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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal DOI :
The Korean Society for Composite Materials
Editor in Chief :
Volume & Issues
Volume 22, Issue 6 - Dec 2009
Volume 22, Issue 5 - Oct 2009
Volume 22, Issue 4 - Aug 2009
Volume 22, Issue 3 - Jun 2009
Volume 22, Issue 2 - Apr 2009
Volume 22, Issue 1 - Feb 2009
Selecting the target year
Characteristics of Structural Behavior and Safety Estimation of Water Supply GFRP Pipe
Lee, Bo-Be ; Lee, Seung-Sik ; Joo, Hyung-Jong ; Yoon, Soon-Jng ;
Composites Research, volume 22, issue 3, 2009, Pages 1~8
In this paper, we present the results of experimental and analytical investigations on the structural behavior of GFRP pipes used in the water supply pipeline system. Cross-section of the pipe is consisted with two GFRP tubes and polymer mortar between the tubes. Due to the advantages such as light-weight, corrosion resistance, smooth surface, flexibility, etc., use of GFRP pipe in the water supply pipeline system is ever increasing trend. Therefore, more optimized structural design methodology should be developed. In the investigation, we conducted theoretical and analytical studies on the load versus radial deformation characteristics of GFRP pipes. In addition, ring stiffness test is also performed. Test results are compared with theoretical and analytical results and it was found that the results are agreed well within 5% of radial deformation. Finally, it was also found that the GFRP pipes used in the water supply pipeline system are strong enough to satisfy the industrial requirements.
Nanoindentation behaviours of silver film/copper substrate
Trandmh, Long ; Kim, Am-Kee ; Cheon, Seong-Sik ;
Composites Research, volume 22, issue 3, 2009, Pages 9~17
Nanoindentation behaviours on the films of softer Ag film/harder Cu substrate structure were studied by the molecular dynamics method. As a result, it was shown that the stiffness and hardness of films were strongly dependent on the thickness of films. The stiffness and hardness increased with the thickness of film within a critical range as an inverse Hall-Petch relation. The stiffness and hardness of Cu substrate with Ag film less than 5 nm were observed to be lower than those of bulk silver. In particular, the flower-like dislocation loop was created on the interface by the interaction between dislocation pile-up and misfit dislocation during the indentation of Ag film/Cu substrate with film thickness less than 4 nm, which seemed to be associated with the drop of load in the indentation load versus displacement curve.
Chain extension effects of para-phenylene diisocyanate on crystallization behavior and biodegradability of poly(lactic acid)/poly(butylene terephthalate) blends
Kim, Myung-Wook ; Hong, Sung-Min ; Lee, Doo-Jin ; Park, Kwang-Seok ; Youn, Jae-Ryoun ;
Composites Research, volume 22, issue 3, 2009, Pages 18~28
Blends of poly(lactic acid) (PLA) and poly(butylene terephthalate) (PBT) were prepared by reaction extrusion with para-phenylene diisocyanate (PPDI). The crystallization behavior and biodegradability were investigated by using a differential scanning calorimeter (DSC), a wide angle X-ray diffractometer (WAXD), a contact angle goniometer, and a buffer solution containing esterase. The addition of PBT into PLA polymer matrix induced the cold crystallization of PLA phase, and the crystallization rate of PLA phase was significantly accelerated when both PBT and PPDI participated in the reaction with PLA simultaneously. But the chain extension caused by PPDI decreased the crystallinity and hydrophilicity of PLA and PBT phases. The crystallinity and hydrophilicity did not affect the biodegradability of PLA/PBT blends. However, phase separation between PLA and PBT in PLA/PBT blends increased the interfacial area exposed to the hydrolysis of enzyme, resulting in the improved degradability rate of PLA phase. In contrast, the improved interfacial adhesion between PLA and PBT matrices by the reaction with PPDI reduced the area exposed to the enzyme to decrease the degradation rate of PLA phase.
Finite element analysis of callus generation in fractured bones according to the strain distribution
Kim, Suk-Hun ; Park, Myong-Gil ; An, Song-Tao ; Cho, Sung-Kyum ; Chang, Seung-Hwan ;
Composites Research, volume 22, issue 3, 2009, Pages 29~34
In this paper, finite element analyses were used to estimate the strain distribution at the fracture site of a tibia bone. A stainless steel bone plate and various composite bone plates were considered to find out the best conditions for callus generation while bone fracture was cured for 16 weeks. Through this research, the appropriate load condition which makes the strains between the appropriate range(
) was sought. From this analysis, it was found that lower level of external load is needed for the appropriate strain for the case of composite bone plate application and it was also found that the composite bone plate had potential advantages for effective bone fracture healing relieved stress shielding effect.
Cross-link Density Measurement and Thermal Oxidative Degradation Analysis of a Carbon Black Compounded EPDM Rubber Hose
Kwak, Seung-Bum ; Choi, Nak-Sam ; Kim, Jin-Kuk ;
Composites Research, volume 22, issue 3, 2009, Pages 35~43
In this study, for a radiator hose made of carbon black filled EPDM(ethylene-propylene diene monomer) rubber, a measuring method of crosslink density was established to analyze the aging behaviors under thermo-oxidative stresses. At
, the crosslink density of the rubber specimens decreased slightly in the initial stage, but increased with increasing the aging time. Such variation in crosslink density was similar to that of tensile strength. This might be due to the formation of sulphoxide crosslinks as well as to additional crosslinks made by the reaction of unvalcunized sulfurs. A high temperature aging of rubber specimens at
caused a slight increase in crosslink density while it did a large decrease in tensile strength and elongation. With aging at high temperature, the formation of carbonyl groups in EPDM molecule chain and formation of sulphoxide crosslink, rather than the crosslink density variation itself, had a large influence on such changes in mechanical property.
