A.P.S.Selvadurai¹

CMES-Computer Modeling in Engineering & Sciences, Vol.52, No.3, pp. 259-278, 2009, DOI:10.3970/cmes.2009.052.259

Abstract The paper deals with a computational approach for modelling the fragmentation of ice sheets during their impact with stationary structures. The modelling takes into consideration the intact continuum behaviour of the ice as a rate-sensitive elastoplastic material. During impact, the ice sheet can undergo fragmentation, which is controlled by a brittle strength criterion based on the current stress state. The fragmentation allows the generation of discrete elements of the ice sheet, the movements of which are governed by the equations of motion. The contact between individual fragments is governed by a Coulomb criterion. The individual fragments can themselves undergo further… More >

Yongfeng Zhang¹, Hanchen Huang^1,2, Satya N. Atluri³

CMES-Computer Modeling in Engineering & Sciences, Vol.35, No.3, pp. 215-226, 2008, DOI:10.3970/cmes.2008.035.215

Abstract Molecular dynamics simulations reveal the asymmetrical yield strength of twinned copper nanowires under tension and compression. The simulation results show that the strength of nanowires depends on loading conditions, morphologies, and twin spacing. Under tensile loading condition the Schmidt factor of the leading partial is larger than that under compression. Effectively, the yield strength under tension is smaller than that under compression. When the cross-section is circular in morphology, dislocation nucleation requires larger stress, and the asymmetry of yield strength depends on the nucleation stress. When the cross section is square in morphology, dislocation nucleation requires smaller stress, and the… More >

N. Shishido, T. Ikeda, N. Miyazaki

CMES-Computer Modeling in Engineering & Sciences, Vol.35, No.1, pp. 1-20, 2008, DOI:10.3970/cmes.2008.035.001

Abstract We propose an image correction method that will accurately measure full-field displacement in a microstructure using the digital image correlation method (DICM); the proposed method is suitable for use with laser-scanned images. Laser scanning microscopes have higher spatial resolution and deeper depth of field than optical microscopes, but errors in laser scanning position (time-dependent distortion) affect the accuracy of the DICM. The proposed image correction method involves the removal of both time-dependant and time-independent distortions. Experimental results using images of prescribed rigid-body motions demonstrate that the proposed correction method is capable of identifying and removing both types of distortion. Specifically,… More >

Yonghua Zhou¹, Chao Mi¹, Xun Yang¹

CMES-Computer Modeling in Engineering & Sciences, Vol.86, No.6, pp. 533-550, 2012, DOI:10.3970/cmes.2012.086.533

Abstract The cellular automaton (CA) model for traffic flow describes the restrictive vehicle movements using the distance headway (gap) between two adjacent vehicles. However, the autonomous and synergistic behaviors also exist in the vehicle movements. This paper makes an attempt to propose a microscopic traffic simulation model such that the feedback control behavior during the driving process is incorporated into the CA model. The acceleration, speed holding and deceleration are manipulated by the difference between the gap and the braking reference distance the driver perceives, which is generally observed in the realistic traffic. The braking reference distance is related to the… More >

C.-D. Tran¹, N. Mai-Duy^1,1, K. Le-Cao¹, T. Tran-Cong¹

CMES-Computer Modeling in Engineering & Sciences, Vol.85, No.6, pp. 499-520, 2012, DOI:10.3970/cmes.2012.085.499

Abstract A numerical computation of continuum-microscopic model for visco-elastic flows based on the Integrated Radial Basis Function (IRBF) Control Volume and the Stochastic Simulation Techniques (SST) is reported in this paper. The macroscopic flow equations are closed by a stochastic equation for the extra stress at the microscopic level. The former are discretised by a 1D-IRBF-CV method while the latter is integrated with Euler explicit or Predictor-Corrector schemes. Modelling is very efficient as it is based on Cartesian grid, while the integrated RBF approach enhances both the stability of the procedure and the accuracy of the solution. The proposed method is… More >

