• 한국항공운항학회지
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• 제30권1호
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• pp.12-19
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• 2022

The exhaust wake of an aircraft engine is discharged in a high temperature and high speed, which can damage objects such as an aircraft in the rear. The exhaust wake can lift small foreign substances lying on the ground or falling off, and the floating foreign substances can enter the intake duct of the aircraft moving from the rear and cause engine FOD (Foreign Object Damage). This study experimentally analyzed how the engine exhaust wake generated from military jet fighters affects the movement of foreign substances and evaluated the effects of foreign substances on the damaged area by measuring wake velocity. The simulation and field experimental results confirmed that the effect of exhaust wake increases as the rear position closer, and that foreign substances lifted by the wake can act as FOD to the adjacent rear aircraft.

• 한국추진공학회지
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• 제11권3호
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• pp.58-64
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• 2007

항공기 엔진 흡입구는 개발시에 조류 충돌에 대한 충분한 안전성을 검토하여 설계 되어야 한다. 항공기의 속도가 점차 증가함에 따라 FOD(Foreign object damage)에 따른 항공기의 사고가 증가하고 있다. 특히 이착륙시 활주로 주변 새들에 의한 항공기 사고는 경제적 손실을 비롯해 탑승객의 생명과 연결되는 중요한 문제이다. 본 연구에서는 유한 요소 상용 코드인 MSC/DYTRAN을 이용해 엔진 흡입구 낫셀 구조에 대한 조류 충돌 해석을 수행하였다. 해석 결과의 타당성 검증을 위해 선행 연구 결과와 비교한 후 조류 충돌 해석 결과의 거동을 분석하였다.

• 한국안전학회지
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• 제18권2호
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• pp.34-39
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• 2003

In this paper, when CF/PEEK laminates for high efficiency space structure are subjected to FOD(Foreign Object Damage), the effects of temperature change on the impact damages(interlaminar separation and transverse crack) of CF/PEEK laminates and the relationship between residual lift and impact damages are experimentally investigated. Composite laminates used in this experiment are CF/PEEK orthotropic laminated plates, which have two-interlaces [$0^{\circ}_4/90^{\circ}_8/0^{\circ}_4$]. A steel ball launched by the air gun collides against CF/PEEK laminates to generate impact damages. And then CF/PEEK specimens with impact damages are observed by a scanning acoustic microscope under room and high temperatures. In this experimental results, various relations are experimentally observed including the delamination area vs. temperature change, the bending strength vs. impact energy and the residual bending strength vs. impact damage of CF/PEEK laminates.

• 한국자동차공학회논문집
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• 제2권6호
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• pp.66-75
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• 1994

In this paper, the effects of temperature change on the impact damages of CF/PEEK laminates are experimentally investigated. Composite laminates used in this experiment are CF/PEEK orthotropic laminated plates, which have two-interfaces$[0^{\circ}_4/90^{\circ}_4]_{9+} A steel ball launched by the air gun collides against CFRP laminates to generate impact damage. The delamination damages are oberved by a scanning acoustic microscope. And various relations are experimentally observed including the impact energy vs. delamination area, the specimen temperature vs. transverse crack, and the impact energy vs. residual bending strength of carbon fiber peek composite laminates subjected to FOD(Foreign Object Damage) under high temperatures.

• 대한기계학회논문집
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• 제18권8호
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• pp.1930-1938
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• 1994

In this paper, the effects of temperature change on the impact of CFRP laminates was experimentally studied. Composite laminates used for this experiment are CFRP orthotropic laminated plates, which have two-interfaces$[0_6^{\circ}/90_7^{\circ}]_s$ and four-interfaces$[0_3^{\circ}/90_6^{\circ}/0_3^{\circ}]_s$. The interrelations between the impact energy vs. delamination area, the impact energy vs. residual bending strength, and the interlayer delamination area vs. the decrease of the residual flexural strength of carbon fiber epoxy composite laminates subjected to FOD(Foreign Object Damage) under high temperatures were experimentally observed.

• 한국정밀공학회지
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• 제10권4호
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• pp.152-162
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• 1993

The purpose of this study is to investigate problems of residual bending strength and the impact damage experimentally when CFRP composite laminates are subjected to Foreign object damage. The specimens composed of four types of CR/EPOXY and a CF/PEEK composite laminates which involved difference of fiber stracking orientation and matrics. The result were summariged as follows : 1) It is found that both orthotropic and guasi-isotropic composite laminates are increasimg lineally between impact energy and damage delamination area. 2) Delamination devel- opment energy(mm$^{2}$J) OF cf/epoxy composite aminates is less than that of CF/PEEK. 3) When impact energy is applied to specimens within 3J, the residual strength of orthotropic is greater than guasi-isotropic composite laminates. On the other hand, it is predicted that residual bending strength of orthotropic composite laminates is less than that of quasi-isotropic when impact energy is more thaen 3J. 4) It is found in CF/PEEK that for the impact side compression, residual of bending strength versus impact energy is almost constant, while in case of impact side tension, residual bending strength is decreased rapidly near 1.2J. of impact energy due to the effect of delamination buckling.

