• Title/Summary/Keyword: interface adhesive layer

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A Study for Creep Effect of the Interfacial Adhesive Layer on the Behavior of Concrete with CFRP (탄소섬유시트로 보강된 콘크리트 구조물 경계면 재료의 크리프 영향 해석)

  • Park, Yong Deuk;Shin, Seung Kyo;Kang, Suk Hwa;Lim, Yun Mook
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.30 no.3A
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    • pp.221-228
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    • 2010
  • External bonding of carbon fiber reinforced polymer (CFRP) sheets has been widely accepted as a popular method for strengthening of deteriorated RC structures. The long-term behavior of CFRP-strengthened RC structure is often affected by that of the interface between CFRP sheets and concrete. This study aims at applying a viscoelastic model to describe the creep behaviour of the adhesive layer bonding CFRP sheet to concrete, the CFRP-concrete interface. Reviews of available models on concrete creep behavior have been first carried out and then new FE analysis model is proposed. The proposed FE analysis model based on the maxwell model has been verified by previous experimental results. It is shown that the creep effect of interfacial adhesive layer is very important on the long-term behavior of concrete structures strengthened with CFRP.

Nondestructive testing for the evaluation of adhesive layer in rocket motor case assembly (연소관 조립체 접합계면의 평가를 위한 비파괴시험에 관한 연구)

  • 박준수;송성진;김영환;임수용;윤남균;조정표
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2001.11a
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    • pp.90-93
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    • 2001
  • In the present work, ultrasonic testing method has been developed to evaluate adhesive layers in rocket motor case assembly for the reliability of the rocket. The main objective of the present work was to find debonding between steel and rubber layers. The relationship between adhesion ratio and reflected ultrasonic amplitude was calculated by considering reflection coefficient at the interface between steel and rubber layers. It was found that the higher amplitude of ultrasound is reflected for the debonding area, and shown good agreements with experimental results. The ultrasonic C-scan images offers good implements for the determination of debonding area. The nondestructive testing results were compared with the micrography of destruective testing. As results, ultrasonic testing could be utilized for the evaluation of adhesive layer in the rocket motor case assembly.

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Development of ultrasonic testing method for the evaluation of adhesive layer of blast tube (토출관 접합계면 평가를 위한 초음파 시험법 개발)

  • Kim, Y.H.;Song, S.J.;Park, J.S.;Cho, H.;Lim, S.Y.;Yun, N.G.;Park, Y.J.
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2003.10a
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    • pp.230-237
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    • 2003
  • Ultrasonic testing method has been developed to evaluate adhesive layers in blast tube for the reliability of the rocket. The main objective of the present work was to find debonding and missing adhesive in epoxy layer between steel and FRP layers. In this approach, the ultrasonic reflection from the interface between the steel sheet and the epoxy adhesive is measured with a high-frequency pulse-echo setup in order to identify contact debonding and missing adhesive. Then, the steel sheet is excited to resonance by low-frequency ultrasound, and the gap size underneath the measuring location is estimated from the resonance responses. For practical application in industry an automated testing system has been developed where the proposed approach is implemented. The performance of the proposed approach has been verified by actual measurement of gap sizes from the cross-sections of cut specimens using an optical microscope.

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EFFECT OF INTERMEDIATE RESIN HYDROPHILICITY ON BOND STRENGTH OF SINGLE STEP ADHESIVE (중간레진의 친수성이 상아질 접착에 미치는 영향)

