Go to the main menu
Skip to content
Go to bottom
REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Journal Basic Information
Journal DOI :
The Korean Society for Composite Materials
Editor in Chief :
Volume & Issues
Volume 27, Issue 6 - Dec 2014
Volume 27, Issue 5 - Oct 2014
Volume 27, Issue 4 - Aug 2014
Volume 27, Issue 3 - Jun 2014
Volume 27, Issue 2 - Apr 2014
Volume 27, Issue 1 - Feb 2014
Selecting the target year
Evolutionary Shape Optimization of Flexbeam Sections of a Bearingless Helicopter Rotor
Dhadwal, Manoj Kumar ; Jung, Sung Nam ; Kim, Tae Joo ;
Composites Research, volume 27, issue 6, 2014, Pages 207~212
DOI : 10.7234/composres.2014.27.6.207
The shape optimization of composite flexbeam sections of a bearingless helicopter rotor is studied using a finite element (FE) sectional analysis integrated with an efficient evolutionary optimization algorithm called particle swarm assisted genetic algorithm (PSGA). The sectional optimization framework is developed by automating the processes for geometry and mesh generation, and the sectional analysis to compute the elastic and inertial properties. Several section shapes are explored, modeled using quadratic B-splines with control points as design variables, through a multiobjective design optimization aiming minimum torsional stiffness, lag bending stiffness, and sectional mass while maximizing the critical strength ratio. The constraints are imposed on the mass, stiffnesses, and critical strength ratio corresponding to multiple design load cases. The optimal results reveal a simpler and better feasible section with double-H shape compared to the triple-H shape of the baseline where reductions of 9.46%, 67.44% and 30% each are reported in torsional stiffness, lag bending stiffness, and sectional mass, respectively, with critical strength ratio greater than 1.5.
A Study on Strength Prediction of Mechanical Joint of Composite under Bending Load
Baek, Seol ; Kang, Kyung-Tak ; Lee, Jina ; Chun, Heoung-Jae ;
Composites Research, volume 27, issue 6, 2014, Pages 213~218
DOI : 10.7234/composres.2014.27.6.213
This paper predicted the strength of mechanical joint of composites under bending load by means of the characteristic curve method. The method has been employed only for tensile and compression load conditions, but in this study, this method was extended to the bending load condition. For the finite element analysis (FEA), the nonlinear analysis was conducted considering the contact and friction effects between composite material and pin. The failure strength and mode on characteristic curve were evaluate with Tsai-Wu failure theory. To validate the results of FEA, the experiments were conducted to find out the failure load by applying bending moment on the composite specimens. The results showed reasonable agreements with theoretical results. These results lead to a conclusion that the characteristic curve method can be applied to predict the bending strength of mechanical joint of composites.
A Study of Damage Sensing and Repairing Effect of CNT Nanocomposites
Kwon, Dong-Jun ; Wang, Zuo-Jia ; Choi, Jin-Young ; Shin, Pyeong-Su ; Park, Joung-Man ;
Composites Research, volume 27, issue 6, 2014, Pages 219~224
DOI : 10.7234/composres.2014.27.6.219
Nancomposites manufacture has been developed rapidly, because of reinforcing effects of CNT in terms of mechanical, electrical and thermal properties. In this study, 10 wt% CNT paste was fabricated with good dispersion state and easy processability. Damage sensing and reinforcing effect of CNT paste were investigated in nanocomposites. 10 wt% CNT paste exhibited better tensile and flexural properties than those of general 1 wt% CNT nanocomposites. To observe the healing effect of CNT paste, a crack was made artificially with 30wt% CF30wt%/PP composites, and the CNT paste was filled inside the crack. The damage sensing of CNT paste in CF30wt%/PP composites was investigated by electrical resistance measurement and mechanical tests. CNT paste exhibited good reinforcing effect in mechanical properties of CF30wt%/PP composites, and this reinforcing effect was getting better with larger cracks. The reason was because CNT paste had good interfacial adhesion with CF30wt%/PP composites to resist crack propagation. In electrical resistance measurement, there was a jump in electrical resistance signal at the adhesion interface. The jumping signal could be used to predict fracture of CF/PP composites. CNT nanocomposites for damage sensing had crack reducing effect and damage detection using electrical resistance method.
Design and Fabrication of Stratified Microwave Absorbing Structure Consisted of Glass/Epoxy - Resistive Sheet - Foam
Choi, Won-Ho ; Shin, Jae-Hwan ; Song, Tae-Hoon ; Lee, Won-Jun ; Kim, Chun-Gon ;
Composites Research, volume 27, issue 6, 2014, Pages 225~230
DOI : 10.7234/composres.2014.27.6.225
In this study, a novel microwave absorber which consists of a structural part, a resistive sheet, and a low dielectric layer is proposed. Unlike the conventional Salisbury screen, a newly proposed absorber is capable of a range of absorbing performance, from narrowband to broadband. In the case of the narrowband absorber, the fabricated absorber with optimized design parameters has a strong resonance at 9.25 GHz and reflection loss of -44 dB with satisfying the -10 dB absorption in whole X-band (8.2 GHz~12.4 GHz). For the broadband absorber design, the reflectivity was minimized in the considered frequency ranges. The designed absorber showed two weak resonances near 6.5 GHz and 16.5 GHz and satisfied the -10 dB absorption from C-band to Ku-band (4 GHz~18 GHz). The measured reflection loss of fabricated absorber was well matched with simulation results, though the measurement was only performed on X-band. For the Salisbury screen to be capable of broadband absorption, it should be stacked multiply in a structure known as the Jaumann absorber. However, for the microwave absorber presented here, broadband as well as narrowband capabilities can be implemented without a change of the structure.
