• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2010년도 정기 학술대회
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• pp.550-553
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• 2010

본 논문에서는 seta와 spatula로 구성된 게코(gecko) 접착 시스템의 해석을 위한 새로운 adhesive beam contact model을 제시한다. adhesive contact 해석에 있어서 기존의 JKR model은 nano pillar와 같은 형태의 접촉방식의 해석에는 매우 유용하지만, seta와 같이 보(beam)의 형상을 가지는 구조물의 접촉방식의 해석에는 부적합하다. 따라서 본 연구에서는 seta와 같은 보의 형상을 가지는 접촉 시스템의 해석을 위해 adhesive beam contact model을 제시하고, 유한요소 해석을 통하여 접촉면에서의 불균일한 응력분포 상태가 분리 메커니즘에 미치는 영향에 대한 해석 결과를 제시한다. 또한 spatula의 기하학적 형상과 보의 접촉각(contact angle)등이 seta adhesion system의 분리 메커니즘(detachment mechanism)에 미치는 영향에 대한 결과를 제시한다.

• 접착 및 계면
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• 제21권1호
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• pp.6-13
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• 2020

The objective of the current study is to characterize the long-term stability and efficacy of a structural adhesive assembly under static load. An apparatus was designed to be used in the Instron tensile test machine that would allow for real time modeling of the failure characteristics of an assembly utilizing a moisture- cure adhesive which was bonded to concrete. A regression model was developed that followed a linear - natural log function which was used to predict the expected life of the assembly. Evaluations at different curing times confirmed the structure was more robust with longer cure durations prior to loading. Finally, the results show that under the conditions the assembly was tested, there was only a small amount of inelastic creep and the regression models demonstrated the potential for a stable structure lasting several decades.

• 한국전산구조공학회논문집
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• 제16권4호
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• pp.401-406
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• 2003

접착제와 피착재의 물성치는 고정된 값을 가지기보다 항상 어느 정도의 불확실성을 내포하고 있으며, 이는 결합부의 성능에 영향을 미치게 된다. 본 논문에서는 컨벤스 모델링을 이용하여 불확실한 물성치를 갖는 단일 겹치기 이음의 응력해석을 수행하였다. 불확실성을 고려한 수치해석 결과, 결합부에 작용하는 전단 및 수직 응력은 증가하였으며 이는 결합부의 강도 해석에 불확실성이 반드시 고려되어야 함을 보여준다. 또한 컨벡스 모델링의 신뢰성과 효율성을 입증하기 위해 몬테카를로 기법에 의한 응력 해석 결과와 비교하였으며, 두 방법에 의한 결과는 잘 일치함을 알 수 있었다.

• Applied Microscopy
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• 제44권4호
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• pp.111-116
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• 2014

This study investigates the developmental pattern of adhesive discs (ADs) to highlight the ontogeny and structural changes that occur during the growth of Boston ivy. Initiation to postmortem features of ADs were examined through light and scanning electron microscopy. The study also reveals a new finding of the dislocation of peripheral tissues of adaxial origin. Four phases of attachment are suggested with regards to its climbing behavior: 1) pre-attachment, 2) upon attachment, 3) after attachment, and 4) final attachment. During initiation, several ADs originate from tendril primordia without epidermal differentiation. However, different growth rates in the epidermis results in completely different ADs. ADs were discerned by size, shape, and color during expansion, but cells in the adaxial surface remained alive longer than the other side. Upon contact, the ADs demonstrate simultaneous growth and deterioration, but once attachment is established the latter process subdues to final stages. Epidermal transformation, adhesive secretion, cellular disruption, and mechanical stress were essential for the self-clinging nature of Boston ivy. The post-attachment sequence is also believed to be critical in achieving maximum mechanical strength to provide extensive support. The developmental process of ADs is prompted by tactile stimulation but in a highly organized and systematic manner.

• Composites Research
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• 제30권6호
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• pp.416-421
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• 2017

CFRP와 금속간의 접합공정이 개선된 구조용 접착제가 제조되었다. 구조용 접착제에 대한 경화시간, 기지재료의 표면상태 그리고 접착제의 양에 따른 최적의 접합공정 조건을 랩쉐어 실험을 통하여 파악하였다. 적합한 접합조건을 확인하기 위해 이종재료간의 접합 파단면 상태를 반사현미경을 이용하여 평가하였다. 이종재료간 접합력 향상을 위해 접착제의 개선뿐만 아니라 CFRP의 표면처리 또한 중요하였다. 구조용 접착제의 경우 180도 조건에 20분의 경화온도 조건이 최적이였으며, CFRP의 표면 처리에 따라 접합특성이 향상됨을 확인하였다. 이종재료 간 접합을 위해 구조용 접착제의 양은 $1.5{\times}10^{-3}g/mm^2$ 조건일 때 최적이었다. 접합공정의 개선 및 최적화를 통해 기존의 접착력 대비 10% 이상의 물성 강화를 나타냄을 확인하였다.

