Ch,ra S. Yerramalli¹, Anthony M. Waas²

CMES-Computer Modeling in Engineering & Sciences, Vol.6, No.1, pp. 1-16, 2004, DOI:10.3970/cmes.2004.006.001

Abstract Results from a 3D finite element based study of the compression response of unidirectional fiber reinforced polymer matrix composites (FRPC) are presented in this paper. The micromechanics based study was used to simulate the compressive response of glass and carbon fiber reinforced polymer matrix composites, with a view to understanding the effect of fiber diameter on compression strength. Results from the modeling and simulation indicate the presence of a complex three dimensional stress state in the matrix of the FRPC. Results from the simulation highlight the role of fiber diameter on the compressive response of FRPC. In particular, it is… More >

Yong Gan^*, Zhen Chen^∗,†

Molecular & Cellular Biomechanics, Vol.3, No.3, pp. 89-94, 2006, DOI:10.3970/mcb.2006.003.089

Abstract Due to their nanoscale size and special features, carbon nanotubes could enter the human body via certain way. The growing use of carbon nanotubes in practical applications, hence, prompts a necessity to study the potential health risks of carbon nanotubes. A numerical study is performed in this paper to investigate the size effect of carbon nanotubes on the bulk modulus of a lipid bilayer by using the constant surface tension molecular dynamics simulation procedure. It is found that the size effect is not monotonic with the increase of nanotube length. An explanation is given on the basis of the atomic… More >

J. Sladek¹, V. Sladek¹, S. Krahulec¹, M. Wünsche², Ch. Zhang²

CMC-Computers, Materials & Continua, Vol.29, No.1, pp. 75-102, 2012, DOI:10.3970/cmc.2012.029.075

Abstract A meshless method based on the local Petrov-Galerkin approach is proposed, to solve static and dynamic problems of two-layered magnetoelectroelastic composites with specific properties. One layer has pure piezoelectric properties and the second one is a pure piezomagnetic material. It is shown that the electric potential in the piezoelectric layer is induced by the magnetic potential in the piezomagnetic layer. The magnetoelectric effect is dependent on the ratio of the layer thicknesses. Functionally graded material properties of the piezoelectric layer and homogeneous properties of the piezomagnetic layer are considered too. The magnetoelectric composites are analyzed under a pure magnetic or… More >

H.T. Liu^1,2, Z. Chen², S. Jiang², Y. Gan³, M.B. Liu⁴, J.Z. Chang¹, Z.H. Tong¹

CMES-Computer Modeling in Engineering & Sciences, Vol.95, No.4, pp. 303-315, 2013, DOI:10.3970/cmes.2013.095.303

Abstract Dissipative particle dynamics (DPD) and molecular dynamics (MD) are both Lagrangian particle-based methods with similar equations except that the DPD specification for the force definition on the particles is the result of coarsegraining, and these two methods usually get the similar results in some specific cases. However, there are still some unknown differences between them. Considering the water response to external force, a comparative study of DPD and MD is conducted in this paper, which provides a better understanding on their relation, and a potential way to effectively bridge nanoscale and mesoscale simulation procedures. It is shown that there is… More >

K. Wang¹, S.J. Zhou^2,3, Z.F. Nie⁴

CMES-Computer Modeling in Engineering & Sciences, Vol.73, No.1, pp. 77-102, 2011, DOI:10.3970/cmes.2011.073.077

Abstract The natural neighbour Galerkin method is tailored to solve boundary value problems of the couple-stress elasticity to model the size dependent behaviour of materials. This method is based on the displacement-based Galerkin approach, and the calculation of the global stiffness matrix is performed using gradient smoothing technique combined with the non-Sibsonian partition of unity approximation scheme. This method possesses the following properties: the complex C1-continuous approximation scheme is avoided without using either Lagrange multipliers or penalty parameters; no domain integrals involved in the assembly of the global stiffness matrix; and the imposition of essential boundary conditions is straightforward. The validity… More >

