• 제목/요약/키워드: ALE Technique

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Application of ALE for detection of rolling ball bearing defects in noisy environment (잡음환경에서 구름 볼 베어링의 결함검출을 위한 ALE의 적용)

  • 김영태;최만용;김기복;박해원;박정학;김종억;류준
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2004.10a
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    • pp.86-91
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    • 2004
  • It is very important to detect the bearing defects in rotating machinery since the critical failure of bearing cause a machinery shutdown. However it is difficult to detect the vibration signal resulting from the initial defects of bearing because of the high level of broadband noise. A signal processing technique, called the adaptive line enhancer(ALE) as one of adaptive filter, is studied in this work. This technique is to eliminate broadband noise without a prior knowledge of the noise and signal characteristics. Also we propose the optimal methods for selecting the three main ALE parameters such as correlation length, filter order and adaptation constant used in the adaptative process. Vibration signals for three abnormal bearings, including inner and outer raceways and ball defects, were acquired from Anderon(angular derivative of radius on)meter. The experimental results showed that the proposed technique can reliably detect the bearing defective signals masked by broadband noise.

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Shock Response Analysis under Underwater Explosion for Underwater Ship using ALE Technique (ALE기법을 이용한 수중함의 수중폭발 충격응답 해석에 관한 연구)

  • Kim, Jae-Hyun
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.10 no.4
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    • pp.218-226
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    • 2007
  • In modern naval ships, the design of submarines has continually evolved to improve survivability and it is also important to design ship against shock response. Exiting underwater ship design has been peformed due to results of static analysis considering shock acceleration by simple method. However, it can not be anticipated good assesment. The present study applied the Arbitrary Lagrangian-Eulerian (ALE) technique, a fluid-structure interaction approach, to simulate an underwater explosion and investigate the survival capability of a damaged submarine liquefied oxygen tank. The Lagrangian-Eulerian coupling algorithm and the equations of state for explosives and seawater were also reviewed. It is shown that underwater explosion analysis using the ALE technique can accurately evaluate structural damage after attack. This procedure could be applied quantitatively to real structural design.

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Application of Arbitrary Lagrangian-Eulerian Technique for Air Explosion Structural Analysis for Naval Ships Using LS-DYNA

  • Kim Jae-Hyun;Shin Hyung-Cheol;Park Myung-Kyu
    • Journal of Ship and Ocean Technology
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    • v.9 no.1
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    • pp.38-46
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    • 2005
  • Survivability improvement method for naval ship design has been continually developed. In order to design naval ships considering survivability, it is demanded that designers should establish reasonable damage conditions by air explosion. Explosion may induce local damage as well as global collapse to the ship. Therefore possible damage conditions should be realistically estimated in the design stage. In this study the authors used ALE technique, one of the structure-fluid interaction techniques, to simulate air explosion and investigated survival capability of damaged naval ships. Lagrangian-Eulerian coupling algorithm, equation of the state for explosive and air, and simple calculation method for explosive loading were also reviewed. It is shown that air explosion analysis using ALE technique can evaluate structural damage after being attacked. This procedure can be applied to the real structural design quantitatively by calculating surviving time and probability.

A new ALE formulation for sloshing analysis

  • Aquelet, N.;Souli, M.;Gabrys, J.;Olovson, L.
    • Structural Engineering and Mechanics
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    • v.16 no.4
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    • pp.423-440
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    • 2003
  • Arbitrary Lagrangian Eulerian finite element methods gain interest for the capability to control mesh geometry independently from material geometry, the ALE methods are used to create a new undistorted mesh for the fluid domain. In this paper we use the ALE technique to solve fuel slosh problem. Fuel slosh is an important design consideration not only for the fuel tank, but also for the structure supporting the fuel tank. "Fuel slosh" can be generated by many ways: abrupt changes in acceleration (braking), as well as abrupt changes in direction (highway exit-ramp). Repetitive motion can also be involved if a "sloshing resonance" is generated. These sloshing events can in turn affect the overall performance of the parent structure. A finite element analysis method has been developed to analyze this complex event. A new ALE formulation for the fluid mesh has been developed to keep the fluid mesh integrity during the motion of the tank. This paper explains the analysis capabilities on a technical level. Following the explanation, the analysis capabilities are validated against theoretical using potential flow for calculating fuel slosh frequency.

