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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.
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.
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.
보론강 고온전단공정에서 전단속도 및 메커니즘에 따른 전단면 특성 파악에 관한 연구
전용준,최현석,이환주,김도언,Jeon, Yong-Jun,Choi, Hyun-Seok,Lee, Hwan-Ju,Kim, Dong-Earn 한국금형공학회 2017 한국금형공학회지 Vol.11 No.2
With light vehicle weight gradually becoming ever more importance due to tightened exhaust gas regulations, hot-stamping processing using boron alloyed steel is being applied more and more by major automobile OEMs since process assures both moldability and a high strength of 1.5 GPa. Although laser trimming is generally applied to the post-processing of the hot-stamped process with high strength, there have been many studies of in-die hot trimming using shear dies during the quenching of material in order to shorten processing times. As such, this study investigated the effects of the Shear rate and Shear mechanism on shear processes during the quenching process of hot-stamping material. In case of pad variable, padding force is very weak compared with shear force, so it does not affect the shear surface. In case of shear rate, the higher the shear at high temperatures and the higher the friction effect. As a result the rollover and the fracture distribution decreased, and the burnish distribution increased. Therefore, it is considered that the shear quality is guaranteed when high shear rate is applied in high temperature shear process.
김병삼(Byeong Sam Kim),이원희(Won Hee Lee),이환주(Hwan Ju Lee) 대한기계학회 2015 대한기계학회 춘추학술대회 Vol.2015 No.11
In this study, variety of wire and cable. decide to measures for the storage method of the replacement cycle, depending on the intended in each condition. Type of travelling cables varies depending on the method for storing cables used for the purposes of control, such as cranes and handling equipment for the construction of the port and the power supply. Accordingly, the first pre-Hanging, to take-up the vertical tension and the reel of the bending stress that is loose repeated continuously applied to the cable, the mechanical strength is high, 1-4 years storage method h cycle time. In a study of three design variables conductor “Unionform-lay(UL)”), “Alternating-lay(AL)”, the “Opposite-lay(OL)” was set up differently depending on conditions. This stress distribution by using the finite element analysis program commercially available ABAQUS program was generated by the bending of the conductor to verify the comparative analysis, reliability test and the finite element model. Also it determines the best way according to the respective design conditions UL, AL, OL.
국내유통 축산물에서의 Staphylococcus aureus 오염도 및 항생제 감수성 조사
양정임(Jung-Im Yang),이선민(Sun-Min Lee),이길(Gil Lee),이환주(Hwan-Ju Lee),김민규(Min-Kyu Kim),정은정(Eun-Jeong Jeong),차용준(Yong-Jun Cha) 한국식품영양과학회 2008 한국식품영양과학회지 Vol.37 No.4
국내 유통 중인 우육 및 돈육을 대상으로 S. aureus의 오염실태와 검출된 S. aureus 대한 항생제 감수성조사 및 내성 plasmid 전달빈도를 조사하였다. 총 421개 축산물 시료의 20.2%에서 S. aureus가 검출되었으며, 품목별로는 돈육 13.9%, 우육 33.8%의 검출률을 보였다. 가공 전 원료육이 포장육에 비해 S. aureus의 검출률이 높았는데, 돈육에서는 원료육 23.3%, 포장육 7.1%였고, 우육에서는 각각 48.6% 및 28.1%였다. 항생제 감수성 시험결과 ampicillin(76.5%), penicllin(75.3%), tertracycline(27.1%) 및 erythromycin(21.1%) 순으로 높은 내성률을 보였다. 특히 우육에서는 penicillin의 내성이 55.6%인 반면 돈육에서는 97.5%로 돈육에서 1.6배 이상의 높은 내성률을 보였고, tetracycline의 경우 우육에서 13.3%의 내성을 보인 반면, 돈육에서는 42.5%로 3배 이상의 내성률을 보였다. 8가지 항생제에 내성을 보이는 다제내성균도 검출되었으며, 약제내성과 관련된 Rplasmid의 특성시험에서 혼합배양에서는 내성이 전달되지 않았고, filter mating법에서 tetracycline내성 plasmid가 1.1×10<SUP>-5</SUP>~1.9×10<SUP>-9</SUP>의 빈도로, erythromycin 내성 plasmid가 1.2×10<SUP>-5</SUP>~4.0×10<SUP>-8</SUP> 빈도로 내성이 전달되었다. 따라서 국내에서는 항생제투입의 정량적인 규제나 법적인 제도장치의 마련이 시급하다고 생각되며 앞으로 항생제 사용규제 및 대책마련에 대한 추가적인 연구가 절실하다고 생각되었다. Staphylococcus aureus is a pathogene of major concern in livestock products. This study was conducted to test imported and domestic meat sold by retail stores for the presence S. aureus. In addition, the antibiotic susceptibility of any S. aureus found was also evaluated. The overall isolation rate of S. aureus was 20.2% (13.9% in pork and 33.8% in beef) in retail meats. The percentage of imported meats found to contain S. aureus (33.3% in pork and 40.4% in beef) was higher than that of domestic meat (13.0% in pork and 14.7% in beef). In addition, the detection rate of S. aureus was higher in raw material meat than in ready to cook packaged meat. When the antibiotic susceptibility of S. aureus isolated from the meat products was evaluated, ampicillin was found to be the highest (76.5%), followed by penicillin (75.3%), tetracycline (27.1%) and erythromycin (21.2%). Penicillin and tetracycline resistant were detected in 55.6% and 13.3% of the beef isolates, respectively, and 97.5% and 42.5% of the pork isolates, respectively. The tetracycline and erythromycin resistant plasmids of the isolated strain were transferred into S. aureus DPRMM2429 by the filter mating method and the frequencies of transfer was found to be 1.1×10<SUP>-5</SUP>~1.9×10<SUP>-9</SUP> and 1.2×10<SUP>-5</SUP>~4.0×10<SUP>-8</SUP> respectively.