L.L. Zhu^1,2,3, X.J. Zheng^1,2

CMC-Computers, Materials & Continua, Vol.18, No.3, pp. 301-320, 2010, DOI:10.3970/cmc.2010.018.301

Abstract The phonon properties of spatially confined nanofilms under the preexisting stress fields are investigated theoretically by accounting for the confinement effects and acoustoelastic effects. Due to the spatial confinement in low-dimensional structures, the phonon dispersion relations, phonon group velocities as well as the phonon density of states are of significant difference with the ones in bulk structures. Here, the continuum elasticity theory is made use of to determine the phonon dispersion relations of shear modes (SH), dilatational modes (SA) and the flexural modes (AS), thus to analyze the contribution of stress fields on the phonon More >

Fei Jia¹, Xiu-Peng Zheng^1,2, Yan-Ping Cao^1,3, Xi-Qiao Feng¹

CMC-Computers, Materials & Continua, Vol.18, No.2, pp. 105-120, 2010, DOI:10.3970/cmc.2010.018.105

Abstract Recently, a novel technique based on the wrinkling of a bilayer composite film resting on a compliant substrate was proposed to measure the elastic moduli of thin films. In this paper, this technique is studied via theoretical analysis and finite element simulations. We find that under an applied compressive strain, the composite system may exhibit various buckling modes, depending upon the applied compressive strain, geometric and material parameters of the system. The physical mechanisms underlying the occurrence of the two most typical buckling modes are analyzed from the viewpoint of energy. When the intermediate layer 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 More >

E. Majchrzak¹, B. Mochnacki², A. L. Greer³, J. S. Suchy⁴

CMES-Computer Modeling in Engineering & Sciences, Vol.41, No.2, pp. 131-146, 2009, DOI:10.3970/cmes.2009.041.131

Abstract Multi-layered thin metal film subjected to a short-pulse laser heating is considered. Mathematical description of the process discussed bases on the equation in which there appear the relaxation time and the thermalization time (dual-phase-lag-model). In this study we develop a three level implicit finite difference scheme for numerical modelling of heat transfer in non-homogeneous metal film. At the interfaces an ideal contact between successive layers is assumed. At the stage of computations a solution of only one three-diagonal linear system corresponds to transition from time t to t + Δt. The mathematical model, numerical algorithm and examples More >

D. S. Liu¹, C.Y. Tsai¹

CMES-Computer Modeling in Engineering & Sciences, Vol.39, No.1, pp. 29-48, 2009, DOI:10.3970/cmes.2009.039.029

Abstract Utilizing a thin copper substrate for illustration purposes, this study presents a novel numerical method for extracting the thermo-mechanical properties of a thin-film. In the proposed approach, molecular dynamics (MD) simulations are performed to establish the load-displacement response of a thin copper substrate nanoindented at temperatures ranging from 300~1400 K. The load data are then input to an artificial neural network (ANN), trained using a finite element model (FEM), in order to extract the material constants of the copper substrate. The material constants are then used to construct the corresponding stress-strain curve, from which the… More >

Nikhilkumar D. Abhangi¹, G. M. Deheri¹

FDMP-Fluid Dynamics & Materials Processing, Vol.5, No.3, pp. 245-260, 2009, DOI:10.3970/fdmp.2009.005.245

Abstract Efforts have been directed to study and analyze the behavior of a magnetic-fluid-based squeeze film between curved rough circular plates when the curved upper plate (with surface determined by an exponential expression) approaches the stationary curved lower plate (with surface governed by a secant function). A magnetic fluid is used as the lubricant in the presence of an external magnetic field oblique to the radial axis. The bearing surfaces are assumed to be transversely rough and the related roughness is characterized via a stochastic random variable with non-zero mean variance and skewness. The associated Reynolds… More >

Hao-Miao Zhou¹, Fang Li¹, Qiang Ye¹, Ji-Xiang Zhao¹, Zhe-Lei Xia¹, YingTang², Jing Wei³

CMC-Computers, Materials & Continua, Vol.13, No.3, pp. 235-248, 2009, DOI:10.3970/cmc.2009.013.235

Abstract At present, there are many methods about Young's modulus measurement of thin films, but so far there is no recognized simple, non-destructive and cheaper standard measurement method. Considering thin films with various thicknesses were sputter deposited on the magnetostrictive resonator and monitoring the resonator's first-order longitudinal resonant frequency shift both before and after deposition induced by external magnetic field, an Young's modulus assessing method based on classical laminated plate theory is presented in this paper. Using the measured natural frequencies of Au, Cu, Cr, Al and SiC materials with various thicknesses in the literature, the More >

Silieti, M.¹, Divo, E.², Kassab, A.J.¹

CMC-Computers, Materials & Continua, Vol.12, No.2, pp. 121-144, 2009, DOI:10.3970/cmc.2009.012.121

Abstract A hybrid singularity superposition/boundary element-based inverse problem method for the reconstruction of multi-dimensional heat flux distributions is developed. Cauchy conditions are imposed at exposed surfaces that are readily reached for measurements while convective boundary conditions are unknown at surfaces that are not amenable to measurements such as the walls of the cooling holes. The purpose of the inverse analysis is to determine the heat flux distribution along cooling hole surfaces. This is accomplished in an iterative process by distributing a set of singularities (sinks) inside the physical boundaries of the cooling hole (usually along cooling… 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 More >

Syh-Tsang Jenq^1,2, Yuen-Sheng Chiu²

CMC-Computers, Materials & Continua, Vol.11, No.1, pp. 33-58, 2009, DOI:10.3970/cmc.2009.011.033

Abstract Current work studies the transient hydroplaning behavior of 200 kPa inflated pneumatic radial tires with various types of tread patterns. Tires were numerically loaded with a quarter car weight of 4 kN, and then accelerated from rest rolling over a water film with a thickness of 5, 10 and 15 mm on top of a flat pavement. Tire structure is composed of outer rubber tread and inner fiber reinforcing composite layers. The Mooney-Rivlin constitutive law and the classical laminated theory (CLT) were, respectively, used to describe the mechanical behavior of rubber material and composite reinforcing… More >