XKT-1(수출형 KT-1) 항공기 열 환경시험에 관한 연구

김진석 항공우주시스템공학회 2021 항공우주시스템공학회지 Vol.15 No.3

This paper delineates the applied thermal environmental test profiles using test conditions and procedures based on MIL-STD-810 Method 501 (High Temperature Test Method) and Method 502 (Low Temperature Test Method). The test profiles have been optimized in order to comply with export customer's requirements and product reliability in high and low temperature environment for XKT-1 (KT-1 Export Version) aircraft. Additionally, the tests are suitable for large sized environmental chambers, which is one of the facilities of ADD (Agency for Defense Development) according to ETEMP (Environmental Test and Evaluation Master Plan). The results of these test profiles and test executions satisfy the customer requirements and product reliability. The present paper can be applied to the other export programs with more severe temperature conditions. 본 논문은 MIL-STD-810 시험법 501(고온 시험법)과 시험법 502(저온 시험법)를 기반으로 XKT-1(수출형 KT-1) 항공기 고객의 운용 환경과 요구사항에 적합하도록 시험조건과 시험절차를 최적화하여 열 환경시험 프로파일을 제시하였다. 또한, 이렇게 최적화된 고온 및 저온시험 프로파일을 환경시험 종합평가 계획서에 반영하여 국방과학연구소의 기후환경 챔버에서 시험수행 하였다. 본 고온 및 저온 환경시험 프로파일로 XKT-1(수출형 KT-1) 항공기의 고온 및 저온 환경시험수행 결과, 고객 환경 요구사항을 만족하고 혹독한 열 환경에서 신뢰성 있음을 확인하였다. 특히 본 논문에서 제안된 고온 및 저온 환경시험절차와 프로파일은 더 혹독한 환경시험 조건의 수출형 항공기 환경시험에도 응용할 수 있다.

MIL-STD-810G w/Change 1의 고온 및 저온 시험 방법에 대한 고찰

박태국(Tae-Kook Park),최병오(Byung-Oh Choi),강보식(Bo-sik Kang),이기천(Gi-Chun Lee),양청광(Cheong-Kwang Yang),송태진(Tae-Jin Song) 대한기계학회 2016 대한기계학회 춘추학술대회 Vol.2016 No.12

The environmental tests is a branch of the reliability tests. The environmental tests has recently been important in the industry. High and low temperature tests has been performed in the basic tests of the environmental tests. So high and low temperature tests has been extensively increased in the industry. The MIL-STD-810G w/Change 1 is used as the basic standards to perform the environmental tests. In this paper, It is reviewed in the method for high and low temperature test of the MIL-STD-810G w/Change 1. The product has to operate in climates of the world in which is expected to be used. The climates of the world is different climatic conditions depending on the location. The product is produced, transported and stored in each different condition. So the product is exposed in a variety of conditions, such as high and low temperature. The purpose of the temperature tests obtains data to help evaluate effects of high(or low) temperature conditions on safety, integrity, and performance during storage, operation, and manipulation.

A Study on Improvement of the low temperature flex resistance test method about high waterproof materials

이민희,홍성돈 한국품질경영학회 2018 한국품질경영학회 학술대회 Vol.2018 No.-

This study is aimed at developing of the flex resistance testing process at low temperature with the waterproof fabric to suit the military environment and is designed to fit for the purpose of the waterproof materials in order to optimize the test method by finding out matters in order to improve from another and through previous studies. The novel test method, which has been applied to flex resistance of existing waterproof materials, was improved and consequently, differentiated test results could be obtained according to the test temperature, sample size, and flexing method as well. We acquired that performance of the military requirement could hardly be met just by presenting the materials or merely 2~3 layers when the quality criteria for high functional water repellent fabrics were applied from the test of 8 samples. The PTFE(Polytetrafluoroethylene) is preferred to the PU(Polyurethane) as waterproof materials in the extremely low-temperature environment, but durability under the low-temperature environment may be varied depending on film thickness or laminating technique even if the materials are identical. Therefore, in addition to the material or texture, the test method capable of reflecting durability under the low-temperature environment should be suggested, and the newly designed test method proposed in this study. The water resistance measurement and the test method following flex resistance with the expanded range of flex will enable the differentiable test of the samples according to the number of flexing. This study is meaningful in that it suggests a novel test method capable of establishing a basis of deciding suitable material when selecting military goods made of the waterproof material by properly improving the test method.

저온조건 비행환경모의 시험을 위한 시험설비 최적화 방안에 대한 연구

정광수(KwangSoo Jung),정규진(GyuJin Jung),최영환(YoungHwan Choi),이준원(JoonWon Lee) 한국추진공학회 2020 한국추진공학회 학술대회논문집 Vol.2020 No.11

항공 추진에 사용되는 개발 엔진의 성능을 검증하기 위해서 비행 환경을 모의할 수 있는 시험설비가 필요하다. 본 논문에서는 비행 환경 중 저온 상태에서 개발 엔진의 성능을 검증할 수 있는 저온조건 비행환경모의 시험설비 방안에 대해 연구하였다. In order to verify the performance of the development engine used for aviation propulsion, a test facility that can simulate the flight environment is required. In this paper, a study was conducted on a test facility for a low-temperature flight environment simulation that can verify the performance on the developed engine in low-temperature condition.

