M.A.Arafin¹, J.A.Szpunar²

CMC-Computers, Materials & Continua, Vol.14, No.2, pp. 125-140, 2009, DOI:10.3970/cmc.2009.014.125

Abstract A novel microstructure, texture and grain boundary character based model has been proposed to simulate the intergranular crack propagation behavior in textured polycrystalline materials. The model utilizes the Voronoi algorithm and Monte Carlo simulations to construct the microstructure with desired grain shape factor, takes the texture description of the materials to assign the orientations of the grains, evaluates the grain boundary character based on the misorientation angle - axis calculated from the orientations of the neighboring grains, and takes into account the inclination of grain boundaries with respect to the external stress direction. Markov Chain theory has been applied to… More >

Xiaohua Hu¹, Gordana A. Cingara¹, David S. Wilkinson¹, Mukesh Jain², PeidongWu², Raja K. Mishra³

CMC-Computers, Materials & Continua, Vol.14, No.2, pp. 99-124, 2009, DOI:10.3970/cmc.2009.014.099

Abstract This work aims to understand the texture distribution in the localized necking band formed during uni-axial tension of AA5754 using an edge-constrained, plane strain post-necking FE model. The model domain is a long cross section of the band. Initial grain structure is mapped into the mesh from EBSD data using a modified Voroni-cell interpolation and considering pre-straining prior to localized necking. The material points in grains are assumed to exhibit isotropic elastoplastic behavior but have a relative strength in terms of Taylor factors which are updated by a Taylor-Bishop-Hill model. The predicted textures and gradients within the localized necking band… More >

H. Elnaiem¹, D. Casimir¹, P. Misra¹, S.M. Gatica^1,2

CMC-Computers, Materials & Continua, Vol.14, No.1, pp. 23-34, 2009, DOI:10.3970/cmc.2009.014.023

Abstract Nanobubbles have been found to form at the interface of water and solid surfaces. We examine the conditions for such bubbles to form and estimate the pressure inside the bubble based on thermodynamic considerations. Using a simple model we calculate the contact angle for a wide range of temperatures and hypothetical substrates possessing a continuous range of strengths. We show that as the temperature increases the shape of a bubble changes continuously from a spherical cap with low curvature to a complete sphere. An equivalent effect results from either increasing the strength of the solid or decreasing the surface tension.… More >

Hao-Miao Zhou¹, Fang Li¹, Qiang Ye¹, Ji-Xiang Zhao¹, Zhe-Lei Xia¹, YingTang², Jing Wei³

CMC-Computers, Materials & Continua, Vol.13, No.3, pp. 235-248, 2009, DOI:10.3970/cmc.2009.013.235

Abstract At present, there are many methods about Young's modulus measurement of thin films, but so far there is no recognized simple, non-destructive and cheaper standard measurement method. Considering thin films with various thicknesses were sputter deposited on the magnetostrictive resonator and monitoring the resonator's first-order longitudinal resonant frequency shift both before and after deposition induced by external magnetic field, an Young's modulus assessing method based on classical laminated plate theory is presented in this paper. Using the measured natural frequencies of Au, Cu, Cr, Al and SiC materials with various thicknesses in the literature, the Young's modulus of the five… More >

B. Tomas Johansson¹, Liviu Marin²

CMC-Computers, Materials & Continua, Vol.13, No.2, pp. 153-190, 2009, DOI:10.3970/cmc.2009.013.153

Abstract We propose two algorithms involving the relaxation of either the given Dirichlet data or the prescribed Neumann data on the over-specified boundary, in the case of the alternating iterative algorithm of Kozlov, Maz'ya and Fomin(1991) applied to Cauchy problems for the modified Helmholtz equation. A convergence proof of these relaxation methods is given, along with a stopping criterion. The numerical results obtained using these procedures, in conjunction with the boundary element method (BEM), show the numerical stability, convergence, consistency and computational efficiency of the proposed methods. More >

D.P.Mondal¹, S.Das¹, Anshul Badkul¹, Nidhi Jha¹

CMC-Computers, Materials & Continua, Vol.13, No.2, pp. 115-134, 2009, DOI:10.3970/cmc.2009.013.115

Abstract The cooling effect by evaporative liquid is modeled by considering that heat is transferred from the system to the surrounding due to evaporation of liquid through the pores present in the medium. The variation of cooling rate with cell size, volume fraction of pores and physical conditions has been analyzed. The model demonstrates that it increases with increase in thickness of the foam slab and with increase in velocity of air. It is also observed that cooling effect decreases with decrease in volume fraction of porosity and with increase in relative density, cell size, thermal conductivity and relative humidity. More >

De-Shin Liu¹, Zhen-Wei Zhuang^1,2, Cho-LiangChung³, Ching-Yang Chen⁴

CMC-Computers, Materials & Continua, Vol.13, No.2, pp. 89-114, 2009, DOI:10.3970/cmc.2009.013.089

Abstract This paper employs a novel numerical technique, designated as the hybrid moisture element method (HMEM), to model and analyze moisture diffusion in a heterogeneous epoxy resin containing multiple randomly distributed particles. The HMEM scheme is based on a hybrid moisture element (HME), whose properties are determined by equivalent moisture capacitance and conductance matrixes calculated using the conventional finite element formulation. A coupled HME-FE scheme is developed and implemented using the commercial FEM software ABAQUS. The HME-FE scheme is then employed to analyze the moisture diffusion characteristics of a heterogeneous epoxy resin layer containing particle inclusions. The analysis commences by comparing… More >

W.F.Yuan¹, K.H.Tan ¹

CMC-Computers, Materials & Continua, Vol.13, No.1, pp. 49-62, 2009, DOI:10.3970/cmc.2009.013.049

Abstract A simple cellular automaton (CA) scheme is proposed to simulate heat conduction in anisotropic domains. The CA is built on random nodes rather than an irregular grid. The local rule used in the CA is defined by physical concepts instead of differential equations. The accuracy of the proposed approach is verified by classical examples. As an application of the proposed method, the CA approach is incorporated into fibre model which is widely used in finite element analysis to calculate the temperature distribution on the cross-section of composite beams. Numerical examples demonstrate that the proposed scheme can be conveniently applied to… More >

J.A.Ferreira^1,2, P. de Oliveira², P. da Silva³, D. M. G. Comissiong⁴

CMC-Computers, Materials & Continua, Vol.13, No.1, pp. 17-48, 2009, DOI:10.3970/cmc.2009.013.017

Abstract A phenomenological formulation is adopted to investigate desorption in polymers. The speed of the front is studied and the well-posedness of the general model is analyzed. Numerical simulations illustrating the dynamics of the desorption process described by the proposed model are included. More >

Chih-Ping Wu^1,2, Shao-En Huang²

CMC-Computers, Materials & Continua, Vol.12, No.3, pp. 251-282, 2009, DOI:10.3970/cmc.2009.012.251

Abstract A modified Pagano method is developed for the three-dimensional (3D) coupled analysis of simply-supported, doubly curved functionally graded (FG) piezo-thermo-elastic shells under thermal loads. Four different loading conditions, applied on the lateral surfaces of the shells, are considered. The material properties of FG shells are regarded as heterogeneous through the thickness coordinate, and then specified to obey an exponent-law dependent on this. The Pagano method, conventionally used for the analysis of multilayered composite elastic plates/shells, is modified to be feasible for the present analysis of FG piezo-thermo-elastic plates/shells. The modifications include that a displacement-based formulation is replaced by a mixed… More >