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백주현(Joo Hyun Baek),조영환(Young Hwan Jo),이병억(Byung Uk Lee),유구현(Gu Hyun Ryu) Korean Society for Precision Engineering 2020 한국정밀공학회지 Vol.37 No.10
This paper addresses two methods to estimate the target incapacitation distance and probability of the arbitrary fragmentation warhead under the static detonation test condition. One is based on the probability equation suggested by Sperrazza and Kokinakis. The other is originated from the stationary detonation test concept to measure the performance of the fragmentation warhead. In the arbitrary fragmentation warhead, the target incapacitation probabilities obtained from the two methods were compared with each other. We found that the size of the fragment with cubic shape should be more than 3.5 mm to maximize the target incapacitation distance in the test method. And we also realized that the difference between the target incapacitation distance of the analysis method based on the test (AMBT) and that of the analysis method based on the probability equation (AMBPE) is decreased according to the increase of the fragment size. In conclusion, this paper can be useful for the estimation of the fragmentation warhead performance at the design stage.
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.
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.
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.
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 유한요소모델 구축 절차
이종학(Jong-Hak Lee),유구현(Gu-Hyun Ryu),양성철(Sung-Chul Yang),정대윤(Dae-Yoon Jung) 한국소음진동공학회 2011 한국소음진동공학회 학술대회논문집 Vol.2011 No.10
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 FEM building of an external mounted pod to predict the dynamic behavior of aircraft structures is described. The simplified FEM reflecting the results of the modal testing of a pod is built through the optimization, applied to the structural dynamic model of an Aircraft, used to verified the stability of vibration and flutter of an aircraft.
전우철(Oo-Chul Jun),전승문(SeungMoon Jun),유구현(Gu-Hyun Ryu),김준(Joon Kim) 한국항공우주학회 2005 韓國航空宇宙學會誌 Vol.33 No.4
새로 개발된 ECM 포드의 비행 적합성 시험을 위한 외부 장착물 비행 시험용 계측 포드를 설계하였다. 비행시험 요구도 분석결과 하중, 진동환경 및 공력 가열적 측면에 대한 측정이 요구되었다. 비행하중 측정을 위하여 1) ECM 포드 무게 중심점에 3축 선형 가속도계, 3축 각속도계, 및 2축 경사계, 2) 장착 걸쇠(Lug)에 스트레인 게이지 8채널, 3) 장착볼트의 하중 측정을 위한 STRAINSERT<SUP>®</SUP> 볼트 2개를 장착하였다. 비행 진동 환경 측정을 위한 3축 선형가속도계와 공력가열에 의한 영향을 분석하기 위한 4개의 열전쌍을 장착하였다. 기동특성 파악을 위하여 항공기의 고도, 속도, 하중배수, 자세등의 신호를 KF-16 MIL-STD-1553B로부터 추출 할 수 있는 버스 모니터(Bus Monitor)를 장착하였다. 획득된 자료는 모두 PCM화 되어 디지털테이프에 기록되도록 하였다. 지상 기능시험으로 계측 포드의 정상작동을 확인하였다. A design of the instrumented pod for the newly developed ECM(Electronic Counter Measure) pod compatibility flight test is presented. A requirement study asks the measurement of load, vibration, and aerodynamic heating. Following sensors are designed for the flight load data evaluation; 1) 3 linear accelerometers, 3 angular rate sensors, and 2 inclinometers at the center of gravity 2) 8 channel strain gages at the lugs, 3) 2 STRAINSERT<SUP>®</SUP> bolts to measure the tensile load. The 3 triaxial linear accelerometers are installed to measure the vibration environment and 4 thermocouples are installed. Finally, a bus monitor is installed to extract the aircraft parameters such as altitude, speed, load factor and attitude from the W-mux of KF-16 MIL-STD-1553B. All the data are recorded in digital tape by PCM(Pulse Coded Modulation) stream. The functional test assures the normal operation of the instrument pod design.