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열습환경을 고려한 항공기용 레이돔 볼트 체결부의 베어링 강도에 관한 연구
김호일,유구현,김준,김광민,이규송,박영주,박범준,유홍균,Kim, Ho Il,Ryu, Guh Yun,Kim, Joon,Kim, Kwang Min,Lee, Kyu Song,Park, Young Ju,Park, Byum Jun,Ryu, Hong Kyun 대한기계학회 2017 大韓機械學會論文集A Vol.24 No.2
This research investigated the hygrothermal effect on the strength of bolt jointed section and moisture contents of composites exposed to hygrothermal environment for composite aircraft radome. The decrease in strength in the test environment is mainly attributed to the change in the material properties of the matrix due to temperature and moisture. The composite specimens were tested in three different environmental conditions: RTD(room temperature and dry), CTD(cold temperature and dry) and ETW(elevated temperature and wet). The failure mode of the bolt jointed composite specimens were studied using tests and finite element analysis. Finite element analysis reasonably predicted the failure load and mode of the joints. A reliability-based design was carried out for the bolt jointed composites of radome. 본 연구에서는 항공기용 레이돔에 적용되는 복합재의 볼트 체결부 강도에 대한 온도 및 습도 환경의 영향을 연구하였으며 열습환경에 노출된 레이돔 체결부에 대해 수분흡수율을 구하고, 온도와 습도환경에 따른 체결부 강도의 물성변화를 확인하였다. 이때 시편은 환경조건을 고려하여 상온건조(RTD), 고온고습(EWT), 저온건조(CTD) 세 가지로 구분하였으며 볼트 체결부의 파손하중 및 파손모드를 결정하기 위한 실험과 유한요소해석을 수행하였다. 유한요소해석의 결과가 체결부 강도와 파손모드에서 실험결과와 잘 일치하였으며 체결부 파손강도 예측이 가능한 효과적인 방법으로 확인하였다.
순차 컨벡스 프로그래밍 기반 무인기 설계 형상의 성능 분석
고효상,최한림,장종윤,김준,유구현,Ko, Hyo-Sang,Choi, Hanlim,Jang, Jong-Youn,Kim, Joon,Ryu, Gu-Hyun 한국항공우주학회 2022 韓國航空宇宙學會誌 Vol.50 No.11
Sequential convex programming based performance analysis of the designed UAV is performed. The nonlinear optimization problems generated by aerodynamics are approximated to socond order program by discretization and convexification. To improve the performance of the algorithm, the solution of the relaxed problem is used as the initial trajectory. Dive trajectory optimization problem is analyzed through iterative solution procedure of approximated problem. Finally, the maximum final velocity according to the performance of the actuator model was compared.
항공기 형상의 외부 장착 포드에 대한 정상 유동장 해석
장종윤(J.Y. Jang),유구현(G.H. Ryu) 한국전산유체공학회 2011 한국전산유체공학회 학술대회논문집 Vol.2011 No.11
In this paper, Pod mounted on the outside of the aircraft that operate the aircraft will have an effect on the basic performance of the aircraft will bring a change in flight characteristics. Generic fighter aircraft and the base is mounted externally mounted pod on the aircraft aerodynamic characteristics throughout the normal fluid flow analysis was calculated And the external mounting pod-like LANTIRN TGP featuring performing analysis and the results were analyzed to compare. Through this the default aircraft mounted pod on the With the addition of external aerodynamic characteristics changed was drawn, and similar forms were compared with the shape of the pod-equipped.
