• Journal of Korea Foundry Society
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• v.35 no.6
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• pp.141-146
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• 2015

Aluminum-based hybrid parts were fabricated through a compound casting process with Al or Cu inserts which can be used for applications requiring high conductivity. Because the interface stability between the insert and the aluminum matrix is important, the effects of process variables on the interfacial adhesion strength were investigated. Additions of Cu and Mg to Al melt were found to enhance the adhesion strength, though the melt fluidity was slightly deteriorated when a small amount of Mg was added. An isothermal heating process after casting further improved the strength. However AlCu intermetallic compounds formed and their thickness increased during the heating process. As a result, deterioration in the interfacial adhesion strength was observed after an excessive annealing treatment.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.55 no.12
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• pp.581-585
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• 2006

Macro interfaces between two different bulk materials which affect the stability of insulation system exist inevitably in the complex insulation system using in extra high voltage (EHV) electric devices. In this paper, Interface between epoxy and ethylene propylene diene terpolymer (EPDM) was selected as an interface in electrical insulation system and the AC dielectric strength of the interface was investigated. Air compress system was used to give pressure to the interface. Specimens were prepared in various ways to generate different surface conditions for each type of interface. Increasing interfacial pressure, decreasing surface roughness and spreading oil over surfaces improve the AC interfacial dielectric strength. Especially, the dielectric strength was saturated at certain interfacial pressure.

• Journal of the Korea institute for structural maintenance and inspection
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• v.1 no.1
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• pp.107-112
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• 1997

A series of reinforced concrete beams was tested to evaluate the flexural performance of the repaired RC beams. The key parameters for this study were the size and location of the patch, and the repair materials, including polymer, polymer-cementitious and cementitious materials. The repaired specimens failed by a typical flexural mode with minor interfacial bond failure. Beams repaired with polymer, polymer-cementitious and cementitious materials recover 100%, 91%, and 97% of the flexural strength respectively, while beams with cement mortar lose approximately 30% of the strength. Compared with the pressure injection techniques the specimens repaired with patching techniques show low flexural strength, with significant interfacial bond failure. Location and size of the repaired part do not affect the recovering performance. Interfacial behavior between repair and strengthening materials is the major influencing factor for the composite structures.

• Transactions of Materials Processing
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• v.27 no.5
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• pp.267-275
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• 2018

The clad sheet material is produced by a roll-bonding process of one or more materials with different properties. Good formability of clad sheet material is an essential property in to deform a clad metal sheet into a part or component. Performance of the clad sheet material largely depends on interfacial bond strength between different materials. In this study, interfacial bond strength of STS/Al clad sheet was analyzed by varying experimental parameters using a blanking process. Experimental parameters are the punching speed, clearance, and stacking order of plate materials. In addition, blanking test results were compared with bond strengths measured by the T-peel test, that analyzes interface bonding strength of the standard clad sheet. The blanking process was analyzed by the finite element method under the sticking condition of interface of different materials, and experimental results and analysis results were compared.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.05a
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• pp.540-543
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• 1999

In order to determine what indluences the interfacial breakdown in EPDM/XLPE laminates. We studied the interfacial breakdown phenomena at several interfacial conditions. Breakdown strength in laminates pasted with silicone oil was higher than that with silicone grease. As a function of heat treatment time in a vacuum, interfacial breakdown strength increased much in XLPE/EPDM laminates pasted with silicone grease but increased a little in that with silcone oil. FT-IR spectrum of silicone oil was similar to that is silicone grease. FT-lR spectrum of silicone oil was not changed by the heat treatment in a vacuum, but in silicone grease another peak appeared.

• Steel and Composite Structures
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• v.43 no.3
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• pp.311-325
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• 2022

For multi-story structural systems, Korean steel industry has fostered development of a steel-concrete composite beam. Configuration of the composite beam is characterized by steel angle shear connectors welded to a U-shaped cold formed-steel beam. Effects of shear connector orientation and spacing were studied to evaluate current application of the angle shear connector design equation in AC495. For the study, interfacial shear resistance behavior was investigated by conducting 24 push-out tests and attuned using unreinforced push-out specimens. Interfacial shear to horizontal slip response was reported along with corresponding failure patterns. Pure shear connector strength was also evaluated by excluding concrete shear contribution, which was estimated in relation to steel beam-slab interface separation or interfacial crack width.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.1359-1360
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• 2011

• Proceedings of the Korean Society For Composite Materials Conference
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• 2001.10a
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• pp.158-162
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• 2001

The effects of chemical treatment on Kevlar-29 fibers have been studied in a composite system. The surface characteristics of the Kevlar-29 fibers were characterized by pH, acid-base value and X-ray photoelectron spectroscopy (XPS). The mechanical interfacial properties of final composites were studied by interlaminar shear strength (ILSS) and critical stress intensity factor ($K_{IC}$). Also, the impact properties of the composites were investigated in the differentiating studies between initiation and propagation energies, and ductile index (DI) along with maximum farce and total energy. It was found that the chemical treatment with phosphoric acid ($H_3PO_4$) solution significantly affected the degree of adhesion at interfaces between fibers and resin matrix, resulting in improving the mechanical interfacial strength of the composites. This was probably due to the presence of chemical polar groups on Kevlar surfaces, leading to an increment of interfacial binding force in a composite system.

• Polymer(Korea)
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• v.27 no.3
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• pp.189-194
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• 2003

Interfacial evaluation, damage sensing and cure monitoring of single carbon fiber/thermo setting composite with different curing processes were investigated using electro-micromechanical test. After curing, the residual stress was monitored by measurement of electrical resistance and then compared to various curing processes. In thermal curing case, matrix tensile strength, modulus and interfacial shear strength were higher than those of ultraviolet curing case. The shrinkage measured during thermal curing occurred significantly by matrix shrinkage and residual stress due to the difference in thermal expansion coefficient. The apparent modulus measured in the thermal curing indicated that mechanical and interfacial properties were highly improved. The reaching time to the same stress of thermal curing was faster than that of UV curing case.

• Macromolecular Research
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• v.13 no.5
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• pp.453-459
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• 2005

Natural fiber henequen/unsaturated polyester (UPE) composites were fabricated by means of a compression molding technique using chopped henequen fibers treated at various electron beam (EB) dosages. The interfacial shear strength (IFSS), dynamic mechanical properties, and thermal expansion behavior were investigated through a single fiber microbonding test, fractographic observation, dynamic mechanical analysis, and thermomechanical analysis, respectively. The results indicated that the interfacial and dynamic mechanical properties significantly depended on the level of the EB treatment irradiated onto the henequen fiber surfaces. The effect of EB treatment on the IFSS, storage modulus and fracture surface of the henequen/UPE composites agreed with each other. The results of this study also suggested that the modification of henequen fiber surfaces at 10 kGy EB is the most effective for improving the interfacial properties of the henequen/UPE composites.