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OOA 공정을 통한 CFRTP 항공기 Frame 보강재 성형에 관한 연구
이환주,전용준,최현석,김동언,Lee, Hwan-Ju,Jeon, Yong-Jun,Choi, Hyun-Seok,Kim, Dong-Earn 한국금형공학회 2017 한국금형공학회지 Vol.11 No.2
Carbon fiber reinforced plastic (CFRP) is applied as structural material. CFRP is excellent in plane strength / stiffness and don't haves rust. Lightweight, rigid and robust at the same time as transportation material. Aluminum alloy and reinforcement material The application is increasing rapidly. In this study, the prototype of a semi - Monocoque structure frame, Longeron, Stringer, Skin of the aircraft, restraining the rigidity Clips of the aircraft was designated as the target product and the experiment was conducted. ln the experiment, (1) For CFRTP 3 points, data on heating, transfer, and cooling were measured using Thermo Couple, and optimum temperature required for flexible state was obtained. Heating was performed at a temperature 15% higher than the provided temperature. (2) By using a pneumatic press during molding, by dividing LH, center and RH according to the cooling time, thickness parameter of the target product due to the load is measured, and thickness control and time-deviations were analyzed and cross sections were observed with a low magnification microscope.
22MnB5 / 탄소섬유 강화 플라스틱으로 제작된 단면 보강 하이브리드 적층판의 강도 보강에 관한 연구
이환주,전용준,김동언,Lee, Hwan-Ju,Jeon, Young-Jun,Kim, Dong-Earn 한국금형공학회 2022 한국금형공학회지 Vol.16 No.2
As environmental regulations are strengthened, automobile manufacturers continuously research lightweight structures based on carbon fiber reinforced plastic (CFRP). However, it is difficult to see the effect of strength reinforcement when using a single CFRP material. To improve this, a hybrid laminate in which CFRP is mixed with the existing body structural steel was proposed. In this paper, CFRP patch reinforcement is applied to each compression/tensile action surface of a 22MnB5 metal sheet, and it was evaluated through a 3-point bending experiment. Progressive failure was observed in similar deflection on bending deformation to each one-sided reinforced specimen. After progressive failure, the tensile reinforced specimen was confirmed to separate the damaged CFRP patch and 22MnB5 sheet from the center of the flexure. The compression reinforced specimen didn't separate that CFRP patch and 22MnB5, and the strength reinforcement behavior was confirmed. In the compression reinforced specimen, damaged CFRP patches were observed at the center of flexure during bending deformation. As a result of checking the specimen of the compression reinforcement specimen with an optical microscope, It is confirmed that the damaged CFRP patch and the reinforced CFRP patch overlapped, resulting in a concentrated load. Through the experimental results, the 22MnB5 strength reinforcement characteristics according to the reinforcement position of the CFRP patch were confirmed.
언더컷 형상의 판재 성형품에 보강용 CFRP 패치의 접합을 위한 공정기술 개발
이환주,전용준,조훈,김동언,Lee, Hwan-Ju,Jeon, Yong-Jun,Cho, Hoon,Kim, Dong-Earn 한국금형공학회 2020 한국금형공학회지 Vol.14 No.4
Partial reinforcement of sheet metal parts with CFRP patch is a technology that can realize ultra-lightweight body parts while overcoming the high material cost of carbon fiber. Performing these patchworks with highly productive press equipment solves another issue of CFRP: high process costs. The A-pillar is the main body part and has an undercut shape for fastening with other parts such as roof panels and doors. Therefore, it is difficult to bond CFRP patches to the A-pillar with a general press forming tool. In this paper, a flexible system that applies uniform pressure to complex shapes using ceramic particles and silicone rubber is proposed. By benchmarking various A-pillars, a reference model with an undercut shape was designed, and the system was configured to realize a uniform pressure distribution in the model. The ceramic spherical particles failed to realize the uniform distribution of high pressure due to their high hardness and point contact characteristics, which caused damage to the CFRP patch. Compression equipment made of silicone rubber was able to achieve the required pressure level for curing the epoxy. Non-adhesion defects between the metal and the CFRP patch were confirmed in the area where the bending deformation occurred. This defect could be eliminated by optimizing the process conditions suitable for the newly developed flexible system.
학교생활 관련 독서치료 연구동향에 관한 탐색적 연구 : 2011년~2020년 석ㆍ박사학위 논문을 중심으로
이환주 ( Lee Hwanjoo ),오영섭 ( Oh Youngsub ) 한국독서학회 2021 독서연구 Vol.0 No.58
This study aims to recognize the importance of bibliotherapy related to school life, and to provide basic data for future research on bibliotherapy for school-aged children and adolescents. In doing so, it analyzes 93 dissertations published from 2011 to 2020 in Korea. To this end, this study reviewed the criteria from four studies on domestic bibliotherapy research trends, and analyzed research trends according to criteria such as basic information, research subjects, research methods and treatment programs. The results are as follows. First, bibliotherapy related to school life has been most actively studied in the course of master’s degrees, and the number of dissertations has decreased since 2014. Bibliotherapy research has been conducted in various fields, including education and psychotherapy. Second, research participants (i.e., clients) were mainly in the third to fifth grades of elementary school, and their number decreased as they went to high school. The client number in a therapy group was selected within the range of 11 to 20. Further, bibliotherapy has been mainly conducted for students who did not have clinical problems. Quantitative and mixed research were the most common research methods. Developmental and preventive programs were major, and the purpose of the programs was predominantly affective. Consequently, implications and future tasks related to bibliotherapy research for the school life adaptation of children and adolescents were presented.
차체 부품 적용을 위한 섬유복합재-금속 적층판의 기계적 물성 특성 평가
이환주(Hwanju Lee),최현석(Hyunseok Choi),전용준(Youngjun Jeon),김흥규(Heungkyu Kim),김동언(Dongearn Kim) 한국자동차공학회 2021 한국자동차공학회 부문종합 학술대회 Vol.2021 No.6
자동차 분야의 연료 효율증대 요구와 엄격한 환경규제 법규로 인해 차체 부품은 소재 다변화가 급속히 진행되고 있다. 글로벌 주요 완성차 OEM을 중심으로 신규 BIW 부품에 CFRP 복합재료를 적용한 사례가 증가하고 있다. 복합재료는 기존 철강 소재 대비 높은 비강성, 비강도 특성으로 높은 경량화 잠재력을 갖고 있어 종래의 금속 소재 부품을 대체하기 위한 신소재로 주목받고 있다. 그러나 복합소재 특성의 이해가 반영되지 않은 단순 소재변경은 부품의 성능향상 구현이 어렵다. 본 논문에서는 금속 판재와 복합소재 라미네이트가 접합된 Fiber metal laminates(FMLs)의 차체 구조물 적용을 위한 변형 거동을 분석하였다. FMLs의 디자인 설계를 통해 플라이 증가에 따른 거동특성 분석과 적층 구조에 따른 파단 형태를 도출하였다. 또한 적층 구조에 따른 장점을 모은 새로운 디자인을 도출하였다. 본 논문에서 제안된 FMLs은 단일소재 대비 높은 에너지흡수능 구현이 가능함을 확인하였다.