Y.C. Shiah, C.L. Tan

The International Conference on Computational & Experimental Engineering and Sciences, Vol.16, No.1, pp. 31-32, 2011, DOI:10.3970/icces.2011.016.031

Abstract In the boundary element method (BEM), interior point solutions for the displacements and the stresses at an interior point of an elastic body are obtained through the numerical evaluation of the Somigliana's identities. It is carried out as a secondary exercise in the BEM analysis, after the boundary integral equation (BIE) has been solved for all the unknown displacements and tractions on the surface of the domain. In the integrals of these identities, the integrands contain terms with up to second order derivatives of the Green's function for the displacements of the elastic problem.

The… More >

V.G. Yakhno¹, H.Çerdik Yaslan²

CMES-Computer Modeling in Engineering & Sciences, Vol.81, No.3&4, pp. 295-310, 2011, DOI:10.3970/cmes.2011.081.295

Abstract The time-dependent differential equations of elasticity for 3D quasicrystals are considered in the paper. These equations are written in the form of a vector partial differential equation of the second order with symmetric matrix coefficients. The Green's function is defined for this vector partial differential equation. A new method of the numerical computation of values of the Green's function is proposed. This method is based on the Fourier transformation and some matrix computations. Computational experiments confirm the robustness of our method for the computation of the time-dependent Green's function in icosahedral quasicrystals. More >

C.B. Du^1,2, S.Y Jiang², W. Qin³, Y.M. Zhang²

CMES-Computer Modeling in Engineering & Sciences, Vol.81, No.3&4, pp. 229-248, 2011, DOI:10.3970/cmes.2011.081.229

Abstract A numerical analysis of concrete composites at the mesoscale based on three-dimensional (3D) reconstruction technology of X-ray computed tomography (CT) images is presented in this paper. For X-ray CT images of concrete, morphology processing was used to recover complete image information, including borders, and the median filtering method was applied to eliminate potential impurities in the images. The final X-ray CT images obtained after processing for a concrete section were composed of three-value pixels that indicated aggregate particles, mortar matrix and air voids, and the 3D structure of the concrete specimen was reconstructed using the More >

Hui-Fen Guo^1,2, Bin-Gang Xu^1,3, Sheng-Yan Li¹, Chong-Wen Yu²

CMES-Computer Modeling in Engineering & Sciences, Vol.80, No.2, pp. 87-112, 2011, DOI:10.3970/cmes.2011.080.087

Abstract Three-dimensional transient simulation is presented for swirling recirculating flow in a nozzle with a slotted-tube (different grooves) and the effect of the groove number is also investigated. The numerical results on the streamline angles are validated by experimental visualization using the surface oil flow technology. In the downstream center of the injectors, the vortex breakdown experiences a transition from bubble- to spiral- breakdown as time is increased. For all cases under study, as the sizes of two recirculation zones near the injector upstream wall and the step retain almost constant, the spiral breakdown shows a More >

Kun Luan¹, Baozhong Sun¹, Bohong Gu^1,2

CMES-Computer Modeling in Engineering & Sciences, Vol.79, No.1, pp. 31-62, 2011, DOI:10.3970/cmes.2011.079.031

Abstract This paper reports finite element multi-scale simulations of ballistic impact damage of three-dimensional angle-interlock woven composite (3DAWC) penetrated under a hemispherical rigid projectile. A multi-scale geometrical model of the 3DAWC was established for the numerical simulation. The multi-scale geometrical model of the 3DAWC consists two parts: one is the microstructure model and another is the continuum model. The microstructure model has the same microstructure with that of the 3DAWC composite panel, including the fiber tows' diameter, fiber tow configuration and fiber volume fraction. The continuum model has the same mechanical properties with the 3DAWC. The… More >

Y.C. Shiah¹, C. L. Tan²

CMES-Computer Modeling in Engineering & Sciences, Vol.78, No.2, pp. 95-108, 2011, DOI:10.3970/cmes.2011.078.095

Abstract By differentiating the Green function of Ting and Lee (1997) for 3D general anisotropic elastotatics in a spherical coordinate system as an intermediate step, and then using the chain rule, derivatives of up to the second order of this fundamental solution are obtained in exact, explicit, algebraic forms. No tensors of order higher than two are present in these derivatives, thereby allowing these quantities to be numerically evaluated quite expeditiously. These derivatives are required for the computation of the internal point displacements and stresses via Somigliana's identity in BEM analysis. Some examples are presented to More >

E. Schnack¹, W. Weber², Y. Zhu³

CMES-Computer Modeling in Engineering & Sciences, Vol.74, No.1, pp. 1-38, 2011, DOI:10.3970/cmes.2011.074.001

Abstract Three dimensional fracture mechanics was done by several groups in the past. One topic for these three dimensional fracture mechanics is to consider re-entrant corners or wedges for isotropic material. An algorithm was developed in the past to compute the dominant eigenvalues for those problems with high accuracy. Based on Kondratiev's Lemma for elliptic boundary value problems it is started with the asymptotic for the displacement and stress distribution around these three dimensional corners. By considering the mixed boundary value problem, the field quantities in the vicinity of corner points are computed by using a… More >

Chun Yang^1,2, Dalin Tang², Satya Atluri³

CMES-Computer Modeling in Engineering & Sciences, Vol.72, No.1, pp. 53-78, 2011, DOI:10.3970/cmes.2011.072.053

Abstract Previously, we introduced a computational procedure based on three-dimensional meshless generalized finite difference (MGFD) method and serial magnetic resonance imaging (MRI) data to quantify patient-specific carotid atherosclerotic plaque growth functions and simulate plaque progression. Structure-only models were used in our previous report. In this paper, fluid-stricture interaction (FSI) was added to improve on prediction accuracy. One participating patient was scanned three times (T1, T2, and T3, at intervals of about 18 months) to obtain plaque progression data. Blood flow was assumed to laminar, Newtonian, viscous and incompressible. The Navier-Stokes equations with arbitrary Lagrangian-Eulerian (ALE) formulation… More >

G.A. Gravvanis¹, K.M. Giannoutakis²

CMES-Computer Modeling in Engineering & Sciences, Vol.71, No.4, pp. 305-330, 2011, DOI:10.3970/cmes.2011.071.305

Abstract In this paper we present parallel explicit approximate inverse matrix techniques for solving sparse linear systems on shared memory systems, which are derived using the finite element method for biharmonic equations in three space variables. Our approach for solving such equations is by considering the biharmonic equation as a coupled equation approach (pair of Poisson equation), using a FE approximation scheme, yielding an inner-outer iteration method. Additionally, parallel approximate inverse matrix algorithms are introduced for the efficient solution of sparse linear systems, based on an anti-diagonal computational approach that eliminates the data dependencies. Parallel explicit More >

Ke Jin¹, Yong Kou¹, Xiaojing Zheng^1,2

CMC-Computers, Materials & Continua, Vol.24, No.2, pp. 143-162, 2011, DOI:10.3970/cmc.2011.024.143

Abstract This paper is concerned with a 3-D general constitutive law of nonlinear magneto-thermo-elastic coupling for magnetostrictive materials. The model considered here is thermodynamically motivated and based on the Gibbs free energy function. A set of closed and analytical expressions of the constitutive relationships for the magnetostrictive materials are obtained, in which all parameters can be determined by those measurable experiments in mechanics and physics. Then the model can be simplified to two cases, i.e. magnetostrictive rods and films. It is found that the predictions from this model are in good accordance with the experimental data More >