Walter Gerstle¹, Stewart Silling², David Read³, Vinod Tewary⁴, Richard Lehoucq⁵

CMC-Computers, Materials & Continua, Vol.8, No.2, pp. 75-92, 2008, DOI:10.3970/cmc.2008.008.075

Abstract A theoretical framework, based upon the peridynamic model, is presented for analytical and computational simulation of electromigration. The framework allows four coupled physical processes to be modeled simultaneously: mechanical deformation, heat transfer, electrical potential distribution, and vacancy diffusion. The dynamics of void and crack formation, and hillock and whisker growth can potentially be modeled. The framework can potentially be applied at several modeling scales: atomistic, crystallite, multiple crystallite, and macro. The conceptual simplicity of the model promises to permit many phenomena observed in microchips, including electromigration, thermo-mechanical crack formation, and fatigue crack formation, to be analyzed in a systematic and… More >

Jae In Kim¹, Kilho Eom², Moon Kyu Kwak³, Sungsoo Na⁴

CMC-Computers, Materials & Continua, Vol.8, No.2, pp. 67-74, 2008, DOI:10.3970/cmc.2008.008.067

Abstract This paper concerns the application of component mode synthesis for biomolecule modeling to understand protein dynamics. As for protein dynamics, eigenvalue problem should be formulated to obtain eigenvalue, eigenvector and thermal fluctuation. To describe the thermal fluctuation of protein, normal mode analysis is introduced and normal modes identify the dynamic behavior of protein very well. Component mode synthesis considers the given complex structure as an assembly of smaller components. The selection of a component may be arbitrary. When the component mode synthesis is applied to formulate the eigenvalue problem of protein structure, we selected a protein which may be composed… More >

Chein-Shan Liu¹

CMC-Computers, Materials & Continua, Vol.8, No.2, pp. 53-66, 2008, DOI:10.3970/cmc.2008.008.053

Abstract Proposed is a time-marching algorithm to solve a nonlinear system of complementarity equations: P_i(x_j) ≥ 0, Q_i(x_j) ≥ 0 , P_i(x_j)Q_i(x_j) = 0, i, j = 1,...,n, resulting from a discretization of nonlinear obstacle problem. We transform the above nonlinear complementarity problem (NCP) into a nonlinear algebraic equations (NAEs) system: F_i(x_j) = 0 with the aid of the Fischer-Burmeister NCP-function. Such NAEs are semi-smooth, highly nonlinear and usually implicit, being hard to handle by the Newton-like method. Instead of, a first-order system of ODEs is derived through a fictitious time equation. The time-stepping equations are obtained by applying a numerical… More >

Amiya K. Samanta¹, Somnath Ghosh²

CMC-Computers, Materials & Continua, Vol.8, No.1, pp. 43-52, 2008, DOI:10.3970/cmc.2008.008.043

Abstract A procedure has been described to carry out three-dimensional elastic analysis of reinforced concrete beam employing finite element technique, which uses lower order elements. The proposed procedure utilizes 8-noded isometric solid /hexahedral elements HCiS18 with enhanced assumed strain (EAS) formulation, recently developed in the literature, to predict load-deformation and internal stresses produced in case of a simply supported RC beams in the elastic regime. It models the composite behaviour of concrete and reinforcements in rigid /perfect bond situation and their mutual interaction in bond-slip condition considering continuous interface elements at the material level. Although, bond-slip relation are very much non-linear… More >

Huanchun Chen¹, Kunigal Shivakumar¹

CMC-Computers, Materials & Continua, Vol.8, No.1, pp. 33-42, 2008, DOI:10.3970/cmc.2008.008.033

