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음향방출법을 응용한 복합재 날개 구조물의 정적구조 건전성 평가
전준탁(Joon-Tak Jun),이영신(Young-Shin Lee) 한국항공우주학회 2009 韓國航空宇宙學會誌 Vol.37 No.8
복합재 날개 구조물에 대한 구조 건전성 및 손상을 평가하기 위하여 정적 구조강도시험에 음향방출(AE)법이 응용되었다. 시험중 스트레인과 변위측정기법을 통하여 정적구조 강도를 확인하였고, 음향방출요소 분석과 위치표정기법을 통하여 구조물의 내부 손상을 평가하고 손상위치를 찾을 수 있었다. 시험은 설계제한하중시험, 2차에 걸친 설계극한하중시험, 파단시험이 수행되었다. 주요한 AE신호는 front lug근처의 표면에 부착된 센서에 의하여 감지되었다. 특히 1차 설계극한하중시험에서 스트레인 및 변위결과는 내부 손상을 보이지 않았으나 AE신호는 내부 손상이 이미 형성된 현상을 나타내었다. 파단시험에서는 AE활성도가 매우 활발하였고, 스트레인 및 변위의 결과는 심한 손상에 의하여 하중경로가 바뀌는 경향을 나타내었다. 음향방출법을 적용하여 정적 구조시험이 진행되는 동안 내부손상이 발생되는 하중과 위치를 정확하게 평가할 수 있었다. 본 연구로부터 음향방출법은 정적 구조강도시험에 있어 내부 손상을 평가하는데 유용한 기법임이 확인되었다. AE technique was applied to the static structural test of the composite wing structure to evaluate the structural integrity and damage. During the test, strain and displacements measurement technique were used to figure out for static structural strength. AE parameter analysis and source location technique were used to evaluate the internal damage and find out damage source location. Design limit load test, the 1st and 2nd design ultimate load tests and fracture test were performed. Main AE source was detected by an sensor attached on skin near by front lug. Especially, at the 1st design ultimate test, strain and displacements results didn't show internal damage but AE signal presented a phenomenon that the internal damage was formed. At the fracture test, AE activities were very lively, and strain and displacements results showed a tendency that the load path was changed by severe damage. The internal damage initiation load and location were accurately evaluated during the static structural test using AE technique. It is certified from this paper that AE technique is useful technique for evaluation of internal damage at static structural strength test.
전준탁(Joon-Tak Jun),강휘원(Hui-Won Kang),양명석(Myung-Seog Yang) 한국항공우주학회 2015 韓國航空宇宙學會誌 Vol.43 No.1
본 논문은 램프의 수명저하 없이 1,000℃이상의 초고온 급속가열 환경을 지속적으로 모사할 수 있고 기존 사용해온 열하중 부가장치 대비 내구성과 신뢰성이 향상된 열하중 부가장치를 개발하여 초고속 비행체 날개의 구조 건전성 평가에 적용, 그 활용가능성을 수록한 내용이다. 본 시험을 통하여 초고온의 운용환경에 노출되는 비행체 날개의 공력가열에 의한 강성저하를 정량적으로 예측할 수 있었으며, 향후 비약적인 증가추세에 있는 공력가열온도를 경험하게 되는 극초음속 비행체에 대한 고온환경에서의 구조 강도특성 평가가 가능해짐으로써 시험 신뢰성 향상과 함께 고온구조강도시험 수행능력을 한 단계 도약시킬 수 있는 계기가 되었다. This paper describes test result of the Supersonic Wing Structure and the utility of thermal test equipment, which is possible to heat rapidly and continuously above 1,000℃, the durability and reliability of which are improved compared with the existing equipment. Through the test, we could predict the amount of strength reduction of the wing due to aerodynamic heating, caused by exposure of high temperature. Recently the aerodynamic heating temperature of the supersonic flying object is rapidly increased. It is possible to carry out the High Temperature Strength est on the hypersonic speed flying object with the newly designed thermal test equipment. Because of that, we can upgrade the High Temperature Strength Structure Test technique and test reliability.
이재옥(Lee Jae-Ok),이영신(Lee Young-Shin),이현승(Lee Hyun-Seung),김재훈(Kim Jae-Hoon),전준탁(Jun Joon-Tak),김철구(Kim Chul-Goo) 대한기계학회 2008 大韓機械學會論文集A Vol.32 No.5
The heavy duty diesel engine must have a large output for maintaining excellent mobility. In this study, a three dimensional finite element model of a heavy-duty diesel engine was developed to conduct the stress analysis. The FE model of the heavy duty diesel engine main parts consisting with four half cylinder was selected. The heavy duty diesel engine parts includes with cylinder block, cylinder head, gasket, liner, bearing cap, bearing and bolts. The loading conditions of engine were pre-fit load, assembly load, and gas load. As the results of structural analysis, because the stress values of cylinder block and bearing cap did not exceed the basic design can be satisfied. But on the part which contacts with cylinder block and bearing cap the stress value exceeds the allowable strength of material. In order to decrease the stress at that part, it was optimized with parametric study.
대형 디젤엔진 실린더 블록의 구조해석 및 위상 최적설계
이현승(Hyun-Seung Lee),이영신(Young-Shin Lee),공정표(Jeong-Pyo Kong),이재옥(Jae-Ok Lee),전준탁(Joon-Tak Jun),김철구(Chul-Goo Kim) 대한기계학회 2008 대한기계학회 춘추학술대회 Vol.2008 No.5
The heavy duty diesel engine must have a large output for maintaining excellent mobility. In this study, three dimensional finite element model of a heavy-duty diesel engine was developed to conduct the stress analysis by using property of CGI. The compacted graphite iron (CGI) is a material currently under study for the engine demanded for high torque, durability, stiffness, and fatigue. The FE model of the heavy duty diesel engine section consisting with four half cylinder was selected. The heavy duty diesel engine section includes cylinder block, cylinder head, gasket, liner, bearing cap, bearing and bolts. The loading conditions of engine are pre-fit load, assembly load, and gas load. Structural analysis on the result was performed in order to optimize on the cylinder block of diesel engine.
이재옥(Lee Jae-Ok),이영신(Lee Young-Shin),이현승(Lee Hyun-Seung),김재훈(Kim Jae-Hoon),전준탁(Jun Joon-Tak),김철구(Kim Chul-Goo) 대한기계학회 2007 대한기계학회 춘추학술대회 Vol.2007 No.5
The heavy duty diesel engine must have a large output for maintaining excellent mobility. The compacted graphite iron (CGI) is a material currently under study for the engine demanded for high torque, durability, stiffness and fatigue. In this study, three dimensional finite element model of a heavy-duty diesel engine was developed to conduct the stress analysis by using property of CGI. The FE model of the heavy duty diesel engine section consisting with four half cylinder was selected. The heavy duty diesel engine section include cylinder block, cylinder head, liner, bearing cap, bearing and bolt. The loading conditions of engine are pre-fit load, assembly force and gas force.