Mathematical Modeling and Analysis for the Ejection Force of Pyrotechnic Suspension System
김정필(Jung Pil Kim),유구현(Gu Hyun Ryu),김준(Joon Kim),유재승(Jae Seung Yoo) Korean Society for Precision Engineering 2021 한국정밀공학회지 Vol.38 No.7
The main function of aircraft ejection system is that it separates the store from the aircraft. The ejection force is important for the safety of the aircraft when the store is ejected, because the store can be lifted by air flow affected by the aircraft’s speed. If the ejection force is low, the aircraft can be damaged by the floating store. The ejection force of the suspension system should be designed in order to release the store safely. In this study, the ejection force of the pyrotechnic suspension using the cartridge to eject the store was researched. This research was performed, based on the precedent study about the over-center linkage mechanism and the pressure drop by the orifice. The ejection force was calculated, after analyzing mathematical fundamentals about the pressure in the system of the suspension and analyzed through AutoDyn and ADAMS software. Finally, the theoretical results were compared with the ejection test results of the suspension system.
항공기 구조 동특성 해석을 위한 외부 장착 포드의 단순화 유한요소 모델 구축
이종학(Lee, Jong-Hak),유구현(Ryu, Gu-Hyun),양성철(Yang, Sung-Chul),김지억(Kim, Ji-Eok),정대윤(Jung, Dae-Yoon) 한국소음진동공학회 2012 한국소음진동공학회 논문집 Vol.22 No.6
In this study, the natural frequencies and mode shape of an external mounting pod were verified using the modal analysis and modal testing technique for a pod mounted on an aircraft. The procedure associated with the FE model building of an external mounted pod to predict the dynamic behavior of aircraft structures is described. The simplified FE model reflecting the results of the modal testing of a pod is built through the optimization and will be applied to the structural dynamic model of an aircraft which is used to verified the stability of vibration and flutter of an aircraft.
열습환경을 고려한 항공기용 레이돔 볼트 체결부의 베어링 강도에 관한 연구
김호일(Ho Il Kim),유구현(Guh Yun Ryu),김준(Joon Kim),김광민(Kwang Min Kim),이규송(Kyu Song Lee),박영주(Young Ju Park),박범준(Byum Jun Park),유홍균(Hong Kyun Ryu) 대한기계학회 2017 大韓機械學會論文集A Vol.41 No.8
본 연구에서는 항공기용 레이돔에 적용되는 복합재의 볼트 체결부 강도에 대한 온도 및 습도 환경의 영향을 연구하였으며 열습환경에 노출된 레이돔 체결부에 대해 수분흡수율을 구하고, 온도와 습도환경에 따른 체결부 강도의 물성변화를 확인하였다. 이때 시편은 환경조건을 고려하여 상온건조(RTD), 고온고습(EWT), 저온건조(CTD) 세 가지로 구분하였으며 볼트 체결부의 파손하중 및 파손모드를 결정하기 위한 실험과 유한요소해석을 수행하였다. 유한요소해석의 결과가 체결부 강도와 파손모드에서 실험결과와 잘 일치하였으며 체결부 파손강도 예측이 가능한 효과적인 방법으로 확인하였다. This research investigated the hygrothermal effect on the strength of bolt jointed section and moisture contents of composites exposed to hygrothermal environment for composite aircraft radome. The decrease in strength in the test environment is mainly attributed to the change in the material properties of the matrix due to temperature and moisture. The composite specimens were tested in three different environmental conditions: RTD(room temperature and dry), CTD(cold temperature and dry) and ETW(elevated temperature and wet). The failure mode of the bolt jointed composite specimens were studied using tests and finite element analysis. Finite element analysis reasonably predicted the failure load and mode of the joints. A reliability-based design was carried out for the bolt jointed composites of radome.
진택성(Taek-Seong Jin),유구현(Gu-Hyun Ryu),강동석(Dong-Seok Kang),이철수(Cheol-Seol Lee),이규송(Kyu-Song Lee) 한국소음진동공학회 2015 한국소음진동공학회 학술대회논문집 Vol.2015 No.4
Avionics equipment mounted inside the aircraft is influenced by excitation which is transmitted through the aircraft structure. This excitation affect electronic performance and can cause deterrioration or failure. Therefore, Avionics equipment must be designed to perform proper function under vibration environment. In this paper, finite element model of the avionics was used to analyze dynamic characteristics of the avionics, via modal and random vibration analysis. The vibration level occurring in the avionics equipment was verified through resonance test and random vibration test.