L. Dong¹, A. Alotaibi², S.A. Mohiuddine², S. N. Atluri³

CMES-Computer Modeling in Engineering & Sciences, Vol.99, No.1, pp. 1-85, 2014, DOI:10.3970/cmes.2014.099.001

Abstract In this expository article, a variety of computational methods, such as Collocation, Finite Volume, Finite Element, Boundary Element, MLPG (Meshless Local Petrov Galerkin), Trefftz methods, and Method of Fundamental Solutions, etc., which are often used in isolated ways in contemporary literature are presented in a unified way, and are illustrated to solve a 4^th order ordinary differential equation (beam on an elastic foundation). Both the primal formulation, which considers the 4^th order ODE with displacement as the primitive variable, as well as two types of mixed formulations (one resulting in a set of 2 second-order ODEs, and the other resulting… More >

J. E. Sebold¹, L. A. Lacerda², J. A. M. Carrer³

CMES-Computer Modeling in Engineering & Sciences, Vol.103, No.2, pp. 111-137, 2014, DOI:10.3970/cmes.2014.103.111

Abstract This work is concerned with the development of the so-called Whitney and Nédélec edge finite element method for the solution of the time-harmonic Maxwell equations. Initially, the second order time harmonic Maxwell systems, as well as their variational formulation, are presented. In the sequence, Whitney and Nédélec element spaces, whose functions present continuous tangential components along the interface are built of adjacent elements. Then, numerical experiments validate the performance of Whitney and Nédélec first order elements in a two-dimensional domain. The discrete dispersion relation for the elements shows that the numerical phase velocity can be used as an error estimator.… More >

S,erson L. Gonzaga de Oliveira¹, Jéssica Renata Nogueira¹, João Manuel R. S. Tavares²

CMES-Computer Modeling in Engineering & Sciences, Vol.100, No.1, pp. 31-57, 2014, DOI:10.3970/cmes.2014.100.031

Abstract Triangulations and tetrahedrizations are important geometrical discretization procedures applied to several areas, such as the reconstruction of surfaces and data visualization. Delaunay and Voronoi tessellations are discretization structures of domains with desirable geometrical properties. In this work, a systematic review of algorithms with linear-time behaviour to generate 2D/3D Delaunay and/or Voronoi tessellations is presented. 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 >

Deli Gao¹, Zhen Dong¹, Hui Zhang¹

CMES-Computer Modeling in Engineering & Sciences, Vol.89, No.2, pp. 111-122, 2012, DOI:10.3970/cmes.2012.089.111

Abstract The bottom hole pendulum assembly is a type of bottom hole assembly (BHA) for controlling the hole deviation, and has been widely used in drilling engineering. Generally, the ability of the drill bit to penetrate laterally, is different from its ability to penetrate axially, so that the drill bit has an anisotropy which affects the hole-deviation-control characteristics of the BHA. The tilt angle and the side force of the drill bit are obtained by a BHA analysis based on the method of weighted residuals. Thus, the effective drilling force can be determined using the rock-bit interaction model. On this basis,… More >

R. Khanna^1,2, D. R. Katti¹, K. S. Katti¹

CMES-Computer Modeling in Engineering & Sciences, Vol.87, No.6, pp. 530-556, 2012, DOI:10.3970/cmes.2012.087.530

Abstract Here we report a new in situ nanoindentation technique developed to evaluate the composite mechanical behavior of cell-biomaterial construct under physiological conditions over the time scale of bone nodule generation. Using this technique, mechanical behavior of osteoblast cell-substrate interfaces on tissue engineered materials (chitosan-polygalacturonic acid-nanohydroxyapatite (CPH) films) is investigated. Mechanical behavior of cells in the elastic regime over the time scale of cell adhesion (1 day), proliferation (4 days), development (8 days) and maturation (22 days) of bone nodules is evaluated. Our results indicate that the elastic properties of flat cells are higher (indicating stiffer response, after 4 days, as… More >

K.W. Luczynski¹, A. Dejaco¹, O. Lahayne¹, J. Jaroszewicz², W.Swieszkowski², C. Hellmich¹

CMES-Computer Modeling in Engineering & Sciences, Vol.87, No.6, pp. 505-529, 2012, DOI:10.3970/cmes.2012.087.505

Abstract A 71 volume-% macroporous tissue engineering scaffold made of poly-l-lactide (PLLA) with 10 mass-% of pseudo-spherical tri-calcium phosphate (TCP) inclusions (exhibiting diameters in the range of several nanometers) was microCT-scanned. The corresponding stack of images was converted into regular Finite Element (FE) models consisting of around 100,000 to 1,000,000 finite elements. Therefore, the attenuation-related, voxel-specific grey values were converted into TCP-contents, and the latter, together with nanoindentation tests,entered a homogenization scheme of the Mori-Tanaka type, as to deliver voxel-specific (and hence, finite element-specific) elastic properties. These FE models were uniaxially loaded, giving access to the macroscopic Young's modulus of the… More >

G. Mattei^1,2, A. Tirella^1,2, A. Ahluwalia^1,2

CMES-Computer Modeling in Engineering & Sciences, Vol.87, No.6, pp. 483-504, 2012, DOI:10.3970/cmes.2012.087.483

Abstract Biological function is intricately linked with structure. Many biological structures are characterised by functional spatially distributed gradients in which each layer has one or more specific functions to perform. Reproducing such structures is challenging, and usually an experimental trial-and-error approach is used. In this paper we investigate how the gravitational sedimentation of discrete solid particles (secondary phase) within a primary fluid phase with a time-varying dynamic viscosity can be used for the realisation of stable and reproducible continuous functionally graded materials (FGMs). Computational models were used to simulate the distribution of a particle phase in a fluid domain. Firstly a… More >

Ziya Aktas¹, Semih Cetin²

CMES-Computer Modeling in Engineering & Sciences, Vol.76, No.2, pp. 133-162, 2011, DOI:10.3970/cmes.2011.076.133

Abstract The knowledge society has been developed and shaped by amazing improvements during the last two decades. On that development and improvement, social sciences such as psychology or anthropology have also had significant impact as much as real sciences like medicine or engineering, in particular, Information Technology or Information and Communications Technology. The new trends and explosion of knowledge due to Internet and Web technologies have radically changed the way we structure business and its main building block, i.e. "knowledge". Though information/knowledge system development efforts have been regarded formerly as mere information technology activities, now we have been experiencing alternative ways… More >

A. Gakwaya¹, H. Sharifi², M. Guillot¹, M. Souli³, F. Erchiqui⁴

CMES-Computer Modeling in Engineering & Sciences, Vol.73, No.3, pp. 209-266, 2011, DOI:10.3970/cmes.2011.073.209

Abstract A mechanical computer aided design and engineering system can be used to reduce the design-to-manufacture cycle time in metal forming process. Such a system could be built upon a solid modeling geometry engine and an efficient finite element (FE) solver. The maintenance of a high-quality mesh throughout the analysis is an essential feature of an efficient finite element simulation of large strain metal forming problems. In this paper, a mesh adaptation technique employing the Arbitrary Lagrangian-Eulerian formulation (ALE) is applied to some industrial metal forming problems. An ACIS boundary representation of the solid model is employed. This type of representation… More >