W.H. Chen¹, H.C. Cheng², Y.C. Hsu³

CMES-Computer Modeling in Engineering & Sciences, Vol.20, No.2, pp. 123-146, 2007, DOI:10.3970/cmes.2007.020.123

Abstract The evaluation of the fundamental mechanical properties of single/multi-walled carbon nanotubes(S/MWCNTs) is of great importance for their industrial applications. The present work is thus devoted to the determination of various mechanical properties of S/MWCNTs using molecular dynamics (MD) simulations. The study first focuses on the exploration of the effect of the weak inlayer van der Waals (vdW) atomistic interactions on the mechanical properties of S/MWCNTs. Secondly, in addition to the zig-zag and armchair types of CNTs, the hybrid type of MWCNTs that comprise a zig-zag outer tube and an inner armchair tube is also analyzed.… More >

K. Han ¹, Y. T. Feng ¹, D. R. J. Owen¹

CMES-Computer Modeling in Engineering & Sciences, Vol.18, No.2, pp. 87-100, 2007, DOI:10.3970/cmes.2007.018.087

Abstract Numerical procedures are introduced for simulations of irregular particle transport in turbulent flows using the coupled lattice Boltzmann method (LBM) and the discrete element method (DEM). The fluid field is solved by the extended LBM with the incorporation of the Smagorinsky turbulence approach, while particle interaction is modeled by the DEM. The hydrodynamic interactions between fluid and particles are realised through an immersed boundary condition, which gives rise to a coupled solution strategy to model the fluid-particle system under consideration. Main computational aspects comprise the lattice Boltzmann formulation for the solution of fluid flows; the More >

T. Nishioka¹, Y. Kobayashi¹, T. Fujimoto¹

CMES-Computer Modeling in Engineering & Sciences, Vol.17, No.3, pp. 231-238, 2007, DOI:10.3970/cmes.2007.017.231

Abstract First, for growing cracks in elastic-plastic materials, an incremental variational principle is developed to satisfy the boundary conditions near newly created crack surfaces. Then using this variational principle, a moving finite element method is formulated and developed, based on the Delaunay automatic triangulation. Furthermore, theoretical backgrounds on numerical prediction for fracture path of curving crack using T* integral are explained. Using the automatic moving finite element method, fracture-path prediction simulations are successfully carried out. More >

Joseph G. Lawrence, Arunan Nadarajah¹

FDMP-Fluid Dynamics & Materials Processing, Vol.3, No.3, pp. 247-254, 2007, DOI:10.3970/fdmp.2007.003.247

Abstract A simplified 2D pseudo steady state model was developed for an atmospheric chemical vapor deposition (CVD) process on glass. This is used to study the feasibility of converting a continuous coating process to one with discrete glass plates with a gap between them. A preliminary estimate employing mass transfer correlations suggested that there would be significant concentration variations due to the gap between the plates. More detailed studies were done by solving the model numerically employing a finite difference scheme with a vorticity-stream function formulation, and employing the commercial computational fluid dynamics program FIDAP which… More >

Ramana M. Pidaparti^1,2, Evan J. Neblett²

CMC-Computers, Materials & Continua, Vol.5, No.1, pp. 1-10, 2007, DOI:10.3970/cmc.2007.005.001

Abstract A neural network (NN) model is developed for the analysis and prediction of the mapping between degradation of chemical elements and electrochemical parameters during the corrosion process. The input parameters to the neural network model are alloy composition, electrochemical parameters, and corrosion time. The output parameters are the degradation of chemical elements in AA 2024-T3 material. The NN is trained with the data obtained from Energy Dispersive X-ray Spectrometry (EDS) on corroded specimens. A very good performance of the neural network is achieved after training and validation with the experimental data. After validating the NN More >

H. Kawai¹

CMES-Computer Modeling in Engineering & Sciences, Vol.11, No.3, pp. 111-120, 2006, DOI:10.3970/cmes.2006.011.111

Abstract ADVENTURE AutoGL (pronounced as ‘Ote- ga-lu’) is a graphics and GUI library, dedicated for simulation-based research and development. It is designed for the simulation users to develop their own data viewers and editors. Currently, the library is used among many researchers and simulation users, mainly in universities and national research centers. Its functionalities and supported platforms are explained. AutoGL applications of various kinds of simulation methods are demonstrated also. More >

J.M.M. Sousa¹

CMES-Computer Modeling in Engineering & Sciences, Vol.9, No.2, pp. 211-220, 2005, DOI:10.3970/cmes.2005.009.211

Abstract Time-dependent numerical simulations of the flow through a spherical bulge in a 90-degree asymmetrical bend have been performed for Reynolds numbers in the range 100-400. The present results have demonstrated that the flow reaches asymptotically steady, symmetrical solutions for Reynolds numbers up to 300, whereas a value of 400 for this parameter leads to unsteadiness. The computed flow behavior at this higher Reynolds number has shown to be characterized by an intermittent transition between small-amplitude, irregular oscillations and large-amplitude bursts occurring at a low frequency. In addition, the unsteady flow was asymmetrical and exhibited swirl More >

J. Ma¹, H. Lu¹, B. Wang¹, S. Roy¹, R. Hornung², A. Wissink², R. Komanduri^1,3

CMES-Computer Modeling in Engineering & Sciences, Vol.8, No.2, pp. 135-152, 2005, DOI:10.3970/cmes.2005.008.135

Abstract In the simulation of a wide range of mechanics problems including impact/contact/penetration and fracture, the material point method (MPM), Sulsky, Zhou and Shreyer (1995), demonstrated its computational capabilities. To resolve alternating stress sign and instability problems associated with conventional MPM, Bardenhagen and Kober (2004) introduced recently the generalized interpolation material point (GIMP) method and implemented for one-dimensional simulations. In this paper we have extended GIMP to 2D and applied to simulate simple tension and indentation problems. For simulations spanning multiple length scales, based on the continuum mechanics approach, we present a parallel GIMP computational method… More >

Charles E. Anderson, Jr.¹, Matthew S. Burkins², James D. Walker¹, William A. Gooch²

CMES-Computer Modeling in Engineering & Sciences, Vol.8, No.2, pp. 91-104, 2005, DOI:10.3970/cmes.2005.008.091

Abstract A modification of Wilkins computational ceramics model is used to simulate experiments of the impact of the APM2 bullet against boron carbide/aluminum targets. Flash radiography provides time-resolved penetration histories. The simulation results are compared to the experimental data; generally, agreement is very good, including capturing dwell and then the onset of penetration. Crater width and debris diameter are also reproduced by the simulations reasonably well. A critical discussion of deficiencies of this computational engineering model is provided. More >

Kathleen Puskar¹, Leonard Apeltsin², Shlomo Ta’asan³, Russell Schwartz², Philip R. LeDuc⁴

Molecular & Cellular Biomechanics, Vol.1, No.2, pp. 123-132, 2004, DOI:10.3970/mcb.2004.001.123

Abstract Understanding the connection between mechanics and cell structure requires the exploration of the key molecular constituents responsible for cell shape and motility. One of these molecular bridges is the cytoskeleton, which is involved with intracellular organization and mechanotransduction. In order to examine the structure in cells, we have developed a computational technique that is able to probe the self-assembly of actin filaments through a lattice based Monte Carlo method. We have modeled the polymerization of these filaments based upon the interactions of globular actin through a probabilistic model encompassing both inert and active proteins. The More >