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Aluminum / Steel 이종소재 접합의 모재강도 및 두께별 SPR 접합성에 관한 연구
정택언(Taek-Eon Jeong),김민규(Min-Gyu Kim),이세헌(Sehun Rhee),감동혁(Dong-Hyuck Kam) 대한용접·접합학회 2019 대한용접·접합학회지 Vol.37 No.3
Dissimilar joining of aluminum and steel is one of the fundamental techniques for achieving weight reduction in the automotive industry. Self-piercing rivets have been widely adopted for the aluminum-steel lap joint because of its simplicity and high joining strength. In this study, the joining quality of the aluminum-steel joint produced by self-piercing rivets is investigated depending on the strength and thickness of the aluminum sheet. Four different tensile strengths (228, 305, 320, and 326 MPa) of aluminum are considered in this study, which corresponds to Al5052-H32, Al5754-H18, Al5083-H32 and Al6061-T6. For the thickness variation test, Al5052-H32 sheets with a thickness of 1.2, 1.5, 2.0, 2.5 mm are used. The SPR joint quality was quantified with cross-sectional visual analysis and tensile lap shear test. In aluminum(top)-steel (bottom) SPR joint, it was observed that the joint load increased with increasing aluminum strength up to 320 MPa. Nevertheless, the thickness of top aluminum was found to not affect the joint strength between the thickness of 1.5 ~ 2.5 mm. In steel(top)-aluminum(bottom) SPR joint, it was found that joint strength did not change with aluminum strength but increased with increasing aluminum thickness.
정택언(Taekeon Jung),이정기(Jeong Gi Lee),양성(Sung Yang) 대한기계학회 2021 대한기계학회 춘추학술대회 Vol.2021 No.11
Sample pretreatment process such as concentration and separation is necessary for rapid and accurate bacteria detection. Immunomagnetic separation is one of the most widely used methods for sample pretreatment by controlling the behavior of the particles. However, free magnetic particles that are not bound to the bacteria can cause an error in the detection signal. In this study, the bacteria conjugated with magnetic were separated from free magnetic particles by using dielectrophoresis. The electrodes were patterned on a glass substrate with 45 degrees to the flow direction of the fluid. When an AC signal is applied to the electrodes, only bacteria are move along the electrode and flow to outlet1. On the other hand, magnetic particles flow to outlet2. The samples with a concentration of 1×10² – 1×10<SUP>6</SUP> CFU/mL were injected into the separation device and it is confirmed that the separation efficiency was greater than 80% for all samples.
Self-Piercing Rivet을 이용한 CFRP/Steel/Aluminum 3매 겹침 접합평가
전남기,정택언,이세헌,감동혁 대한용접접합학회 2019 대한용접·접합학회지 Vol.37 No.1
Multi-material integration between lightweight materials such as aluminum alloy, carbon fiber reinforced plastic (CFRP), ultra-high-strength steel (UHSS), etc. is one of the key techniques for achieving weight reduction. For its wide use, productive and reliable technologies for the dissimilar joining of the lightweight materials is required. In this study, three-layer dissimilar joining of CFRP, GA-590DP, and Al5052-H32 was investigated using self-piercing rivet (SPR). The tensile shear load and the failure modes were evaluated for four different layering sequences. It was identified that the failure originates from the CFRP which rips out the rivet as it tears off from the joint. Therefore, the joining strength was stronger when the CFRP was sandwiched between the metals preventing the fractured CFRP from prematurely ripping out the rivets. Also, it was found that using Al5052-H32 as the lower sheet exhibited similar joining strength compared to that of using GA-590DP as the lower sheet. Finally, the tensile shear load increased as the CFRP thickness is increased in all the layering sequences.