  • Kim, Yong-Sung;Park, Sang-Hyuk;Choi, Gi-Woon;Choi, Kyoung-Kyu
    • Restorative Dentistry and Endodontics
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    • v.32 no.5
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    • pp.445-458
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    • 2007
  • The purpose of this study was to evaluate the bond strength of a new Single step system with different curing mode composites, and to evaluate the effect of the intermediate resins which have different hydrophilicity on bonding ability by means of the micro shear bond testing and TEM examination for the adhesive interface. The adhesive used in this study was an experimental single step system (Bisco Inc., Schaumburg IL). Experimental groups were produced by using six kinds of intermediate resin having different hydrophilicity that was hydrophilic, hydrophobic and most hydrophobic resin and as filled or not after applying adhesive. Each experimental group was further divided into two subgroups whether the adhesive was light cured or not. Dual cured composite (Bis Core, Bisco Ltd., Schaumburg, IL) was placed on the adhesive layer as light cure or self cure mode. The results or bond strength were statistically analyzed using one way ANOVA and multiple comparisons are made using Tukey's test at ${\alpha}\;<\;0.05$ level. The results of this study were as follows ; 1. The application of intermediate resin did not increase the bond strength for light cured composite. 2. The bond strength of an experimental adhesive with self cured composite was significantly increased by the application of intermediate resin layer. 3. The bond strength of adhesive was irrespective of the cure or not of itself before intermediate resin layer applied. 4. As applied hydrophilic resin layer was, the initial bond strength was higher than both hydrophobic and most hydrophobic one used but there was no significance. Using a single step adhesive with dual/self cured composite, the incompatibility between both of them should be solved by the application of intermediate hydrophobic resin to reduce the adhesive permeability. However, Single step adhesive can be used in the light cured composite restoration without any decrease of the initial bond strength.

Studies on the Vibration Controllability of Smart Structure Depending on the Interfacial Adhesion Properties of Composite Materials (복합재료내의 계면 접착 특성에 따른 지능형 구조물의 진동제어에 관한 연구)

  • 한상보;박종만;차진훈
    • Journal of KSNVE
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    • v.8 no.6
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    • pp.1093-1102
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    • 1998
  • The success of controllability of smart structures depends on the quality of the bonding along the interface between the main structure and the attached sensing and acuating elements. Generally, the analysis procedures neglect the effect of the interfacial bond layer or assume that this bond layer behaves like viscoelastic material. Three different bond layers. two modified epoxy adhesives, and one isocyanate adhesive were prepared for their toughness and moduli. Bond layer of the chosen adhesive provides an almost perfect bonding condition between the composite structure and the PZT while bended significantly like arrow-shape. The perfect bonding condition is tested by considering various material properties of the bond layers. and based on this perfect bonding condition, the effects of the interfacial bond layer on the dynamic behavior and controllability of the test structure is experimentally studied. Once the perfect bonding condition is achieved. dynamic effects of the bond layer itself on the dynamic characteristics of the main structure is negligible. but the contribution of the attached PZT elements on the stiffness of the multi-layered structure becomes significant when the thickness of the bond layer increased.

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Composite aluminum-slab RC beam bonded by a prestressed hybrid carbon-glass composite material

  • Rabahi Abderezak;Tahar Hassaine Daouadji;Bensatallah Tayeb
    • Structural Engineering and Mechanics
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    • v.85 no.5
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    • pp.573-592
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    • 2023
  • This paper presents a careful theoretical investigation into interfacial stresses in composite aluminum-slab reinforced concrete beam bonded by a prestressed hybrid carbon-glass composite material. The model is based on equilibrium and deformations compatibility requirements in and all parts of the strengthened beam, i.e., the aluminum beam, the slab reinforced concrete, the hybrid carbon-glass composite plate and the adhesive layer. The theoretical predictions are compared with other existing solutions. Numerical results from the present analysis are presented both to demonstrate the advantages of the present solution over existing ones and to illustrate the main characteristics of interfacial stress distributions. It is shown that the stresses at the interface are influenced by the material and geometry parameters of the composite beam. This research is helpful for the understanding on mechanical behaviour of the interface and design of the hybrid structures.

Development of Ultrasonic Testing Method for Evaluation of Adhesive Layer of Blaster Tube (토출관 접합계면 평가를 위한 초음파 시험법 개발)

  • Kim, Y.H.;Song, S.J.;Park, J.S.;Cho, H.;Lim, S.Y.;Yun, N.G.;Park, Y.J.
    • Journal of the Korean Society of Propulsion Engineers
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    • v.8 no.2
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    • pp.46-53
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    • 2004
  • Ultrasonic testing method has been developed to evaluate flaw of adhesive layers in blast tube for the reliability of the rocket nozzle. The ultrasonic reflection from the interface between the steel sheet and the epoxy adhesive is measured with a high-frequency Pulse-echo setup in order to identify contact debonding and missing adhesive in epoxy layer between steel and FRP layers. The steel sheet is resonated by low-frequency ultrasound, and the gap size underneath the measuring location is estimated from the resonance responses. For practical application in industry an automated testing system has been developed where the proposed approach is implemented. The performance of the proposed approach has been verified by actual measurement of gap sizes from the cross-sections of cut specimens using an optical microscope.

