Z.Y. Qian, Z.D. Han¹, S.N. Atluri^{1, 2}

CMES-Computer Modeling in Engineering & Sciences, Vol.91, No.6, pp. 463-484, 2013, DOI:10.3970/cmes.2013.091.463

Abstract To predict the sound field in an acoustic problem, the well-known non-uniqueness problem has to be solved. In a departure from the common approaches used in the prior literature, the weak-form of the Helmholtz differential equation, in conjunction with vector test-functions, is utilized as the basis, in order to directly derive non-hyper-singular boundary integral equations for the velocity potential ∅, as well as its gradients q;. Both ∅-BIE and q-BIE are fully regularized to achieve weak singularities at the boundary [i.e., containing singularities of O(r^-1)]. Collocation-based boundary-element numerical approaches [denoted as BEM-R-∅-BIE, and BEM-R-q-BIE] are implemented to solve these. To… More >

Yasunori Yusa¹, Shinobu Yoshimura¹

CMES-Computer Modeling in Engineering & Sciences, Vol.91, No.6, pp. 445-461, 2013, DOI:10.3970/cmes.2013.091.445

Abstract For large-scale fracture mechanics simulation, a partitioned iterative coupling method is investigated. In this method, an analysis model is decomposed into two domains, which are analyzed separately. A crack is introduced in one small domain, whereas the other large domain is a simple elastic body. Problems concerning fracture mechanics can be treated only in the small domain. In order to satisfy both geometric compatibility and equilibrium on the domain boundary, the two domains are analyzed repeatedly using an iterative solution technique. A benchmark analysis was performed in order to validate the method and evaluate its computational performance. The computed stress… More >

X.F. Guan¹, X. Liu², J.Z. Cui³

CMES-Computer Modeling in Engineering & Sciences, Vol.91, No.6, pp. 425-444, 2013, DOI:10.3970/cmes.2013.091.425

Abstract In this paper, a stochastic geometrical modeling method for reconstructing three dimensional multiscale pore structures of porous materials is presented. In this method, the pore structure in porous materials is represented by a random but spatially correlated pore-network, in which the results of the Mercury Intrusion Porosimetry (MIP) experiment are used as the basic input information. Beside that, based on the Monte Carlo techniques, an effective computer generation algorithm is developed, and the quantities to evaluate the properties of porous materials are defined and described. Furthermore, numerical implementations are conducted based on experimental data afterwards. This method can be used… More >

S. Saha Ray¹, A. K. Gupta¹

CMES-Computer Modeling in Engineering & Sciences, Vol.91, No.6, pp. 409-424, 2013, DOI:10.3970/cmes.2013.091.409

Abstract In this paper, Haar wavelet method is applied to compute the numerical solutions of non-linear partial differential equations like Huxley and Burgers- Huxley equation. The approximate solutions of the Huxley and Burgers-Huxley equations are compared with the exact solutions. The present scheme is very simple, effective and convenient with small computational overhead. More >

Ying Xu¹, Shuling Hu¹, Shengping Shen¹

CMES-Computer Modeling in Engineering & Sciences, Vol.91, No.5, pp. 397-408, 2013, DOI:10.3970/cmes.2013.091.397

Abstract Flexoelectricity presents a strong size effect, and should not be ignored for nanodevices. In this paper, the flexoelectric effect is taken into account to investigate the electrostatic potential distribution in a bent flexoelectric semiconductive nanowire, and the numerical solution is obtained by using the finite difference method. The effect of donor concentration on the electrostatic potential are also investigated. The results show that, the flexoelectricity increases the value of the voltage on the cross section. The flexoelectric effect is varied with the size, i.e. when the radius of the nanowire is small the flexoelectric effect is significant. It is also… More >

G. Kosec^1,2, P. Zinterhof³

CMES-Computer Modeling in Engineering & Sciences, Vol.91, No.5, pp. 377-396, 2013, DOI:10.3970/cmes.2013.091.377

Abstract This paper deals with the implementation of the local meshless numerical method (LMM) on general purpose graphics processing units (GPU) in solving partial differential equations (PDE). The local meshless solution procedure is formulated in a way suitable for parallel execution and has been implemented on multiple GPUs. The implementation is tested on a solution of diffusion equation in a 2D domain. Different setups of the meshless approach regarding the selection of basis functions are tested on an interval up to 2.5 million of computational points. It is shown that monomials are a good selection of the basis when working with… More >

Da-guo Wang^1,2, Leslie-George Tham², Qing-xiang Shui¹

CMES-Computer Modeling in Engineering & Sciences, Vol.91, No.5, pp. 355-376, 2013, DOI:10.3970/cmes.2013.091.355

Abstract A finite element method, which is the characteristic-based operatorsplitting (CBOS) algorithm, is adopted to solve unsteady incompressible Navier- Stokes (N-S) equations. In each time step, the equations are split into the diffusive part and the convective part. The convective part is discretized using the characteristic Galerkin method and solved explicitly. The moving interface is captured by the pseudo-concentration method, thus, a new dam-break model is established. Through the validation of a dam-break onto a downstream dry bed or wet bed, it is shown that the present model can accurately simulate the moving interface flows. We also study dam-break in a… More >

Julieta António¹, António Tadeu^1,2, Patrícia Ferreira³

CMES-Computer Modeling in Engineering & Sciences, Vol.91, No.5, pp. 337-354, 2013, DOI:10.3970/cmes.2013.091.337

Abstract The first of these two companion papers addressed the iterative coupling between a formulation based on the normal derivative of the integral equation (TBEM) and the method of fundamental solutions (MFS), which was used to solve scattering problems involving the propagation of acoustic waves in the vicinity of multiple thin barriers and domes. This second part extends these results to the more complicated case of in-plane wave propagation and presents their application to scattering problems involving SV-P waves. The formulation is first presented and verified by computing the number of iterations required and measuring the CPU time. Afterwards the formulation… More >

Q.W.Yang¹, J.K.Liu², C.H. Li³

CMES-Computer Modeling in Engineering & Sciences, Vol.91, No.4, pp. 313-335, 2013, DOI:10.3970/cmes.2013.091.313

Abstract A method based on best achievable flexibility change is presented in this paper to localize and quantify multiple damages in structures. The key process of the damage localization approach is the computation of the Euclidean distances between the measured flexibility change and the best achievable flexibility changes. The location of damage can be identified by searching for a value that is considerably smaller than others in these distances. For the multiple-damage case, a sequential damage localization approach is proposed to locate the damage sites one by one. With the suspected damaged elements determined, the flexibility sensitivity method is employed to… More >

Daguo Wang¹

CMES-Computer Modeling in Engineering & Sciences, Vol.91, No.4, pp. 289-312, 2013, DOI:10.3970/cmes.2013.091.289

Abstract A 2-D time-domain numerical coupled model for non-linear wave forces acting on a fixed ship is developed in the present study. The whole domain is divided into the inner domain and the outer domain. The inner domain is the area around the ship section and the flow is described by the Laplace equation. The remaining area is the outer domain and the flow is defined by the higher-order Boussinesq equations in order to consider the nonlinearity of the wave motions. The matching conditions on the interfaces between the inner domain and the outer domain are the continuation of volume flux… More >