Chein-Shan Liu¹

CMES-Computer Modeling in Engineering & Sciences, Vol.98, No.4, pp. 375-407, 2014, DOI:10.3970/cmes.2014.098.375

Abstract In this paper we study the nonlinear dynamical system x^·=f(x,t) from a newly developed theory, viewing the time-varying function of sign(||f||²||x||²− 2(f·x)²) = −sign(cos 2θ) as a key factor, where θ is the intersection angle between x and f. It together with sign(cos θ) can reveal the complexity of nonlinear Duffing oscillator and a quadratic ship rolling oscillator. The barcode is formed by plotting sign(||f||²||x||²− 2(f·x)²) with respect to time. We analyze the barcode to point out the bifurcation of subharmonic motions and the range of chaos in the parameter space. The bifurcation diagram obtained by plotting the More >

Ankush Aggarwal¹, Jiun-Shyan Chen², William S. Klug³

CMES-Computer Modeling in Engineering & Sciences, Vol.98, No.1, pp. 69-99, 2014, DOI:10.3970/cmes.2014.098.069

Abstract Mechanical properties of proteins play an important role in their biological function. For example, microtubules carry large loads to transport organelles inside the cell, and virus shells undergo changes in shape and mechanical properties during maturation which affect their infectivity. Various theoretical models including continuum elasticity have been applied to study these structural properties, and a significant success has been achieved. But, the previous frameworks lack a connection between the atomic and continuum descriptions. Here this is accomplished through the development of a meshfree framework based on reproducing kernel shape functions for the large deformation… More >

Shueei-Muh Lin¹, Min-Jun Teng²

CMES-Computer Modeling in Engineering & Sciences, Vol.103, No.3, pp. 189-213, 2014, DOI:10.3970/cmes.2014.103.189

Abstract The control and separation of a scanning device moving along an arbitrary trajectory on an elastic plate is investigated. The system is a moving mass problem and is difficult to analyze directly. A semi-analytical method for the movingmass model is presented here. Without vibration control, the separation of a vehicle from a plate is likely to happen. The mechanism of separation of a vehicle from a plate is studied. Moreover, the effects of several parameters on vibration separation and the critical speed of system are studied. An effective control methodology is proposed for suppressing vibration More >

A. Sellier¹, S. H. Aydin², M. Tezer-Sezgin³

CMES-Computer Modeling in Engineering & Sciences, Vol.102, No.5, pp. 393-406, 2014, DOI:10.3970/cmes.2014.102.393

Abstract The fundamental free-space 2D steady creeping MHD flow produced by a concentrated point force of strength g located at a so-called source point x₀ in an unbounded conducting Newtonian liquid with uniform viscosity µ and conductivity σ > 0 subject to a prescribed uniform ambient magnetic field B = Be₁ is analytically obtained. More precisely, not only the produced flow pressure p and velocity u but also the resulting stress tensor field σ are expressed at any observation point x ≠ x₀ in terms of usual modified Bessel functions, the vectors g, x-x₀ and the so-called Hartmann layer thickness d = (√µ/σ)/B More >

M. Kriraa^1,2, M.EL Alami¹, M. Abouricha¹

FDMP-Fluid Dynamics & Materials Processing, Vol.10, No.4, pp. 443-464, 2014, DOI:10.3970/fdmp.2014.010.443

Abstract Natural Convection in a vertical channel with internal objects is encountered in several technological applications, among them particular interest of heat dissipation from electronic circuits, refrigerators, heat exchangers, nuclear reactors fuel elements, dry cooling towers, home ventilation, etc. This numerical study deals with the study of natural convection in a vertical convergent channel with a circular block. The considered parameters are 10⁴ ≤ Ra ≤ 10⁶, Prandtl number Pr = 0.71, channel height 10 ≤ A ≤ 30, inclination angle of the channel φ = 0,2.86°,5.74°. The size block conductivity and the block radius are assumed to be More >

