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소성유동층을 갖는 마찰압접 계면의 회전굽힘응력 파괴거동
김대열(Dae Yeul Kim),오환섭(Hwan Sup Oh) 대한기계학회 2012 대한기계학회 춘추학술대회 Vol.2012 No.11
Friction Welding(FW) Technology is about Mechanical Connection in Solid state. When one material which is rotating(Rotation Part) approaches another material which is fixed(Fixed Part), Temperature in Connection Interface is going up to recrystallization degree in the material. That means Friction Welding has Elastic Flow. In this study, I can study the evidence of Elastic Flow in Friction Welding using the Carbon Steel, Stainless Steel, Aluminum that are widely used in industry. In first step, Similar material and dissimilar material Friction Welding are processed in the factory, depending on each mechanical property. In second step, I will try to test Tension Strength and Fatigue Strength with Universal testing machine and Rotary bending machine. Finally I can look for the evidence in Elastic Flow and Spiral Deformation with Scanning Electron Microscope(SEM) in Fractography.
유리섬유 강화 플라스틱과 알루미늄 합금 접합을 위한 유한요소해석
조해용,김동범,Cho, Hae-Yong,Kim, Dongbum 대한용접접합학회 2015 대한용접·접합학회지 Vol.33 No.2
Self-piercing rivet(SPR) is mechanical joining methods and which can be joining dissimilar materials. Unlike conventional riveting, SPR also needs no pre-drilled holes. During plastically deformation, SPR pierces upper sheet and joins it to under sheet. SPR has been mainly applied to the joining the automobile body and some materials, such as glass fiber reinforced polymer and aluminum alloy, which represent the sheet-formed materials for lightweight automobile. Glass fiber reinforced plastic(GFRP) has been considered as a partial application of the automobile body which is lighter than steels and stronger than aluminium alloys. It is needed SPR to join Al alloy sheets and GFRP ones. In this paper, in order to design the rivet and anvil, which are suitable for GFRP, the joinability was examined through simulations of SPR joining between GFRP and Al alloy sheets. For this study, AutoCAD was used for the modeling and the simulated using commercial FEM code DEFORM-2D. The simulated results for SPR process joining between GFRP and Al alloys were confirmed by the same conditions as experimental trials.
티탄과 알루미늄의 마찰용접에서 발생하는 잔류응력.소성변형
김유철,박정웅 대한용접접합학회 2000 대한용접·접합학회지 Vol.18 No.5
Friction welding of titanium and aluminium is numerically modeled by the axisymmetric thermal elastic-plastic analysis. In titanium/aluminium friction welding, heat transfers into the titanium substrate to a distance of z=10(mm) on the side of the bondline and into the whole region of the aluminium substrate having the large thermal conductivity. Adjacent to the bondline, $^{\sigma}r\;and\;^{\sigma\theta}$ are tensile in the substrate whose thermal shrinkage is large, and are compressive in the substrate whose thermal shrinkage is small. $\sigma_z$ along the radial direction is large tensile at the periphery of the component. Plastic strain occurs only close to the bondline in the aluminium substrate. In the components of plastic strain, $\varepsilon^p_r\;and\;\varepsilon^p_{\theta}$ have positive values and $\varepsilon^p_r$ has large negative value. However, $\varepsilon^p_r$ is produced not because of the severity of the mechanical restraint condition, but on purpose to satisfy the condition of the volume constant. A plastic work is proposed as a measure to evaluate the mechanical severity. The plastic work is larger in the aluminium substrate than that in the titanium substrate. The mechanical condition is severer in the aluminium substrate.
Effect of Process Parameters on CFRP/Steel Joints Using Self-Piercing Rivets
Dong-Won Choi,Min-Seung Kang,Bum-Su Go,Hee-Seon Bang 한국정밀공학회 2024 International Journal of Precision Engineering and Vol.25 No.4
Self- piercing riveting (SPR) is an advanced process of the mechanical joining of two or more sheet metals by piercing a rivet into the sheets. SPR has been widely applied to join dissimilar materials that are difficult to join, such as aluminum alloys and steels, especially in automobile industries. In the present work, the Carbon Fiber Reinforced Plastics (CFRP) with thickness of 1.3 mm to SPFC 590DP steel with thickness of 1.2 mm was mechanical joined in lap configuration by the SPR process, and the effect of process parameters of force and shape of rivets on joints were investigated. The integrity of the joints was estimated by quality criteria in terms of the gap between the rivet head and the upper plate, remaining thickness of bottom plate and the length of interlock between the rivet and bottom plate. Furthermore, the tensile shear load, fatigue load and the fracture mode characteristics were investigated. From the result, maximum tensile-shear load of 1.94 kN was obtained at a force of 29 kN, which showed separation of CFRP due to fiber split phenomenon on interface of CFRP side in joints.
표면처리를 적용한 CFRP/Steel 레이저 용접부 평가
김종희,박동민,방희선,김철희 대한용접·접합학회 2021 대한용접학회 특별강연 및 학술발표대회 개요집 Vol.2021 No.5
최근 자동차 산업 분야의 배기가스 저감과 연비 향상의 대응책으로 경량화에 대한 다양한 연구가 활발하다. 차량 경량화를 위한 방안으로 철강 소재 대비 비강도가 뛰어난 CFRP(Carbon Fiber Reinforced Plastic)를 주목하고 있고 금속재료와의 이종 용접에 대한 다양한 연구가 제안되고 있다. 그 중 레이저 용접은 추가적인 재료 없이 용접이 가능하고 빠른 공정속도로 생산성 향상을 기대할 수 있어 기존 기계적 체결 및 접착법의 단점을 보완할 수 있는 접합법으로 대두되고 있으며, 아울러 용접부의 강도 향상을 목적으로 소재의 표면처리에 따른 효과에 대한 연구가 활발히 진행되고 있다. 본 연구에서는 나노초 레이저를 통한 표면처리를 적용하여 CFRP/Steel 간의 레이저 용접 특성을 평가하고자 하였다. 주요 용접 공정변수로 레이저 출력, 이송 속도, 레이저 초점 위치를 고려하였고 아울러 표면처리 변수로는 레이저 출력, 스캔 속도, 스캔 횟수, 피치를 고려하였다. 표면처리 적용에 따른 강도와의 상관관계를 규명하기 위해 전단인장시험을 수행하였고 광학현미경 및 주사전자현미경을 이용해 용접부 단면 및 파단면을 분석하였다.