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RISS 인기검색어
- 검색키워드
- 저자 : 탁윤학 ( Yun-hak Tak ) (검색결과 4 건)
- 무료
- 기관 내 무료
- 유료
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Process Design of Automobile Seat Rail Lower Parts using Ultra-High Strength, DP980 Steel
Dong-Hwan Park(박동환),Yun-Hak Tak(탁윤학),Hyuk-Hong Kwon(권혁홍) 한국기계가공학회 2018 한국기계가공학회지 Vol.17 No.2
The purpose of this study is to develop a process for forming a ㎫ ultra-high strength steel sheet to reduce weight and improve product strength. To do this, we performed the initial process design based on empirical formulas in a handbook and experience of skilled engineers, and researched the effects of major process variables on spring back by analyzing the forming analysis and experimental results. This paper suggests an optimal process design of the seat rail lower parts, using a ㎫ ultra-high strength steel sheet. This satisfies the dimensional accuracy and strength requirements for the product.
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무산소동 소재를 활용한 태양광 일렉트로드 바디 단조 부품 개발
박동환(Dong-Hwan Park),탁윤학(Yun-Hak Tak) 한국기계가공학회 2016 한국기계가공학회지 Vol.15 No.3
Forging operations are non-stationary processes occurring because of indirect pressure, generally, under conditions of three-dimensional stress and deformation. Furthermore, due to friction and the constraints of die geometry, deformation is not homogeneous. Material flow and deformation are largely determined by the shape of the tools. It is well known that net-shape forging can improve the mechanical strength of the final product as well as reduce material waste. Oxygen-free copper that is used for electrical and electronic components has excellent electrical and thermal conductivity. Oxygen-free copper parts have a low productivity in cutting process. Thus, the forging process is performed in order to improve the low productivity in cutting process. The forging of oxygen-free copper for electrode body parts was modeled using finite element simulation and forging experiments that were conducted for producing electrode body parts at room temperature. In order to reduce the cost of cutting products, the forging was performed in a closed cavity to obtain near-net or net-shape parts.
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마그네슘 합금 판재를 활용한 차체 Reinforced Dash 부품 온간성형 공정 연구
박동환(Dong Hwan Park),탁윤학(Yun Hak Tak) 한국생산제조학회 2014 한국생산제조학회지 Vol.23 No.5
The use of light weight magnesium alloy offers significant potential towards improvement of the automotive fuel efficiency. However, the application of formed magnesium alloy components in auto-body structures is restricted due to the low formability at room temperature and lack of knowledge for processing magnesium alloys at elevated temperatures. In this study, a warm tensile test of magnesium alloys was performed to measure tensile strength and elongation. An improvement in formability was confirmed at increased temperatures above about 250°C. Car body warm forming technology was conducted for forming forming reinforced dash components of the magnesium alloy AZ31B sheet at elevated temperatures.
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섬유부피분율 증가와 공극 감소를 위한 VARTM 공정의 대기압 제어에 관한 연구
곽성훈 ( Seong-hun Kwak ),김태준 ( Tae-jun Kim ),탁윤학 ( Yun-hak Tak ),권성일 ( Sung-il Kwon ),이재현 ( Jea-hyun Lee ),김상용 ( Sang-yong Kim ),이종천 ( Jong-cheon Lee ) 한국복합재료학회 2021 Composites research Vol.34 No.2
VARTM(Vacuum-assisted resin transfer molding) 공정은 OoA(Out of Autoclave)에 속하는 저가형 공정기술로 다양한 분야에 널리 사용되어 왔다. 그러나 오토클레이브 공정보다 품질이 낮아 고신뢰성이 요구되는 항공산업에는 적용하기 어려웠다. VARTM 공정의 주요 문제는 오토클레이브 대비 낮은 섬유부피분율과 높은 Void 함량에 의한 기계적 물성의 손실이었다. 따라서 많은 연구자들이 Void를 줄이고 섬유부피분율을 높일 수 있는 연구를 수행해 왔다. 이러한 연구의 흐름에 따라 본 연구에서는 수지 주입 과정 중 대기압을 제어하는 방법이 섬유부피분율을 높이고 Void를 감소시킬 수 있는지 검토하였다. 신뢰성 평가는 Void와 연관성이 있는 압축강도시험, 섬유부피분율 분석, 광학현미경 촬영을 통해 확인하였다. 결과적으로 VARTM 공정에서 수지 주입과정 중 대기압을 단계별로 높이는 방법이 섬유부피분율 증가와 Void 감소에 직접적인 효과가 있음을 확인하였다. VARTM (Vacuum-assisted resin transfer molding) process is a low-cost process technology and affiliated with OoA (Out of Autoclave). Besides, it has been widely used in various fields. However, because of its lower quality than the autoclave process, it isn't easy to apply the VARTM process to the aerospace industry, which requires high reliability. The main problem of the VARTM process is the loss of mechanical properties due to the low fiber volume fraction and high void content in comparison to the autoclave. Therefore, many researchers have studied to reduce void and increase fiber volume fraction. This study examines whether the method of controlling atmospheric pressure could increase the fiber volume fraction and reduce void during the resin impregnation process. Reliability evaluation was confirmed by compressive strength test, fiber volume fraction analysis, and optical microscopy. As a result, it was confirmed that increasing the atmospheric pressure step by step in the VARTM process of impregnating the preform with resin effectively increases the fiber volume fraction and reduces void.
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