• Title, Summary, Keyword: 손상허용

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A Study on Flaw Tolerance Evaluation of a Main Rotor Actuator for Rotorcraft (회전익 항공기용 주 로터 작동기에 대한 손상허용 평가 연구)

  • Park, Juwon;Jeong, Jeongrae
    • Journal of Aerospace System Engineering
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    • v.14 no.spc
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    • pp.1-6
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    • 2020
  • The flaw tolerance evaluation requirement prescribed in Federal Aviation Regulation (FAR) §29.571 Amendment 55 was established in 2012. As a result, there are not many datas of flaw tolerance evaluation. This paper introduces the series of processes and evaluation methods carried out for certification based on the flaw tolerance evaluation. An initial flaws were artificially formed on the main rotor actuator and then the damage tolerance test was performed, which was twice life time of design requirements, to demonstrate that the main rotor actuator of the rotorcraft is sufficiently capable of flaw tolerance.

Investigation on Damage Tolerance of Thick Laminate for Aircraft Composite Structure (항공기 복합재 구조에 적용된 두꺼운 적층판의 손상 허용 기준 평가)

  • Park, Hyun-Bum;Kong, Chang-Duk;Shin, Chul-Jin
    • Composites Research
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    • v.25 no.4
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    • pp.105-109
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    • 2012
  • Recently, development of a small aircraft has been carried out for the BASA(Bilateral Aviation Safety Agreement) program in Korea. This aircraft adopted all composite structures for environmental friendly by low fuel consumption due to its lightness behavior. However the composite structure has disadvantage which is very weak against impact damages. Therefore, damage allowable design of aircraft structure must be performed considering compressive fracture strength. This point is very important for certification of composite structure aircraft. In this paper, it is performed the research on damage tolerance of thick laminate adopting aircraft structure. The damage tolerance of three different types of thick laminates such as no damage, open hole and impact damage is evaluated under compression loading.

Damage Tolerance Analysis Using Surrogate Model (근사모델을 사용한 손상허용해석)

  • Jang, Byung-Wook;Im, Jae-Hyuk;Park, Jung-Sun
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.39 no.4
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    • pp.306-313
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    • 2011
  • The damage tolerance analysis is required to guarantee the structural safety and the reliability for aircraft components. The damage tolerance method, which evaluate the life considering the initial crack, considers a fatigue design model of the aircraft main structure. The fatigue crack growth life should be calculated in damage tolerance analysis and the inspection time to define the replacement cycle. In this paper, the damage tolerance analysis is performed for a turbine wheel which has complex geometry. The equation of the stress intensity factor for complex geometry is hard to know, so that they are usually processed by finite element analysis which takes long time. To solve this problem, the stress intensity factors at specified crack are obtained by the FEA and the crack growth life is evaluated using the surrogate model which is generated by the regression analysis of the FEA data. From the results, the efficiency of the crack growth life calculation and the damage tolerance analysis could be increased by taking the surrogate model.

A Study on Prediction of Fatigue Damage Crack Growth for Stiffener Bonded Composite Laminate Panel (보강재 본딩접합 복합재 적층판구조 피로손상 균열진전 수명예측에 대한 연구)

  • Kwon, Jung-Ho;Jeong, Seong-Moon
    • Composites Research
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    • v.26 no.2
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    • pp.79-84
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    • 2013
  • The prediction and analysis procedure of fatigue damage crack growth life for a stiffener bonded composite laminate panel including center hole and edge notch damage, was studied. It was performed on the basis of fatigue damage growth test results on a laminated skin panel specimens and the analysis results of stress intensity factor for the stiffener bonded composite panel. According to the comparison between experimental test and prediction results of fatigue damage growth life, it was concluded that the residual strength and damage tolerance assessment can be carried out along to the edge notch crack growth.

Static Test of a Composite Wing with Damage Tolerance Design (손상 허용 설계를 적용한 복합재 날개의 정하중 시험)

  • Park, Min-Young
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.46 no.6
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    • pp.471-478
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    • 2018
  • Static tests of the composite wing structure were performed to verify damage tolerance design. Both 5 cases of DLLT and 3 cases of DULT were completed to meet requirements for static strength. After inducing BVID and open hole damages on the critical areas of the composite wing based on associated regulations, the DULT and fracture test were performed. In major wing parts, the measured strains and displacements agreed well with those of structural analysis. The initial structural fracture occurred at the area having minimum margin of safety as expected by analysis. As a result, it was confirmed that results from analytic model and strength evaluation were similar to behaviors of the composite wing structure.