Study on Pullout Behavior of Embedded Suction Anchors in Sand using ALE (Arbitrary Lagrangian Eulerian) Technique (ALE 기법을 이용한 모래지반에서 석션 매입 앵커의 인발 거동 분석)

  • Na, Seon Hong;Jang, In Sung;Kwon, O Soon;Lee, Seung Hyun
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.34 no.1
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    • pp.167-173
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    • 2014
  • The embedded suction anchor, ESA, is one type of mooring anchor systems which utilizes the suction pile or caisson to penetrate the anchor into the sea bed and develops its capacity under pullout load. In this study, the numerical analysis using ALE (Arbitrary Lagrangian Eulerian) Adaptive Meshing technique was performed to simulate the pullout behavior of the ESA, and the results were compared to those of the previous research, centrifuge model tests and the analytical method based on limit equilibrium theory. The pullout behaviors of the ESA under horizontal, vertical, and inclined loading were evaluated. The analysis results showed that the maximum horizontal pullout load was developed when the location of loading point was at the mid-point, and the each vertical pullout load gave the similar value regardless of the locations of the loading points. The pullout load decreased as the load inclination angle increased at the mid-point of the anchor.

Evaluation of Pullout Capacity of Embedded Suction Anchors in Uniform Clay using Numerical Analysis with ALE(Arbitrary Lagrangian Eulerian) Technique (ALE 기법이 적용된 수치해석을 통한 점토지반에서 석션 매입 앵커의 인발 저항력 평가)

  • Na, SeonHong;Jang, In-Sung;Kwon, OSoon;Lee, Seung-Hyung
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.15 no.4
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    • pp.2428-2435
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    • 2014
  • Numerical analysis with ALE (Arbitrary Lagrangian Eulerian) Adaptive Meshing technique was performed to evaluate the pullout capacity of the embedded suction anchors (ESA) in uniform clay. The numerical method was verified by the previous study, analytical results based on limit-equilibrium theory and centrifuge tests. The pullout capacity of the ESA under horizontal, vertical, and inclined loading were evaluated, and the effect of initial rotation of the ESA on pullout capacity was also investigated. The analysis results showed that the maximum horizontal capacity was obtained at the mid-point, and the each vertical capacity gave the similar value regardless of the loading points. Furthermore, the inclined capacity was decreased as the load inclination angle increased at the mid-point of the anchor, and almost the same pullout capacity was obtained when the initial rotation angles were below 30 degrees.

Application of Adaptive Line Enhancer for Detection of Ball Bearing Defects (볼 베어링의 결함검출을 위한 Adaptive Line Enhancer의 적용)

  • Kim Young Tae;Choi Man Yong;Kim Ki Bok;Park Hae Won;Park Jeong Hak;Kim Jong Ock;Lyou Jun
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.14 no.2
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    • pp.96-103
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    • 2005
  • The early detection of the bearing defects in rotating machinery is very important since the critical failure of bearing causes a machinery shutdown. However it is not easy to detect the vibration signal caused by the initial defects of bearing because of the high level of random noise. A signal processing technique, called the adaptive line enhancer(ALE) as one of adaptive filter, is used in this study. This technique is to eliminate random noise with little a prior knowledge of the noise and signal characteristics. Also we propose the optimal methods fir selecting the three main ALE parameters such as correlation length filter order and adaptation constant. Vibration signals f3r three abnormal bearings, including inner and outer raceways and ball defects, were acquired by Anderon(angular derivative of radius on) meter. The experimental results showed that ALE is very useful f3r detecting the bearing defective signals masked by random noise.