Imen Mejri^1,2, Ahmed Mahmoudi¹, Mohamed Ammar Abbassi¹, Ahmed Omri¹

FDMP-Fluid Dynamics & Materials Processing, Vol.10, No.1, pp. 83-114, 2014, DOI:10.3970/fdmp.2014.010.083

Abstract This study examines natural convection in a square enclosure filled with a water-Al₂O₃ nanofluid and subjected to a magnetic field. The side walls of the cavity have spatially varying sinusoidal temperature distributions. The horizontal walls are adiabatic. A Lattice Boltzmann method (LBM) is applied to solve the governing equations for fluid velocity and temperature. The following parameters and related ranges are considered: Rayleigh number of the base fluid, from Ra=10³ to 10⁶, Hartmann number from Ha=0 to 90, phase deviation (γ =0, π/4, π/2, 3π/4 and π) and solid volume fraction of the nanoparticles between ø = 0 and More >

K.B. Mustapha ^1,2

CMC-Computers, Materials & Continua, Vol.42, No.2, pp. 141-174, 2014, DOI:10.3970/cmc.2014.042.141

Abstract This study investigates the sensitivity of the flexural response of a ribconnected system of coupled micro-panels with traction-free surfaces. Idealized as a two-dimensional elastic continuum with a finite transverse stiffness, each micropanels’ behavior is examined within the framework of the biharmonic mathematical model derived from the higher-order, size-dependent strain energy formulation. The model incorporates the material length scale, which bears an associative relationship with the underlying polymer’s averaged Frank elastic constant. Upper estimates of the eigenvalue of the system, under fully clamped edges and simplysupported edges, are determined by the Rayleigh method. The adopted theory… More >

Yuvaraj P¹, A Ramachra Murthy², Nagesh R Iyer³, S.K. Sekar⁴, Pijush Samui⁵

CMC-Computers, Materials & Continua, Vol.41, No.3, pp. 193-214, 2014, DOI:10.3970/cmc.2014.041.193

Abstract This paper presents fracture mechanics based Artificial Neural Network (ANN) model to predict the fracture characteristics of high strength and ultra high strength concrete beams. Fracture characteristics include fracture energy (Gf), critical stress intensity factor (KIC) and critical crack tip opening displacement (CTODc). Failure load of the beam (Pmax) is also predicated by using ANN model. Characterization of mix and testing of beams of high strength and ultra strength concrete have been described. Methodologies for evaluation of fracture energy, critical stress intensity factor and critical crack tip opening displacement have been outlined. Back-propagation training technique… More >

Cherl-Hee Lee, Jonghun Lee¹

CMC-Computers, Materials & Continua, Vol.39, No.3, pp. 289-299, 2014, DOI:10.3970/cmc.2014.039.289

Abstract The broadband design of a metamaterials-based zeroth-order resonance (ZOR) mushroom antenna with an I-shaped slit is presented and experimentally studied. The presented metamaterials-based antenna uses a unit cell based on a composite right/left handed (CRLH) transmission line and can provide a ZOR frequency. By designing the I-shaped slot resonance frequency adjacently to the ZOR frequency, the presented antenna can achieve a 10-dB bandwidth enhancement of roughly 7 times with respect to a conventional rectangular-shaped mushroom structure. More >

Greg Ball, John Polansky, Tarik Kaya^*

Frontiers in Heat and Mass Transfer, Vol.4, No.1, pp. 1-9, 2013, DOI:10.5098/hmt.v4.1.3002

Abstract The fluid flow and heat transfer in an evaporating extended meniscus are numerically studied. Continuity, momentum, energy equations and the Kelvin-Clapeyron model are used to develop a third order, non-linear ordinary differential equation which governs the evaporating thin film. It is shown that the numerical results strongly depend on the choice of the accommodation coefficient and Hamaker constant as well as the initial perturbations. Therefore, in the absence of experimentally verified values, the numerical solutions should be considered as qualitative at best. It is found that the numerical results produce negative liquid pressures under certain More >