S. Brischetto¹

CMES-Computer Modeling in Engineering & Sciences, Vol.95, No.5, pp. 391-430, 2013, DOI:10.3970/cmes.2013.095.391

Abstract This paper gives an exact three-dimensional elastic model for the free vibration analysis of functionally graded one-layered and sandwich simply-supported plates and shells. An exact elasticity solution is proposed for the differential equations of equilibrium written in general orthogonal curvilinear coordinates. The equations consider a geometry for shells without simplifications, and allow the analysis of the cases of spherical shell panels, cylindrical shell panels, cylindrical closed shells and plates. The main novelty is the possibility of a general formulation for these geometries. The coefficients in equilibrium equations depend on the thickness coordinate because of the radii of curvature for the… More >

Seyed Mahmoud Hosseini ¹

CMES-Computer Modeling in Engineering & Sciences, Vol.95, No.1, pp. 1-29, 2013, DOI:10.3970/cmes.2013.095.001

Abstract In this article, the effects of carbon nanotubes distributions on natural frequency are studied for a functionally graded nanocomposite thick hollow cylinder reinforced by single-walled carbon nanotubes using a hybrid mesh-free method. The FG nanocomposite cylinder is excited by a shock loading, which is applied on the inner surface of cylinder. The first natural frequency is obtained for various nonlinear grading patterns of distributions of the aligned carbon nanotubes. The effects of various nonlinear grading patterns on natural frequency are obtained and discussed in details. The presented hybrid mesh-free method is based on the generalized finite difference (GFD) method for… More >

A.V. Ekhlakov^1,2, O.M. Khay^1,3, Ch. Zhang¹, X.W. Gao⁴, J. Sladek⁵, V. Sladek⁵

CMES-Computer Modeling in Engineering & Sciences, Vol.92, No.6, pp. 595-614, 2013, DOI:10.3970/cmes.2013.092.595

Abstract A boundary-domain integral equation method is applied to the transient thermoelastic crack analysis in functionally graded materials. Fundamental solutions for homogeneous, isotropic and linear elastic materials are used to derive the boundary-domain integral equations. The radial integration method, the Cartesian transformation method and the cell-integration method are applied for the evaluation of the arising domain-integrals. Numerical results for dynamic stress intensity factors obtained by the three approaches are presented, compared and discussed to show the accuracy and the efficiency of the domain-integral evaluation techniques. 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 being similar to the equivalent… More >

J. Sladek¹, P. Stanak¹, Z-D. Han², V. Sladek¹, S.N. Atluri²

CMES-Computer Modeling in Engineering & Sciences, Vol.92, No.5, pp. 423-475, 2013, DOI:10.3970/cmes.2013.092.423

Abstract A review is presented for analysis of problems in engineering & the sciences, with the use of the meshless local Petrov-Galerkin (MLPG) method. The success of the meshless methods lie in the local nature, as well as higher order continuity, of the trial function approximations, high adaptivity and a low cost to prepare input data for numerical analyses, since the creation of a finite element mesh is not required. There is a broad variety of meshless methods available today; however the focus is placed on the MLPG method, in this paper. The MLPG method is a fundamental base for the… More >

Yaochan Zhu¹, Eckart Schnack¹, Al Mahmudur Rahman¹

CMES-Computer Modeling in Engineering & Sciences, Vol.92, No.3, pp. 315-326, 2013, DOI:10.32604/cmes.2013.092.315

Abstract A novel multiphase field model is formulated to simulate the complex microstructure evolution during chemical vapor infiltration (CVI) process, which is widely used technique to produce SiC matrix composites reinforced by SiC fibers in ceramic engineer. The model consists of a set of nonlinear partial differential equations by coupling Ginzburg-Landau type phase field equations with mass/heat balance equations as well as modified Navier-Stokes equations. The microstructure evolution of preferential codeposition of Si, SiC and C under high ratio of H2 to MTS is simulated. The simulation is in good agreement with experiments result. The potential risk of blockage of the… More >

J. A. Nairn¹

CMES-Computer Modeling in Engineering & Sciences, Vol.92, No.3, pp. 271-299, 2013, DOI:10.32604/cmes.2013.092.271

Abstract The “multimaterial” version of the material point method (MPM) extrapolates each material to its own velocity field on a background grid. By reconciling momenta on nodes interacting with two or more materials, MPM is able to automatically handle contact without any need for special contact elements. This paper extends multimaterial MPM to automatically handle imperfect interfaces between materials as well. The approach is to evaluate displacement discontinuity on multimaterial nodes and then add internal forces and interfacial energy determined by an imperfect interface traction law. The concept is simple, but implementation required numerous corrections to make the analysis mesh independent,… More >

Xiaoxia Yang¹, Shili Chen¹, Fang Sun¹, Shijiu Jin¹, Wenshuang Chang¹

CMES-Computer Modeling in Engineering & Sciences, Vol.90, No.6, pp. 487-500, 2013, DOI:10.3970/cmes.2013.090.487

Abstract Ultrasonic phased array inspection technology is widely used in nondestructive evaluation (NDE) applications and it has been proved to be an effective method for flaw detections in industry. In our study, this nondestructive evaluation method is proposed to detect the corrosion defects on engine cylinders. In order to demonstrate its feasibility, it is necessary to study the characteristics of the acoustic field produced by a linear phased array ultrasonic transducer in the engine cylinders. In this paper, according to multi-Gaussian beam model and ray acoustics theory, we derive the expression of the acoustic field from a linear phased array ultrasonic… More >

D.-A. An-Vo¹, C.-D. Tran¹, N. Mai-Duy¹, T. Tran-Cong¹

CMES-Computer Modeling in Engineering & Sciences, Vol.89, No.4, pp. 303-359, 2012, DOI:10.3970/cmes.2012.089.303

Abstract Many important engineering problems have multiple-scale solutions. Thermal conductivity of composite materials, flow in porous media, and turbulent transport in high Reynolds number flows are examples of this type. Direct numerical simulations for these problems typically require extremely large amounts of CPU time and computer memory, which may be too expensive or impossible on the present supercomputers. In this paper, we develop a high order computational method, based on multiscale basis function approach and integrated radialbasis- function (IRBF) approximant, for the solution of multiscale elliptic problems with reduced computational cost. Unlike other methods based on multiscale basis function approach, sets… More >

Yongsheng An¹, Xiaodong Wu¹, Deli Gao¹

CMES-Computer Modeling in Engineering & Sciences, Vol.89, No.2, pp. 123-142, 2012, DOI:10.3970/cmes.2012.089.123

Abstract The accuracy of numerical simulation of a two-phase (oil and water) flow in a fractured horizontal well depends greatly upon the types of grids used in the computation. Cartesian grids have been widely used in recent years, but they have some disadvantages in describing complex structural wells, such as fractured horizontal wells. For example, Cartesian grids are not efficient in describing the main wellbores and the fractures of fractured horizontal wells, and the results can frequently suffer from grid orientation effects, even though a grid-refinement is often introduced to enhance the adaptability of a Cartesian grid. The PEBI (Perpendicular Bisector)… More >