Study on the numerical model of complex permittivity of composites based on the percolation theory
Kim, Jin-Bong ; Lee, Sang-Kwan ; Kim, Chun-Gon ;
Composites Research, volume 22, issue 3, 2009, Pages 44~54
In this paper, we proposed a numerical model the complex permittivity for the E-glass fabric/epoxy composite laminate containing electrical conductive carbon black. The model is based on the percolation theory and for the composites over than the percolation threshold and in higher frequency band in that the AC conductivity is fully proportional to the frequency. The measurement for the complex permittivity wasperformed at the frequency band of 0.5 GHz
18.0 GHz using a vector network analyzer with a 7 mm coaxial air line. The proposed model is composed of the numerical equations of the scaling law used in percolation theory and constants obtained from experiments to quantify the model itself. The model describes the complex permittivity as the function of frequency and filler concentration. The model was verified by being compared with the measurements.
Design and Impact Testing of Cylindrical Composite Antenna Structures
Lee, Sang-Min ; Cho, Sang-Hyun ; Lee, Chang-Woo ; Hwang, Woon-Bong ;
Composites Research, volume 22, issue 3, 2009, Pages 55~59
Microstrip antennas are low profile, are conformable to planar and nonplanar surfaces, are simple and inexpensive to manufacture, mechanically robust when mounted on rigid surfaces and are compatible with MMIC(Monolithic microwave integrated circuit) designs; they have been used in diverse communication systems. The rectangular microstrip patch antenna is designed for a central frequency of 12.5 GHz, and the final product is a
array antenna with curvature radius of 200 mm. The microstrip antenna is embedded in a sandwich structure which consists of skin and core material. After impact, the performance of damaged antenna is estimated by measuring the return loss and radiation pattern. The antenna performance was not affected by this impact damage.
Effect of Cold Temperature Dry and Elevated Temperature Wet on Mechanical Properties of CFRP Composites
Kim, Hyo-Jin ; Lee, Sih-Joong ; Han, Sang-Ho ; Kim, Sang-Kuk ; Park, Seong-Jun ;
Composites Research, volume 22, issue 3, 2009, Pages 60~65
The mechanical behavior of carbon fiber reinforced polymeric (CFRP) composites was investigated. Both strength and modulus were measured at room temperature dry, cold temperature dry,
, and elevated temperature wet,
on seven different laminate configurations consisting of
cross-ply laminate, a 36-ply laminate
. Based on the experimental data presented, it is shown that the strength at cold temperature dry,
is increased with the brittleness of fiber or matrix. Moreover, it is shown that both shear strength and modulus at elevated temperature wet,
are decreased by the cause of interfacial deterioration between fiber and matrix with moisture absorption.
Impact Absorption Performance of Multi-layered Composite Structures based on Material-Structure Optimization
Kim, Byung-Jo ; Kim, Tae-Won ;
Composites Research, volume 22, issue 3, 2009, Pages 66~73
Total thickness, areal density and mass moment of inertia of materials are important material factors for structural characteristics. In this work, a material-structural optimization was performed up to the maximum ballistic limit of multi-layered composite structures under high impact velocity followed by the investigation of the influence of these factors on an impact absorption performance. A unified model combined with Florence's and Awerbuch-Bonder's models was used in optimizing the multi-layered composite structure consisting of CMC, rubber, aluminum and Al-foam. Total thickness, areal density and mass moment of inertia were used for the optimization constraint. As shown in the results, the ballistic limit determined from a newly developed unified model was closely similar to the finite clement analysis. Additionally, the ballistic limit and impact absorption energy obtained by the optimized structure were improved approximately 16.8% and 26.7%, respectively comparing with a not optimized multi-layered structure.
Initiation and Growth Behavior of Small Surface Fatigue Crack in SiC Reinforced Aluminum Composite
Lee, Sang-Hyoup ; Choi, Young-Geun ; Kim, Sang-Tae ;
Composites Research, volume 22, issue 3, 2009, Pages 74~81
Reversed plane bending fatigue tests were conducted on SiC particle reinforced and SiC whisker reinforced aluminum composite. The initiation and growth behaviors of small surface fatigue cracks were continuously monitored by the replica technique and the causes of fracture and fracture mechanism were investigated by SEM. The relationship between da/dn and
show that da/dn increases in high stress level while decrease and again increases with increasing of
in low stress level for two materials.
Effect of Filled Hole on Strength Behavior of CFRP Composites at Cold Temperature Dry and Elevated Temperature Wet
Kim, Hyo-Jin ;
Composites Research, volume 22, issue 3, 2009, Pages 82~88
The effect of open and filled holes on the strength behavior of carbon fiber reinforced polymeric (CFRP) composites was investigated. The strength was measured at room temperature dry, cold temperature dry,
, and elevated temperature wet,
on several different laminate configurations. Based on the experimental data presented, it is shown that the filled hole tensile strength is larger than that of open hole by reducing damage around the hole due to the constraint imposed by the fastener. The tensile strength at cold temperature dry,
is increased with the brittleness by the thermal expansion coefficient of fiber and matrix. The compressive strength at elevated temperature wet,
is decreased by the cause of interfacial deterioration between fiber and matrix with moisture absorption.