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손대성,현종민,Salim Chaki,Chung Hae Park,이정율 한국항공우주학회 2021 International Journal of Aeronautical and Space Sc Vol.22 No.5
In this study, a pattern for an active frequency selective surface (AFSS) applicable to stealth radomes was designed and manufactured. Subsequently, its effectiveness was verified via measurements of its electromagnetic performance, and its mechanical performance was numerically evaluated in an actual flight environment. An AFSS equipped with a PIN diode was designed to have a transmission frequency in the X-band using only one side of a surface. To evaluate the mechanical performance when the designed AFSS was applied to a stealth radome, flow analysis was performed on the basis of the shape of the F-35 combat aircraft. Moreover, structural analysis of the stealth radome was performed using the pressure distribution at the maximum velocity of the F-35, as determined via the flow analysis. On the basis of the structural analysis results, the mechanical performance of the designed stealth radome was evaluated via analysis of the stress distribution of the AFSS diode. Through this study, an AFSS pattern applicable to stealth radomes was proposed, and its mechanical/electromagnetic performance was evaluated to verify the feasibility of stealth radomes incorporated with AFSSs.
동시 경화법으로 제조된 T800/에폭시 복합재료-알루미늄 단면겹치기조인트의 성형압력 및 부가압력에 따른 접착강도에 관한 연구
손대성 ( Dae Sung Son ),배지훈 ( Ji Hun Bae ),장승환 ( Seung Hwan Chang ) 한국복합재료학회 2011 Composites research Vol.24 No.5
본 논문에서는 필라멘트 와인딩 시 장력에 의해 복합재료에 발생한 압력 정보를 이용하여 동시경화법으로 제조된 T800 탄소섬유/에폭시 복합재료-알루미늄 단면겹치기 접착조인트의 접착강도를 부가압력의 크기에 따라 측정하였다. 실험시편은 오토 클레이브 진공백 성형을 통해 성형압력 (절대압력 0.1MPa, 0.3MPa, 0.7MPa)을 조절하여 제작하였다. 접착강도를 측정하기 위하여 인장실험이 실시되었으며, 필라멘트 와인딩 공정에 의해 제조된 Type III 수소저장용기의 복합재료-알루미늄 라이너의 계면 접착강도를 측정하기 위해 단면겹치기 접착조인트의 접착부에 일정한 압력을 가해줄 수 있는 압력부가 장치를 설계하였다. 적층된 복합재료에 가해지는 부가압력이 접착강도에 미치는 영향을 확인하기 위해 서로 다른 세 종류의 부가압력 (절대압력 0.1MPa, 0.3MPa, 0.7MPa)을 시편에 부가하여 접착강도를 측정하고, 그 결과를 비교하였다. In this paper, the bonding strengths of co-cured T800 carbon/epoxy composite-aluminum single lap joints with and without additional pressures were investigated using the pressure information induced by the fiber tension during a filament winding process. The specimens of all the tests were fabricated by an autoclave vacuum bag de-gassing molding being controlled forming pressures (absolute pressures of 0.1MPa, 0.3MPa and 0.7MPa including vacuum). A special device which can act uniform additional pressures on the joining part of the single lap joint specimen was designed to measure the bonding strengths of composite-aluminum liners of type III hydrogen pressure vessel fabricated by a filament winding process. After the three different additional pressures(absolute pressures of 0.1MPa, 0.3MPa and 0.7MPa) were applied to the specimens the effect of the additional pressures on the bonding strengths of the co-cured single-lap joints were evaluated.
특집 논문(特輯 論文) : 메카노 규제 이론에 기초한 복합재료 IM-rod가 적용된 골절부의 세포분화과정의 유한요소해석
손대성 ( Dae Sung Son ),( Hassan Mehboob ),장승환 ( Seung Hwan Chang ) 한국복합재료학회 2012 Composites research Vol.25 No.5
본 논문에서는 복합재료 IM rod가 적용된 골절부의 세포 분화과정을 모사하기 위해 유한요소해석을 실시하였다. 세포의 골화과정을 해석하기 위해 편향 변형률을 이용한 메카노 규제 이론을 사용하였으며, 반복 계산을 위해 Python 코드를 이용하여 서브루틴을 구현하였다. 치료에 가장 적절한 복합재료 IM rod의 강성을 찾기 위해 직물 탄소섬유/에폭시 복합재료 (WSN3k)의 적층각도를 바꾸어 해석을 실시하였다. 골절부에 가해지는 기계적 자극에 따른 치료효율을 비교하기 위해 두 가지 초기 하중 조건을 적용하였다. 그 결과 치료효율은 강성의 차이보다 하중에 의해 큰 영향을 받았으며, 초기 하중이 몸무게의 10%이고, 적층순서가 [±45]nT일 때 치료효율이 가장 높았다. This paper describes the bone healing process of fractured long bones such as a tibia applied by composite IM rods using finite element analysis. To simulated tissue differentiation process mechano-regulation theory with a deviatoric strain was implemented and a user`s subroutine programmed by a Python code for an iterative calculation was used. To broadly find the appropriate rod modulus for healing bone fractures, composite IM rods were analyzed considering the stacking sequence. To compare mechanical stimulation at fracture gap, two kinds of initial loading conditions were applied. As a result, it was found that the initial loading condition was the most sensitive factor for the healing performance. In case a composite IM rod made of a plain weave carbon fiber/epoxy (WSN3k) had a stacking sequence of [±45]nT, the healing efficiency was the most effective under a initial load of 10%BW.
방사선 중합에 의한 폴리프로필렌 부직포-아크릴산 공중합체의 합성과 금속 흡착 특성에 관한 연구
손원근,신경섭,황대성,황택성,황의환 忠南大學校 産業技術硏究所 1998 산업기술연구논문집 Vol.13 No.2
The PP-g-AAc copolymers were synthesized by the irradiation grafting reaction of acrylic acid onto polypropylene nonwoven fabrics. The physicochemical properties of PP-g-AAc copolymers, such as structure, thermal stability and morphology were investigated by using FT-IR, TGA and SEM analyzer. It was observed that the degree of grafting increased linearly with the increase of acrylic acid monomer concentration. After the adsorption of metal ions in PP-g-AAc copolymers, their morphology seemed like small brain, lump and sponge.