Dan Ma^1,2, Xianbiao Mao¹

CMC-Computers, Materials & Continua, Vol.26, No.3, pp. 187-200, 2011, DOI:10.3970/cmc.2011.026.187

Abstract Roof is one of the most important structures in coal mining engineering, which needs to be studied thoroughly at the theoretical level, while elastic roof is treated as one of the problems for elastic plates in this paper. The existing literatures on elastic plates have largely restricted to different engineering but all most minority for coal mining engineering. Based on the mechanical models of plane and bending stress for elastic roof, using the boundary integral equations which is obtained by the natural boundary reduction, this paper obtains the elastic roof's Airy stress functions of the… More >

Cheng-Hung San¹, Chuang-Pin Chiu¹, Che-Wun Hong^1,2

CMC-Computers, Materials & Continua, Vol.26, No.3, pp. 167-186, 2011, DOI:10.3970/cmc.2011.026.167

Abstract An improvement in the catalytic process of oxygen reduction reactions is of prime importance for further progress in low temperature fuel cell performance. This paper intends to investigate this problem from a fundamental quantum mechanics viewpoint. For this purpose, a hybrid density functional theory is employed to analyze the catalytic mechanism of the oxygen reduction at the fuel cell cathode. Major steps in the oxygen reduction that include the oxygen adsorption on solid metal clusters (e.g. Cu and Pt) and complete four proton transfer steps are simulated. Proton transfer processes from hydroniums to the adsorbed More >

Deli Gao¹, Zengxin Zhao²

CMC-Computers, Materials & Continua, Vol.26, No.2, pp. 157-166, 2011, DOI:10.3970/cmc.2011.026.157

Abstract The research on casing corrosion in sour environment by a synergism of sweet corrosion and H₂S corrosion has become the basis of casing selection and casing string safety evaluation with more and more sour reservoirs containing high H₂S concentration being developed. It is essential to scientifically utilize casing service ability and reasonably control production rate of gas well to achieve the effective and safe developing of gas resources during the safety period of casing service with a precise casing life prediction. Scanning electron microscopy and tensile testing were applied to investigate the corrosion of TP110TS tube More >

Ligia Munteanu¹, Veturia Chiroiu¹, Valeria Mosnegutu¹

CMC-Computers, Materials & Continua, Vol.26, No.2, pp. 137-156, 2011, DOI:10.3970/cmc.2011.026.137

Abstract In this paper, yet another method for evaluating the elastic modulus for human bones is introduced and investigated. This method adopts the Jankowski and Tsakalakos strain energy function in which, the Born-Mayer energy term is the predominant term for calculations the elastic constants. By taking accounts the directional aspects of the spatial structure of bones, we obtain different values for the Young's modulus depending on the direction of the applied force with respect to the material's structure. The inverse problem analyzed in this paper is solved by inversion of the experimental data. An efficient stopping More >

De-Shin Liu¹, Zhen-Wei Zhuang¹, Shaw-Ruey Lyu^2,3, Cho-Liang Chung⁴, Pai-Chen Lin¹

CMC-Computers, Materials & Continua, Vol.26, No.2, pp. 111-136, 2011, DOI:10.3970/cmc.2011.026.111

Abstract This study proposes a two-dimensional heterogeneous hybrid moisture element method (HHMEM) for modeling transient moisture diffusion in permeable fiber-reinforced polymer composites.
The HHMEM scheme is based on a heterogeneous hybrid moisture element(HHME), with properties determined through an equivalent hybrid moisture capacitance/conductance matrix. This matrix was calculated using the conventional finite element formulation in space discretization as well as the θ-method in time discretization with similar mass/stiffness properties and matrix condensing operations. A coupled HHME-FE scheme was developed and implemented in computer code MATLAB in order to analyze the transient moisture diffusion characteristics of composite materials containing multiple… More >

Surkay D. Akbarov^1,2, Tamer Kepceler¹, M. Mert Egilmez¹, Ferhat Dikmen¹

CMC-Computers, Materials & Continua, Vol.26, No.2, pp. 91-110, 2011, DOI:10.3970/cmc.2011.026.091

Abstract This paper studies the torsional wave dispersion in the hollow bi-material compounded cylinder with finite initial strains. The investigations are carried out within the scope of the piecewise homogeneous body model with the use of the three-dimensional linearized theory of elastic waves in initially stressed bodies. The mechanical relations of the materials of the cylinders are described through the harmonic potential. The numerical results on the influence of the initial stretching or compression of the cylinders along the torsional wave propagation direction are presented and discussed More >

M. Morii¹, N. Hu^1,2, H. Fukunaga³, J.H. Li¹, Y.L. Liu¹, S. Atobe³, Alamusi³, J.H. Qiu⁴

CMC-Computers, Materials & Continua, Vol.26, No.1, pp. 37-66, 2011, DOI:10.3970/cmc.2011.026.037

Abstract Lamb wave tomography (LWT) is a potential and efficient technique for non-destructive tomographic reconstruction of damage images in structural components or materials. A new two-stage inverse algorithm with a small amount of scanning data for quickly reconstructing damage images in aluminum and CFRP laminated plates was proposed in this paper. Due to its high sensitivity to damages, the amplitude decrease of transmitted Lamb waves after travelling through the inspected region was employed as a key signal parameter related to the attenuation of Lamb waves in propagation routes. A through-thickness circular hole and a through-thickness elliptical More >

Y. Zhang^1,2, Z.H. Xiang^1,3

CMC-Computers, Materials & Continua, Vol.26, No.1, pp. 19-36, 2011, DOI:10.3970/cmc.2011.026.019

Abstract Vibration based damage detection methods play an important role in the maintenance of beam structures such as bridges. However, most of them require the accurate measurement of structural mode shapes, which may not be easily satisfied in practice. Since the measurement of frequencies is more accurate than that of mode shapes, this paper proposes a frequency shift curve (FSC) method, based on the equivalence between the FSC due to auxiliary mass and the mode shape square, which has been demonstrated to be effective in structural damage detection. Two damage indices based on the FSC are More >

J. H. Qiu^1,2, H. Jiang¹, H. L. Ji¹, N. Hu³

CMC-Computers, Materials & Continua, Vol.26, No.1, pp. 1-18, 2011, DOI:10.3970/cmc.2011.026.001

Abstract Piezoelectric actuators based motion-producing devices are widely used in precision machining, deformable mirrors, micropumps and piezoelectric injection systems. However, because of their hysteresis nonlinear property, the piezoelectric actuators can not provide absolutely precise displacements. To solve this problem, researchers applied inverse control method to compensate the nonlinearity of piezoelectric actuators, and the inverse models are mainly based on traditional hysteresis models such as the Preiasch model or Prandtl-Ishlinskii model. In this paper, a new approach for inverse control of piezoelectric actuators is presented. The new method utilize a modified Prandtl-Ishlinskii model which is based on More >

V.K. Tewary¹, M. D. Vaudin²

CMC-Computers, Materials & Continua, Vol.25, No.3, pp. 265-290, 2011, DOI:10.3970/cmc.2011.025.265

Abstract A semicontiuum Green's-function-based model is proposed for analysis of averaged mechanical characteristics of Si_xGe_{1 - x}. The atomistic forces in the model are distributed at discrete lattice sites, but the Green's function is approximated by the continuum GF in the far field and by the averaged lattice GF in the near field. Averaging is achieved by replacing Si and Ge atoms by identical hypothetical atoms that are x fraction Si and (1-x) fraction Ge. The parameters of the model are derived using the atomistic model from the interatomic potential between the hypothetical atoms. The interatomic potential… More >