Chein-Shan Liu¹, Chih-Wen Chang²

CMC-Computers, Materials & Continua, Vol.25, No.2, pp. 107-134, 2011, DOI:10.3970/cmc.2011.025.107

Abstract We consider two inverse problems for estimating radiative coefficients α(x) and α(x, y), respectively, in T_t(x, t) = T_xx(x, t)-α(x)T(x, t), and T_t(x, y, t) = T_xx(x, y, t) + T_yy(x, y, t)-α(x, y)T(x, y, t), where a are assumed to be continuous functions of space variables. A Lie-group adaptive method is developed, which can be used to find a at the spatially discretized points, where we only utilize the initial condition and boundary conditions, such as those for a typical direct problem. This point is quite different from other methods, which need the overspecified final time data. Three-fold advantages can be gained More >

Zone-Ching Lin¹, Ying-Chih Hsu¹

CMC-Computers, Materials & Continua, Vol.25, No.1, pp. 75-106, 2011, DOI:10.3970/cmc.2011.025.075

Abstract The three-dimensional quasi-steady molecular statics nanocutting model is used by this paper to carry out simulation analysis of nanocutting of sapphire in order to explore the effects of conical tools with different tip radii of probe and straight-line cutting at different cutting depths, on cutting force. Meanwhile, this paper uses a cutting tool of atomic force microscopy (AFM) with a probe tip similar to a semisphere to conduct nanocutting experiment of sapphire substrate. Furthermore, from the experimental results of nanocutting sapphire substrate, this paper innovatively proposes the theoretical model and equation that the specific down… More >

Bhashya V.¹, Ramesh G.¹, Sundar Kumar S.¹, Bharatkumar B. H.¹, Krishnamoorthy T.S.¹, Nagesh R Iyer.¹

CMC-Computers, Materials & Continua, Vol.25, No.1, pp. 47-74, 2011, DOI:10.3970/cmc.2011.025.047

Abstract Fibre-reinforced polymers (FRPs) are being introduced into a wide variety of civil engineering applications. These materials have been found to be particularly attractive for applications involving the strengthening and rehabilitation of existing reinforced concrete structures. In this paper, experimental investigations and analytical studies on four series of the concrete cylinders wrapped with FRP are presented. First series consist of concrete cylinders wrapped with one layer carbon fiber reinforced polymer (CFRP), second series concrete cylinders wrapped with two layers CFRP, in third series, concrete cylinders were wrapped with one layer glass fiber reinforced polymer (GFRP) and… More >

Kentaro Doi^1,2, Ikumi Onishi¹, Satoyuki Kawano^1,3

CMES-Computer Modeling in Engineering & Sciences, Vol.77, No.2, pp. 113-136, 2011, DOI:10.3970/cmes.2011.077.113

Abstract Hydrogen technologies are currently one of the most actively researched topics. A lot of researches have tied to enhance their energy conversion efficiencies. In the present study, numerical analyses have been carried out focusing on hydrogen-storage carbon materials which are expected to realize high gravimetric and volumetric capacities. In particular, dissociative adsorption processes of H₂ molecules above graphene surfaces have been investigated by ab initio molecular dynamics. The present results indicate that a steric graphene surface plays an important role in enhancing the charge transfer which induces dissociation of H₂ and adsorption of H atoms on the More >

W. A. El-Askary^1,2, S. A. Wilson², A. Hegab²

CMES-Computer Modeling in Engineering & Sciences, Vol.76, No.3&4, pp. 235-266, 2011, DOI:10.3970/cmes.2011.076.235

Abstract In the present work, a complete simulation of reactive flow in the combustion chamber of a rocket motor equipped with convergent-divergent nozzle has been introduced. The model describes the combustion process inside the combustion chamber considering a steady premixed reactant gas injected through side porous walls of the combustion chamber. The products flow through a convergent-divergent nozzle with adiabatic impermeable walls. The reactants are treated as two-dimensional, multi-components, turbulent compressible flow. The local properties of the mixture are calculated and updated during the solution process. At the boundary of the combustion chamber, a constant mass More >

