Aimin Jiang^1,2, Yili Wu²

CMC-Computers, Materials & Continua, Vol.12, No.2, pp. 101-120, 2009, DOI:10.3970/cmc.2009.012.101

Abstract This paper presents a development of the boundary contour method (BCM) for piezoelectric media. Firstly, the divergence-free of the integrand of the piezoelectric boundary element method is proved. Secondly, the boundary contour method formulations are obtained by introducing quadratic shape functions and Green's functions (Computer Methods in Applied Mechanics and Engineering1998;158: 65-80) for piezoelectric media and using the rigid body motion solution to regularize the BCM and avoid computation of the corner tensor. The BCM is applied to the problem of piezoelectric media. Finally, numerical solutions for illustrative examples are compared with exact ones. The numerical results of the BCM… More >

LiviuMarin ¹

CMC-Computers, Materials & Continua, Vol.12, No.1, pp. 71-100, 2009, DOI:10.3970/cmc.2009.012.071

Abstract In this paper, the alternating iterative algorithm originally proposed by Kozlov, Maz'ya and Fomin (1991) is numerically implemented for the Cauchy problem in anisotropic heat conduction using a meshless method. Every iteration of the numerical procedure consists of two mixed, well-posed and direct problems which are solved using the method of fundamental solutions (MFS), in conjunction with the Tikhonov regularization method. For each direct problem considered, the optimal value of the regularization parameter is chosen according to the generalized cross-validation (GCV) criterion. An efficient regularizing stopping criterion which ceases the iterative procedure at the point where the accumulation of noise… More >

Amiya K. Samanta¹, Somnath Ghosh²

CMC-Computers, Materials & Continua, Vol.12, No.1, pp. 1-38, 2009, DOI:10.3970/cmc.2009.012.001

Abstract This paper presents a formulation of hypo-elasticity based RC beam model with bond-slip. Details of the constitutive model and analysis method used are provided. A procedure has been described to carry out three-dimensional analysis considering both geometrical as well as material nonlinearity for a simply supported RC beam employing finite element technique, which uses 8-noded isoparametric hexahedral element HCiS18. Enhanced assumed strain (EAS) formulation has been utilized to predict load-deformation and internal stresses both in the elastic as well as nonlinear regime. It models the composite behaviour of concrete and reinforcements in rigid /perfect bond situation and their mutual interaction… More >

D. S. Liu¹, C. Y. Tsai¹, S. R. Lyu²

CMC-Computers, Materials & Continua, Vol.11, No.2, pp. 147-164, 2009, DOI:10.3970/cmc.2009.011.147

Abstract This study presents a novel numerical method for extracting the tempe -rature-dependent mechanical properties of the gold and aluminum thin-films. In the proposed approach, molecular dynamics (MD) simulations are performed to establish the load-displacement response of the thin substrate nanoindented at temperatures ranging from 300-900 K. A simple but effective procedure involving genetic algorithm (GA) and finite element method (FEM) is implemented to extract the material constants of the gold and aluminum substrates. The material constants are then used to construct the corresponding stress-strain curve, from which the elastic modulus, yield stress and the tangent modulus of the thin film… More >

Chein-Shan Liu¹

CMC-Computers, Materials & Continua, Vol.11, No.1, pp. 15-32, 2009, DOI:10.3970/cmc.2009.011.015

Abstract Motivated by the evolutionary and dissipative properties of parabolic type partial differential equation (PDE), Liu (2008a) has proposed a natural and mathematically equivalent approach by transforming the quasilinear elliptic PDE into a parabolic one. However, the above paper only considered a rectangular domain in the plane, and did not treat the difficulty arisen from the quasilinear PDE defined in an arbitrary plane domain. In this paper we propose a new technique of internal and boundary residuals in a fictitious rectangular domain, which are driving forces for the ordinary differential equations based on the Fictitious Time Integration Method (FTIM). Several numerical… More >

Deepak A Apte¹, Ranjan Ganguli^1,2

CMC-Computers, Materials & Continua, Vol.10, No.2, pp. 139-162, 2009, DOI:10.3970/cmc.2009.010.139

Abstract The influence of electric field and temperature on power consumption of piezoelectric actuated integrated structure is studied by using a single degree of freedom mass-spring-damper system model coupled with a piezoactuator. The material lead zirconate titanate, is considered as it is capable of producing relatively high strains (e.g., 3000με). Actuators are often subject to high electric fields to increase the induced strain produced, resulting in field dependant piezoelectric coefficient d₃₁, dielectric coefficient ε₃₃ and dissipation factor δ. Piezostructures are also likely to be used across a wide range of temperatures in aerospace and undersea operations. Again, the piezoelectric properties can… More >

Chein-Shan Liu¹

CMC-Computers, Materials & Continua, Vol.10, No.1, pp. 97-116, 2009, DOI:10.3970/cmc.2009.010.097

Abstract A new numerical method is proposed for solving the delay ordinary differential equations (DODEs) under multiple time-varying delays or state-dependent delays. The finite difference scheme is used to approximate the ODEs, which together with the initial conditions constitute a system of nonlinear algebraic equations (NAEs). Then, a Fictitious Time Integration Method (FTIM) is used to solve these NAEs. Numerical examples confirm that the present approach is highly accurate and efficient with a fast convergence. More >

CMC-Computers, Materials & Continua, Vol.10, No.1, pp. 65-96, 2009, DOI:10.3970/cmc.2009.010.065

Abstract This work proposed an alternative formulation for the prediction of martensite start temperature (Ms) of Fe-Mn-Si shape memory alloys (SMAs) depending on the various compositions and heat treatment techniques by using Neural Network (NN) and genetic programming (GP) soft computing techniques. The training and testing patterns of the proposed NN and GP formulations are based on well established experimental results from the literature. The NN and GP based formulation results are compared with experimental results and found to be quite reliable with a very high correlation (R2=0.955 for GEP and 0.999 for NN). More >

J. Ghanbari¹, R. Naghdabadi^1,2

CMC-Computers, Materials & Continua, Vol.10, No.1, pp. 41-64, 2009, DOI:10.3970/cmc.2009.010.041

Abstract Continuum-based modeling of nanostructures is an efficient and suitable method to study the behavior of these structures when the deformation can be considered homogeneous. This paper is concerned about multiscale nonlinear tensorial constitutive modeling of carbon nanostructures based on the interatomic potentials. The proposed constitutive model is a tensorial equation relating the second Piola-Kirchhoff stress tensor to Green-Lagrange strain tensor. For carbon nanotubes, some modifications are made on the planar representative volume element (RVE) to account for the curved atomic structure resulting a non-planar RVE. Using the proposed constitutive model, the elastic behavior of the graphene sheet and carbon nanotube… More >

S. Straface¹, S. Troisi, V. Gagliardi

CMC-Computers, Materials & Continua, Vol.3, No.3, pp. 155-166, 2006, DOI:10.3970/cmc.2006.003.155

Abstract The present work shows an alternative to the classical methods to solve the Richards' Equation (RE), used to model flow in unsaturated porous media. This alternative is named Cell Method (CM). The CM is based on a preliminary reformulation of the mathematical model in a partially discrete form, which preserves as much as possible the physical and geometrical content of the original problem, and is made possible by the existence and properties of a common mathematical structure of field theories. The goal is to maintain the focus, both in the modelling and discretization steps, on the physics of the problem.… More >