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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 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
Bending and Torsional Characteristics of Rectangular CFRP Tubes with Various Aspect Ratios
Lee, Yongsung ; Cheong, Seong-Kyun ;
Composites Research, volume 27, issue 2, 2014, Pages 37~41
DOI : 10.7234/composres.2014.27.2.037
Fiber reinforced composite materials have outstanding specific strength and specific stiffness. So the use of composite materials increases in various kinds of industrial fields including sports goods such as bicycles. Composite materials are used to make structural parts with various kinds of shapes. Specially, rectangular composite tubes are used to make a few of composite bicycle frames, but there has been a few of research on this issue. Rectangular composite tubes are designed to have appropriate radius of curvature and endure bending and torsional loads. In this research, nine kinds of rectangular composite tubes having aspect ratios 1:1, 1:1.5, 1:2 and radius of curvatures R5, R10, R15 were fabricated. The carbon fiber reinforced composite material was used to make tubes having same cross sectional areas. The stacking sequence of tubes is
. Experimental evaluation was accomplished to apply bending and torsional load to the tubes. Experimental results show that bending and torsional characteristics depend on radius of curvature and aspect ratio of rectangular composite tubes.
An Experimental Study on the Absorbed Energy of Polymeric Foam According to Different Mass and Impact Velocity Based on the Constant Impact Energy
Kim, Byeong-Jun ; Kim, Han-Kook ; Cheon, Seong S. ;
Composites Research, volume 27, issue 2, 2014, Pages 42~46
DOI : 10.7234/composres.2014.27.2.042
In the present study, impact tests were carried out to investigate the crashworthy behaviour of the expanded polypropylene under the constant incident energy (100 J and 200 J) with five different combinations of striker mass and velocity. Also, preliminary quasi-static test was performed to obtain basic characteristics of the expanded polypropylene. MTS 858 and Instron dynatup 9250 HV were used for the quasi-static test and impact tests, respectively. In consequence, it was found that the impact energy absorption characteristics of the expanded polypropylene was more influenced by the striker mass instead of the velocity of the striker.
Piezo-Composite Actuator for Control Surface of a Small Unmanned Air Vehicle
Yoon, Bum-Soo ; Park, Ki-Hoon ; Yoon, Kwang-Joon ;
Composites Research, volume 27, issue 2, 2014, Pages 47~51
DOI : 10.7234/composres.2014.27.2.047
The purpose of the present study is to develop lightweight and simple smart actuators in order to replace conventional hydraulic/pneumatic actuators, and to apply the developed actuators to the actuation systems of a small unmanned air vehicle. This research describes the procedures of design, manufacturing of the piezo-composite actuator, and the performance evaluation. From the test results of the developed devices, we found the possibility of piezo-composite actuator could be used as a control surface of a small UAV system. We have designed and manufactured two kinds of piezo-composite actuators, unimorph actuator and bimorph actuator. The manufactured actuators were evaluated through the performance testes. It was found that the bimorph type actuator showed more linear angle change for the same excitation voltage variation than unimorph type. It is expected that piezo-composite actuator has a possibility to be used not only as a control surface of small unmanned flying vehicle but also as a control surface actuator of a guided missile fin through the miniaturization of power supply and control system.
A Study on the Effect of Fiber Orientation on Impact Strength and Thermal Expansion Behavior of Carbon Fiber Reinforced PA6/PPO Composites
Won, Hee-Jeong ; Seong, Dong-Gi ; Lee, Jin-Woo ; Um, Moon-Kwang ;
Composites Research, volume 27, issue 2, 2014, Pages 52~58
DOI : 10.7234/composres.2014.27.2.052
Short fiber reinforced composites manufactured by injection molding have diverse fiber orientations variable with measuring positions even in the same specimen, which is caused by the flow induced fiber orientation. Fiber orientations considerably affect the mechanical and thermal properties of final composite products. In this study, fiber orientation of injection molded carbon fiber reinforced PA6/PPO composite was measured at several points of the specimen by optical microscopy analysis and the corresponding izod impact strength, coefficients of thermal expansion (CTE) were also measured to investigate the influence of local fiber orientation on the mechanical and thermal properties. Izod impact strength where fiber was perpendicular to the direction of crack propagation was higher than where fiber was parallel to the direction, which could be explained be the impact resistance reinforcing mechanism by fiber orientation. CTE was also lower where fiber was parallel to the measurement direction of CTE than where fiber was perpendicular to the direction, which could be also explained by the dimensional stability mechanism by fiber orientation.