Damage Tolerance Design and Prediction of Fatigue Life in Aircraft Structure (항공기구조의 손상허용설계와 피로수명 예측)

  • 황돈영
    • Journal of the KSME
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    • v.35 no.6
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    • pp.468-480
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    • 1995
  • 항공기구조는 항상 피로하중에 노출되어 있고 조류충돌과 같은 불시의 상황에 의해 손상을 입을 가능성을 가지고 있어서 이에 대한 대비책을 마련하지 않으면 인명과 재산상에 막대한 손실을 초래할 가능성이 있다. 따라서 항공기가 개발되는 초기의 설계단계부터 항공기의 안전성확보가 중요하며, 이를 위해서는 적절한 피로수명예측과 손상허용설계를 해나아가는 것이 중요하며, 그 내용을 정리하면 다음과 같다. (1) 항상 손상의 가능성을 인정하고, 이 손상이 존재하는 경우에도 항공기의 안전이 보장 되도록 설계한다. (2) 손상이 발생하면 쉽게 발견되도록 설계한다. (3) 한 부재의 손상이 전 구조물의 파괴로 이루어지지 않도록 다중하중 경로로 설계한다. (4) 손상의 가능성이 있는 부품은 특별관리한다. (5) 안전균열성장 및 잔류강도 요구조건이 충족되도록 검사계획을 수립하며, 이 검사계획에 따라 검사를 수행한다.

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항공기 구조 설계에서의 손상허용 해석

  • 권정호
    • Journal of the KSME
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    • v.30 no.2
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    • pp.131-140
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    • 1990
  • 손상 허용 설계 개념의 목적은 항공기 성능의 최대 관건이 구조물 무게가 과도하게 증가하는 것 을 방지하고 동시에 충분한 신뢰도를 만족시키는데 있다. 이러한 테크놀로지의 설계 적용에 대하 여 몇 가지 중요한 점을 지적하면 결함 검사를 위하여 외부에서 접근이 용이하게 설계되어야 하 고 단일 하중 전달 구조에 비하여 다중 하중 전달 구조가 바람직한 것이다. 또한 해석적 방법에 대하여 충분한 시험으로 해석과정의 유효성이 인정되어야 하며 일반적으로 전체 구조의 수명을 위하여 재료의 인성치를 증가시키는 것보다 균열 검출 기술을 향상시켜 검출 가능 결함 크기를 낮추는 것이 효과적이라 할 수 있다.

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화재원인조사실무 - 발화원의 감정(V)

  • Kim, Yun-Hoe
    • 방재와보험
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    • pp.28-33
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    • 2005
  • 절연된 물질 상호간에 전기저항이 감소하여 많은 전류를 흐르게 하는 절연파괴는 화재발생의 원인중 하나이다. 절연파괴의 원인으로는 기계적 손상, 절연피복의 손상, 허용전류를 넘어선 열적손상 등이 있다. 이번 호에는 절연 내력이 점차 저하하여 마침내 절연파괴를 일으키는 배선에서의 전기력 발연원인에 대해 고찰해보기로 하자.

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A Study on Damage Tolerance Assessment for the Butt Lap Joint Structure with the Effects of Fretting Fatigue Cracks (프레팅 피로균열 영향을 고려한 항공기 맞대기중첩연결 구조 손상허용성 연구)

  • Kwon, Jung-Ho;Hwang, Kyung-Jung
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.31 no.1
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    • pp.8-17
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    • 2003
  • The butt lap joint structures which are usually designed by the concept of slow crack growth damage tolerance, show frequently the behaviors of multiple site fatigue crack growth around the fastener hole edges due to the fretting between the two jointed parts. In this paper, experimental tests of fatigue crack growth have been performed of a bolted butt lap joint structure having an initial corner crack at the fastener hole edge, with different fretting conditions under a flight load spectrum. The obtained test results were reviewed to investigate the effects of fretting fatigue cracks on the damage tolerance crack growth life. Computations of corner crack growth were also carried out using an existed model to compare with test results.