H.F. Zhan, Y.T. Gu¹

CMES-Computer Modeling in Engineering & Sciences, Vol.80, No.1, pp. 23-56, 2011, DOI:10.3970/cmes.2011.080.023

Abstract Based on the embedded atom method (EAM) and molecular dynamics (MD) method, in this paper, the tensile deformation properties of Cu nanowires (NWs) with different pre-existing defects, including single surface defects, surface bi-defects and single internal defects, are systematically studied. In-depth deformation mechanisms of NWs with pre-existing defects are also explored. It is found that Young's modulus is insensitive to different pre-existing defects, but yield strength shows an obvious decrease. Defects are observed influencing greatly on NWs' tensile deformation mechanisms, and playing a role of dislocation sources. Besides of the traditional deformation process dominated by the nucleation and propagation of… More >

Lianhua Ma¹, Bernard F. Rolfe², Qingsheng Yang^1,3, Chunhui Yang^2,3

CMES-Computer Modeling in Engineering & Sciences, Vol.79, No.2, pp. 131-158, 2011, DOI:10.3970/cmes.2011.079.131

Abstract For fluid-filled closed cell composites widely distributed in nature, the configuration evolution and effective elastic properties are investigated using a micromechanical model and a multiscale homogenization theory, in which the effect of initial fluid pressure is considered. Based on the configuration evolution of the composite, we present a novel micromechanics model to examine the interactions between the initial fluid pressure and the macroscopic elasticity of the material. In this model, the initial fluid pressure of the closed cells and the corresponding configuration can be produced by applying an eigenstrain at the introduced fictitious stress-free configuration, and the pressure-induced initial microscopic… More >

J. Cugnoni¹, M. Galli²

CMES-Computer Modeling in Engineering & Sciences, Vol.66, No.2, pp. 165-186, 2010, DOI:10.3970/cmes.2010.066.165

Abstract With the progress of miniaturization, in many modern applications the characteristic dimensions of the physical volume occupied by particle-reinforced composites are getting comparable with the reinforcement size and many of those composite materials undergo plastic deformations. In both experimental and modelling contexts, it is therefore very important to know whether, and up to which characteristic size, the description of the composites in terms of effective, homogenized properties is sufficiently accurate to represent their response in the actual geometry. Herein, the case of particle-reinforced composites with elastoviscoplastic matrix materials and polyhedral randomly arranged linear elastic reinforcement is considered since it is… More >

Zone-Ching Lin¹, Jia-Rong Ye²

CMES-Computer Modeling in Engineering & Sciences, Vol.50, No.3, pp. 227-252, 2009, DOI:10.3970/cmes.2009.050.227

Abstract The paper develops a quasi-steady molecular statics model to analyze nanoscale cutting of copper materials by diamond cutters with different shapes. Cutting action, cutting force, equivalent strain and equivalent stress are discussed and compared. The quasi-steady molecular statics nanocutting model first assumes the trajectory of each atom of the copper workpiece being cut whenever the diamond cutter goes forward one step. It then uses the optimization search method to solve the force equilibrium equation of the Morse force in the X and Y directions when each atom moves a small distance, so as to find the new movement position of… More >

G. Desmeulles, S. Bonneaud, P. Redou>, V. Rodin, J. Tisseau

CMES-Computer Modeling in Engineering & Sciences, Vol.47, No.3, pp. 299-330, 2009, DOI:10.3970/cmes.2009.047.299

Abstract Virtual reality can enable computer scientists and domain experts to perform in virtuo experiments of numerical models of complex systems. Such dynamical and interactive experiments are indeed needed when it comes to complex systems with complex dynamics and structures. In this context, the question of the modeling tool to study such models is crucial. Such tool, called a virtuoscope, must enable the virtual experimentation of models inside a conceptual and experimental framework for imagining, modeling and experimenting the complexity of the studied systems. This article describes a conceptual framework and a meta model, called RéISCOP, that enable the construction and… More >