항공기 부착물 및 투하물 환경시험 기준값 설정에 관한 연구

김영래(Youngrae Kim),정성록(Seongrok Jeong),홍연웅(YeonWoong Hong),김동길(DongGil Kim) 한국데이터정보과학회 2018 한국데이터정보과학회지 Vol.29 No.5

환경시험은 시험대상품이 운용환경에 노출되었을 때 수명주기 동안 정상기능을 수행할 수 있는지 확인하는 과정이며, 효과적인 환경시험을 수행하기 위해서는 시험대상품이 겪을 것으로 예상되는 환경을 적절하게 모사하는 것이 필요하다. 특히, 군수품은 민수품에 비해 극한 환경에 노출되는 경우가 많으므로 정확한 환경시험을 설계하는 것은 매우 중요하다. 미국의 경우 군수품 환경시험 기준값을 결정하기 위해 전 세계 기후 데이터를 수집하여 활용하고 있다. 따라서, 우리 환경에 적합한 환경 시험을 위해서는 군수품의 주요 운용 환경인 우리나라 기후 데이터에 대한 연구가 필요하다. 본 논문에서는 우리나라 고고도 온도 데이터에 대한 분석 결과를 제시한다. 이를 위해 1997년부터 2016년까지 남한 9개 지역의 고고도 (압력고도 1~30km) 온도 데이터를 분석하였다. 분석 결과로 대한민국 고고도 저온 극한값과 발생빈도값을 산출하였으며, 이 결과는 항공기 외장 탑재물 및 투하물의 환경시험 기준으로 활용할 수 있다. Environmental tests are used to verify if the materiel can withstand harsh environments. In order to conduct effective environmental tests, it is important to simulate proper environment condition that the materiel may endure during its life-cycle. The environmental test process is very important for military products since materiel are more likely to be exposed to extreme environments than commercial products. In the U.S., global climate data are collected and utilized to determine the environmental criteria for the materiel products. ROK’s military products are mostly operated in the Korean Peninsula. Thus, a study on climate data of the Korean Peninsula is necessary. In this paper, the extremes of low temperature and FOO of high altitude low temperature are analyzed. The analysis showed that the world’s extreme low temperature and it of Korea were significantly different below the altitude of 4km. Especially, the difference between those at 1km altitude was -29.9℃. These results can be used as the criteria of environmental test for aircraft materiel which is external mounts and releases.

초저온용 밸브의 초저온성능 시험평가방법 국제표준에 대한 연구

김윤철(Yoon-Chul Kim),허중식(Joong-Sik Heo),황선역(Sun-Yeok Hwang) 표준인증안전학회 2013 표준인증안전학회지 Vol.3 No.2

There have not been international standards about the test evaluation for cryogenic valves so far. It just follows local or organization standards at the moment. To develop the international standard of cryogenic test method and procedure, we have studied domestic and international techniques and trends about the test method. We also have attended international conference meetings and seminars for technical agreement of the standard procedure and test method. The standard procedure has been revised by analysing a lot of test results using the standard test method. Finally we try to register the test method for cryogenic valves as an international standard through activities in the international working group or international conference meetings. In this paper, the results of the ISO international conference meeting(ISO/TC 153) at Canada are briefly presented.

소형펀치 시험을 이용한 API X52 저온 수소환경 파괴인성 예측

김재윤,서기완,김윤재,김기석 한국압력기기공학회 2023 한국압력기기공학회 논문집 Vol.19 No.2

Hydrogen embrittlement of a pipe is an important factor in hydrogen transport. To characterize hydrogen embrittlement, tensile and fracture toughness tests should be conducted. However, in the case of hydrogen-embrittled materials, it is difficult to perform tests in hydrogen environment, particularly at low temperatures. It would be useful to develop a methodology to predict the fracture toughness of hydrogen-embrittled materials at low temperatures using more efficient tests. In this study, the fracture toughness of API X52 steels in hydrogen at low temperatures is predicted from numerical simulation using coupled finite element (FE) damage analyses with FE diffusion analysis, calibrated by analyzing small punch test data.

