초소성 및 확산접합을 이용한 우주항공 부품 성형기술 개발

이호성,윤종훈,이영무,Lee, Ho-Sung,Yoon, Jong-Hoon,Yi, Yeong-Moo 한국군사과학기술학회 2005 한국군사과학기술학회지 Vol.8 No.3

In this paper, a near net shape technology using superplasticity and diffusion bonding characteristics was presented for application to various components of aircraft and missiles. Due to these special characteristics of some aerospace alloys, it is possible to produce complex components to shape very near final dimension with enhanced design freedom, reduced material usage, and overall saving of weight and cost. The high pressure vessel for a space launcher was fabricated with Ti-6Al-4V alloy by superplastic forming and diffusion bonding process and the failure characteristics are compared with conventionally fabricated vessel spin formed and TIG welded. The structural integrity of the superplastic forming and diffusion bonding process was successfully demonstrated.

Ti-6Al-4V 샌드위치 패널제작을 위한 초소성/확산접합 기술개발

이호성,윤종훈,이승철,박동규,이영무,Lee, Ho-Sung,Yoon, Jong-Hoon,Lee, Seung-Chul,Park, Dong-Kyu,Yi, Yeong-Moo 한국군사과학기술학회 2008 한국군사과학기술학회지 Vol.11 No.3

Ti-6Al-4V alloy is a critical strategic metal used in aerospace structure due to the high specific strength, toughness, durability, low density, corrosion resistance. Examples of application of this alloy are airframe structural components, aircraft gas turbine disks and blades. Forming of this alloy is not easy due to its high strength and low formability. However, this alloy shows superplastic properties that allow for large plastic deformation under certain conditions. Combination of superplastic forming and diffusion bonding(SPF/DB) processes of this alloy has been widely used to replace mechanically fastened structures with reduced weight and fabrication costs. In this study, superplastic forming/diffusion bonding technology has been developed for fabricating lightweight sandwich panels with Ti-6Al-4V alloy. The experimental results show the forming of titanium lightweight sandwich structure is successfully performed from 3 and 4 sheets of Ti-6Al-4V.

퍼지확률회귀모형(確率回歸模型)

이호성,오창혁,Lee, Ho-Sung,O, Chang-Hyeok 한국데이터정보과학회 1994 한국데이터정보과학회지 Vol.5 No.1

기존의 퍼지회귀모형은 모수의 퍼지성질에 의해 관측된 종속변수의 변동을 설명하는 방법이다. 그러나 일반적으로 종속변수에 영향을 미치는 모든 독립변수를 모형화하는 일은 불가능하므로 종속변수가 삼각퍼지숫자로 관측된 경우 모형화되지 않은 변수들의 영향을 랜덤 오차항으로 두는 퍼지확률회귀모형을 소개하고 이에 따른 모수추정법을 다룬다. 이 방법은 통계적 회귀모형의 일반화로 간주할 수 있다.

우주항공 재료시스템 품질인증

이호성,Lee, Ho-Sung 항공우주시스템공학회 2007 항공우주시스템공학회지 Vol.1 No.2

Structural qualification plan (SQP) for aerospace vehicle is based on material certification methodology, which must be approved by certification authority. It is internationally required to use of statistically based material allowables to design aerospace vehicles with aerospace materials. In order to comply with this regulation, it is necessary to establish relatively large amount of database, which increases test costs and time. Recently NASA/FAA develop the new methodology which results in cost, time, and risk reduction, and satisfies the regulation at the same time. This paper summarizes the certification methodology of materials system as a part of structural qualification plan (SQP) of aerospace vehicles and also thermal management of the vehicle system, like thermal protection materials system and thermally conductive material system. Materials design allowable was determined using this method for a carbon/epoxy composite material.

무장애 주택설계에 관한 국내외 국가표준의 비교 연구 -현관, 침실, 거실을 중심으로

이호성,최찬환,이특구,Lee, Ho Sung,Choi, Chan-Hwan,Lee, Teuk-Koo 한국의료복지건축학회 2010 의료·복지 건축 Vol.16 No.1

This is a comparative study mainly on foreign countries' domestic standards and laws on barrier free housing construction that can be applied to the dwelling of elderly friendly apartment housing. Eight countries - the United States, Germany, Canada, Switzerland, the United Kingdom, Australia, Japan, and China - were reviewed as foreign cases. The analyzed subjects were design standards only for the disabled and the aged. To compare barrier-free guides of the eight countries, each barrier-free guide on three space units (entrance, bedroom, living room) was divided into 11 design items and 36 design factors. The comparative analysis on foreign cases was based on the design guide according to Korea's KS P 1509 (principle and recommendation for designing dimension of dwelling in consideration of the elderly). Some factors -if with dimensions- were compared by means of the skewness of distribution. In the analysis result, there were not only common standards for the nine countries such as a dimension of the space for wheelchair movement but also different standards such as heights of outlets and horizontal lengths of bathtub grab bars. The detailed analysis shows that it is urgently necessary to prepare new domestic national design standards for 8 factors that foreign countries already have. It is also needed to immediately prepare dimension standards for the design factors, which have no detailed dimensions but only national guides, in consideration for anthropometric dimension.