D. C. C. Lam¹, L-H Keung¹, P. Tong²

CMES-Computer Modeling in Engineering & Sciences, Vol.66, No.1, pp. 73-100, 2010, DOI:10.3970/cmes.2010.066.073

Abstract Additional molecular rotations in long chained macromolecules lead to additional size dependence. In this investigation, we developed the higher order viscoelasticity framework and conducted experiments to determine the higher order material length scale parameters needed to describe the higher order viscoelastic behavior in the new framework. In the first part of the investigation of high order deformation behavior of macromolecular solids, the higher-order viscoelasticity theories for Maxwell and Kelvin-Voigt materials, and models of higher-order viscoelastic beam deflection creep are developed in this study. We conducted creep bending experiments with epoxy beams to show that the creep deflection behavior followed the… More >

Letícia Fleck Fadel Miguel¹, Ignacio Iturrioz², Jorge Daniel Riera³

CMES-Computer Modeling in Engineering & Sciences, Vol.56, No.1, pp. 1-16, 2010, DOI:10.3970/cmes.2010.056.001

Abstract Numerical predictions of the failure load of large structures, accounting for size effects, require the adoption of appropriate constitutive relations. These relations depend on the size of the elements and on the correlation lengths of the random fields that describe material properties. The authors proposed earlier expressions for the tensile stress-strain relation of concrete, whose parameters are related to standard properties of the material, such as Young's modulus or specific fracture energy and to size. Simulations conducted for a typical concrete showed that as size increases, the effective stress-strain diagram becomes increasingly linear, with a sudden rupture, while at the… More >

Tai-Ming Chang¹, Chien-Chou Weng¹, Mei-Jiau Huang^1,2, Chun-KaiLiu², Chih-Kuang Yu²

CMES-Computer Modeling in Engineering & Sciences, Vol.50, No.1, pp. 47-66, 2009, DOI:10.3970/cmes.2009.050.047

Abstract We employ the non-equilibrium molecular dynamics (NEMD) simulation to calculate the in-plane thermal conductivity of silicon thin films of thickness 2.2nm and 11nm. To eliminate the finite-size effect, samples of various lengths are simulated and an extrapolation technique is applied. To perform the quantum correction which is necessary as the MD simulation temperature is lower than Debye temperature, the confined phonon spectra are obtained in advance via the EMD simulations. The investigation shows the thermal conductivities corrected based on the bulk and thin-film phonon densities of states are very close and they agree excellently with the theoretical predictions of a… More >

Arun K. Nair¹, Diana Farkas², Ronald D. Kriz¹

CMES-Computer Modeling in Engineering & Sciences, Vol.24, No.2&3, pp. 239-248, 2008, DOI:10.3970/cmes.2008.024.239

Abstract The indentation response of Ni thin films of thicknesses in the nano scale was studied using molecular dynamics simulations with embedded atom method (EAM) interatomic potentials. Simulations were performed in single crystal films in the [111] orientation with thicknesses of 7nm and 33nm. In the elastic regime, the loading curves observed start deviating from the Hertzian predictions for indentation depths greater than 2.5% of the film thickness. The observed loading curves are therefore dependent on the film thickness. The simulation results also show that the contact stress necessary to emit the first dislocation under the indenter is nearly independent of… More >

Shuji Takashima¹, Michihiko Nakagaki², Noriyuki Miyazaki¹

CMES-Computer Modeling in Engineering & Sciences, Vol.20, No.3, pp. 193-202, 2007, DOI:10.3970/cmes.2007.020.193

Abstract Composite materials have complicated microstructures. These microstructures affect the macroscopic deformation of composite materials. In the present study, we focus on the effect of particle size in a particle-dispersed composite material on the mechanical strength of the material. For this purpose, we derived a macroscopic elastic-plastic constitutive equation using a modified version of the Eshelby's equivalent inclusion method combined with the gradient plasticity. We incorporated this macroscopic elastic-plastic constitutive equation into a finite element program and performed a homogenized finite element analysis of a particle-dispersed composite material in which both the macroscopic and microscopic behaviors of the composite material were… More >