Estimation of Acceleration Response of Freefall Lifeboat using FSI Analysis Technique of LS-DYNA Code (LS-DYNA 코드의 유체-구조 연성해석 기법을 이용한 자유낙하식 구명정의 가속도 응답 추정)

  • Bae, Dong-Myung;Zakki, A.F.;Kim, Hag-Soo;Kim, Joo-Gon
    • Journal of the Society of Naval Architects of Korea
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    • v.47 no.5
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    • pp.681-688
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    • 2010
  • During certification of freefall lifeboats, it is necessary to estimate the injury potential of the impact loads exerted on the occupants during water entry. This paper focused on the numerical simulation to predict the acceleration response during the impact of freefall lifeboats on the water using FSI(Fluid-Structure Interaction) analysis technique of LS-DYNA code. FSI problems could be conveniently simulated by the overlapping capability using Arbitrary Lagrangian Eulerian(ALE) formulation and Euler-Lagrange coupling algorithm of LS-DYNA code. Through this study, it could be found that simulation results were in relatively good agreement with experimental ones in the acceleration peak values, and that the loading conditions were very sensitive to the acceleration responses by the experimental and simulation results.

Thermal Atomic Layer Etching of the Thin Films: A Review (열 원자층 식각법을 이용한 박막 재료 식각 연구)

  • Hyeonhui Jo;Seo Hyun Lee;Eun Seo Youn;Ji Eun Seo;Jin Woo Lee;Dong Hoon Han;Seo Ah Nam;Jeong Hwan Han
    • Journal of Powder Materials
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    • v.30 no.1
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    • pp.53-64
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    • 2023
  • Atomic layer etching (ALE) is a promising technique with atomic-level thickness controllability and high selectivity based on self-limiting surface reactions. ALE is performed by sequential exposure of the film surface to reactants, which results in surface modification and release of volatile species. Among the various ALE methods, thermal ALE involves a thermally activated reaction by employing gas species to release the modified surface without using energetic species, such as accelerated ions and neutral beams. In this study, the basic principle and surface reaction mechanisms of thermal ALE?processes, including "fluorination-ligand exchange reaction", "conversion-etch reaction", "conversion-fluorination reaction", "oxidation-fluorination reaction", "oxidation-ligand exchange reaction", and "oxidation-conversion-fluorination reaction" are described. In addition, the reported thermal ALE processes for the removal of various oxides, metals, and nitrides are presented.

Analysis of Flexible Media Using ALE Finite Element Method (ALE 유한요소법을 이용한 유연매체의 거동해석)

  • Jee, Jung-Geun;Jang, Yong-Hoon;Park, No-Cheol;Park, Young-Pil
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2007.05a
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    • pp.247-250
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    • 2007
  • Flexible media such as the paper, the film, etc. are thin, light and very flexible. They behave in geometrically nonlinear. Any of small force makes large deformation. So we must including aerodynamic effect when its behavior is predicted. Thus, it becomes fully coupled fluid-structure interaction(FSI) problem. In FSI problems, where the fluid mesh near the structure undergoes large deformations and becomes unacceptably distorted, which drive the time step to a very small value for explicit calculations, the arbitrary Lagrangian-Eulerian(ALE) methods or rezoning are used to create a new undistorted mesh for the fluid domain, which allows the calculations to continue. In this paper, FE sheet model considering geometric nonlinearity is formulated to simulate the behavior of the flexible media. Aerodynamic force to the media by surrounding air is calculated by solving the incompressible Navier-Stokes equations. Q2Q1(Taylor-Hood) element which means biquadratic for velocity and bilinear for pressure is used for fluid domain. Q2Q1 element satisfies LBB condition and any stabilization technique is not needed. In this paper, cantilevered sheet in the viscous incompressible Navier-Stokes flow is simulated to check the mesh motion and numerical integration scheme, and then falling paper in the air is simulated and the effects of some representative parameters are investigated.

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