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 More >

Liming Xiong¹, Youping Chen¹

CMES-Computer Modeling in Engineering & Sciences, Vol.24, No.2&3, pp. 203-214, 2008, DOI:10.3970/cmes.2008.024.203

Abstract This paper presents the application of an atomistic field theory (AFT) in modeling and simulation of boron- , boron/nitrogen and silicon/nitrogen-doped nanocrystalline silicon carbide (B-, BN-, SiN-SiC). Intergranular glassy films (IGFs) and nano-sized pores have been obtained in triple junctions of the grains in nanocrystalline SiC (nc-SiC). Residual tensile stress in the SiC grains and compressive stress in the grain boundaries (GBs) are observed. Under uniaxial tension, the constitutive responses of nanocrystalline SiC were reproduced from the simulations. It is found that the mechanical properties of nanocrystalline SiC are strongly dependent on the compositions of More >

I. Ueno¹, T. Konisho², T. Kawase³, T. Watanabe⁴

FDMP-Fluid Dynamics & Materials Processing, Vol.4, No.1, pp. 21-26, 2008, DOI:10.3970/fdmp.2008.004.021

Abstract The present authors carried out an experimental study with a special interest upon the dynamics of the fluid in the vicinity of the boundary line of three phases; solid-liquid-gas interface, which is so-called `contact line.' The moving droplet on the solid substrate is accompanied with the movement of the boundary line of three phases; solid-liquid-gas interface, which is so-called macroscopic 'contact line.' Existing studies have indicated there is a thin liquid film known as 'precursor film' ahead the contact line of the droplet. In the present study the precursor film was detected by applying conventional More >

A. A. Nepomnyashchy^1,2, I. B. Simanovskii¹

FDMP-Fluid Dynamics & Materials Processing, Vol.4, No.3, pp. 185-198, 2008, DOI:10.3970/fdmp.2008.004.185

Abstract The development of instabilities under the joint action of the van der Waals forces and Marangoni stresses in a two-layer film on a heated or cooled substrate is considered. It is found that heating from below leads to the acceleration of the decomposition, decrease of the characteristic lateral size of structures, and the increase of the droplets heights. Heating from above leads to slowing down the instability rate and eventually to a complete suppression of the instability. More >

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 More >

A. Ovcharova¹, N.Stankous²

FDMP-Fluid Dynamics & Materials Processing, Vol.3, No.4, pp. 349-356, 2007, DOI:10.3970/fdmp.2007.003.349

Abstract We consider a deformation of a thin film which is hanging between two solid flat walls under thermal load action. A two-dimensional model is applied to describe the motion of thin layers of viscous nonisothermal liquid under microgravity conditions. The model is based on the Navier-Stokes equations. A numerical analysis of the influence of thermal loads on the deformation and break of freely hanging thin films has been carried out. The mutual influence of capillary and thermo-capillary forces on thin film free surface position has been shown. The results of model problem solutions are presented. More >

A. Pereira¹, P.M.J. Trevelyan², U. Thiele³, S. Kalliadasis¹

FDMP-Fluid Dynamics & Materials Processing, Vol.3, No.4, pp. 303-316, 2007, DOI:10.3970/fdmp.2007.003.303

Abstract We investigate the interaction between thin films and chemical reactions by using two prototype systems: a thin liquid film falling down a planar inclined substrate in the presence of an exothermic chemical reaction and a horizontal thin liquid film with a reactive mixture of insoluble surfactants on its surface. In the first case the chemical reaction has a stabilizing influence on the dynamics of the film and dampens the free-surface solitary pulses. In the second case the chemical reaction can destabilize the film and lead to the formation of free-surface solitary pulses. More >

A. Sellier¹, L. Pasol²

CMES-Computer Modeling in Engineering & Sciences, Vol.16, No.3, pp. 187-196, 2006, DOI:10.3970/cmes.2006.016.187

Abstract This paper examines the slow viscous settling migration of a solid particle immersed in a viscous fluid film confined by {two plane and parallel solid wall and free surface}. The approach rests on the use of suitable boundary-integral equations on the surface of the particle and the analytical calculation of a new Green tensor that complies with all the boundary conditions satisfied by the liquid flow on the plane boundaries. The numerical implementation resorts to standard boundary elements on the particle's surface and provides at a reasonable cpu time cost the motion of the particle More >

Daiki Shiozawa¹, Shiro Kubo², Takahide Sakagami², Masaaki Takagi²

CMES-Computer Modeling in Engineering & Sciences, Vol.11, No.1, pp. 27-36, 2006, DOI:10.3970/cmes.2006.011.027

Abstract The passive electric potential CT (computed tomography) method using piezoelectric film was applied to the identification of plural through cracks. The use of piezoelectric material made it possible to obtain electric potential field without applying electric current. For identification of cracks an inverse analysis scheme based on the least residual method was applied, in which square sum of residuals is evaluated between the measured electric potential distributions and those computed by using the finite element method. Akaike information criterion (AIC) was used to estimate the number of cracks. Numerical simulations were carried out on the More >

Luming Shen¹, Zhen Chen²

CMES-Computer Modeling in Engineering & Sciences, Vol.7, No.3, pp. 305-320, 2005, DOI:10.3970/cmes.2005.007.305

Abstract To simulate the dynamic responses involving different material phases in a finite computational domain without discretizing the whole problem domain, a silent boundary scheme is proposed within the framework of the material point method (MPM) that is an extension from Computational Fluid Dynamics to Computational Solid Dynamics. Because the MPM does not employ fixed mesh connectivity, a robust spatial discretization procedure in the moving domain of influence could be designed by applying viscous damping forces along the computational boundary. To establish a simple interface between the discretization procedures with and without fixed mesh connectivity, a More >