Comparison of the elastic modulus among three dentin adhesives before and after thermocycling (열시효 처리에 따른 상아질 접착 계면의 탄성계수의 변화 비교)

  • Chang, Ju-Hea;Lee, In-Bog;Cho, Byeong-Hoon;Kim, Hae-Young;Son, Ho-Hyun
    • Restorative Dentistry and Endodontics
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    • v.33 no.1
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    • pp.45-53
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    • 2008
  • The purpose of this study was to determine the effects on the elastic moduli of the adhesive and the hybrid layer from thermocycling. Twenty one human molars were used to create flat dentin surfaces. Each specimen was bonded with a light-cured composite using one of three commercial adhesives (OptiBond FL [OP], Clearfil SE Bond [CL], and Xeno III [XE]). These were sectioned into two halves and subsequently cut to yield 2-mm thickness specimens; one specimen for immediate bonding test without thermocycling and the other subjected to 10,000 times of thermocycling. Nanoindentation test was performed to measure the modulus of elasticity of the adhesive and the hybrid layer, respectively, using an atomic force microscope. After thermocycling, XE showed a significant decrease of the modulus in the adhesive layer (p < 0.05). Adhesives containing hydrophilic monomers are prone to hydrolytic degradation. It may result in the reduced modulus of elasticity, which leads to the mechanically weakened bonding interface.

Evaluation of Fracture Behavior of Adhesive Layer in Fiber Metal Laminates using Cohesive Zone Models (응집영역모델을 이용한 섬유금속적층판 접착층의 모드 I, II 파괴 거동 물성평가)

  • Lee, Byoung-Eon;Park, Eu-Tteum;Ko, Dae-Cheol;Kang, Beom-Soo;Song, Woo-Jin
    • Composites Research
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    • v.29 no.2
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    • pp.45-52
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    • 2016
  • An understanding of the failure mechanisms of the adhesive layer is decisive in interpreting the performance of a particular adhesive joint because the delamination is one of the most common failure modes of the laminated composites such as the fiber metal laminates. The interface between different materials, which is the case between the metal and the composite layers in this study, can be loaded through a combination of fracture modes. All loads can be decomposed into peel stresses, perpendicular to the interface, and two in-plane shear stresses, leading to three basic fracture mode I, II and III. To determine the load causing the delamination growth, the energy release rate should be identified in corresponding criterion involving the critical energy release rate ($G_C$) of the material. The critical energy release rate based on these three modes will be $G_{IC}$, $G_{IIC}$ and $G_{IIIC}$. In this study, to evaluate the fracture behaviors in the fracture mode I and II of the adhesive layer in fiber metal laminates, the double cantilever beam and the end-notched flexure tests were performed using the reference adhesive joints. Furthermore, it is confirmed that the experimental results of the adhesive fracture toughness can be applied by the comparison with the finite element analysis using cohesive zone model.

Enhanced Adhesion of Cu Film on the Aluminum Oxide by Applying an Ion-beam-mixd Al Seed Layar

  • Kim, Hyeong-Jin;Park, Jae-Won
    • Proceedings of the Korean Vacuum Society Conference
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    • 2012.08a
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    • pp.229-229
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    • 2012
  • Adhesion of Copper film on the aluminum oxide layer formed by anodizing an aluminum plate was enhanced by applying ion beam mixing method. Forming an conductive metal layer on the insulating oxide surface without using adhesive epoxy bonds provide metal-PCB(Printed Circuit Board) better thermal conductivities, which are crucial for high power electric device working condition. IBM (Ion beam mixing) process consists of 3 steps; a preliminary deposition of an film, ion beam bombardment, and additional deposition of film with a proper thickness for the application. For the deposition of the films, e-beam evaporation method was used and 70 KeV N-ions were applied for the ion beam bombardment in this work. Adhesions of the interfaces measured by the adhesive tape test and the pull-off test showed an enhancement with the aid of IBM and the adhesion of the ion-beam-mixed films were commercially acceptable. The mixing feature of the atoms near the interface was studied by scanning electron microscopy, Auger electron spectroscopy, and X-ray photoelectron spectroscopy.

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