• Proceedings of the Korean Society For Composite Materials Conference
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• 2004.10a
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• pp.88-91
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• 2004

In this study, a number of natural fiber henequen reinforced polymer matrix composites were successfully fabricated by means of a compression molding technique using chopped henequen fibers surface-treated with different electron beam irradiation (EBI) dosages, thermoplastic poly(butylene succinate), thermosetting unsaturated polyester and phenolic resins. Their interfacial and thermal characteristics were studied in terms of interfacial shear strength, fracture surface, dynamic mechanical properties, dimensional stability, and thermal stability using single fiber microbonding test, SEM, DMA, TMA, and TGA. The results show that their interfacial and thermal properties significantly depend on the intensity of EBl treatment on the natural fiber surface.

• Macromolecular Research
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• v.10 no.1
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• pp.24-33
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• 2002

Interfacial and microfailure properties of carbon fiber/epoxy composites were evaluated using both tensile fragmentation and compressive Broutman tests. A monomeric and two polymeric coupling agents were applied via the electrodeposition (ED) and the dipping applications. A monomeric and a polymeric coupling agent showed significant and comparable improvements in interfacial shear strength (IFSS) compared to the untreated case under both tensile and compressive tests. Typical microfailure modes including cone-shaped fiber break, matrix cracking, and partial interlayer failure were observed under tension, whereas the diagonal slipped failure at both ends of the fractured fiber appeared under compression. Adsorption and shear displacement mechanisms at the interface were described in terms of electrical attraction and primary and secondary bonding forces.

• Computational Structural Engineering
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• v.10 no.1
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• pp.129-134
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• 1997

Interfacial stress singularity in a unidirectional two-dimensional laminate model consisting of an elastic fiber and a viscoelastic matrix has been investigated using the time-domain boundary element method. First, the interfacial singular stresses between the fiber and the matrix of a unidirectional laminate subjected to a uniform transverse tensile strain have been investigated near the free surface, but without any defect or any edge crack. Such a stress singularity might lead to fiber-matrix debonding or interfacial edge cracks. Then, the overall stress intensity factor for the case of a small interfacial edge crack of length a has been computed.

• KEPCO Journal on Electric Power and Energy
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• v.1 no.1
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• pp.127-134
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• 2015

Recently, the external bonding of carbon fiber reinforced polymer (CFRP) sheets has come to be regarded as a very effective method for strengthening of reinforced concrete structures. The behavior of CFRP-strengthened RC structure is mainly governed by the interfacial behavior, which represents the stress transfer and relative slip between concrete and the CFRP sheet. In this study, the effects of bonded length, width and concrete strength on the interfacial behavior are verified and a bond-slip model is proposed. The proposed bond-slip model has nonlinear ascending regions and exponential descending regions, facilitated by modifying the conventional bilinear bond-slip model. Finite element analysis results of interface element implemented with bond-slip model have shown good agreement with the experimental results performed in this study. It is found that the failure load and strain distribution predicted by finite element analysis with the proposed bond-slip are in good agreement with results of experiments.

• Journal of the Korean institute of surface engineering
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• v.48 no.6
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• pp.275-282
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• 2015

The cost for maintenance (replacement cost) of Ni-superalloy components in plant industry is very expensive because of high unit price of INCONEL 718. A development of repairing technology using kinetic spray process can be very helpful for reducing the maintenance cost. However, it is very difficult to produce well-deposited INCONEL 718 layer showing high interfacial bond strength via kinetic spraying. Thus, INCONEL 718 was deposited on SCM 440 substrate and the interfacial properties were investigated, in order to elucidate the cause of hindrance to the bonding between INCONEL 718 layer and SCM 440 substrate. As a result, it was revealed that the dominant obstacle to the interfacial bonding was excessive compressive residual stress accumulated in the coating layer, resulting from low plastic-deformation susceptibility of INCONEL 718. Nevertheless, the bonding state was enhanced by the post heat-treatment through relieving the residual stress and generating a diffusion/metallurgical bonding between the INCONEL 718 deposit and SCM 440 substrate.