Prediction of Deformation of Carbon-fiber Reinforced Polymer Matrix Composite for Tool Materials and Surface Conditions
Sung, Su-Hwan ; Kim, Wie-Dae ;
Composites Research, volume 27, issue 6, 2014, Pages 231~235
DOI : 10.7234/composres.2014.27.6.231
Autoclave processing has a good quality of product, but manufacturing cost is expansive. After curing of composite, the unwanted deformation and distortion increase the manufacturing cost by redesign of tool parts. Therefore, manufacturing cost down is a big issue in processing level. For the reduction of tool costs, it is important to investigate the effects of tool materials and tool surface conditions. In this paper, we organized user subroutine in ABAQUS to consider the thermal effects of part and tool, and the results are compared with commercial code, COMPRO. And this paper suggests reference point for the selection of tool materials to reduce manufacturing costs.
Evaluation of Mechanical Property Variation of Epoxy Based Compliant Polymer Concretes Exposed to UV Light
Roh, In-Taek ; Jung, Kyung-Chae ; Chang, Seung-Hwan ;
Composites Research, volume 27, issue 6, 2014, Pages 236~241
DOI : 10.7234/composres.2014.27.6.236
This paper aims to evaluate material property variation of polymer concretes under ultra-violet exposure condition. The components and mixing ratio of the polymer composite specimens were determined by the previous research results. The equivalent UV exposure time was calculated with the consideration of the power of metal halide lamp and maximum 3 years were selected for the experiments. From the tests, it was found that the generated heat during UV exposure affected much the material properties of polymer concrete by means of post cure. As a result, the compressive strength increased and ductility factor decreased.
A Study on the Fabrication of Flexible Composite Electrodes and Its Bonding Characteristics According to Surface Roughness
Lee, Han-Young ; Jung, Kyung-Chae ; Han, Min-Gu ; Chang, Seung-Hwan ;
Composites Research, volume 27, issue 6, 2014, Pages 242~247
DOI : 10.7234/composres.2014.27.6.242
The fabrication of flexible electrodes coated on the surface of a dielectric elastomer film, which is a type of electroactive polymer (EAP), was carried out. Controlled amounts of Xylitol powder were added (10, 30, 50 and 70 wt%) to the commercial conductive polymer (PEDOT:PSS) to enhance resilience of the electrode. To check resilience of the fabricated composite electrodes, tensile tests were carried out using silicone films coated with the polymer electrodes. From the test results, it was found that 70 wt% Xylitol containing conductive polymer had excellent elongation and high failure strains. Furthermore, surface of the silicone film was uniformly polished with various abrading papers to enhance the wettability of the conductive polymers on the surface of the silicone film. It was found that the silicone film polished with #120 abrading paper had the best wettability and guaranteed excellent bonding behavior.
Shear Experiment and Simulation Analysis at Bonded Surface of Specimen Tapered Double Cantilever Beam with Expanded Aluminum
Sun, Hong-Peng ; Cheon, Seong S. ; Cho, Jae-Ung ;
Composites Research, volume 27, issue 6, 2014, Pages 248~253
DOI : 10.7234/composres.2014.27.6.248
In this study, tapered double cantilever beam specimens are designed with the variable of angle to investigate the fracture property at the bonded surface of adjoint structure. These specimens are made with four kinds of models as the length of 200 mm and the slanted angles of bonded surfaces on specimens of
. By investigating experiment and analysis result of these specimens, the maximum loads are happened at 120 N, 137 N, 154 N and 171 N respectively in cases of the specimens with slanted angles of
. As the analysis result approach the experimental value, it is confirmed to have no much difference with the values of experiment and analysis. It is thought that the material property can be investigated effectively on shear behavior of the material composed of aluminum foam bonded with adhesive through simulation instead of experiment by applying this study method.
Development and Analysis of the Autoclave Alternative Composite Material Molding Process Using a Pressure Device
Kim, Jung-Soo ; Kim, Byung-Ha ; Joe, Chee-Ryong ;
Composites Research, volume 27, issue 6, 2014, Pages 254~259
DOI : 10.7234/composres.2014.27.6.254
In this study, a device and pressure press process that is able to substitute autoclave process is developed. This process complements disadvantages of autoclave process which are long process-time and high production cost. The developed device provides air pressure as well as the vacuum which are greatest feature of autoclave process. The device is sealed using hydraulic pressure to keep the air pressure inside the mold. The transfer of the heat is designed to be direct. The heating and pressure charging time are decreased by reducing the interior space. Tooling cost is reduced dramatically compared to autoclave process. Spring-back phenomenon is measured and compared. The temperatures of several parts of the mold during molding are measured. The fiber volume fraction of the parts molded by autoclave process and by the developed process are compared.