He Xufei¹, Deng Zhongmin², Song Zhitao¹

Structural Durability & Health Monitoring, Vol.8, No.3, pp. 193-208, 2012, DOI:10.32604/sdhm.2012.008.193

Abstract This paper describes an information optimizing scheme which is developed by integrating rough set and hierarchical data fusion. The novel structural damage indices are extracted using the information from different sources and then imported into probabilistic neural network (PNN) for classification and health assessment. In order to enhance the accuracy of diagnosis, results from separate PNN classification are fused to achieve comprehensive decision. Rough set is employed to decrease the spatial dimension of data. The predictive accuracy of optimizing scheme is demonstrated on a helicopter, taken as an example, with varied sensors, for multiple damage More >

S.D. Akbarov^1,2

CMC-Computers, Materials & Continua, Vol.32, No.1, pp. 29-60, 2012, DOI:10.3970/cmc.2012.032.029

Abstract By the use of the Murnaghan potential the influence of third order elastic constants on axisymmetric longitudinal wave propagation velocity in a pre-stressed two-layered circular hollow cylinder is investigated. This investigation is carried out within the scope of the piecewise homogeneous body model by utilizing the first version of the small initial deformation theory of the Three-dimensional Linearized Theory of Elastic Waves in Initially Stressed Bodies. Numerical results are obtained and analyzed for the cases where the material of the outer hollow cylinder material is aluminum, but the material of the inner cylinder is steel More >

Cherl-Hee Lee¹, Jonghun Lee¹

CMC-Computers, Materials & Continua, Vol.31, No.2, pp. 147-156, 2012, DOI:10.3970/cmc.2012.031.147

Abstract The guided modes are investigated in a five-layered slab waveguide with double claddings of metamaterials using a new graphical method. The dispersion equations in the symmetric and asymmetric five-layered slab waveguide are derived from the presented graphical method, and corresponding field distributions are plotted for the oscillating guided and surface guided modes. The energy flux distribution along the axis is plotted for the surface TE₁ mode. More >

Chien-Ching Ma^1,2, Yi-Hsien Lin², Shih-Hao Lin²

CMC-Computers, Materials & Continua, Vol.31, No.1, pp. 37-64, 2012, DOI:10.3970/cmc.2012.031.037

Abstract In this article, the transient response in a functionally graded material (FGM) slab is analyzed by Laplace transform technique. The numerical Laplace inversion (Durbin's formula) is used to calculate the dynamic behavior of the FGM slab. The slab is subjected an uniform loading at the upper surface, and the lower surface are assumed to be traction-free or fixed conditions. The analytical solutions are presented in the transform domain and the numerical Laplace inversion is performed to obtain the transient response in time domain. To take the accuracy and computational efficiency in consideration, Durbin's method is More >

Shiv Narayan¹, Shamala Joshi B¹, Raveendranath U. Nair¹, R M Jha¹

CMC-Computers, Materials & Continua, Vol.31, No.1, pp. 1-16, 2012, DOI:10.3970/cmc.2012.031.001

Abstract The electromagnetic design and performance analysis of dual/ multi-band metamaterial frequency selective surface (FSS) structures have been carried out for radome applications in microwave and millimeter wave frequency regimes. The proposed metamaterial FSS structure, consisting of cascaded MNG (mu-nega -tive) and DPS (double positive) layers, exhibits dual-band transmission responses at V-band and W-band. Excellent transmission efficiency (more than 95%) has been obtained over the frequency range 45.8-53.1 GHz at first resonance, and from 93.0-97.1 GHz at second resonance. The incorporation of additional DPS layer to the proposed metamaterial-FSS structure facilitates multiband bandpass characteristics at 30 More >

S. D. Akbarov^1,2, C. Ipek³

CMC-Computers, Materials & Continua, Vol.30, No.2, pp. 99-144, 2012, DOI:10.3970/cmc.2012.030.099

Abstract This paper studies the dispersion of the axisymmetric longitudinal wave propagation in the pre-strained hollow cylinder consisting of two-layers under the shear-spring type imperfectness of the contact conditions between these layers. The investigations are made within the framework of the piecewise homogeneous body model by utilizing the 3D linearized theory of elastic waves in elastic bodies with initial stresses. It is assumed that the layers of the cylinder are made from compressible hyper-elastic materials and their elasticity relations are given through the harmonic potential. The degree of the mentioned imperfectness is estimated by the shear-spring More >

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

CMC-Computers, Materials & Continua, Vol.30, No.1, pp. 83-98, 2012, DOI:10.3970/cmc.2012.030.083

Abstract This paper develops the investigations started in a work by Akbarov, Kepceler and Mert Egilmez (2011) and studies the some particularities of the torsional wave dispersion in a finitely pre-deformed sandwich hollow cylinder. The mentioned particularities relate to the influence of the stiffness ratio of the core and face layers' materials and the influence of the thickness ratio of these layers on the dispersion character of the wave under consideration. Moreover, the mentioned influences are studied for the various values of the parameter which characterizes the initial strains in the cylinder's layers. The mechanical relations More >

Jiun-Yu Wu^1,2, Hui-Ching Wang¹, Ming-I Char¹, Bo-Chen Tai¹

CMC-Computers, Materials & Continua, Vol.28, No.3, pp. 261-280, 2012, DOI:10.3970/cmc.2012.028.261

Abstract In this paper, we use the Local adaptive differential quadrature method (La-DQM) to solve multi-dimensional inverse scattering problem (ISP) of wave propagation. The La-DQM uses fictitious points to tackle the high-order differential equations with multi-boundary conditions and numerical results can be obtain directly in the calculation process. Six examples show the effectiveness and accuracy of the La-DQM in providing excellent estimates of unknown wave propagation from the given data. We think that the scheme is applicable to the ISP of wave propagation. Numerical results show that the La-DQM is powerful method for solving the inverse More >

Ligia Munteanu¹, Veturia Chiroiu¹

CMC-Computers, Materials & Continua, Vol.28, No.1, pp. 57-80, 2012, DOI:10.3970/cmc.2012.028.057

Abstract This paper discusses the modeling and feedforward control of hysteresis in a Cantor-like piezoelectric plate. The generalized play operator is analyzed in connection with the plate equations. Results show that hysteresis can be reduced to less than 40% when applying the feedforward control. The subject of the paper belongs to the field of dynamics, characterization and control at the micro/nanoscale. The choose of the Cantor-like piezoelectric plate is motivated by its special property to generate the subharmonic waves due to the anharmonic coupling between the extended-vibration (phonon) and the localized-mode (fracton) regimes. This behavior is… More >

Jinxia Wei¹, Yiming Chen¹, Baofeng Li², Mingxu Yi¹

CMES-Computer Modeling in Engineering & Sciences, Vol.89, No.6, pp. 481-495, 2012, DOI:10.3970/cmes.2012.089.481

Abstract In this paper, we present a computational method for solving a class of space-time fractional convection-diffusion equations with variable coefficients which is based on the Haar wavelets operational matrix of fractional order differentiation. Haar wavelets method is used because its computation is sample as it converts the original problem into Sylvester equation. Error analysis is given that shows efficiency of the method. Finally, a numerical example shows the implementation and accuracy of the approach. More >