• 제목/요약/키워드: Multilayered

검색결과 559건 처리시간 0.035초

Vibration of multilayered functionally graded deep beams under thermal load

  • Bashiri, Abdullateef H.;Akbas, Seref D.;Abdelrahman, Alaa A.;Assie, Amr;Eltaher, Mohamed A.;Mohamed, Elshahat F.
    • Geomechanics and Engineering
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    • 제24권6호
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    • pp.545-557
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    • 2021

  • Since the functionally graded materials (FGMs) are used extensively as thermal barriers in many of applications. Therefore, the current article focuses on studying and presenting dynamic responses of multilayer functionally graded (FG) deep beams placed in a thermal environment that is not addressed elsewhere. The material properties of each layer are proposed to be temperature-dependent and vary continuously through the height direction based on the Power-Law function. The deep layered beam is exposed to harmonic sinusoidal load and temperature rising. In the modelling of the multilayered FG deep beam, the two-dimensional (2D) plane stress continuum model is used. Equations of motion of deep composite beam with the associated boundary conditions are presented. In the frame of finite element method (FEM), the 2D twelve-node plane element is exploited to discretize the space domain through the length-thickness plane of the beam. In the solution of the dynamic problem, Newmark average acceleration method is used to solve the time domain incrementally. The developed procedure is verified and compared, and an excellent agreement is observed. In numerical examples, effects of graduation parameter, geometrical dimension and stacking sequence of layers on the time response of deep multilayer FG beams are investigated with temperature effects.

  • https://doi.org/10.12989/gae.2021.24.6.545 인용 KSCI

Tribological and Corrosion Behavior of Multilayered $WC-Ti_{1-x}Al_xN$ Coatings Deposited by Cathodic Arc Deposition Process on High Speed Steel

  • S.H. Ahn;J.H. Yoo;Park, Y.S.;Kim, J.G.;Lee, H.Y.;J.G. Han
    • 한국표면공학회:학술대회논문집
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    • 한국표면공학회 2001년도 추계학술발표회 초록집
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    • pp.31-32
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    • 2001

  • Recently, many of the current development in surface modification engineering are focused on multilayered coatings. Multilayered coatings have the potential to improve the tribological and corrosion properties of tools and components. By using cathodic arc deposition, $WC-Ti_{1-x}Al_xN$ multilayers were deposited on steel substrates. Wear tests of four multiplayer coatings were performed using a ball-on-disc configuration with a linear sliding speed of 0.1m/s, 5N load. The tests were carried out at room temperature in airby employing AISI 52100 steel ball ($H_v=848N$) of 11mm in diameter. Electrochemical tests were performed using the potentiodynamic and electrochemical impedance spectroscopy (EIS) measurements. The surface morphology and topography of the wear scars of tribo-element and the corroded specimen have been determined by using scanning electron spectroscopy (SEM). Also, wear mechanism was determined by using SEM coupled with EDS. Results have showed an improved wear resistance and corrosion resistance of the $WC-Ti_{1-x}Al_xN$ coatings.

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가상 절점을 이용한 적층 구조물의 페리다이나믹 층간 결합 모델링 검토 (Study on Peridynamic Interlayer Modeling for Multilayered Structures)

  • 안태식;하윤도
    • 한국전산구조공학회논문집
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    • 제30권5호
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    • pp.389-396
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    • 2017

  • 결합 기반 페리다이나믹 모델은 취성재료의 동적파괴 해석에 많이 이용되고 있으며, 최근의 연구(Bobaru et al., 2012)를 통해 적층유리 구조물의 동적 파괴 패턴 분석에도 활용되었다. 특히 실험(Bless et al., 2010)에서 나타난 적층유리 구조물의 다양한 손상 형태(압축 영역, Floret, Hertz-type 균열 등)를 결합 기반 페리다이나믹 시뮬레이션을 이용하여 구현하였다. 그러나 실제 적층 구조물은 각 유리판 사이를 탄성이 있는 층간 재료로 결합하는 반면, 기존의 페리다이나믹 수치 시뮬레이션에서는 층간 재료 결합을 무시하고 각 유리판이 직접 결속되도록 가정하여 층간 재료 효과가 무시되었다. 본 연구에서는 페리다이나믹 층간 재료 모델링을 통해 실제 적층 구조물에 보다 근접한 페리다이나믹 수치 해석 모델을 제안한다. 일반적으로 층간 재료는 매우 얇기 때문에 층간 재료를 명시적으로 모델링할 경우 많은 해석시간과 메모리가 소모되어 비효율적이다. 따라서 본 연구에서는 명시적 모델링을 대신하여 가상 절점을 통해 층간 재료를 모델링한다. 수치 예제를 통해 제안된 층간 재료 모델링의 효율성 및 정확성을 검토한다. 또한 압축 상태의 적층 구조물 해석을 위해 단거리 상호작용력에 기반한 투과 방지 기법을 도입하고 파라미터 테스트를 통해 검증한다.

  • https://doi.org/10.7734/COSEIK.2017.30.5.389 인용 PDF KSCI