• Computers and Concrete
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• v.26 no.6
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• pp.515-531
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• 2020

Due to the construction difficulties of steel reinforced concrete (SRC), a new composite structure of steel and steel fiber reinforced concrete (SSFRC) is proposed for solving construction problems of SRC. This paper aims to investigate the bond properties and composition of interfacial bond stress between steel and steel fiber reinforced concrete. Considering the design parameters of section type, steel fiber ratio, interface embedded length and concrete cover thickness, a total of 36 specimens were fabricated. The bond properties of specimens were studied, and three different methods of calculating interfacial bond stress were analyzed. The results show: relative slip first occurs at the free end; Bearing capacity of specimens increases with the increase of interface embedded length. While the larger interface embedded length is, the smaller the average bond strength is. The average bond strength increases with the increase of concrete cover thickness and steel fiber ratio. And calculation method 3 proposed in this paper can not only reasonably explain the hardening stage after the loading end curve yielding, but also can be applied to steel reinforced high-strength concrete (SRHC) and steel reinforced recycled coarse aggregate concrete (SRRAC).

• Proceedings of the KOSOMBE Conference
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• v.1997 no.05
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• pp.35-38
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• 1997

The interfacial bonding energy between laser surface treated HA layer and Ti alloy substrate was investigated using a mechanical push-out tester. The initial slope of shear-stress and reduced displacement curves, maximum interfacial bond strength and bonding energy were calculated from results of the push-out test. The calculated initial slpoes are 38 MPa for the Ti alloy(A), 65 MPa for the sandblast finished specimen(B), 95 MPa for the HA plasma spray coated specimen and 49 MPa for the laser surface treated specimen(D). The maximum interfacial bonding strength are 3 MPa for the A, 19 MPa for the B, 20 MPa for the C, 10 MPa for the D. The interfacial bonding energies are $3.3\times10^{-9}J/mm^2$ for the A, $15.5\times10^{-9}J/mm^2$ for the B, $15.6\times10^{-9}J/mm^2$ for the C and $18.3\times10^{-9}J/mm^2$ for the D. Microscopic observation shows that the breaking of the laser treated specimen had been occured through the boundary between HA layer and polymer resin, but the untreated specimen had been occured through the inside of HA coating layer.

• Journal of the Microelectronics and Packaging Society
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• v.25 no.3
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• pp.7-12
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• 2018

The effects of Ru deposition temperature and post-annealing conditions on the interfacial adhesion energies of atomic layer deposited (ALD) Ru diffusion barrier layer and Cu thin films for the advanced Cu interconnects applications were systematically investigated. The initial interfacial adhesion energies were 8.55, 9.37, $8.96J/m^2$ for the sample deposited at 225, 270, and $310^{\circ}C$, respectively, which are closely related to the similar microstructures and resistivities of Ru films for ALD Ru deposition temperature variations. And the interfacial adhesion energies showed the relatively stable high values over $7.59J/m^2$ until 250h during post-annealing at $200^{\circ}C$, while dramatically decreased to $1.40J/m^2$ after 500 h. The X-ray photoelectron spectroscopy Cu 2p peak separation analysis showed that there exists good correlation between the interfacial adhesion energy and the interfacial CuO formation. Therefore, ALD Ru seems to be a promising diffusion barrier candidate with reliable interfacial reliability for advanced Cu interconnects.

• Composites Research
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• v.32 no.2
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• pp.96-101
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• 2019

Interfacial adhesion between fiber and resin are related to composites performance, so it is very important to evaluate them accurately. In this study, the interfacial properties of microdroplets under fatigue loading conditions were evaluated. The mechanical properties and interfacial adhesion of epoxy resin with dopamine were studied. Tensile specimens were prepared to evaluate mechanical properties and epoxy microdroplets specimens were used for the evaluation of interfacial adhesion. In addition, in the microdroplet fatigue test, the same diameter of the microdroplet was used and the experiment was performed under the same conditions. As a result, it was confirmed that mechanical and interfacial properties were improved when dopamine was applied to epoxy resin through tensile and microdroplet experiments. It is considered that dopamine improves the degree of curing of the epoxy resin and imparts hydroxyl groups to the epoxy resin to increase the mechanical properties and the interfacial adhesion between the glass fibers.

• Structural Engineering and Mechanics
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• v.69 no.3
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• pp.327-334
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• 2019

The purpose of this paper is to investigate the hygrothermal effects on the behavior of reinforced-concrete beams strengthened by bonded composite laminate plates (${\theta}n/90m)s$. This work is based on a simple theoretical model to estimate the interfacial stresses developed between the concrete beam and the composite with taking into account the hygrothermal effect. Fibre orientation angle effects of number of $90^{\circ}$ layers and effects of plate thickness and length on the distributions of interfacial stress in the concrete beams reinforced with composite plates have also been studied.