• Title/Summary/Keyword: 분리해석법

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A Study on Fracture Behaviors of Single-Edge-Notched Glass Fiber/Aluminum Laminates Using Acoustic Emission (음향방출법을 이용한 편측노치를 갖는 유리섬유/알루미늄 적층판의 파괴거동 해석)

  • Woo Sung-Choong;Choi Nak-Sam
    • Composites Research
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    • v.18 no.2
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    • pp.1-12
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    • 2005
  • Fracture behaviors of single-edge-notched monolithic aluminum plates and glass fiber/aluminum laminates under tensile loadings have been studied using acoustic emission(AE) monitoring. AE signals from monolithic aluminum could beclassified into two different types. For glass fiber/aluminum laminates, AE signals with high amplitude and long duration were additionally confirmed on FFT frequency analysis, which corresponded to macrocrack propagation and/or delamination. AE source location determined by signal arrival time showed the zone of fracture. On the basis of the above AE analysis and fracture observation, characteristic features of fracture processes of single-edge-notched glass fiber/aluminum laminates were elucidated according to different fiber ply orientations and fiber/aluminum lay-up ratios.

An Application Example of SEA for the KOMPSAT-1 Satellite Model (KOMPSAT-1 위성구조체에 대한 SEA 적용사례)

  • Jeong C. H.;Ih J. G.;Kim Y. K.;Kim H. B.
    • Proceedings of the Acoustical Society of Korea Conference
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    • autumn
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    • pp.211-214
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    • 2004
  • 이륙과 음속 통과시 랜덤진동형태의 음향/진동환경에 노출되는 위성체의 음향/진동시험은 시제품을 완성한 후에 슨1행되므로 않은 시행착오를 겪거나, 과다한 안전계수를 사용하여 불필요한 무게증가 등의 문제점을 가지고 있다. 이러한 문제점을 극복하기 위하여 통계적 에너지 해석법 (Statistical Energy Analysis)을 이용한 선행 해석이 필요하다. 본 연구에서는 KOMPSAT-1 (Korea Multi-Purpose Satellite-1) 위성체의 SDM (Structural Dynamic Model)에 대하여 SEA 해석을 수행하였다. 감쇠 손실 인자 (Damping Loss Ffactor)는 단판을 분리하여, 연성 손실 인자(Coupling Loss Factor)는 SDM모델 하부의 두 샌드위치 패널을 분리하여 실험적으로 산정하였다.

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Linear Discriminant Analysis in Agricultural Experiment (농업실험에서 직선분리함수의 이용)

  • Young-Am Chae
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.22 no.1
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    • pp.80-82
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    • 1977
  • Using head length and head width of two wheat monosomic lines linear discriminant function of these two variables was calculated and also illustrated how one can effectively classify unknown individuals into a correct group belonging by means of this linear discriminant function in reverse. Brief suggestion on the utilization of this analysis in genetics and breeding program was given.

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Simulation of Separating Isoclinics and Isochromatics from Photoelastic Fringes of a Disk using 8-step Phase Shifting Methodology (광탄성 프린지 위상이동법을 적용한 디스크의 등경 및 등색프린지 분리법에 관한 시뮬레이션)

  • Baek, Tae-Hyun;Kim, Myung-Soo;Cho, Sung-Ho
    • Journal of the Korean Society for Nondestructive Testing
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    • v.21 no.2
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    • pp.189-196
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    • 2001
  • Photoelasticity is one of the most widely used methods for whole field stress analysis. In photoelasticity, the difference and the directions of the principal stresses we given isochromatic and isoclinic fringe patterns. Conventionally, principal stress directions are measured manually by relating the polarizer and analyzer of a plane polariscope at the same time. This is known to be the Tardy compensation method. This measurement can be very tedious and time consuming in whole field analysis. It is not possible to separate isoclincs from photoelastic fringes by conventional photoelastic technique. In this study, photoelastic theory is represented by Jones matrices and 4-steps and 8-steps phase shifting methods are described A feasibility study using computer simulation is done to separate isoclincs and isochomatics from photoelastic fringes of a circular disk under diametrical compression. Fringe patterns of the disk are generated using stress optic law. The magnitudes of isoclincs and isochromatics obtained from 8-step phase shifting method are compared with those of theories. From computer simulation, it is verified to separate isoclincs and isochomatics from photoelastic fringes.

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Chaos analysis for the periodic nonlinear system using harmonic balance method (조화함수법을 이용한 주기 비선형 시스템의 Chaos 해석)

  • Kim, Y.B.
    • Journal of the Korean Society for Precision Engineering
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    • v.11 no.6
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    • pp.75-85
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    • 1994
  • 주기함수의 외력을 갖는 버선형 시스템의 다양한 응답 특성을 구하기 위해 새로운 조화함수법(HBM)을 적용하였다. 새로운 조화함수법의 해는 비선형항을 선형항으로부터 따로 분리시킨 다음 같은 주파수 성분을 갖는 비선형 방정식들을 Newton-Raphosn법으로 풀어서 구하였다. 다양한 천이(Bifurcation) 특성을 해석적으로 판별하기 위하여 HBM의 해를 이용하여 구한 섭동 방정식의 Floquet 지수의 고유해를 사용하였다. 새로이 개발한 HBM과 천이 판별법을 1차원 비선형항을 갖는 구조물인 ALP(Articulated Loading Platform) 모델과 다차원인 비선 형 회전체 모델에 적용시켜 HBM의 해의 정확성과 이들 시스템의 천이 특성의 하나인 Chaos 존재를 확인 하였다.

