B.J. Yang¹, K.J. Cho¹, G.M. Kim¹, H.K. Lee^1,2

CMES-Computer Modeling in Engineering & Sciences, Vol.103, No.5, pp. 343-365, 2014, DOI:10.3970/cmes.2014.103.343

Abstract The addition of carbon nanotubes (CNTs) to a matrix material is expected to lead to an increase in the effective electrical properties of nanocomposites. However, a CNT entanglement caused by the matrix viscosity and the high aspect ratio of the nanotubes often inhibits the formation of a conductive network. In the present study, the micromechanics-based model is utilized to investigate the effect of CNT agglomeration on the electrical conductivity and percolation threshold of nanocomposites. A series of parametric studies considering various shapes and curviness distributions of CNTs are carried out to examine the effects of entanglement on the electrical performance… More >

S. H. Kwon¹, B. R. Kim², H. K. Lee^2,3

CMC-Computers, Materials & Continua, Vol.21, No.1, pp. 65-86, 2011, DOI:10.3970/cmc.2011.021.065

Abstract The electromagnetic shielding effectiveness of grid-mesh films made of polyaniline was numerically investigated, and the optimal size of the polyaniline grid was determined through numerical analyses. The permittivity of polyaniline was first determined from an inverse analysis based on experimental data. A series of numerical analyses were carried out with 225 polyaniline grid-mesh films of different thickness, spacing, and width, and the shielding effectiveness of every grid was examined. In addition to the numerical analysis, the transparency of the grid-mesh films and the amount of polyaniline material required to manufacture the unit grid area (1mx1m) were calculated. The optimal dimensions… More >

S.H. Kwon¹, H.K. Lee²

CMC-Computers, Materials & Continua, Vol.12, No.3, pp. 197-222, 2009, DOI:10.3970/cmc.2009.012.197

Abstract The electromagnetic shielding effectiveness of steel fiber-reinforced mortar was numerically examined in this study. A series of numerical analysis on twenty-seven types of specimens of different diameters, lengths, and volume fractions of fibers were conducted using the FE program HFSS to investigate the effect of the dimensions of steel fibers and the amount of fibers added to the mortar on the shielding effectiveness. S-parameters of some specimens were experimentally measured by the free space method and the experimentally measured S-parameters were compared with those computed in order to verify the present numerical analysis method. It was found that smaller diameters… More >