• Journal of the Korean Wood Science and Technology
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• 제35권4호
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• pp.38-44
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• 2007

환경문제의 대두에 따라 포름알데히드를 방산하는 접착제를 대신할 수 있도록 로진을 이용한 천연접착제를 개발하고자 한다. 경화속도와 접착물성을 향상시키기 위해 건조제의 배합에 따라 천연접착제를 제조하였다. 건조제의 배합에 따른 경화속도와 접착물성을 Texture Analyzer를 이용하여 얻어진 tack값과 single lap shear test를 통해 얻어진 접착력을 기반으로 평가하였으며, 외국에서 사용되고 있는 AURO, BioFa, Livos의 식물계 천연접착제와의 성능을 비교 분석하였다. 최적의 배합비는 Co 0.7 part, Zr 1.0 part, Ca 0.5 part, Activ8 0.1 part를 첨가하였을 때이며, 이 때의 접착력은 $93.2{\pm}19.1N/cm^2$의 수준에 도달하였다.

• 한국자동차공학회논문집
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• 제10권3호
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• pp.130-135
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• 2002

This study investigates the effect of curing method on the bonding strength of aluminum/CFRP composites. The surface of aluminum panel was treated by DC plasma. Lap shear tests and T-peel tests were performed based on the procedure of ASTM 906-94a and ASTMD1876-95, respectively. Test samples were fabricated by using the co-curing method and the secondary curing method. The results showed that the shear strength of test samples made by the co-curing method was 2.5 times greater than that of test samples made by the secondary curing method. The T-peel strength of the co-curing method case was almost 2 times greater than that of the secondary curing method case.

• 한국정밀공학회지
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• 제15권6호
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• pp.159-166
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• 1998

The problem of interface crack in the bonded structures has received a great deal of attention in recent years. In this paper the aluminum bonded single lap-joint containing the interface edge crack is investigated. The tensile load and the average shear stress of the adhesive joints which have different crack length are obtained from the static tensile tests. The critical value of crack length to provoke the interface fracture is determined to a/L=0.4, where a is the interface crack length and L is the adhesive lap-length. The fracture mechanical parameters are introduced to confirm the existence of the critical crack length. The compliance and the stress intensity factors are calculated using the displacement and the stress near the interface crack tip by the boundary element method. These numerical results support the experimental results that the critical value of a/L is 0.4. It is known that the compliance and the stress intensity factors are the efficient parameters to estimate the bonded single lap-joint containing the interface edge crack.

• 한국산학기술학회논문지
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• 제21권11호
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• pp.334-339
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• 2020

본 연구에서는 탄소섬유 및 유리섬유 강화 복합소재를 대상으로 하여, 접합면에 기계적인 결합력 향상을 위해 물리적인 표면처리 방법을 적용할 때, 알루미늄 및 복합소재, 복합소재 및 복합소재 간의 접합특성을 비교 분석하였다. 접합시편은 접합을 위해 쓰이는 모재 종류와 모재 접합면의 표면처리 방법으로 각각 구분하였다. 물리적인 표면처리 방법으로는 기계적인 마모 (사포) 처리, sand blasting 처리 및 플라즈마 처리기법을 적용하였다. 접합시편은 single lap joint 시편으로 제작하였으며 lap shear strength 측정 실험을 진행하여 그 결과값을 비교하였다. 실험 결과에서 기계적인 마모 및 sand blasting 표면 처리 방법이 물리적인 표면 처리를 진행하지 않은 일반 시편 대비하여 약 4~5배의 접합강도 향상이 있음을 확인하였다. 플라즈마 처리 기법을 적용한 방안에서는 플라즈마 출력과 처리 시간을 150 W 5분, 150 W 10분 및 300 W 3분 처리 조건으로 정의하여 실험을 진행하였으며, lap shear strength 결과에서 앞선 기계적 표면 처리 방안과 유사한 결과를 보였다. 다만 처리 조건에 따라서 접합특성에 미치는 영향은 적음을 확인하였다.

