Showing papers by "Dai Gil Lee published in 2007"
TL;DR: In this article, the conductive carbon black with the binder matrix of the E-glass/polyester composite has been used for fabricating the radar absorbing structure (RAS) of desired performance.
118 citations
TL;DR: In this paper, the residual stresses in carbon fabric phenolic composites were measured by a new radial-cut-cylinder bending method and the thermal residual stresses were also calculated by finite element method considering shear deformation of fabric layers, and compared with the measured residual stresses by the new method.
31 citations
TL;DR: In this article, the performance of an interference fit joint between a composite tube and a steel shaft under torsional load was investigated and some important design parameters were presented and addressed based on the results from analytical and numerical models.
29 citations
TL;DR: In this article, the dielectric properties of E-glass/epoxy laminate composites were measured by the free space method in the X-band frequency (8.2-12.4 GHz).
26 citations
TL;DR: In this article, a cure control system using dielectrometry for co-cured metal/composite hybrid structures was devised to reduce the fabricational thermal residual stress of the bonding layer between metal and composite material.
21 citations
TL;DR: In this paper, the effect of deformations of composite bearings due to thermal residual stresses on the adhesive joint performance was estimated with respect to stacking sequence by finite element method, and compared to the experimental results.
14 citations
Patent•
26 Feb 2007TL;DR: In this paper, a bearing assembly capable of assuring mechanical strength and reducing a friction coefficient and stress concentration, and a method for manufacturing the same, is presented, which comprises a spherical journal and a hemispherical bearing that is made of a fiber reinforced composite.
Abstract: The present invention discloses a bearing assembly capable of assuring mechanical strength and reducing a friction coefficient and stress concentration, and a method for manufacturing the same. The present invention comprises a spherical journal and a hemispherical bearing that is made of a fiber reinforced composite and has a bearing surface for establishing a spherical pair with the spherical journal. The fiber reinforced composite can be constructed by arranging a uni-directional prepreg, woven fiber prepregs and staple-fiber prepregs in a variety of configurations, and thermoplastic resin particles or self-lubrication particles are uniformly provided on the bearing surface. It is possible to alleviate stress concentration generated on the bearing surface by forming a plurality of air channels capable of imparting directivity on an outer surface of the hemispherical bearing.
14 citations
TL;DR: In this article, the dielectric properties of an E-glass-polyester composite containing conductive carbon black are measured with the free space method in the X-band frequency range.
Abstract: The electromagnetic (EM) absorption or shielding characteristics of a material is an important issue not only for military purposes but also for commercial use such as in radar, electric and telecommunication devices. Nowadays studies on investigating the radar absorbing structures (RAS) using fiber reinforced polymeric (FRP) composites are becoming a popular research field. Since carbon black is widely used for EM absorption applications, in this study, the dielectric properties of the E-glass-polyester composite containing conductive carbon black are measured with the free space method in the X-band frequency range. In order to describe the dielectric behavior of the anisotropic FRP composite containing carbon black, the quantitative analysis of the measured permittivity is performed with respect to the content of carbon black, and the two-dimensional tensor transformation equation for estimating its dielectric properties is modified. Finally, the modified tensor transformation equation for the FRP comp...
14 citations
TL;DR: In this article, a hybrid composite shaft composed of outside stainless steel tube and inside carbon/epoxy composite layer was designed to increase the specific stiffness of the shaft, and the composite layers were stacked inside the steel tube to protect the composite material from acid liquid for cleaning, and co-cured using a flexible pressure tube to decrease manufacturing cost.
12 citations
TL;DR: In this article, the tribological behavior of carbon epoxy composites whose surfaces have many small grooves was compared with respect to the coating method under dry sliding and water lubricating conditions.
10 citations
Proceedings Article•
01 Jan 2007
TL;DR: A lighter nozzle dam was designed and manufactured using a carbon-epoxy composite, a glass-ep oxygen fabric composite, an aluminium plate and honeycomb, and the variation in mechanical properties of composites with respect to radiation emission was investigated.