Structural Design and Installation of Tracking-type Floating PV Generation System
Kim, Sun-Hee ; Lee, Young-Guen ; Seo, Su-Hong ; Joo, Hyung-Joong ; Yoon, Soon-Jong ;
Composites Research, volume 27, issue 2, 2014, Pages 59~65
DOI : 10.7234/composres.2014.27.2.059
Most of energy are obtained from oil, coal, and natural gas, most likely, fossil fuel which is limited throughout the world. Recently, high crude oil price, climate change, oil depletion, etc. are main reason to get attention to non-fossil energy including renewable energy in the world. In this study, we studied analysis and design of structure system composed of pultruded fiber reinforced polymer composite (PFRP) which has many advantages such as high specific strength and stiffness, high corrosion resistance and chemical resistance. For the design and construction of floating-type structure, PFRP structural members may be the first choice. Design of tracking-type floating PV generation structure was performed by using the results of the finite element analysis. The structure is fabricated and installed on the water surface. Before the installation of the structure, safety related problems associated with installation and operation are investigated using the finite element simulation and it was found that the structure is safe enough to resist externally applied loads.
Natural Frequency Characteristics of GFRP Pole Structures for Civil Structures with Different Fiber-Volume Fraction
Lee, Sang-Youl ;
Composites Research, volume 27, issue 2, 2014, Pages 66~71
DOI : 10.7234/composres.2014.27.2.066
This study carried out finite element vibration analysis of pole structures made of GFRP, which is based on the micro-mechanical approach for different fiber-volume fractions. The finite element (FE) models for composite structures using multi-scale approaches described in this paper is attractive not only because it shows excellent accuracy in analysis but also it shows the effect of the material combination. The FE model is used for studying free vibrations of laminated composite poles for various fiber-volume fractions. In particular, new results reported in this paper are focused on the significant effects of the fiber-volume fraction for various parameters, such as fiber angles, layup sequences, and length-thickness ratios. It may be concluded from this study that the combination effect of fiber and matrix, largely governing the dynamic characteristics of composite structures, should not be neglected and thus the optimal combination could be used to design such civil structures for better dynamic performance.
Experiment and Analysis on Impact of Tapered Double Cantilever Beam with Aluminum Alloy
Gao, Teng ; Cho, J.U. ; Cheon, Seong S. ;
Composites Research, volume 27, issue 2, 2014, Pages 72~76
DOI : 10.7234/composres.2014.27.2.072
This study is investigated by experiments and analyses at rates of 2.5m/s, 7.5m/s and 12.5m/s on the impact of tapered double cantilever beam specimens with aluminium alloy. It aims to examine the mechanical property of aluminum alloy by evaluating energy release rate and equivalent stress happened at the bonded part of specimen. Because bonding force remains after the separation of specimen, the energy release rate at the bonded part becomes highest. As crack propagates and the high stress happens at the end of the bonded part, the maximum equivalent stress becomes higher at the last stage, regardless of impact rate. These results of experiments and analyses are the data necessary to develop the safe design of composite material to prevent crack propagation due to impact.
A Study on 4 Point Bending Strength of Carbon/epoxy Face Sheet and Honeycomb Core Sandwich Composite Structure after Open Hole Damage
Park, Hyunbum ;
Composites Research, volume 27, issue 2, 2014, Pages 77~81
DOI : 10.7234/composres.2014.27.2.077
In this study, it was performed damage assessment and repair of small scale aircraft adopted on composite. This aircraft adopted the sandwich structure to skin of wing. This study aims to investigate the residual strength of sandwich composites with nomex honeycomb core and carbon fiber face sheets after the open hole damage by the experimental investigation. The 4-point bending tests were used to find the bending strength, and the open hole was applied to introduce the simulated damage on the specimen. The bending strength test results after open hole were compared with the results of no damaged specimen test. In addition, The damaged composite structure was repaired using external patch repair method after removing damaged area. After that, this study presents comparison results of the experimental investigation between the damaged and the repaired specimen. It was found that the bending strength of repaired specimen was recovered up to 95% of undamaged specimen.