내환경 온도시험의 촉진시간에 관한 연구

한철호(Chul Ho Han),김경훈(Kyoung Hoon Kim),김형의(Hyoung Eui Kim) 대한기계학회 2011 大韓機械學會論文集A Vol.35 No.3

내환경 시험시 시험물체가 요구시험온도가 되게 온도시험조를 가열 또는 냉각하는 계단형 온도시험 프로파일에서 적정 촉진온도 유지시간을 예측하는 집중용량법에 의한 새로운 해석적 방법을 제안하였다. 해석은 주어진 온도시험조건에 대해 시험시간을 줄이고 에너지를 절약하는 촉진시간이 존재함을 보여주고 있다. 이론결과는 작업소재로 강을 사용한 몇 가지 실험결과와 비교적 잘 부합하고 있다. 제안된 적정촉진시간은 동일재료에 대해 시편의 질량/표면적비와 근사적으로 비례한다. A new method to predict the proper promotion time on the near-step-temperature test profile when heating or cooling the test-piece in a test chamber to the test temperature for environmental tests has been proposed by using the lumped analysis. For a given test condition the analysis shows the existence of a promotion time that reduces the testing time and saves energy. The theoretical results are in reasonably good agreements with experimental results for steel specimens. The suggested promotion time is approximately proportional to the mass/surface area of the test-piece for a given material.

고주기 피로특성에서 응력비가 S355NL 소재의 피로수명에 미치는 영향

신상훈(Sang Hun Shin),김정돈(Jung Don Kim),이승갑(Seung Gap Lee),김남용(Nam Yong Kim),이현우(Hyun Woo Lee) 대한기계학회 2011 대한기계학회 춘추학술대회 Vol.2011 No.5

S355NL은 풍력발전의 금속소재로 현재 사용되고 있다. 본 연구의 S355NL에 대한 기계적 물성치들은 상온 및 저온의 환경조건에 의해서 인장시험에 의해서 평가하였다. 고주기 피로시험은 이러한 인장시험들에 의해서 획득된 데이터들을 통해서 수행하였다. 응력비 -1, 0,1, 0.2, 0.3 에 대해서 하중제어 방식으로 피로시험을 수행하였다. 또한 응력비 0.1 은 저온 및 상온환경조건에 대해서 비교하였다. Raw Material에 대해서 Goodman, Gerber, Morrow 식들을 적용한 결과 Morrow식이 근접한 경향성이 나타났다. S355NL is used in wind power structural steel. In this study, mechanical properties were evaluated by tensile test at room temperature and -20℃, respectively. Based on the Tensile Test, High Cycle Fatigue Test was conducted on S355NL (Raw Material, Production Type). The tests were performed under load controlled conditions for the various stress ratios of -1(Raw Material), 0.1, 0.2 and 0.3. In addition, that of 0.1 compared the room temperature and -20℃ from two materials. Goodman’s, Gerber’s and Morrow’s Equations were considered for Raw Material. As a result, it is shown that Morrow’s Equation correlated fairly well those of 0.1 and 0.2.

상온접합 본딩이 있는 복합재 날개의 저온 구조시험

하재석(Jae Seok Ha),박찬익(Chan Yik Park),이기범(Kee Bhum Lee) 한국항공우주학회 2015 韓國航空宇宙學會誌 Vol.43 No.10

본 논문에서는 상온접합이 있는 무인기 복합재 날개의 저온 구조시험에 대하여 소개하였다. 본 시험에 사용된 날개구조는 탄소섬유 강화 복합재료로 구성되며, 내부 구조물과 스킨은 상온접착제로 접합되었다. 또한 날개구조의 손상허용성을 검증하기 위하여 육안으로 확인이 거의 불가능한 충격손상을 스킨의 주요 부위에 인위적으로 적용하였다. 무인기 운용 고도의 온도환경을 모사하기 위한 저온 챔버를 특별히 제작하였으며, 날개구조는 챔버내에 고정시키고 챔버 외부에 설치한 유압 작동기를 이용하여 하중을 부가하였다. 구조시험은 변형률 개관시험 및 1배 수명 피로하중 스펙트럼에 대한 손상허용시험으로 구성된다. 변형률 게이지와 광섬유 센서를 이용하여 본딩영역 및 주요 부위의 변형률을 측정하였으며, 압전 구동기/센서를 이용하여 손상의 변화를 모니터링 하였다. 시험결과로부터 날개구조는 1배 수명에 대한 운용환경을 모사한 환경 하에서 구조적 건전성을 보유하고 있음을 확인하였다. This paper presents low temperature structural tests of a UAV wing which has room temperature-curing adhesive bond. The wing structure is made of carbon fiber reinforced composites, and the skins are bonded to the inner structures (such as ribs and spars) using room temperature-curing adhesive bond. Also, to verify damage tolerance design of the wing structure, barely visible impact damages are intentionally created in the critical areas. The attachment fittings of the wing are fixed in a specially designed chamber which can simulate the low temperature environments of the operating altitudes. The test load is applied by hydraulic actuators which are placed outside the chamber. The structural tests consist of strain survey tests and a durability test for 1-life fatigue load spectrum. During the tests, strains of major parts are measured by strain gauges and FBG sensors. The change of the initial impact damages is also monitored using piezoelectric sensors. The 1-life damage tolerance of the composite structure is verified by the structural tests under the simulated environments.