• Journal of the Earthquake Engineering Society of Korea
• /
• v.7 no.1
• /
• pp.1-7
• /
• 2003

The carbon composite tube can play an important role in replacing or complementing longitudinal and transverse reinforcing steels by providing ductility and strength for conventional columns. In this study, both the experimental and analytical investigations of axial behavior of large-scale square concrete columns confined by carbon composite tube are presented. The specimens are filament-wound carbon composite with 90$^{\circ}$+30$^{\circ}$, 90$^{\circ}$+45$^{\circ}$ winding angle respect to longitudinal axis of tube. The instrumented large-scale concrete-filled composite tubes(CFCT) are subjected to monotonic axial loads exerted by 10,000kN UTM. The influence of winding angle, thickness of tube on stress-strain relationships of the confined columns is identified and discussed. Proposed equations to predict both the strength and ductility of confined columns by carbon composite tube demonstrate good correlation with test data obtained from large-scale specimens.

• Proceedings of the Korean Society For Composite Materials Conference
• /
• 2005.04a
• /
• pp.33-36
• /
• 2005

In this research, for the smart health monitoring of the hydrogen storage high pressure composite vessel, the feasibility study of an embedded fiber Bragg grating(FBG) sensor is carried out. To verify strain measurement in various temperature environment which is needed for the hydrogen pressure vessel, tensile test of a composite specimen with both an embedded FBG sensor and a strain gauge is made in low temperature. Before we try a real-size hydrogen storage pressure vessel, a small & cheap composite pressure vessel having the same structure is fabricated with embedded FBG sensors and tested. In the case of an aluminum liner inside the vessel, survivability of FBG sensors at the interface is lower than the other areas.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.37 no.2
• /
• pp.147-155
• /
• 2009

The buckling and failure of filament wound thick composite cylinders under external hydrostatic pressure were investigated by the finite element analysis and test. ACOS, MSC.NASTRAN, and MSC.MARC were used for finite element analysis. T700 carbon-epoxy filament wound composite cylinders were fabricated to have winding angles of $[\pm30/90]_{FW}$, $[\pm45/90]_{FW}$, $[\pm60]_{FW}$, $[\pm60/90]_{FW}$, and tested to verify the finite element analysis. Among the softwares, ACOS predicted buckling load the best with about 1.7~14.3% deviation from test. Analysis and test shows cylinders do not recover the initial buckling pressure after buckling and directly lead to final failure.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2003.07a
• /
• pp.436-439
• /
• 2003

FRP has been used widely for insulator. FRP consists of fiber and resin. The fiber contributes the high strength and modulus to the composite. The fiber orientation in FRP has a great effect on the strength of FRP because the strength of FRP mainly depends on the strength of fiber. In this study, FRP was made unidirectionally by pultrusion method. Outer part of the FRP was made by filament winding method to give fiber orientation to the FRP. And outer part of FRP was also made by wrapping method. The bending strength and bending stresses of FRP rods were simulated according to the winding orientation of glass fiber. The bending strength of FRP was also evaluated. The results of simulation and evaluation were compared each other to investigate main stresses which affect the fracture of FRP. The main stresses which had a great effect on the strength of FRP were shear stresses. Bending strength of the FRP was different with the winding angle. The bending strength of $15^{\circ}$ winded FRP was the highest.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2008.06a
• /
• pp.493-494
• /
• 2008

During the last years hollow core insulators started their success story in the field of high voltage engineering for electrical apparatus, substituting porcelain insulators. The termination, also named top and bottom fittings are used for the connection to the rest of the electrical apparatus. The top and bottom flange are attached to the composite to transmit mechanical load and also ensure the gas tightness. They are bonded by epoxy glue with a glass transition temperature of about $130^{\circ}C$-$150^{\circ}C$ the glass reinforced epoxy tube of filament winding. This paper describes the results of a study on the bonded joints of fiber reinforced epoxy tube and cast aluminum. This suggests that surface roughness and glue types play an important role in evaluating of gas sealing capability on the flange and fiber reinforced epoxy tube in the composite hollow bushing.

• Proceedings of the Korean Society For Composite Materials Conference
• /
• 2004.10a
• /
• pp.241-245
• /
• 2004

Among the various manufacturing processes of composites, the tape lay-up process of thermoset prepreg has many advantages compared to autoclave or hot press forming. It has a high potential to process automation and continuous fabrication .. Fiber placement developed as a logical combination of filament winding and automated tape placement to overcome some of the limitations of each manufacturing method. Fiber placement uses a compaction device to apply direct contact between the incoming materials in the fiber placement head and Heat is added to the materials at the nip point of the compaction roller. This paper will discuss property of thermoset composite as compaction and heat effect in Automated fiber placement

• New & Renewable Energy
• /
• v.4 no.3
• /
• pp.51-57
• /
• 2008

The objective of this study is to develop and validate a compressed hydrogen storage system for fuel cell vehicles. The type3 composite cylinder consists of full wrapped composites on a seamless aluminum liner. The key technologies, including design, analysis, and optimized fabrication process for 350bar composite cylinder, were established and verified, and the facilities for fabrication and validation testing have been constructed. Prototype cylinders were fabricated and validated through burst test and ambient cycling test in accordance with international standard.

• Proceedings of the Korean Society For Composite Materials Conference
• /
• 2004.04a
• /
• pp.9-12
• /
• 2004

Presented is a preliminary design concept of the carbon-glass hybrid composite rebars for the application in the construction field. A glass fiber rod with indentation is used for the core of the rebar. Carbon fibers are placed over the glass core by pultrusion. To increase the mechanical locking force and bonding surface, carbon filament windings are added in the hoop direction over the carbon face. Finite element analysis and test were conducted to evaluate the effective stiffness and strength of the rods. The results show that the effective axial stiffness of the rebar with indentation are about $50\%$ of the straight rebar.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2010.11a
• /
• pp.205-209
• /
• 2010

The technology of production of the thermoplastic composite rocket propellants is based on a two-phase production procedure. The first phase represents the production of a semi-product in the sheet (foil) form (thickness: 0.5 mm ~ 5 mm), whereas the second phase is realized independently from the first one and it is based on the semi-produced product and thus the final form of the propellant grain is realized in relation to the defined geometry. Well done mechanical characteristics of the propellant grain enable that the same thing could be used as a mandrel in the filament winding procedure in creating the motor chamber of the composite material.

• Composites Research
• /
• v.15 no.1
• /
• pp.53-60
• /
• 2002

Composite ablative tubes required capabilities of ablative and structural characteristics were fabricated through filament winding technique and several experiments were conducted to evaluate the structural performance of composite ablative tubes. For this purpose, manufacturing procedures were briefly described and then resin digestion method was applied to measure the fiber volume fraction and the void content of composite ablative tubes. The configuration of tensile specimen fur composite ablative tubes with not losing the continuity of reinforced fibers was suggested by evaluating mechanical properties of several types of the specimen with different widths. Also, suitable processing variables for composite ablative tubes were determined by evaluating mechanical properties of several types of the specimen with different processing variables. In addition, acoustic emission signals were obtained during the proof test and could be applicable to study the crack initiation and the damage mode of composite ablative tubes. Finally, the structural reliability of composite ablative tubes could be verified to satisfy design requirements through the proof and burst tests.