimes time dependent but in most cases follows a periodic pattern, and slender yarn motion in textile engineering is a typical problem of this category. In the present paper, we propose a nonlinear approach to model the dynamic behavior of slender threadline structures with a real example in the analysis of slender yarn motion in spinning. Moving boundary conditions of yarn are derived and a consequence of the perturbation analysis for the dimensionless governing equations provides the zero More >