Open Access
ARTICLE
F. Guarracino 1
CMES-Computer Modeling in Engineering & Sciences, Vol.72, No.3, pp. 167-184, 2011, DOI:10.3970/cmes.2011.072.167
Abstract The design of many engineering problems requires accurate test results and interpretation in order to evaluate the carrying capacity of circular cylindrical shells subjected to various loads including bending. Apparently anomalous values of axial tensile and compressive strains from recent test results have been lately investigated and explained using Finite Element modeling. As a complement to numerical analyses, in the present paper a simple analytical formula for the estimation of the effects of local conditions in tubes testing and design is provided on the basis of an extended Ritz's approach and of the general linear theory of shells. The findings… More >
Open Access
ARTICLE
D. Mirzaei1, M. Dehghan1
CMES-Computer Modeling in Engineering & Sciences, Vol.72, No.3, pp. 185-210, 2011, DOI:10.3970/cmes.2011.072.185
Abstract The meshless local Petrov-Galerkin (MLPG) method with an efficient technique to deal with the time variable are used to solve the heat conduction problem in this paper. The MLPG is a meshless method which is (mostly) based on the moving least squares (MLS) scheme to approximate the trial space. In this paper the MLS is used for approximation in both time and space domains, and we avoid using the time difference discretization or Laplace transform method to overcome the time variable. The technique is applied for continuously nonhomogeneous functionally graded materials (FGM) in a finite strip and a hallow cylinder.… More >
Open Access
ARTICLE
Che-Wun Hong1,2, Wei-Hui Chen1
CMES-Computer Modeling in Engineering & Sciences, Vol.72, No.3, pp. 211-228, 2011, DOI:10.3970/cmes.2011.072.211
Abstract This paper intends to use semiconductor quantum dots (cadmium sulphide- CdS) and/or biological pigments (chlorophyll-a derivatives) to replace those expensive ruthenium (Ru) dyes in photoelectrochemical solar cells. Based on the computational quantum chemistry, the molecular structures of (CdS)n (n=1 ~ 22) clusters and chlorophyll-a derivatives (chlorin-H3+ and chlorin-H17+) are configured and optimized. Density functional theory (DFT) of the first principles calculations, which chose B3LYP (Becke 3-parameter Lee-Yang-Parr) and PBE (Perdew-Burke- Ernzerhof) exchange correlation functionals, is employed. Photoelectric properties, such as: molecular orbital, density of state (DOS), highest occupied molecular orbital (HOMO), lowest unoccupied molecular orbital (LUMO) and resultant band gaps… More >
Open Access
ARTICLE
Veturia Chiroiu1, Ligia Munteanu2, Ioan Ursu3
CMES-Computer Modeling in Engineering & Sciences, Vol.72, No.3, pp. 229-246, 2011, DOI:10.3970/cmes.2011.072.229
Abstract Chaotic behavior of uncertain nonlinear systems offers a rich variety of orbits, which can be controlled by bounding the signals involved in closed-loop systems. In this paper, systems with nonlinear uncertainties with no prior knowledge of their bounds, unmodeled dynamic law and rapidly varying disturbances are analyzed in order to propose a stabilization controller of the chaotic behavior via the fuzzy logic systems. More >