X.P. Shen¹, J.L. Feng²

CMC-Computers, Materials & Continua, Vol.20, No.2, pp. 185-204, 2010, DOI:10.3970/cmc.2010.020.185

Abstract The characteristic length of a gradient-dependent damage model is a key parameter, which is usually regarded as the length of damage process zone (DPZ). Value and evolution of the size of DPZ were investigated by both a numerical method and an experimental manner. In the numerical study, the geometrical model adopted was a set of four-point shearing beams; the numerical tool used was the Abaqus/Explicit software. The distance between the front and end of a complete DPZ was obtained. Values of strain components at these points were given out at given time points. The experimental study of the evolution process… More >

E. Hayward¹, C. Deo¹

CMC-Computers, Materials & Continua, Vol.16, No.2, pp. 101-116, 2010, DOI:10.3970/cmc.2010.016.101

Abstract Damage cascades representative of those that would be induced by neutron irradiation have been simulated in systems of pure iron and iron containing 0.01 at.% hydrogen. Results from molecular dynamics simulations using three different embedded-atom method (EAM) type potentials are compared for primary knock-on atom energies of 5, 10, and 20 keV to assess the effect of hydrogen on the primary damage state. We examine the influence of hydrogen on the primary damage state due to a single radiation cascade. These results can serve as an atomistic database for methods and simulations for long time scale evolution of radiation damage. More >

Stephen R. Niezgoda¹, Surya R. Kalidindi^1,2

CMC-Computers, Materials & Continua, Vol.14, No.2, pp. 79-98, 2009, DOI:10.3970/cmc.2009.014.079

Abstract The generalized Hough transform is a common technique for feature detection in image processing. In this paper, we develop a size invariant Hough framework for the detection of arbitrary shapes in three dimensional digital microstructure datasets. The Hough transform is efficiently implemented via kernel convolution with complex Hough filters, where shape is captured in the magnitude of the filter and scale in the complex phase. In this paper, we further generalize the concept of a Hough filter by encoding other parameters of interest (e.g. orientation of plate or fiber constituents) in the complex phase, broadening the applicability of Hough transform… More >

Yeau-Ren Jeng¹,Ping-Chi Tsai¹,Guo-Zhe Huang¹, I-Ling Chang¹

CMC-Computers, Materials & Continua, Vol.11, No.2, pp. 109-126, 2009, DOI:10.3970/cmc.2009.011.109

Abstract This study performs a series of Molecular Dynamics (MD) and Molecular Statics (MS) simulations to investigate the mechanical properties of single-walled carbon nanotubes (SWCNTs) under a uniaxial tensile strain. The simulations focus specifically on the effects of the nanotube helicity, the nanotube diameter and the percentage of vacancy defects on the bond length, bond angle and tensile strength of zigzag and armchair SWCNTs. In this study, a good agreement is observed between the MD and MS simulation results for the stress-strain response of the SWCNTs in both the elastic and the plastic deformation regimes. The MS simulations reveal that in… More >

Chien-Ching Ma^1,2, Wen-Cha Wu²

CMC-Computers, Materials & Continua, Vol.11, No.2, pp. 79-108, 2009, DOI:10.3970/cmc.2009.011.079

Abstract The two-dimensional problem of a planar transversely isotropic piezoelectric layered half-plane subjected to generalized line forces and edge dislocations in the layer is analyzed by using the Fourier-transform method and the series expansion technique. The full-field solutions for displacements, stresses, electrical displacements and electric fields are expressed in explicit closed forms. The complete solutions consist only of the simplest solutions for an infinite piezoelectric medium with applied loadings. It is shown in this study that the physical meaning of this solution is the image method. The explicit solutions include Green's function for originally applied loadings in an infinite piezoelectric medium… More >

Heng-Cheng Lin¹, Chieh Kung², Rong-Sheng Chen¹, Gin-Tiao Liang¹

CMC-Computers, Materials & Continua, Vol.3, No.2, pp. 55-64, 2006, DOI:10.3970/cmc.2006.003.055

Abstract Wafer level chip scale package (WLCSP) has been recognized providing clear advantages over traditional wire-bond package in relaxing the need of underfill while offering high density of I/O interconnects. Without the underfill, the solder joint reliability becomes more critical. Adding to the reliability concerns is the safety demand trend toward "green'' products on which unleaded material, e.g. lead-free solders, is required. The requirement of lead-free solders on the packages results in a higher reflow temperature profile in the package manufacturing process, in turn, complicating the reliability issue. This paper presents an optimization study, considering the fatigue reliability, for a wafer… More >

Shen Yubin¹, Xie Huicai^1,2, Den Wei¹

CMC-Computers, Materials & Continua, Vol.3, No.2, pp. 49-54, 2006, DOI:10.3970/cmc.2006.003.049

Abstract Bonding an overlay of new concrete onto the damaged concrete is a usual repair method. Because of the different shrinkage rate of the new and old concrete, restrained shrinkage cracks will appear in the new concrete. The cracks will reduce durability and strength of the repaired structure. A new repair method using an interface layer of carbon fiber reinforced cement mortar between new and old concrete was developed in this paper. The new method was found to be very effective in reducing shrinkage cracking of repaired beams and slabs. Comparing with normal repaired beams, the maximum observed width of the… More >

I. Smojver¹, J. Sorić²

CMC-Computers, Materials & Continua, Vol.3, No.1, pp. 13-24, 2006, DOI:10.3970/cmc.2007.003.013

Abstract The paper addresses the problem of impact on layered fibre composites. The behaviour of composite laminates under impact loading is dependent not only on the velocity but also on the mass and geometry of the impactor. Using micromechanical Mori-Tanaka approach, mechanical properties of the laminate have been calculated utilizing the material constants of the fibre and matrix. General purpose FEM software ABAQUS has been modified by means of user written subroutines for modelling of composite laminate and rigid impactor. The kinematics of the impact has been simulated using transient dynamic analysis. Employing user defined multi point constraints, delamination zones have… More >