B.Y. Tian¹, B. Tie¹, D. Aubry¹, X.Y. Su²

CMES-Computer Modeling in Engineering & Sciences, Vol.76, No.3&4, pp. 217-234, 2011, DOI:10.3970/cmes.2011.076.217

Abstract The present work is devoted to a theoretical analysis and numerical modeling of elastic wave propagation firstly in a one-dimensional periodic elastic rod structure and then in two-dimensional periodic elastic beam structures by using Bloch wave theorem. The dispersion relation between Bloch wave vectors and eigen frequencies is obtained and its dependency upon the micro-structural characteristics of the periodic cellular structure is analyzed. Thanks to the Bloch wave transforms, only the primitive cell is considered theoretically or numerically and the phenomena of frequency band-gaps and the diffracted waves caused by the periodic cells are modeled More >

Şahin Emrah Amrahov¹, Iman N. Askerzade¹

CMES-Computer Modeling in Engineering & Sciences, Vol.76, No.3&4, pp. 207-216, 2011, DOI:10.3970/cmes.2011.076.207

Abstract We consider a fuzzy linear system with crisp coefficient matrix and with an arbitrary fuzzy number in parametric form on the right-hand side. It is known that the well-known existence and uniqueness theorem of a strong fuzzy solution is equivalent to the following: The coefficient matrix is the product of a permutation matrix and a diagonal matrix. This means that this theorem can be applicable only for a special form of linear systems, namely, only when the system consists of equations, each of which has exactly one variable. We prove an existence and uniqueness theorem, More >

Yun Chen¹, Junzhi Cui², Yufeng Nie¹, Yiqiang Li¹

CMES-Computer Modeling in Engineering & Sciences, Vol.76, No.3&4, pp. 189-206, 2011, DOI:10.3970/cmes.2011.076.189

Abstract This paper presents a new numerical algorithm for thermal-mechanical coupled analysis of polycrystalline aggregates based on the plastic slip theory inside crystals and the frictional contact on their interfaces. It involves the mechanics and heat conduction behaviors caused by both force loads and temperature changing within crystal and contact interfaces between crystals. Firstly, the constitutive relationship inside single crystal, and the moment equations and energy equations are derived by means of rate-dependent plastic deformation theory and the formulation of elastic-plastic tangent modulus depended on temperature. Secondly, the contact conditions with friction, including frictional heat generation… More >

Qin Lou¹, Zhaoli Guo^1,2, Chuguang Zheng¹

CMES-Computer Modeling in Engineering & Sciences, Vol.76, No.3&4, pp. 175-188, 2011, DOI:10.3970/cmes.2011.076.175

Abstract Due to the mesoscopic and kinetic nature, the lattice Boltzmann equation (LBE) method has become an efficient and powerful tool for modeling and simulating interfacial dynamics of multi-phase flows. In this work we discuss several fundamental properties of two-phase LBE models. Particularly, the effects of force discretization, spurious currents in the vicinity of interfaces, and checkerboard effects with the underlying lattices, are investigated. More >

J. A. Ferreira¹, P. de Oliveira², P. M. da Silva³

CMES-Computer Modeling in Engineering & Sciences, Vol.76, No.3&4, pp. 163-174, 2011, DOI:10.3970/cmes.2011.076.163

Abstract In two previous papers the authors presented mathematical models that simulate the mass of drug delivered, in vitro Ferreira, Oliveira, Silva, Carreira, Gil and Murta (2010) and in vivo Ferreira, Oliveira, Silva and Murta (2011), from a therapeutic contact lens. In the present paper the time it takes to reach an equilibrium state is studied. A closed formula based on the concept of effective time is derived and the influence of the parameters of the model is analyzed. More >