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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal DOI :
The Korean Society for Composite Materials
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Volume & Issues
Volume 17, Issue 6 - Dec 2004
Volume 17, Issue 5 - Oct 2004
Volume 17, Issue 4 - Aug 2004
Volume 17, Issue 3 - Jun 2004
Volume 17, Issue 2 - Apr 2004
Volume 17, Issue 1 - Feb 2004
Selecting the target year
Three-Dimensional Numerical Simulation of Mold-Filing and Void Formation During Vacuum-Assisted Resin Transfer Molding
Composites Research, volume 17, issue 3, 2004, Pages 1~7
In the vacuum assisted RTM (VARTM) process that has become the center of attention for manufacturing massive composite structures, a good evacuation of air in the fiber preform is recognized as the prime factor. The microvoids, or the dry spots, are formed as a result of improper gate/vent locations and the mold geometry. The non-uniform resin velocity at the flow front leads to the formation of microvoids in the fibers, whereas the air in the microvoids can migrate along with the resin flow during mold filling. The residual air in the internal voids of a composite structure may cause a degradation of the mechanical properties as well as the structural failure. In this study, a unified macro- and micro analysis methods were developed to investigate the formation and transport of air in resin during VARTM process. A numerical simulation program was developed to analyze the three-dimensional flow pattern as well as the macro- and microscopic distribution of air in a composite part fabricated by VARTM process.
A Study on Degradation in the Moisture Environment and Recovery of Carbon Fiber Reinforced Composites
Composites Research, volume 17, issue 3, 2004, Pages 8~14
The effect of moisture absorption on the mechanical properties in carbon fiber reinforced composites has been investigated with various moisture environment such as sea water, tap water and distilled water. It also has been studied about the influence of drying of the immersed specimen for a certain period of time on the mechanical properties. As a result, we found that the ratio of moisture absorption mainly depended on the immersion time in the moisture environment and that of the immersed specimen for a certain period of time decreased with the drying time. We also found that tensile strength decreased with the increasing of the ratio of moisture absorption and the tensile strength decreased by moisture absorption recovered up to some extent by drying the specimen.
Acoustic Loads Reduction of Composite Plates for Nose Fairing Structure
Composites Research, volume 17, issue 3, 2004, Pages 15~22
Acoustic load generated by rocket propulsion system is one of major dynamic loads during lift-off phase so that it causes the structural failure and electronic malfunction of payloads. Acoustic loads can be greatly reduced by an appropriate acoustical design of nose faring structures. This paper deals with the acoustical design of the nose fairing structure for launch vehicle. It is well known that a honeycomb sandwich structure is a poor sound insulator because of its high specific stiffness. In this paper, the sound transmission characteristics of four kinds of honeycomb structures for noise fairing were investigated by means of numerical and experimental ways. In order to estimate transmission loss, infinite plate theory by Moore and Lyon and statistical energy analysis (SEA) method were used. The predicted results showed a good agreement with measured ones. These enabled us to determine a proper core material for nose fairing, which shows good sound insulation performance per weight.
Simple Method of Vibration Analysis of Three Span Continuous Reinforced Concrete Bridge with Elastic Intermediate Support
Kim, Duk-Hyun ; Han, Bong-Koo ;
Composites Research, volume 17, issue 3, 2004, Pages 23~28
A method of calculating the natural frequency corresponding to the first mode of vibration of beams and tower structures, with irregular cross sections and with arbitrary boundary conditions was developed and reported by Kim, D. H. in 1974. In this paper, the result of application of this method to the three span continuous reinforced concrete bridge with elastic intermediate supports is presented. Such bridge represents either concrete or sandwich type three span bridge on polymeric supports for passive control or on actuators for active control. The concrete slab is considered as a special orthotropic plate. Any method may be used to obtain the deflection influence surfaces needed for this vibration analysis. Finite difference method is used for this purpose, in this paper, The influence of the modulus of the foundation and
stiffnesses on the natural frequency is thoroughly studied.
Aeroelastic Stability Analysis of Bearingless Rotors with Composite Flexbeam in Hover
Composites Research, volume 17, issue 3, 2004, Pages 29~37
The aeroelastic stability analysis of composite bearingless rotors is investigated using a large deflection beam theory in hover. The bearingless rotor configuration consists of a single flexbeam with a wrap-around type torque tube and the pitch links located at the leading edge and trailing edge of the torque tube. The outboard main blade, flexbeam and torque tube are all assumed to be an elastic beam undergoing flap bending, lead-lag bending, elastic twist and axial deflections, which are discretized into beam finite elements. For the analysis of composite bearingless rotors, flexbeam is assumed to be a rectangular section made of laminate. Two-dimensional quasi-steady strip theory is used for aerodynamic computation. The finite element equations of motion for beams are obtained from Hamilton's principle. The p-k method is used to determine aeroelastic stability boundary. Numerical results are presented for selected bearingless rotor configurations based on the lay-up of laminae in the flexbeam and pitch links location. A systematic study is made to identify the importance of the stiffness coupling terms on aeroelastic stability for various fiber orientation and for different configuration.
A Study on Permittivity of Multi-walled Carbon nanotube/Epoxy Composites
Composites Research, volume 17, issue 3, 2004, Pages 38~44
The electromagnetic interference (EMI) shielding is very essential for commercial and military purposes. We fabricated multi-walled carbon nanotube (MWNT)/epoxy composites and studied the electromagnetic characteristics of the composites before we study the characteristics of MWNT-added glass fiber-reinforced composites. After setting up the fabrication process, we measured the permittivity of MWNT/epoxy composites with process variables and MWNT concentrations in X-band (8.2GHz~12.4GHz). We also observed re-aggregation phenomenon of MWNTs and investigated its effect on the permittivity. The permittivity of the composites was influenced by the degree of dispersion of MWNTs and increased almost linearly as MWNT concentration increases.
A Study on Dynamic Properties of Short-fiber Reinforced Chloroprene Rubber
Composites Research, volume 17, issue 3, 2004, Pages 45~50
The dynamic properties of short-fiber reinforced chloroprene rubber with different interphase conditions and fiber contents have been studied as functions of frequency, amplitude and temperature. The loss factor(LF) slightly increased more than 1.33% of strain and the dynamic ratio(DR) rapidly decreased with increasing strain amplitude. The LF rapidly decreased with increasing frequency especially more than 50Hz. The DR showed the lower when it compared to virgin material with increasing frequency. The LF showed the maximum at
and rapidly decreased after that temperature. The DR showed the lower when it compared with virgin rubber with increasing temperature. Generally, the better interphase condition showed the lower LF and DR at the same testing condition. Therefore, the short-fiber reinforced rubber could have the better isolation when the frequency ratio is more than
compared with frequency ratio less than
How Phenolic Composites were chosen - In Case of England (3)
Nomaguchi, Kanemasa ; Forsdyke, Ken L. ; Brown, Denver E. ;
Composites Research, volume 17, issue 3, 2004, Pages 52~61
"Phenolic composites", one of safety composites, was also chosen to build boats in England. One of the authors, Mr. Forsdyke and his researcher, Dr. Orpin describe how phenolic composites were chosen as construction material for marine application. The reader can get very good understandings from design point of view through this paper.his paper.
200km/h급의 한국형 고속틸팅열차(TTX) 개발사업 소개
Composites Research, volume 17, issue 3, 2004, Pages 62~65