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Analysis of Carbon Dioxide Separation with Countercurrent Flow in Hollow Fiber Membrane by Numerical Analysis (수치해석에 의한 향류 흐름 중공사 분리막의 이산화탄소 분리 성능 해석)

  • Lee, Yong-Taek;Song, In-Ho;Ahn, Hyo-Seong;Lee, Young-Jin;Jeon, Hyun-Soo;Kim, Jeong-Hoon;Lee, Soo-Bok
    • Membrane Journal
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    • v.16 no.4
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    • pp.252-258
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    • 2006
  • A numerical analysis was performed for a separation process of carbon dioxide from a flue gas stream using polyethersulfone hollow fiber membranes. Countercurrent flow governing equations were regarded to be two point boundary-value problem and the nonlinear ordinary differential equation were simultaneously solved using the finite- difference method. A computer program was developed using the Compaq Visual Fortran 6.6 software. The carbon dioxide permeate driving force and the fred gas residence time at the inside of membrane were found to be very important factors affecting the permeation characteristics of carbon dioxide. The carbon dioxide concentration in the permeate and the flow rate of the permeate were found to be slightly larger by a few percent with a countercurrent flow analysis than those with a cocurrent flow analysis.

Thermal Analysis of Lithium-ion Cell Using Equivalent Properties and Lumped Capacitance Method (등가물성 및 집중용량법을 이용한 리튬-이온 전지의 열해석)

  • Lee, Hee Won;Park, Il Seouk
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.37 no.8
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    • pp.775-780
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    • 2013
  • In general, the battery module of an electric vehicle (EV) consists of lithium-ion cells. A lithium-ion battery is a secondary rechargeable battery, and it consists of numerous stacked plates that serve as electrodes and separators. Owing to these microstructural features, its numerical analysis is very expensive. Therefore, this study aims to present a simplified thermal analysis model using equivalent thermal properties, and we compare the experimental results with numerical results for 185.3Ah and 20Ah cells. Furthermore, we show the thermal behavior of cells without the finite element method (FEM) or finite volume method (FVM) by adopting the lumped capacitance method (LCM).

Scale-Up Factor for Seismic Analysis of Building Structure for Various Coordinate Systems (건축구조물의 지진해석에서 좌표축의 설정에 따른 보정계수 산정법)

  • Yu, Il-Hyang;Lee, Dong-Guen;Ko, Hyun;Kim, Tae-Ho
    • Journal of the Earthquake Engineering Society of Korea
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    • v.11 no.5
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    • pp.33-47
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    • 2007
  • In a practical engineering, the equivalent static analysis (E.S.A) and the response spectrum analysis (R.S.A) are generally used for the seismic analysis. The base shears obtained from the E.S.A are invariable no matter how the principal axes of building structures are specified on an analysis program while those from the R.S.A are variable. Accordingly, the designed member size may be changed by how an engineer specify the principal axes of a structure when the R.S.A is used. Moreover, the base shears in the normal direction to the excitation axis are sometimes produced even when an engineer performs a response spectrum analysis in only one direction. This tendency makes the base shear, which is used to calculate the scale-up factor, relatively small. Therefore the scale-up factor becomes larger and it results in uneconomical member sizes. To overcome these disadvantages of the R.S.A, an alternative has been proposed in this study. Three types of example structures were adapted in this study, i.e. bi-direction symmetric structure, one-direction antisymmetric structure and bi-direction antisymmetric structure. The seismic analyses were performed by rotating the principal axes of the example structures with respect to the global coordinate system. The design member forces calculated with the scale-up factor used in the practice were compared with those obtained by using the scale-up factor proposed in this study. It can be seen from this study that the proposed method for the scale-up factor can provide reliable and economical results regardless of the orientation of the principal axes of the structures.

Penetration Model in Soil Considering J-hook Trajectory (토양 내 J-hook 궤적을 고려한 침투해석 모델 개발)

  • Sung, Seung-Hun;Ji, Hun
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.35 no.1
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    • pp.1-8
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    • 2022
  • This study proposes a penetration model in soil considering the wake separation and reattachment based on the integrated force law (IFL). Rigid body dynamics, the IFL, and semi-empirical resistance function about soil are utilized to formulate the motion of the hard projectile. The model can predict the trajectory in soil considering the spherical cavity expansion phenomenon under various oblique angles and angles of attack (AOA). The Mohr-Coulomb yield model is utilized as the resistance function of the soil. To confirm the feasibility of the proposed model, a comparative study is conducted with experimental results described in the open literature. From the comparative study, the penetration depth estimated from the proposed model had about 13.4% error compared to that of the experimental results. In general, the finite element method is widely used to predict the trajectory in soil for a projectile. However, it takes considerable time to construct the computational model for the projectile and perform the numerical simulation. The proposed model only needs to the dimension of the projectile and can predict the trajectory of the projectile in a few seconds.

Structural Studies of Membrane Protein by Solid-state NMR Spectroscopy (고체상 핵자기공명 분광법을 이용한 막단백질의 구조연구)

  • Kim, Yongae
    • Analytical Science and Technology
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    • v.17 no.5
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    • pp.388-392
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    • 2004
  • Structural studies of membrane proteins, importantly involving interpretation of genomics information, many signaling pathway and major drug target for drug discovery, are having difficulty in characterizing the function using conventional solution nmr spectroscopy and x-ray crystallography because phospholipid bilayers hindered fast tumbling and crystallization. Here, we studied the structure of the pf1 coat protein in oriented phospholipid bilayers by home-built solid-state NMR probe. Bacteriophage pf1 was purified from Paeudomonas Aeruginosa and coat protein of bacteriophage pf1 was isolated from DNA and other proteins.