• 한국소성가공학회:학술대회논문집
• /
• 한국소성가공학회 2008년도 춘계학술대회 논문집
• /
• pp.517-520
• /
• 2008

Recently, use of adhesive bonding technology is increased to achieve the multi-material design for lightweight structure in automobile industry. In this paper, the fracture strength of adhesive has been studied with the single lap shear test conducted at different temperatures. The joint specimens are made from Al 5052 and SPRC 440 bonded with structural epoxy adhesive. The operating temperature has been considered up to $150[^{\circ}C]$ and the single lap shear test has been conducted with 5mm/min tensile rate. Fracture strength of adhesive bonded joint has been decreased with increase of operating temperature. The fracture strength at the $100[^{\circ}C]$ was shown about half of that at room temperature.

• Structural Engineering and Mechanics
• /
• 제59권1호
• /
• pp.123-132
• /
• 2016

Many military and commercial aging aircrafts flying beyond their design life may experience severe crack and corrosion damage, and thus lead to catastrophic failures. In this paper, were used in a finite element model to evaluate the effect of corrosion on the adhesive damage in bonded composite repair of aircraft structures. The damage zone theory was implemented in the finite element code in order to achieve this objective. In addition, the effect of the corrosion, on the repair efficiency. Four different patch shapes were chosen to analyze the adhesive damage: rectangular, trapezoidal, circular and elliptical. The modified damage zone theory was implemented in the FE code to evaluate the adhesive damage. The obtained results show that the adhesive damage localized on the level of corrosion and in the sides of patch, and the rectangular patch offers high safety it reduces considerably the risk of the adhesive failure.

• 대한기계학회논문집
• /
• 제16권4호
• /
• pp.667-674
• /
• 1992

본 연구에서는 복합재료의 접착이음에 대한 강도 평가법을 확립하기 위한 기 초연구로써 접착이음의 가장기본적인 형태의 하나인 겹치기 이음(single-lap joint: SLJ)에 대한 응력해석과 정적 및 피로 강도시험을 실시하고, 종래의 강도평가법의 문 제점을 파악.검토하고 정량적이고 통일적인 접착이음의 강도평가법의 확립 및 설계 기 준의 설정에 대한 새로운 방향을 모색 하고저 한다.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2003년도 추계학술대회
• /
• pp.1039-1044
• /
• 2003

Adhesive-bonded joints are widely used in the industry. Recently aircraft applications of adhesive bonding joints have been increased extensively in automobile and air industry. Because adhesives which are available for structural applications have been developed a lot and understanding of adhesive bonding has been improved so much. In this study, as the fundamental research of design of adhesive bonding joints, this study considers specimen shape are affect strength and durability of Al/Polymer lap joints. In this research, cross head speed difference were concerned to evaluate their effects on the adhesive strength. Cross head speed makes a change 0.05mm/min, 0.5mm/min, 5mm/min. The result is load-displacement diagram showed brittleness fracture tendency. Fracture tendency that is shown enough on stress distribution of trigonal single lap joint and trigonal edged single lap joint occur the inside of adhesive.

• 한국전산구조공학회논문집
• /
• 제23권4호
• /
• pp.403-407
• /
• 2010

게코 접착 시스템은 보(beam)의 형상을 가지는 seta와 접착패드 역할을 하는 spatula로 구성된다. 본 논문에서는 보 접착 모델(ahhesive beam contact model)을 사용하여 게코(gecko) 접착 시스템의 접착 메커니즘의 해석을 수행한다. 보 접착 모델은 접촉면에서 불균일한 응력 분포를 가지는 특징이 있으며, 접촉면에서의 최대 인장 응력(tensile stress)에 의하여 접착/분리 메커니즘이 결정된다. 접착패드 역할을 하는 spatula는 최대 인장응력을 감소시키는 역할을 하며, 이로 인해 접착력이 증가한다. 역방향 하중에 대해서는 spatula에 의하여 최대 압축 응력(compressive stress)이 감소하며, 이러한 현상에 의하여 접착력과 분리력의 비대칭성이 발생한다. 본 연구에서는 보 접착 모델의 해석을 위해 유한요소법(Finite Element Method)을 사용되며, spatula effect를 위한 해석 결과가 제시된다.