• Journal of Welding and Joining
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• 제24권3호
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• pp.55-59
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• 2006

This paper is concerned with a study on cyclic bending load of bus folding door pillar including adhesive bonding and spot welding. Three specimen types were used such as spot welding, I-type adhesive bonding and M-type adhesive bonding in this study. The tensile-shear tests were carried out to evaluate the tensile-shear strength of these three specimen types. Also four-point bending tests were carried out to evaluate the static and dynamic bending load. From the results, using adhesive bonding has a better effect on the static and dynamic bending load than using spot welding. Therefore, manufacturing better structural products can be expected by applying hybrid welding using adhesive and spot welding to those.

• 접착 및 계면
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• 제4권2호
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• pp.21-29
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• 2003

Hot AC anodising has been evaluated us pre-treatment for aluminium prior to structural adhesive bonding. Phosphoric and sulphuric acid hot AC anodising showed very promising adhesion promoter capabilities with durability comparable with the best standard DC anodising procedures. AC anodising does not required etching prior to anodising and offers u pre-treatment time down to 20 seconds. The interface/interphase between the aluminium substrate and the adhesive was investigated in order to get a better understanding of the involved adhesion mechanisms and to explain the long-tenn properties. The alkaline medium formed at the oxide layer/adhesive interface has been shown to induce a partial dissolution of the oxide layer leading to the formation of metallic ions which diffuse in the adhesive (EPMA measurements). The effect of diffusion of the Al ions on adhesion and joint durability is still uncertain but studies showed that pre-bond moisture affected the joints durability and to some extent the diffusion length. specially for DC anodised samples. So far no direct correlation could be established between the diffusion length d and the joints durability but new trials with better control over the elapsed time between bonding and adhesive curing are expected to help getting a better understanding of the involved mechanisms.

• Composites Research
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• 제20권2호
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• pp.27-31
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• 2007

미래의 환경에서는 위성을 이용한 통신서비스의 운송체 내에서의 사용이 기하급수적으로 확대될 전망이다. 이를 위해서는 안테나의 성능 향상 및 역학적 에너지의 고효율성에 기하고, 구조적인 안정을 보장하기 위한 복합 안테나 구조의 설계, 제조 및 해석 기술이 필요하다. 복합 안테나 구조가 안테나의 역할 및 구조체로의 역할을 하기 위해서는 접착필름의 사용이 필수적이다. 하지만 접착필름은 얇은 두께로 인하여 설계시 고려되지 못하고 유전체로 작용하여 전자기적 영향을 끼치게 되어 설계자가 기대하는 성능을 얻지 못한다. 따라서, 이러한 접착필름의 전자기적 특성을 실험적으로 알아본다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.860-864
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• 2004

This article discusses the use of pulse-echo ultrasonic testing for the stress analysis of adhesive bonds between metal sheets. The method is based on the measurement of the reflection wave at the metal/adhesive interface. After describing briefly the physical aspects of the phenomenon, an index is defined to detect defective zone of the joint(both for the lack of adhesive and for insufficient adhesion); the influence of the experimental variables(variables stress...) on the measurement is discussed. By means of a control experiment it is shown that Stress Variation in Adhesive Joints are separate to be distingguished. In this paper, Quantitative Nondestructive Evaluation in Adhesive Joints are together with Ultrasonic Testing and Finite Element Method.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2018년도 추계 학술논문 발표대회
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• pp.81-82
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• 2018

The structure of the RC structure is actively reinforcing the structure of the building which has suffered from aging, artificial and natural damage of the building. Among various reinforcement methods, epoxy adhesive is used to attach FRP in FRP reinforcement method which is reinforcing by attaching FRP to the structural part. At this time, the epoxy adhesive having a low critical temperature has a sudden adhesive failure upon exposure to heat, and thus, the development of an inorganic fireproof adhesive having a high critical temperature has progressed. Therefore, in this study, the compositional change of inorganic fire - resistant adhesive exposed to high temperature heat was analyzed by XRD.