Giacomo Landi¹, Surya R. Kalidindi²

CMC-Computers, Materials & Continua, Vol.16, No.3, pp. 273-294, 2010, DOI:10.3970/cmc.2010.016.273

Abstract In this paper, we present a computationally efficient multi-scale framework for predicting the local fields in the representative volume element of a multiphase material system subjected to thermo-mechanical loading conditions. This framework for localization relationships is a natural extension of our recent work on two-phase composites subjected to purely mechanical loading. In this novel approach, the localization relationships take on a simple structure expressed as a series sum, where each term in the series is a convolution product of local structure and the governing physics expressed in the form of influence coefficients. Another salient feature of this approach is its… More >

Zone-Ching Lin¹and Ren-Yuan Wang¹

CMC-Computers, Materials & Continua, Vol.16, No.3, pp. 247-272, 2010, DOI:10.3970/cmc.2010.016.247

Abstract The paper establishes a new three-dimensional quasi-steady molecular statics nanoscale abrasive cutting model to investigate the abrasive cutting behavior in the downpressing and abrasive cutting process of a workpiece in chemical mechanical polishing (CMP) process. The downpressing and abrasive cutting process is a continuous process. The abrasive cutting process is done after the single abrasive particle has downpressed and penetrated a workpiece to a certain depth of a workpiece. The paper analyzes the effects of the abrasive particles with different diameters on action force. It also analyzes the action force change of abrasive particles with different diameters on the projected… More >

Xue-Qian Fang^1,2, Xiao-Hua Wang¹, Le-Le Zhang³

CMC-Computers, Materials & Continua, Vol.16, No.3, pp. 229-246, 2010, DOI:10.3970/cmc.2010.016.229

Abstract In the design of advanced micro- and nanosized materials and devices containing inclusions, the effects of surfaces/interfaces on the stress concentration become prominent. In this paper, based on the surface/interface elasticity theory, a two-dimensional problem of an elliptical nano-inhomogeneity under anti-plane shear waves is considered. The conformal mapping method is then applied to solve the formulated boundary value problem. The analytical solutions of displacement fields are expressed by employing wave function expansion method, the expanded mode coefficients are determined by satisfying the boundary conditions at the interfaces of the nano-inhomogeneity. Analyses show that the effect of the interfacial properties on… More >

M.R. Khoshravan¹ and M.A. Setoodeh¹

CMC-Computers, Materials & Continua, Vol.16, No.3, pp. 195-228, 2010, DOI:10.3970/cmc.2010.016.195

Abstract The use of welding to permanently join plates is common in industry due to its high efficiency. But welding creates thermal stresses, which can lead to residual stresses and physical distortion. This phenomenon directly influences the buckling stiffness of the welded structure. The welding distortion not only makes difficult the erection of the project, but also influences the final quality and cost of production. In this research, the thermo-elastic-plastic conditions were simulated by a three-dimensional (3D) finite element model (FE). Mechanical and thermal properties of the material were applied to the model, leading to eigenvalue analysis of the thermal and… More >

Hieu H. Pham¹, Tahir Ça ˇgın¹

CMC-Computers, Materials & Continua, Vol.16, No.2, pp. 175-194, 2010, DOI:10.3970/cmc.2010.016.175

Abstract We analyze the lattice dynamics of Fe in different crystal phases (bcc, fcc and hcp) by using density-functional theory. The study on equations of states indicates that bcc Fe is more stable than fcc and hcp Fe at low pressures. However, dynamical instabilities in lattice vibrations of bcc Fe predict a phase transformation from bcc to hcp at higher pressures. We reported a complete set of second-order and third-order elastic constants of Fe in these three phases. We observed a linear variation in the values of second order elastic constant as a function of increased pressures. The phonon spectra were… More >

O. U. Ojeda¹ and T. Çagınˇ ¹

CMC-Computers, Materials & Continua, Vol.16, No.2, pp. 127-174, 2010, DOI:10.3970/cmc.2010.016.127

Abstract The large discrepancy in length and time scales at which characteristic processes of energetic materials are of relevance pose a major challenge for current simulation techniques. We present a systematic study of crystalline energetic materials of different sensitivity and analyze their properties at different theoretical levels. Information like equilibrium structures, vibrational frequencies, conformational rearrangement and mechanical properties like stiffness and elastic properties can be calculated within the density functional theory (DFT) using different levels of approximations. Dynamical properties are obtained by computations using molecular dynamics at finite temperatures through the use of classical force fields. Effect of defects on structure… More >

W. F. Yuan^1,2, H. B. Zhang¹

CMC-Computers, Materials & Continua, Vol.16, No.2, pp. 117-126, 2010, DOI:10.3970/cmc.2010.016.117

Abstract Corrosion pits on a steel plate can reduce the strength of the plate. However, it is difficult to calculate the corrosion effect analytically since the pits are normally distributed on the plate's surface randomly. In this manuscript, a simple approach is proposed to convert the corroded plate into a perfect one. By this method, the corrosion pits are treated as inclusions embedded in the plate. Then the analytical mechanics model used for composite material can be adopted in the calculation of the steel plate's effective material properties. To verify the proposed approach, numerical simulation is conducted using finite element method. More >

E. Hayward¹, C. Deo¹

CMC-Computers, Materials & Continua, Vol.16, No.2, pp. 101-116, 2010, DOI:10.3970/cmc.2010.016.101

Abstract Damage cascades representative of those that would be induced by neutron irradiation have been simulated in systems of pure iron and iron containing 0.01 at.% hydrogen. Results from molecular dynamics simulations using three different embedded-atom method (EAM) type potentials are compared for primary knock-on atom energies of 5, 10, and 20 keV to assess the effect of hydrogen on the primary damage state. We examine the influence of hydrogen on the primary damage state due to a single radiation cascade. These results can serve as an atomistic database for methods and simulations for long time scale evolution of radiation damage. More >

Veturia Chiroiu¹, Ligia Munteanu¹, Pier Paolo Delsanto²

CMC-Computers, Materials & Continua, Vol.16, No.1, pp. 75-100, 2010, DOI:10.3970/cmc.2010.016.075

Abstract Conventional continuum theories are unable to capture the observed indentation size effects, due to the lack of intrinsic length scales that represent the measures of nanostructure in the constitutive relations. In order to overcome this deficiency, the Toupin-Mindlin strain gradient theory of nanoindentation is formulated in this paper and the size dependence of the hardness with respect to the depth and the radius of the indenter for multiple walled carbon nanotubes is investigated. Results show a peculiar size influence on the hardness, which is explained via the shear resistance between the neighboring walls during the buckling of the multiwalled nanotubes. More >

J. Zidek¹ , J. Kucera¹, J. Jancar¹

CMC-Computers, Materials & Continua, Vol.16, No.1, pp. 51-74, 2010, DOI:10.3970/cmc.2010.016.051

Abstract It has been shown that in particulate filled composites, a cross-property relationship exists between various transport properties (e.g., electrical conductivity, mechanical reinforcement, gas permeation) of a macroscale composite. Thus, knowledge of the effective mechanical properties of a composite immediately places bounds on its electrical conductivity or gas permeation behavior. Using these bounds allows us to predict the phase dispersion state that optimizes one or multiple properties of the composite and, thus, the knowledge of how spatial arrangement of filler particles at their given content affects physical properties of the composite can be valuable. In this paper, a new numerical model… More >