Chih-Wen Chang¹, Chein-Shan Liu², Jiang-Ren Chang¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.3, No.2, pp. 69-80, 2007, DOI:10.3970/icces.2007.003.069

Abstract By using a quasi-boundary regularization we can formulate a two-point boundary value problem of the backward heat conduction equation. The ill-posed problem is analyzed by using the semi-discretization numerical schemes. Then, the resulting ordinary differential equations in the discretized space are numerically integrated towards the time direction by the Lie-group shooting method to find the unknown initial conditions. The key point is based on the erection of a one-step Lie group element G(T) and the formation of a generalized mid-point Lie group element G(r). Then, by imposing G(T) = G(r) we can seek the missing More >

Chein-Shan Liu¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.3, No.2, pp. 57-68, 2007, DOI:10.3970/icces.2007.003.057

Abstract A new method is developed to solve the interior and exterior Dirichlet problems for the two-dimensional Laplace equation, namely the meshless regularized integral equation method (MRIEM), which consists of three parts: Fourier series expansion, the second kind Fredholm integral equation and an analytically regularized solution of the unknown boundary condition on an artificial circle. We find that the new method is powerful even for the problem with very complex boundary shape and with boundary noise. More >

W. Chen¹, B. Song¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.3, No.1, pp. 51-56, 2007, DOI:10.3970/icces.2007.003.051

Abstract Polymeric nanocomposite materials present potentials in applications with high-rate loading. In the experiments to determine the dynamic response of such nanocomposites, we used pulse shaping techniques on a split Hopkinson pressure bar (SHPB) for constant-strain-rate deformation under dynamically equilibrated stresses in specimens such that accurate stress-strain curves at various dynamic strain rates were obtained. Corresponding quasi-static stress-strain was also obtained to study the rate effects over a wide range. In this paper, the dynamic and quasi-static compression experimental results are presented and discussed on two types of polymeric nanocompositres: a polycarbonate (PC)/clay nano-composite and a More >

Ronald D. Kriz¹, Arun K. Nair²

The International Conference on Computational & Experimental Engineering and Sciences, Vol.3, No.1, pp. 43-50, 2007, DOI:10.3970/icces.2007.003.043

Abstract This article has no abstract. More >

B.B. Karki¹, R. Kumar¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.3, No.1, pp. 35-42, 2007, DOI:10.3970/icces.2007.003.035

Abstract We report important preliminary results from atomistic simulations of grain boundaries in minerals. The recently developed parallel PCMD (polycrystal molec-ular dynamics) program was used to perform structural optimization. In particular, we have simulated the {310}/[001] symmetric tilt grain boundary of MgO as a function of pressure. The simulation cell containing about 55,000 atoms was used. Visualization of the atomic position-time series data show that the structure changes dramatically on compression from a simple open-structure at zero pressure to a highly dense structure containing high coordination state and a screw-like dislocation at high pressure, consistent with More >

Erik T. Thostenson¹, Chunyu Li¹, Tsu-Wei Chou¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.3, No.1, pp. 29-34, 2007, DOI:10.3970/icces.2007.003.029

Abstract With their well-known novel mechanical and electrical properties, carbon nanotubes are inherently multifunctional. Toward the development of multifunctional composite materials we have experimentally and theoretically investigated the use of carbon nanotubes as sensors and actuators. In this research work, we consider the nanotube within an external electric field with non-uniform charge distribution. Subsequently the charge induced deformations are investigated. We also demonstrate that conducting carbon nanotube networks formed in an epoxy polymer matrix can be utilized as highly-sensitive sensors for detecting the onset, nature and evolution of damage in advanced polymer-based composites. Using direct-current measurements More >

K.G. Wang¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.3, No.1, pp. 21-28, 2007, DOI:10.3970/icces.2007.003.021

Abstract A framework of applications of multiscale modeling to property prediction of advanced materials will be briefly presented. A methodology will be shown to link micro-scale to the continuum scale, integrating micro-scale modeling of microstructure with the large Thermo-Calc© database. This paradigm is successfully applied to the case of Fe-12Ni-6Mn maraging steel. We predict the mechanical properties of the maraging steel such as hardness. We found that our predictions in hardness is in agreement with experimental data. More >

S.P. Xiao¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.3, No.1, pp. 15-20, 2007, DOI:10.3970/icces.2007.003.015

Abstract A bridging domain method for coupling continuum models with molecular models is described. In this method, the continuum and molecular domains are overlapped in a bridging subdomain, where the Hamiltonian is taken to be a linear combination of the continuum and molecular Hamiltonians. We enforce the compatibility in the bridging domain by Lagrange multipliers or by the augmented Lagrangian method. An explicit algorithm for dynamic solutions is developed. In this paper, the bridging domain multiscale method is employed to study nanotube-based composites. More >

L. Roy Xu¹, Charles M. Lukehart², Lang Li², Huacheng Kuai¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.3, No.1, pp. 9-14, 2007, DOI:10.3970/icces.2007.003.009

Abstract Graphitic carbon nanofibers were used to reinforce epoxy resin to form nanocomposite adhesive bonding. Good dispersion and polymer wetting of the GCNF component is evident on the nanoscale. Tensile and shear joint strength measurements were conducted for metal-metal and polymer-polymer joints using pure epoxy and nanocomposite bonding. Very little bonding strength increase, or some bonding strength decrease, was measured. More >

Jie Wang¹, Tong-Yi Zhang¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.3, No.1, pp. 1-8, 2007, DOI:10.3970/icces.2007.003.001

Abstract Two-dimensional phase field simulations of stress-free ferroelectric nanoparticles with different long-range (LR) electrostatic interactions are conducted based on the time-dependent Ginzburg-Landau equation. Polarization patterns and the toroidal moment of polarization are found to be dependent on the LR electrostatic interaction and the size of the simulated nanoparticle. Phase field simulations exhibit vortex patterns with purely toroidal moments of polarization and negligible macroscopic polarization in the stress-free ferroelectric nanoparticles when the LR electrostatic interaction is fully taken into account. However, a single-domain structure without any toroidal moment of polarization is formed in small particles if the More >