• 전기전자학회논문지
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• 제25권4호
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• pp.750-755
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• 2021

본 논문에서는 YOLOv4를 이용하여 차량의 부위별 파손현황을 검출하는 기법을 제안한다. 제안 알고리즘은 YOLOv4를 통해 차량의 부위와 파손을 각각 학습시킨 후 검출되는 바운딩 박스의 좌표 정보들을 추출하여 파손과 차량부위의 포함관계를 판단하는 알고리즘을 적용시켜 부위별 파손현황을 도출한다. 또한 성능비교의 객관성을 위하여 동일분야의 VGGNet을 이용한 기법, 이미지 분할과 U-Net 모델을 이용한 기법, Weproove.AI 딥러닝 모델 등을 대조 모델로 포함한다. 이를 통하여 제안 알고리즘의 성능을 비교, 평가하고 검출 모델의 개선 방안을 제안한다.

• 대한기계학회논문집
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• 제17권11호
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• pp.2752-2761
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• 1993

The purpose of this study is to confirm the decreasing problems of residual bending strength, and the fracture machanism experimentally when CFRP composite laminates are subjected to Foreign Object Damage. Composite laminates used for this experiment are CFRP orthotropy laminated plates, which have two-interfaces [O/sub 6//sup o//90/sub 6//sup o/]sub sym/ and four-interfaces [O/sub 3//sup o//90/sub 6//sup o//O/sub 3//sup o]/sub sym/. When the specimen is subjected to transverse impact by a steel ball, the delamination area generated by impact damage is observed by using SAM(Scanning Acoustic Microscope). also, Thefracture surfaces obtained by three-point bending test were observed by using SEM (Scanning Electron Microscope). Then, fracture mechanism was investigated based on the observed delamination area and fracture surface. The results were summarized as follows; (1) It is found that for the specimen with more interface, the critical delamination energy is increased while delamination-development energy is decreased. (2) Residual bending strength of specimen A is greater than that of Specimen B within the impact range of impact energy 1. 65J (impacted-side compression) and 1. 45J (impacted-side tension). On the other hand, when the impact energy is beyond the above ranges, residual bending strength of specimen A is smaller than that of specimen B. (3) In specimen A and B, residual strength of CFRP plates subjected to impact damage is lower in the impacted-side compression than in the impacted-side tension. (4) In the case of impacted-side compression, fracture is propagated from the transverse crack generat-ed near impact point. On the other hand, fracture is developed toward the impact point from the edge of interface-B delamination in the case of impacted-side tension.

• 한국항공운항학회지
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• 제22권1호
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• pp.130-135
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• 2014

FOD(Foreign Object Debris) has the potential threat to damage aircraft during critical phases of take-off and landing roll with some objects including metal on the runway. FOD can be found anywhere on an airport's air operation areas such as runway, taxiway and apron. It can lead to catastrophic loss of life and airframe, and increased maintenance and operating costs. In this paper, we defined FOD and surveyed its riskiness and necessity of automatic FOD detection system. We compared the requirements of the environment in Korea to the FAA advisory circular. Also we analyzed operation methods of FOD detection systems already installed at some airports. Based on the surveys mentioned above, we propose hybrid type of FOD detection system considering the environment in Korea which uses millimeter wave radar, optical camera and thermal imaging camera to detect FOD efficiently. In management approach, fixed type of the system should be installed for real-time monitoring, and mobile type of the system can be used additionally.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2007년도 제28회 춘계학술대회논문집
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• pp.67-70
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• 2007

항공기 엔진 흡입구는 개발시에 조류 충돌에 대한 충분한 안전성을 검토하여 설계되어야 한다 항공기의 속도가 점차 증가함에 따라 FOD(Foreign object damage)에 따른 항공기의 사고가 증가하고 있다. 특히 이착륙시 활주로 주변 새들에 의한 항공기 사고는 경제적 손실을 비롯해 탑승객의 생명과 연결되는 중요한 문제이다 본 연구에서는 유한 요소 상용 코드인 MSC/DYTRAN을 이용해 엔진 흡입구 낫셀 구조에 대한 조류 충돌 해석을 수행하였다. 해석 결과의 타당성 검증을 위해 선행 연구 결과와 비교한 후 조류 충돌 해석 결과의 거동을 분석하였다.