• Composites Research
• /
• 제24권1호
• /
• pp.31-36
• /
• 2011

본 연구에서는 유도무기의 탐색기에 적용되는 지존 접착제의 대체 가능성을 조사하기 위해 환경인자의 노출시간에 따른 기존 접착제와 대제 접착제의 접착전단장도들을 평가하고 이들의 화학구조 변화를 조사하였다. 이때 접착제는 기존 접착제와 대체 접착제에 대해 각각 구조용 접착제와 실링용 접착제의 두 종류를 고려하였다. 이들 접착제는 온도, 수분, 자외선 등의 복합적인 환경인자에 최대 1000시간 동안 노출시켰다. 환경인자의 노출시간에 따른 접착제의 접착전단강도를 평가하기 위해 접착전단시험을 수행하고 화학구조 변화를 조사하기 위해 ATR 적외선 분광분석을 수행하였다. 연구결과에 따르면 대체 접착제의 접착전단강도는 기존 접착제의 경우에 비해 높으며 환경인자의 노출에도 매우 안정적으로 나타나 대체 접착제는 기존 접착제의 대체용으로 적용이 가능함을 알 수 있었다.

• Journal of Welding and Joining
• /
• 제31권5호
• /
• pp.71-76
• /
• 2013

The effect of zirconate having - NH functional group on the T-peel and lap shear strength of $CaCO_3$ containing structural epoxy adhesive for car body assembly was investigated. Curing behavior of epoxy adhesive samples were investigated by differential scanning calorimeter (DSC) techniques. The addition of zirconate up to 7.5 phr did not affect the curing mechanism of epoxy adhesive. While the small amount of zirconate addition less than 1.1 phr increased the cross-linking density, the excess addition of zirconate resulted in the increase of uncross-linked impurity. From the increase of T-peel and lap shear strength and the change of fracture mode from the adhesive failure to the mixed one, it was considered that the small addition of zirconate was effective in improving the adhesion strength of epoxy adhesive to the adherend and inorganic filler surfaces. The formation of uncross-linked impurity with the excess addition of zirconate was considered to decrease the joint strength by decreasing the cohesive strength of the cured epoxy.

• Structural Engineering and Mechanics
• /
• 제83권5호
• /
• pp.693-707
• /
• 2022

Bonded joints have proven their performance against conventional joining processes such as welding, riveting and bolting. The single-lap joint is the most widely used to characterize adhesive joints in tensile-shear loadings. However, the high stress concentrations in the adhesive joint due to the non-linearity of the applied loads generate a bending moment in the joint, resulting in high stresses at the adhesive edges. Geometric optimization of the bonded joint to reduce this high stress concentration prompted various researchers to perform geometric modifications of the adhesive and adherends at their free edges. Modifying both edges of the adhesive (spew) and the adherends (bevel) has proven to be an effective solution to reduce stresses at both edges and improve stress transfer at the inner part of the adhesive layer. The majority of research aimed at improving the geometry of the plate and adhesive edges has not considered the effect of temperature and water absorption in evaluating the strength of the joint. The objective of this work is to analyze, by the finite element method, the stress distribution in an adhesive joint between two 2024-T3 aluminum plates. The effects of the adhesive fillet and adherend bevel on the bonded joint stresses were taken into account. On the other hand, degradation of the mechanical properties of the adhesive following its exposure to moisture and temperature was found. The results clearly showed that the modification of the edges of the adhesive and of the bonding agent have an important role in the durability of the bond. Although the modification of the adhesive and bonding edges significantly improves the joint strength, the simultaneous exposure of the joint to temperature and moisture generates high stress concentrations in the adhesive joint that, in most cases, can easily reach the failure point of the material even at low applied stresses.

• Structural Engineering and Mechanics
• /
• 제18권3호
• /
• pp.315-330
• /
• 2004

A four-point bending RC beam strengthened with FRP plate is investigated based on the theory of elasticity. Taking the adhesive layer into account but ignoring some secondary parameters, the analytical solutions of the normal stress and shear stress on concrete-adhesive interface are obtained and discussed. Besides, the pure bending region of the beam is analyzed and the ultimate load of the beam is predicted. The results obtained in the present paper agree very well with both the results of FEM and the experimental findings.

• 접착 및 계면
• /
• 제5권2호
• /
• pp.1-7
• /
• 2004

A novel carboxyl terminated butadiene-acrylonitrile (CTBN) modified, low temperature cure epoxy film adhesive was developed in this paper. It can be cured at as low as $75^{\circ}C$ for 4 hours with a pressure of 0.1MPa. After post cure at $120^{\circ}C$ for 2 hours, the bonding strengths of Phosphoric Acid Anodizing(PAA) surface treated aluminum adherend were similar to those of structural film adhesives curing at $120^{\circ}C$. It is suitable to bond both metal/composite laminate-to-laminate and laminate to honeycomb structure.