Shuji Takashima¹, Michihiko Nakagaki², Noriyuki Miyazaki¹

CMES-Computer Modeling in Engineering & Sciences, Vol.20, No.3, pp. 193-202, 2007, DOI:10.3970/cmes.2007.020.193

Abstract Composite materials have complicated microstructures. These microstructures affect the macroscopic deformation of composite materials. In the present study, we focus on the effect of particle size in a particle-dispersed composite material on the mechanical strength of the material. For this purpose, we derived a macroscopic elastic-plastic constitutive equation using a modified version of the Eshelby's equivalent inclusion method combined with the gradient plasticity. We incorporated this macroscopic elastic-plastic constitutive equation into a finite element program and performed a homogenized finite element analysis of a particle-dispersed composite material in which both the macroscopic and microscopic behaviors More >

Amit Shaw¹, D Roy²

CMES-Computer Modeling in Engineering & Sciences, Vol.19, No.1, pp. 69-98, 2007, DOI:10.3970/cmes.2007.019.069

Abstract A novel discretization strategy and derivative reproduction based on reproducing kernel (RK) particle approximations of functions are proposed. The proposed scheme is in the form of an RK interpolation that offers significant numerical advantages over a recent version of the strategy by Chen et al. (2003), wherein the authors added a set of primitive functions to the reproducing kernel (enrichment) functions. It was also required that the support size of the primitive function be less than the smallest distance between two successive grid points. Since the primitive function was required to vary from 0 to… More >

J.A. Sanz, M. Solis, J. Dominguez¹

CMES-Computer Modeling in Engineering & Sciences, Vol.17, No.3, pp. 215-230, 2007, DOI:10.3970/cmes.2007.017.215

Abstract A general mixed boundary element formulation for three-dimensional piezoelectric fracture mechanics problems is presented in this paper. The numerical procedure is based on the extended displacement and traction integral equations for external and crack boundaries, respectively. Integrals with strongly singular and hypersingular kernels appearing in the formulation are analytically transformed into weakly singular and regular integrals. Quadratic boundary elements and quarter-point boundary elements are implemented in a direct way in a computer code. Electric and stress intensity factors are directly computed from nodal values at quarter-point elements. Crack problems in 3D piezoelectric bounded and unbounded More >

S. Hagihara¹, M. Tsunori², T. Ikeda³, N. Miyazaki³

CMES-Computer Modeling in Engineering & Sciences, Vol.17, No.2, pp. 63-72, 2007, DOI:10.3970/cmes.2007.017.063

Abstract The element-free Galerkin (EFG) method is applied to the calculation of elastic-plastic fracture mechanics parameters such as the J-integral and T*-integral. The fields of displacement, strain and stress for a crack problem are obtained using the elastic-plastic EFG method. Then the elastic-plastic fracture mechanics parameters J-integral and T*-integral are calculated from path and domain integrals. In the finite element analysis, paths for the path integral and domains for the domain integral are selected depending on finite element mesh division. On the other hand, they can be arbitrarily selected in the EFG method, and we can… More >

Akira Hirata¹

FDMP-Fluid Dynamics & Materials Processing, Vol.3, No.3, pp. 203-230, 2007, DOI:10.3970/fdmp.2007.003.203

Abstract This article is a summary of author's typical research works (over the last four decades) on interphase transport phenomena in the presence of interfacial fluid motion and surface tension gradients on liquid-fluid interfaces, and related applications to single crystal growth and microgravity sciences. A unified theory for momentum, heat and mass transfer on liquid-fluid and solid-fluid interfaces is proposed, which takes into account interface mobility. It is shown that interface contamination and turbulence can be well explained, respectively, by suppression and enhancement of the interfacial velocity induced by surface tension gradients. Transport phenomena on solid More >

H. Tang¹, L.C. Wrobel², Z. Fan²

FDMP-Fluid Dynamics & Materials Processing, Vol.3, No.2, pp. 129-146, 2007, DOI:10.3970/fdmp.2007.003.129

Abstract This paper presents an overview of diverse extrusion techniques and, in particular, a focused discussion about the rheoextrusion process for semi-solid casting (a novel casting process for the fabrication of high quality metals). The review reveals a wealth of interesting rheological and microstructural features, illustrating qualitative and quantitative data. The analysis is supported by relevant numerical results and examples. It is shown how numerical studies can lead to significant insights into these processes by providing more detailed information on the fundamental mechanisms of morphology development (during phase change) and profile forming. The die filling and More >

A. Frangi¹, L. Ghezzi, P. Faure-Ragani²

CMES-Computer Modeling in Engineering & Sciences, Vol.15, No.1, pp. 41-48, 2006, DOI:10.3970/cmes.2006.015.041

Abstract Three dimensional magneto-mechanical problems at low frequency are addressed by means of a coupled fast Boundary Element - Finite Element approach with total scalar potential and focusing especially on the issue of global force calculation on movable ferromagnetic parts. The differentiation of co-energy in this framework and the use of Maxwell tensor are critically discussed and the intrinsic links are put in evidence. Three examples of academic and industrial applications are employed for validation. More >

A. Wacher¹, D. Givoli²

CMES-Computer Modeling in Engineering & Sciences, Vol.15, No.3, pp. 147-164, 2006, DOI:10.3970/cmes.2006.015.147

Abstract The recently proposed String Gradient Weighted Moving Finite Element (SGWMFE) method is extended to include remeshing and refining. The method simultaneously determines, at each time step, the solution of the governing partial differential equations and an optimal location of the finite element nodes. It has previously been applied to the nonlinear time-dependent two-dimensional shallow water equations, under the demanding conditions of large Coriolis forces, inducing large mesh and field rotation. Such effects are of major importance in geophysical fluid dynamics applications. Two deficiencies of the original SGWMFE method are (1) possible tangling of the mesh… More >

Paola Gardano¹, Peter Dabnichki^1,2

CMES-Computer Modeling in Engineering & Sciences, Vol.15, No.2, pp. 87-98, 2006, DOI:10.3970/cmes.2006.015.087

Abstract The work presents a numerical simulation of hydrodynamic forces generated in front crawl swimming. The three dimensional Laplace's equation is used for the analysis of the flow around a moving body in an infinite domain and considers the effect of the added mass and the acceleration on the hydrodynamic forces (Drag and Lift) generated by the interaction between the flow and the body at different geometric configurations of the arm -- variable elbow angle. Boundary Element Method (BEM) was used to obtain the solution of the three dimensional equation numerically. The aim of the work… More >

S. Noroozi¹, P. Sewell¹, J. Vinney¹

CMES-Computer Modeling in Engineering & Sciences, Vol.14, No.3, pp. 171-180, 2006, DOI:10.3970/cmes.2006.014.171

Abstract A method that combines a modified back propagation Artificial Neural Network (ANN) and Boundary Element Analysis (BEA) was introduced and discussed in the author's previous papers. This paper discusses the development of an automated inverse boundary element problem engine. This inverse problem engine can be applied to both potential and elastostatic problems.
In this study, BEA solutions of a two-dimensional potential problem is utilised to test the system and to train a back propagation Artificial Neural Network (ANN). Once training is completed and the transfer function is created, the solution to any subsequent or new… More >