Abstract Thermal cycling degradation effect on tensile and flexural properties of Cytec T650 carbon/Lonza Primaset PT-30 cyanate ester composite rods used for gas turbine engine brush seals was evaluated. The composite rods were thermal cycled in air from room temperature to 315°C for 100, 200, 400, 600 and 800 cycles. Each thermal cycle is a one hour period with 28 minutes hold at peak temperature and a high heating/cooling rate of 73°C/min. The composite withstood the first 100 thermal cycles with less than 10% property change. After that, tensile strength and fracture strain as well as flexural modulus were gradually reduced.… More >

B. Yang², V. K. Tewary³

CMC-Computers, Materials & Continua, Vol.8, No.1, pp. 23-32, 2008, DOI:10.3970/cmc.2008.008.023

Abstract A three-dimensional Green's function for a material system consisting of anisotropic and linearly elastic planar multilayers with interfacial membrane and flexural rigidities has been derived. The Stroh formalism and two-dimensional Fourier transforms are applied to derive the general solution for each homogeneous layer. The Green's function for the multilayers is then solved by imposing the surface boundary condition, the interfacial displacement continuity condition, and the interfacial traction discontinuity condition. The last condition is given by the membrane and bending equilibrium equations of the interphases modeled as Kirchhoff plates. Numerical results that demonstrate the validity and efficiency of the formulation are… More >

Yan Zhang¹, Shengping Shen¹

CMC-Computers, Materials & Continua, Vol.8, No.1, pp. 17-22, 2008, DOI:10.3970/cmc.2008.008.017

Abstract In this paper, an existed model for adsorption-induced surface stress is modified with physical clarity, based on the equilibrium of force. In the proposed multiscale model, a four-atom system is used, instead of the existed three-atom system which did not consider the force equilibrium. By analyzing the force state of an atom, the thickness of the first layer atoms can be determined. Thus, the proposed model does not need to determine the layer-thickness by experiments or artificially. The results obtained from the proposed model agree very well with the experimental data. This paper is helpful to investigate the atomistic theory… More >

Chein-Shan Liu¹

CMC-Computers, Materials & Continua, Vol.8, No.1, pp. 1-16, 2008, DOI:10.3970/cmc.2008.008.001

Abstract In the present work we study numerical computations of inverse thermal stress problems. The unknown boundary conditions of an elastically deformable heat conducting rod are not given a priori and are not allowed to measure directly, because the boundary may be not accessible to measure. However, an internal measurement of temperature is available. We treat this inverse problem by using a semi-discretization technique, of which the time domain is divided into many sub-intervals and the physical quantities are discretized at these node points of discrete times. Then the resulting ordinary differential equations in the discretized space are numerically integrated towards… More >

Arnab Chakrabarty¹, Tahir Çağin¹

CMC-Computers, Materials & Continua, Vol.7, No.3, pp. 167-190, 2008, DOI:10.3970/cmc.2008.007.167

Abstract The excellent set of properties of carbon nanotube and carbon nanotube-based nanostructures has been established by various studies. However the claimed property values and trends have not been unanimously agreed upon. Using state of the art molecular dynamics and ab initio methods, we have extensively studied the mechanical, thermal and structural properties of carbon nanotubes and carbon nanotube based nanostructures. Additionally this study aims to address the approaches used in various studies to assess the validity and influence of various definitions used for determining the physical properties as reported in earlier experiments and theoretical calculations. We have come up with… More >

X.G. Yuan^1,2, R.J. Zhang³, H.W. Zhang¹

CMC-Computers, Materials & Continua, Vol.7, No.3, pp. 155-166, 2008, DOI:10.3970/cmc.2008.007.155

Abstract In this paper, the dynamic inflation problems are examined for infinitely long cylindrical tubes composed of a class of transversely isotropic incompressible Ogden material models. The inner surface of the tube is subjected to a class of periodic step radial pressures relating to time. The influences of various parameters, namely, the material parameters, the structure parameters and the applied pressures, on dynamic behaviors of the tube are discussed in detail. Significantly, for some given material parameters, it is proved that the motion of the tube would present a class of nonlinear periodic oscillations for any given pressures and the amplitude… More >