T.B Jönsthövel¹, M.B. van Gijzen², C.Vuik², C. Kasbergen¹, A. Scarpas¹

CMES-Computer Modeling in Engineering & Sciences, Vol.47, No.2, pp. 97-118, 2009, DOI:10.3970/cmes.2009.047.097

Abstract The introduction of computed x-ray tomography allows for the construction of high quality, material-per-element based 3D meshes in the field of structural mechanics. The use of these meshes enables a shift from meso to micro scale analysis of composite materials like cement concrete, rocks and asphalt concrete. Unfortunately, because of the extremely long execution time, memory and storage space demands, the majority of commercially available finite element packages are not capable of handling efficiently the most computationally demanding operation of the finite element solution process, that is, the inversion of the structural stiffness matrix. To More >

J. Sladek¹, V. Sladek¹, P. Solek², C.L. Tan³, Ch. Zhang⁴

CMES-Computer Modeling in Engineering & Sciences, Vol.47, No.1, pp. 61-96, 2009, DOI:10.3970/cmes.2009.047.061

Abstract The meshless local Petrov-Galerkin (MLPG) method for transient linear thermoelastic analysis is presented. Orthotropic material properties are considered here. In uncoupled thermoelasticity, the temperature field is not influenced by displacements. Therefore, in the first step, the heat conduction equation is solved for the temperature distribution in the domain. The equations of motion are then solved with the inertial term considered. A Heaviside step function as the test functions is applied in the weak-form to derive local integral equations for solving two- and three-dimensional problems. Local integral equations are written on small sub-domains with circular or More >

J. Noorzaei¹, K.H. Bayagoob², A.A. Abdulrazeg¹, M.S. Jaafar^1,1, T.A. Mohammed¹

CMES-Computer Modeling in Engineering & Sciences, Vol.47, No.1, pp. 43-60, 2009, DOI:10.3970/cmes.2009.047.043

Abstract This paper focuses on the development, verification and application of a three-dimensional finite element code for coupled thermal and structural analysis of roller compacted concrete dams. The Kinta RCC gravity dam, which is the first roller compacted concrete dam in Malaysia, has been taken for the purpose of verification of the finite element code. The actual climatic conditions and thermal properties of the materials were considered in the analysis. The structural stress analysis was performed using the elasto-plastic stress analysis. The Mohr yield criterion which is widely used for concrete plasticity modeling was adopted in More >

A. Djeukou¹, O. von Estorff²

CMES-Computer Modeling in Engineering & Sciences, Vol.47, No.1, pp. 23-42, 2009, DOI:10.3970/cmes.2009.047.023

Abstract The paper deals with the response of rectangular composite plates to low-velocity impact. A third-order shear deformation theory as well as the Newmark integration are used to determine the contact force history analytically. The interaction between the impactor and the plate is modeled with the help of a two degrees-of-freedom system, consisting of springs and masses. The Choi's linearized Hertzian contact model is used to determine the contact force. The maximum impact force is employed for a static damage analysis of the composite plate by means of the radial point interpolation method, while the Tsai-Wu More >

Chein-Shan Liu¹

CMES-Computer Modeling in Engineering & Sciences, Vol.47, No.1, pp. 1-22, 2009, DOI:10.3970/cmes.2009.047.001

Abstract In this paper an analytical method for approximating the solution of backward heat conduction problem is presented. The Fourier series expansion technique is used to formulate a first-kind Fredholm integral equation for the temperature field u(x,t) at any time t < T, when the data are specified at a final time T. Then we consider a direct regularization, instead of the Tikhonov regularization, by adding the term αu(x,t) to obtain a second-kind Fredholm integral equation. The termwise separable property of kernel function allows us by transforming it to a two-point boundary value problem, and thus a closed-form solution More >

Xie Ming-Liang^1,2, Zhou Huai-Chun¹, Chan Tat-Leung³

CMES-Computer Modeling in Engineering & Sciences, Vol.46, No.3, pp. 271-290, 2009, DOI:10.3970/cmes.2009.046.271

Abstract A Fourier-Chebyshev Petrov-Galerkin spectral method is described for computation of temporal linear stability in a circular jet. Basis functions presented here are exponentially mapped Chebyshev functions. They satisfy the pole condition exactly at the origin, and can be used to expand vector functions efficiently by using the solenoidal condition. The mathematical formulation is presented in detail focusing on the analyticity of solenoidal vector field used for the approximation of the flow. The scheme provides spectral accuracy in the present cases studied and the numerical results are in agreement with former works. More >

T.N. Killian¹, S.M. Rao¹ and M.E. Baginski¹

CMES-Computer Modeling in Engineering & Sciences, Vol.46, No.3, pp. 255-270, 2009, DOI:10.3970/cmes.2009.046.255

Abstract In this work, we present a new method of moments solution procedure for calculating acoustic/electromagnetic scattering and radiation by a metallic body whose physical dimension is very large with respect to wavelength. The specially computed basis functions and the testing procedure results in a block-diagonally-dominant moment matrix where each block along the diagonal corresponds to a portion of the structure. The new solution procedure results in considerable savings in terms of computer storage and processing times. Although the procedure is outlined in general mathematical terms, the numerical results are presented only for electromagnetic scattering from More >

Liviu Marin¹

CMES-Computer Modeling in Engineering & Sciences, Vol.46, No.3, pp. 221-254, 2009, DOI:10.3970/cmes.2009.046.221

Abstract We investigate the stable numerical reconstruction of an unknown portion of the boundary of a two-dimensional domain occupied by a functionally graded material (FGM) from a given boundary condition on this part of the boundary and additional Cauchy data on the remaining known portion of the boundary. The aforementioned inverse geometric problem is approached using the method of fundamental solutions (MFS), in conjunction with the Tikhonov regularization method. The optimal value of the regularization parameter is chosen according to Hansen's L-curve criterion. Various examples are considered in order to show that the proposed method is More >

Huamin Zhou¹, Hua Zhang, Dequn Li²

CMES-Computer Modeling in Engineering & Sciences, Vol.46, No.3, pp. 209-220, 2009, DOI:10.3970/cmes.2009.046.209

Abstract Gas-assisted injection molding is an innovative process to manufacture hollow polymeric products, in which gas penetration is the primary and key problem. An analytical solution of the gas penetration interface is presented, based on perturbation method. First, the governing equations and boundary conditions are transformed to be dimensionless, where Capillary number Ca is introduced. Then matching asymptotic expansion method is applied to solve these equations, by using Ca and as perturbation parameters to get the inner and outer solutions, respectively. By matching these two solutions, the analytical model of gas penetration is obtained. More >

Itsuo Hanasaki, Hirofumi Shintaku, Satoshi Matsunami, Satoyuki Kawano¹

CMES-Computer Modeling in Engineering & Sciences, Vol.46, No.2, pp. 191-208, 2009, DOI:10.3970/cmes.2009.046.191

Abstract Self-assembly is one of the physical phenomena that are promising for the manufacturing process of the devices on which DNA molecules are mounted as the components. We have conducted a structural study of self-assembled poly(dA)\discretionary poly(dT) DNA networks on mica surface to discuss the design requirements. The results indicate that the network formation process consists of the adsorption and the subsequent coarsening. The final form of the component filaments are roughly straight. These characteristics imply the possible tensile loads during the network formation. Therefore, we have conducted molecular dynamics simulations of tensile tests of a More >