• 한국재료학회지
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• 제5권2호
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• pp.191-196
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• 1995

비정질 PEEK 필름의 self-bonding강도는 접합시의 공정변수(시간, 온도, 그리고 압력)와 밀접한 관계가 있다. 본 연구에서는 이러한 공정변수의 효과를 규명하기 위하여 각기 다른 접합조건하에서 개발된 시편들의 self-bonding강도를 single lap-shear test를 통하여 측정된 각각의 전단 응력(shear strength)으로 나타내었다. 개발된 self-bonding강도는 접합온도가 증가함에 따라 증가하였으며, 접합시간의 1/4승에 일차함수적으로 비례증가하였다. 접합공정 중의 압력의 효과는 단지 초기 접합단계인 wetting에 기여하였을 뿐 self-bonding강도 자체에는 거의 영향을 미치지 않는 것으로 사려되었다. 결론적으로 비정질 PEEK 필름의 self-bonding현상은 현장에서의 실제 접합공정에서 어떠한 접착재료의 사용없이도 모재와 같은 강도를 개발하는데 무한한 가능성이 있는 것으로 판단되었다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.626-629
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• 2004

Recently, the self-healing technique is being investigated to repair the damaged polymeric composites by the use of microcapsules with the healing agent. This technique can obtains both the damage detection and the damage repair simultaneously over the converntional repairing techniques. In this study, the effects of the catalyst ratio to the healing agent and thermal characteristics to the mixtures of healing agent are investigated through single lap shear tests and DSC. The Healing agents such as DCPD, ENB, and their mixtures are considered and Grubb's catalyst is used as a catalst.

• Steel and Composite Structures
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• 제34권6호
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• pp.877-889
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• 2020

This work features the outcomes of an empirical investigation into the characteristics of steel reinforced grout (SRG) composite - concrete interfaces. The parameters varied were loading rate, densities of steel fibres and types of load displacement responses or measurements (slip and machine grips). The following observations and results were derived from standard single-lap shear tests. Interfacial debonding of SRG - concrete joints is a function of both fracture of matrix along the bond interface and slippage of fibre. A change in the loading rate results in a variation in peak load (P_max) and the correlative stress (σ_max), slip and machine grips readings at measured peak load. Further analysis of load responses revealed that the behaviour of load responses is shaped by loading rate, fibre density as well as load response measurement variable. Notably, the out-of-plane displacement at peak load increased with increments in load rates and were independent of specimen fibre densities.

• 한국자동차공학회논문집
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• 제6권1호
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• pp.143-150
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• 1998

The evaluation of joint fatigue strength of light weight materials for electrical vehicle body has been performed through single lap joint tests with the design parameters such as joint style, adherend, bonding overlap length and bonding thickness. Fatigue strength was evaluated through 5-Hz, tension-tension, load controlled test with the stress ratio zero value. It is experimentally observed that fatigue strength of joint increases for the increase of overlap length. The combinations of Al-Al and Al-FRP adherends show that fatigue strength of joint is hardly changed for the increase of bonding thickness, but FRP-FRP adherend specimen shows that fatigue strength of joint increases after decreases for the increase of bonding thickness. Al-Al adherend specimen has much higher fatigue length than Al-FRP and FRP-FRP adherend specimens. Riveting at adgesive bonded joint gives little effect on fatigue strength.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2004년도 춘계학술발표대회 논문집
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• pp.266-269
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• 2004

In this study, bond strengths for the self-healing agents were evaluated through the modified lap shear test in order to suggest the optimal healing conditions for the repair of polymeric composites. The healing agents of DCPD, ENB, and their mixtures were activated with Grubbs' catalysts. According to the results, the mixture of DCPD and ENB gave better opportunity than DCPD only due to the rapid acivation with catalyst in view of the economic and practical use.

• Journal of Welding and Joining
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• 제32권3호
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• pp.81-88
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• 2014

As the industrial technology has been developed, a dissimilar welding has been received huge attention in various engineering fields. To understand the mechanical properties and possibility of applications of dissimilar metals joining, the laser welding of Cu and Ni dissimilar metals was studied in this paper. Cu and Ni have differences in materials properties, and Cu and Ni make no intermetallic compounds according to typical binary phase of Cu and Ni system. In this study, lap welds of Cu and Ni dissimilar metals using single-mode fiber laser with high welding speed were tried, and mechanical properties of the welds zone were evaluated using a Vickers hardness test and a tensile shear test. To recognize the relation between hardness and tensile shear load, weld fusion zone of interface weld area were observed. And it was confirmed that the ultra-high welding speed could make good weld beads and higher hardness parts had higher tensile shear load under the all conditions.