Hsien-Chie Cheng¹, Yu-Chen Hsu², Wen-Hwa Chen²

The International Conference on Computational & Experimental Engineering and Sciences, Vol.12, No.2, pp. 73-74, 2009, DOI:10.3970/icces.2009.012.073

Abstract Due to the limitation of fabrication technologies nowadays, initial defects in carbon nanotubes (CNTs) are inevitably perceived particularly during the manufacturing process or chemical treatment. The investigation of the effects of initial defects existing in CNTs on their mechanical properties and fracture behaviors becomes essential for their potentiality in engineering applications.
In this study, the defect effects, including number in percentage, type, and location, are explored using the molecular dynamics (MD) simulation with Tersoff Brenner potential. Results show that the mechanical properties, such as the elastic modulus, failure strength and strain, are strongly affected by the… More >

Hsien-Chie Cheng¹, Yu-Chen Hsu², Wen-Hwa Chen²

CMC-Computers, Materials & Continua, Vol.11, No.2, pp. 127-146, 2009, DOI:10.3970/cmc.2009.011.127

Abstract Due to the limitation of fabrication technologies nowadays, structural or atomistic defects are often perceived in carbon nanotubes (CNTs) during the manufacturing process. The main goal of the study aims at providing a systematic investigation of the effects of atomistic defects on the nanomechanical properties and fracture behaviors of single-walled CNTs (SWCNTs) using molecular dynamics (MD) simulation. Furthermore, the correlation between local stress distribution and fracture evolution is studied. Key parameters and factors under investigation include the number, type (namely the vacancy and Stone-Wales defects), location and distribution of defects. Results show that the nanomechanical More >

D.W. Kelly¹, M.C.W. Lee¹, A.C. Orifici^2,3, R.S.Thomson³, R. Degenhardt^4,5

CMC-Computers, Materials & Continua, Vol.10, No.2, pp. 163-194, 2009, DOI:10.3970/cmc.2009.010.163

Abstract An experimental program for collapse of curved stiffened composite shell structures encountered a wide range of initial and deep buckling mode shapes. This paper presents work to determine the significance of the buckling deformations for determining the final collapse loads and to understand the source of the variation. A finite element analysis is applied to predict growth of damage that causes the disbonding of stiffeners and defines a load displacement curve to final collapse. The variability in material properties and geometry is then investigated to identify a range of buckling modes and development of deep More >

B. Yang^1,2, S.-C. Wong³, S. Qu³

CMES-Computer Modeling in Engineering & Sciences, Vol.24, No.2&3, pp. 81-94, 2008, DOI:10.3970/cmes.2008.024.081

Abstract In the modeling of overall property of composites, the effect of particle interaction has been either numerically taken into account within a (representative) volume element of a small number of particles or neglected/ignored in order for efficient solution to a large system of particles. In this study, we apply the point-defect Green's function (GF) to take into account the effect of particle interaction. It is applicable to small volume fractions of particles (within 10 %). The high efficiency of the method enables a simulation of a large system of particles with generally elastic anisotropy, arbitrary… More >

Can Talug, Jeffrey Mullins, Susan E. Saunders, Stanley Zaslau

Canadian Journal of Urology, Vol.14, No.5, pp. 3707-3709, 2007

Abstract In a patient with a prior history of pancreatitis or abdominal trauma, radiographic imaging may only show abnormalities in the urinary tract. When these patients are first seen with subcapsular or perinephric fluid collections, percutaneous drainage can be both diagnostic and therapeutic. More >

K. R. Gratz¹, B. L. Wong¹, W. C. Bae¹, R. L. Sah¹

Molecular & Cellular Biomechanics, Vol.3, No.4, pp. 199-200, 2006, DOI:10.32604/mcb.2006.003.199

Abstract This article has no abstract. More >

B. Yang², V. K. Tewary³

CMES-Computer Modeling in Engineering & Sciences, Vol.15, No.3, pp. 165-178, 2006, DOI:10.3970/cmes.2006.015.165

Abstract Green's function (GF) modeling of defects may take effect only if the GF as well as its various integrals over a line, a surface and/or a volume can be efficiently evaluated. The GF is needed in modeling a point defect, while integrals are needed in modeling line, surface and volumetric defects. In a matrix of multilayered, generally anisotropic and linearly elastic and piezoelectric materials, the GF has been derived by applying 2D Fourier transforms and the Stroh formalism. Its use involves another two dimensions of integration in the Fourier inverse transform. A semi-analytical scheme has… More >

G. Kakuba¹, R.M.M. Mattheij², M.J.H. Anthonissen³

CMES-Computer Modeling in Engineering & Sciences, Vol.15, No.3, pp. 127-136, 2006, DOI:10.3970/cmes.2006.015.127

Abstract This paper presents an efficient way to implement the Boundary Element Method (BEM) to capture high activity regions in a boundary value problem. In boundary regions where accuracy is critical, like in adaptive surface meshes, the method of choice is Local Defect Correction (LDC). We formulate the method and demonstrate its applicability and reliability by means of an example. Numerical results show that LDC and BEM together provide accurate solutions with less computational requirements given that BEM systems usually consist of dense matrices. More >

Radek Pecher¹, Steve Elston, Peter Raynes

CMES-Computer Modeling in Engineering & Sciences, Vol.13, No.2, pp. 91-102, 2006, DOI:10.3970/cmes.2006.013.091

Abstract Meshfree techniques for solving partial differential equations in physics and engineering are a powerful new alternative to the traditional mesh-based techniques, such as the finite difference method or the finite element method. The elimination of the domain mesh enables, among other benefits, more efficient solutions of nonlinear and multi-scale problems. One particular example of these kinds of problems is a Q-tensor based model of nematic liquid crystals involving topological defects.
This paper presents the first application of the meshless local Petrov-Galerkin method to solving the Q-tensor equations of nematostatics. The theoretical part introduces the Landau More >

L. Nasdala¹, G. Ernst¹, M. Lengnick¹, H. Rothert¹

CMES-Computer Modeling in Engineering & Sciences, Vol.7, No.3, pp. 293-304, 2005, DOI:10.3970/cmes.2005.007.293

Abstract Like any other geometric structure or building, carbon nanotubes may break down due to either material failure or structural failure. In this paper, it is shown that the failure mechanism of carbon nanotubes not only depends on the type and direction of loading but also on the location and number of defects. For the finite element simulations we use a new 4-node finite element without rotational degrees of freedom based on the force field method. For the examples shown here, mainly a single-walled (10,10) armchair nanotube with different Stone-Wales defects, the material parameters are directly… More >