B.K. Raghu Prasad¹, T.V.R.L. Rao¹, A.R. Gopalakrishnan¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.9, No.3, pp. 179-196, 2009, DOI:10.3970/icces.2009.009.179

Abstract A simple numerical method namely Initial Stiffness Method using finite element method has been employed to study the size effect which is prominent in concrete structures. Numerous experimental investigations performed on notched plain concrete beams subjected to three point or four-point bending have revealed the fracture process to be dependent on size of the structural member. It was found that, the nominal stress at maximum load decreases as the size of the structure increases. The nominal stress at failure on the characteristic dimension of structure is termed as size effect. This has also been explained More >

Ronan Madec¹, Dimitri Komatitsch^1,2, Julien Diaz³

CMES-Computer Modeling in Engineering & Sciences, Vol.49, No.2, pp. 163-190, 2009, DOI:10.3970/cmes.2009.049.163

Abstract When studying seismic wave propagation in fluid-solid models based on a numerical technique in the time domain with an explicit time scheme it is often of interest to resort to time substepping because the stability condition in the solid part of the medium can be more stringent than in the fluid. In such a case, one should enforce the conservation of energy along the fluid-solid interface in the time matching algorithm in order to ensure the accuracy and the stability of the time scheme. This is often not done in the available literature and approximate More >

C.M. Hefferan¹, S.F. Li¹, J. Lind¹, U. Lienert², A.D. Rollett³, P. Wynblatt³, R.M. Suter^1,3

CMC-Computers, Materials & Continua, Vol.14, No.3, pp. 209-220, 2009, DOI:10.3970/cmc.2009.014.209

Abstract We have measured and reconstructed via forward modeling a small volume of microstructure of high purity, well annealed nickel using high energy x-ray diffraction microscopy (HEDM). Statistical distributions characterizing grain orientations, intra-granular misorientations, and nearest neighbor grain misorientations are extracted. Results are consistent with recent electron backscatter diffraction measurements. Peaks in the grain neighbor misorientation angle distribution at 60 degrees (∑3) and 39 degrees (∑9) have resolution limited widths of ≈ 0.14 degree FWHM. The analysis demonstrates that HEDM can recover grain and grain boundary statistics comparable to OIM volume measurements; more extensive data sets More >

Y.B. Zhang¹, A. Godfrey², D. Juul Jensen¹

CMC-Computers, Materials & Continua, Vol.14, No.3, pp. 197-208, 2009, DOI:10.3970/cmc.2009.014.197

Abstract Two methods to quantify protrusions/retrusions and to estimate local boundary curvature from sample plane sections are proposed. The methods are used to evaluate the driving force due to curvature of the protrusions/retrusions for partially recrystallized pure nickel cold rolled to 96% reduction in thickness. The results reveal that the values calculated by both these methods are reasonable when compared with the stored energy measured by differential scanning calorimetry. The relationship between protrusions and the average stored energy density in the deformed matrix is also investigated for partially recrystallized pure aluminum cold rolled to 50%. The More >

H. Ghasemnejad¹, H. Hadavinia^1,2, D. Marchant¹, A. Aboutorabi¹

Structural Durability & Health Monitoring, Vol.4, No.1, pp. 29-46, 2008, DOI:10.3970/sdhm.2008.004.029

Abstract In this paper the crashworthiness capabilities of thin-walled corrugated crash boxes in axial crushing relative to flat sidewall boxes from the same material are investigated. In order to achieve this, various design of corrugated aluminium alloy 6060 temper T4 crash boxes were chosen and their axial crushing behaviour under impact loading was studied by developing a theoretical model based on Super Folding Element theory and by conducting finite element analysis using LS-DYNA in ANSYS. From the theoretical and FE analysis the crush force efficiency, the specific energy absorption and the frequency and amplitude of fluctuation of More >

Shueei-Muh Lin^1,3, Sen-Yung Lee², Cheng-Chuan Tsai², Chien-Wi Chen²,Wen-Rong Wang³, Jenn-Fa Lee³

CMES-Computer Modeling in Engineering & Sciences, Vol.34, No.1, pp. 33-54, 2008, DOI:10.3970/cmes.2008.034.033

Abstract The conventional theories for circulation of arteries are emphasized on fluid behavior or some simplified models for experimental utility. In this study, a new mathematical theory is proposed to describe the wave propagation through the elastic tube filled with viscous and incompressible fluid. The radial, longitudinal and flexural vibrations of a tube wall are introduced simultaneously. Meanwhile, the linearlized momentum and continuity equations of tube flow field are expressed in the integral form. Based on these considerations, three wave modes are obtained simultaneously. These wave modes are the flexural, Young and Lamb modes, respectively. The… More >

E. Pan^1,2, Y. Zhang², P. W. Chung³, M. Denda⁴

CMES-Computer Modeling in Engineering & Sciences, Vol.24, No.2&3, pp. 157-168, 2008, DOI:10.3970/cmes.2008.024.157

Abstract Quantum-dot (QD) semiconductor synthesis is one of the most actively investigated fields in strain energy band engineering. The induced strain fields influence ordering and alignment, and the subsequent surface formations determine the energy bandgap of the device. The effect of the strains on the surface formations is computationally expensive to simulate, thus analytical solutions to the QD-induced strain fields are very appealing and useful. In this paper we present an analytical method for calculating the QD-induced elastic field in anisotropic half-space semiconductor substrates. The QD is assumed to be of any polyhedral shape, and its… More >

S. Sabbaghi¹, M. Shariaty-Niassar², Sh. Ayatollahi¹, A. Jahanmiri¹

FDMP-Fluid Dynamics & Materials Processing, Vol.4, No.2, pp. 113-124, 2008, DOI:10.3970/fdmp.2008.004.113

Abstract In this study, the Onset of Asphaltene Precipitation is predicted by a modified Virial equation of state. The bases of quantum mechanics and statistical thermodynamics are used to evaluate the potential energy and intermolecular forces related to asphaltene molecules. The Virial equation of state is modified using group-contribution-methods for asphaltenes, which are assumed to be polymeric-like compounds consisting of aggregates of monodisperse asphaltene monomers. It is shown how the modified Virial equation of state with the Peneloux correction leads to estimate the molar volume and solubility parameter. These parameters are also compared successfully with results More >

M. Daian¹, A. Taube², G. Torgovnikov³, G. Daian⁴, Y. Shramkov⁵

CMC-Computers, Materials & Continua, Vol.8, No.3, pp. 165-172, 2008, DOI:10.3970/cmc.2008.008.165

Abstract Microwave wood modification and treatment technologies become more and more essential within the wood industry due to their technical and economical advantages. Microwave processing of wood involves many complicated physical phenomena and requires a very careful control of variables (such as intensity of microwave power, loading period, maximum temperature, etc.) in order to reduce structural deformations of the processed wood. To optimise and minimise the project design engineers' work, modelling and simulation of the microwave energy-wood interaction represents an indispensable tool.
This research work has been undertaken with the aim to design and optimise microwave… More >

P.H. Wen¹, M.H. Aliabadi²

Structural Durability & Health Monitoring, Vol.3, No.2, pp. 107-120, 2007, DOI:10.3970/sdhm.2007.003.107

Abstract In the last decade, meshless methods for solving differential equations have become a promising alternative to the finite element and boundary element methods. Based on the variation of potential energy, the element-free Galerkin method is developed on the basis of finite element method by the use of radial basis function interpolation. An enriched radial basis function is formulated to capture the stress singularity at the crack tip. The usual advantages of finite element method are retained in this method but now significant improvement of accuracy. Neither the connectivity of mesh in the domain by the More >