Ali Shokri¹, Mehdi Dehghan¹

CMES-Computer Modeling in Engineering & Sciences, Vol.84, No.4, pp. 333-358, 2012, DOI:10.3970/cmes.2012.084.333

Abstract The Ginzburg-Landau equation has been used as a mathematical model for various pattern formation systems in mechanics, physics and chemistry. In this paper, we study the complex Ginzburg-Landau equation in two spatial dimensions with periodical boundary conditions. The method numerically approximates the solution by collocation method based on radial basis functions (RBFs). To improve the numerical results we use a predictor-corrector scheme. The results of numerical experiments are presented, and are compared with analytical solutions to confirm the accuracy and efficiency of the presented method. More >

P. L. Bishay¹, S.N. Atluri¹

CMES-Computer Modeling in Engineering & Sciences, Vol.84, No.1, pp. 41-98, 2012, DOI:10.3970/cmes.2012.084.041

Abstract Higher-order two-dimensional as well as low and higher-order three-dimensional new Hybrid/Mixed (H/M) finite elements based on independently assumed displacement, and judiciously chosen strain fields, denoted by HMFEM-2, are developed here for applications in macro-mechanics. The idea of these new H/M finite elements is based on collocating the components of the independent strain field, with those derived from the independently assumed displacement fields at judiciously and cleverly chosen collocation points inside the element. This is unlike the other techniques used in older H/M finite elements where a two-field variational principle was used in order to enforce… More >

L. Dong¹, S. N. Atluri²

CMES-Computer Modeling in Engineering & Sciences, Vol.83, No.2, pp. 183-220, 2012, DOI:10.32604/cmes.2012.083.183

Abstract In this paper, we develop T-Trefftz Voronoi Cell Finite Elements (VCF -EM-TTs) for micromechanical modeling of composite and porous materials. In addition to a homogenous matrix in each polygon-shaped element, three types of arbitrarily-shaped heterogeneities are considered in each element: an elastic inclusion, a rigid inclusion, or a void. In all of these three cases, an inter-element compatible displacement field is assumed along the element outer-boundary, and interior displacement fields in the matrix as well as in the inclusion are independently assumed as T-Trefftz trial functions. Characteristic lengths are used for each element to scale… More >

Jonathan N. Warner¹, Rafael N. Nunez¹, Chinedu O. Mmeje¹, Thomas V. Colby², Robert G. Ferrigni¹, Mitchell R. Humphreys¹, Paul E. Andrews¹, Erik P. Castle¹

Canadian Journal of Urology, Vol.18, No.6, pp. 6043-6049, 2011

Abstract Introduction: We evaluate the impact of margin length, location, and pathologic stage on biochemical recurrence (BCR) after robot assisted radical prostatectomy (RARP) at 37 months of follow up.
Materials and methods: A total of 1420 patients underwent a robot assisted radical prostatectomy between March 2004 and May 2010. Patients who received adjuvant therapy, those who never achieved an undetectable prostate-specific antigen (PSA), and those who had less than 18 months of follow up were excluded. Patients were then divided and evaluated based on margin status.
Results: In total, 419 patients were included in the analysis. Eighty-three had a… More >

S. Atobe¹, H. Fukunaga¹, N. Hu²

CMC-Computers, Materials & Continua, Vol.26, No.1, pp. 67-90, 2011, DOI:10.3970/cmc.2011.026.067

Abstract This paper presents a method for identifying the location and force history of an impact force acting on CFRP structures such as laminated plates and stiffened panels. The identification method is an experimental one without using any analytical model of the structure. Here, experimental transfer matrices, which relate the impact force to the corresponding responses of PZT sensors, are used to identify the impact force. The transfer matrices are preliminarily constructed from the measured data obtained by impact tests with an impulse hammer. To identify the impact location, the arrival times of the flexural waves More >

V.K. Tewary

The International Conference on Computational & Experimental Engineering and Sciences, Vol.19, No.4, pp. 113-114, 2011, DOI:10.3970/icces.2011.019.113

Abstract Interfacial region between two nanomaterials can be treated as a separate material since its atomistic structure and characteristics are different than the two materials on its either side. The mechanical as well as electronic properties of composite materials are sensitive to the interfaces. For industrial application of the nanomaterial systems, it is vital to model and measure the discrete atomistic locations in the interface during operating conditions. As the dimensions of nanomaterial systems shrink, the role of interfaces become increasingly important. Because of its nanothickness, the conventional characterization and design parameters like elastic constants, stress… More >

Wei-Ming Lee, Jyun-Sian He, Jhong-Sian Guo

The International Conference on Computational & Experimental Engineering and Sciences, Vol.18, No.3, pp. 65-66, 2011, DOI:10.3970/icces.2011.018.065

Abstract A semi-analytical approach is presented to solve two-dimensional interior and exterior acoustic problems with elliptical boundaries. The eigenproblems for the interior domain and the scattering problems for the exterior domain are both to be investigated. To satisfy the Helmholtz equation in elliptical coordinates, the multipole expansion for the acoustic pressure is formulated in terms of angular and radial Mathieu functions. The boundary conditions are satisfied by uniformly collocating points on the boundaries. The acoustic pressure at each boundary point is directly calculated in each local elliptical coordinate system. For the multiply connected domain problems, the… More >

H.F. Chan, C.M. Fan

The International Conference on Computational & Experimental Engineering and Sciences, Vol.19, No.1, pp. 29-30, 2011, DOI:10.3970/icces.2011.019.029

Abstract The inverse boundary optimization problem, which is governed by Helmholtz equation, is analyzed by the modified collocation Trefftz method (MCTM) and the exponentially convergent scalar homotopy algorithm (ECSHA). In the inverse boundary optimization problem, the position for part of boundary with given boundary condition is unknown, and the position for the rest of boundary with additionally specified boundary conditions is given. Therefore, it is very difficult to handle the boundary optimization problem by any numerical scheme. In order to stably solve the boundary optimization problem, the MCTM, one kind of boundary-type meshless methods, will be… More >

Yansheng He, Qingchuan Zhang, Shihua Fu, Qi Hu

The International Conference on Computational & Experimental Engineering and Sciences, Vol.18, No.1, pp. 5-6, 2011, DOI:10.3970/icces.2011.018.005

Abstract Abstract: The interaction of dislocation and solute atoms has great influence on the macroscopic mechanical behavior in alloys as well as the deformation of alloys. A dynamic Monte Carlo method is developed to simulate the interaction between dislocation and solute atom. The results show that dislocation motion is retarded by solute atoms in certain conditions. In the condition of constant external stress, the retarding effect of solute atoms becomes more inefficient with the increment of external stress. In the condition of constant stress rate, a step-like curve of the displacement-time indicates the intermittent motion of… More >

G. Kosec¹, B. Šarler^1,2

CMC-Computers, Materials & Continua, Vol.26, No.3, pp. 227-254, 2011, DOI:10.3970/cmc.2011.026.227

Abstract This paper introduces an effective H-adaptive upgrade to solution of the transport phenomena by the novel Local Radial Basis Function Collocation Method (LRBFCM). The transport variable is represented on overlapping 5-noded influence-domains through collocation by using multiquadrics Radial Basis Functions (RBF). The involved first and second derivatives of the variable are calculated from the respective derivatives of the RBFs. The transport equation is solved through explicit time stepping. The H-adaptive upgrade includes refinement/derefinement of one to four nodes to/from the vicinity of the reference node. The number of the nodes added or removed depends on… More >