남한 예비교사의 북한 화학 교과서에 제시된 과학 용어 이해

이호성,노봉오,박현주,Lee, Ho-Sung,Ro, Bong-Oh,Park, HyunJu 대한화학회 2008 대한화학회지 Vol.52 No.6

한국의 초고령사회를 대비한 최소주거면적 기준의 인체측정학적 방법 연구 - Karl H. E. Kroemer의 인체측정학적 데이터 적용 방법 -

이호성,Lee, Ho Sung 한국의료복지건축학회 2017 의료·복지 건축 Vol.22 No.3

Purpose: Korea is expected to enter an aged society in 2018 and then a super-aged society in early 2025. The country's aging is progressing faster than any other country in the world. However, the foundation of the elderly friendly industry is weak, and measures at the government level are urgently needed. Especially, housing problems of the elderly are one of the most urgent measures to be taken. Korea does not have the minimum residential area standard for the elderly, and the current general minimum residential area standard is based on the survey of the housing situation without scientific evidence. Therefore, both standards need to be revised as soon as possible based on scientific evidence. Methods: The minimum residential area standard has been calculated following Karl H. E. Kroemer's Min or Max design also being called as-single cut and dual cut theory- as the maximum population value and minimum population value theory of Ernest J. McCormick. Therefore there is a need for a formula made using a few key factors, such as corresponding dimension, practical dimension, clearance, spare dimension, integrated dimension. These elements can be defined and used as formulas to calculate minimum residential area standards. Results: Assuming the results of the spatial variability in this study showed that it is possible to raise the standard of living in a terms of sustainable minimum size for the young, old and all residents. Implications: The government should set a minimum residential area standard with scientific grounds and set up a policy improving the life of people who live in an needy residential environment.

유도무기용 날개구동기의 동적 강성 측정을 위한 유압 구동장치의 토크제어 기법에 관한 연구

이호성,Lee, Ho-Sung 한국군사과학기술학회 2007 한국군사과학기술학회지 Vol.10 No.3

This paper presents a torque control method of a hydraulic actuation system for measuring the dynamic stiffness of missile fin actuators. We propose a new control technique called Dual Dynamic Torque Feedback Control(DDTFC), which improves the stability of the torque control system and enables fast tracking of torque command. The developed control scheme is derived from the physical understanding based on mathematical modelling and analysis. The dynamics of hydraulic torque control servo-system is unravelled via physics-based modelling and nonparametric system identification. In order to verify the effectiveness of the method, the experiment is carried out with a test equipment for measuring the dynamic stiffness. The experiment and simulation results show that DDTFC gives stability improvement.

국산 항공기용 재료의 평가

이호성(Ho-Sung Lee),신돈수(Don-Soo Shin) 한국항공우주학회 1997 韓國航空宇宙學會誌 Vol.25 No.1

소형항공기용 복합재료 인증시험

이호성(Ho-Sung Lee),민경주(Kyung-Ju Min) 한국항공우주학회 2007 韓國航空宇宙學會誌 Vol.35 No.5

그동안 소형항공기에 사용하는 재료에 대해서도 대형항공기와 동일하게 요구하여 왔으나, 대형항공기 제조사에 비해 규모가 작은 소형항공기 제조사에서는 이 기준을 맞추기 위하여 많은 시험을 수행해야 하므로 큰 어려움을 겪어왔다. 최근 미국 FAA/NASA에서는 새로운 정책으로 요구조건을 변경하여 복합재 소형항공기를 인증하여 소형항공기 산업을 발전시키고 있다. 본 논문에서는 새롭게 바뀐 복합재료 인증 방법론에 대하여 설명하고, 예로서 이 방법을 사용하여 국산 350°F 탄소섬유/에폭시 복합재료의 설계허용값을 산출하였다. Since the introduction of advanced composite materials for use in aircraft, the material qualification has been a costly burden to the small airframe manufacturer. For each manufacturer, extensive qualification testing has often been performed to develop the base material properties and allowables at operating environmental conditions, regardless of whether this material system had been previously certificated by other manufacturers. In recent years, NASA, industry, and the FAA have worked together to develop a cost-effective method of qualifying composite material systems by the sharing of a central material qualification database. In this paper, the new methodology of composite material qualification is presented and material allowable of 350°F carbon fiber/epoxy composite material produced domestically is determined with this methodology.