• Title/Summary/Keyword: interface parameters

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Performance Analysis Model for Flap Actuation System using MATLAB/Simulink

  • Cho, Hyunjun;Joo, Choonshik;Kim, Kilyeong;Park, Sangjoon
    • International Journal of Aerospace System Engineering
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    • v.4 no.1
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    • pp.13-21
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    • 2017
  • In this paper, we present some results on performance analysis for flap actuation system of aircraft. For this, by utilizing MATLAB/Simulink solution, which is widely used physical model-based design tool, we particularly construct the architecture of the analysis model consisting of the main three phases: 1)commanding and outer-controlling the flap angle through flight control computer; 2)generating hydraulic/mechanical power through control module and power drive unit; 3)transmitting torque and actuating the flap through torque tube and rotary geared actuators. For mimicking the motion of the actual flap, we apply each mechanical component, which is already being used in actual aircraft, to our performance analysis model so that it guarantees the congruency of the simulation results. That is, we reflect the actual specifications of flap hardware and software as parameters of the model. Finally, simulation results are presented to illustrate the model.

Hardness and Microstructure evolution of SUS630 Stainless steel Fabricated by Directed Energy Deposition (Direct energy deposition 공정으로 제조된 SUS630 스테인리스강 적층조형체의 경도 및 미세조직 연구)

  • Back, Seong Eun;Noh, Kyung-Ho;Park, Jin Yong;Cho, Yong Ju;Kim, Jeoung Han
    • Journal of Powder Materials
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    • v.25 no.3
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    • pp.220-225
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    • 2018
  • The microstructure and mechanical characteristics of SUS630 specimens fabricated using the direct energy deposition (DED) process are investigated. In DED, several process parameters such as laser scan speed, chamber gas flow, powder carrier gas flow, and powder feed rate are kept fixed; the laser power is changed as 150 W, 180 W, and 210 W. As the laser power increases, the surface becomes smooth, the thickness uniformity improves, and the size and number of pores decreases. With the increase in laser power, the hardness deviation decreases and the average hardness increases. The microstructure of the material is columnar; pores are formed preferentially along the columnar interface. The lath-martensite phase governs the overall microstructure. The volumetric fraction of the retained austenite phase is measured to increase with the increase of laser input power.

Wear Characteristics of Wheel/Rail Material under Dry and Wet Conditions (건식 및 수분조건에 따른 차륜/레일의 마모특성 평가)

  • Seo, Jung Won;Kwon, Suk Jin;Jun, Hyun Kyu;Lee, Dong Hyeong
    • Journal of the Korean Society for Precision Engineering
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    • v.33 no.7
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    • pp.541-549
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    • 2016
  • Rolling contact fatigue and wear on rails are inevitable in railway operations due to excessive wheel-rail contact stress. The wear is influenced by vehicle speed, contact pressure, environmental conditions, and many other factors. Speeding on a curved track causes many problems such as wear on the gauge of the rail and rolling contact fatigue. Managing environmental conditions can reduce problems on the wheel and rail interface. In this study, the wear characteristics of wheel and rail materials were investigated by twin-disc testing using various parameters. The results of the wear test indicated that the wear rate under dry conditions was larger than that under wet conditions. We found that contact fatigue damage occurred on the rail in dry conditions, however, the surface of the specimen under water remained smooth. Also, the friction coefficient in dry conditions was larger than in wet conditions.

Dynamics of the system consisting of the hollow cylinder and surrounding infinite elastic medium under action an oscillating moving ring load on the interior of the cylinder

  • Akbarov, Surkay D.;Mehdiyev, Mahir A.
    • Coupled systems mechanics
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    • v.7 no.5
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    • pp.525-554
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    • 2018
  • The paper deals with the study of the dynamics of the oscillating moving ring load acting in the interior of the hollow circular cylinder surrounded by an elastic medium. The axisymmetric loading case is considered and the study is made by employing the exact equations and relations of linear elastodynamics. The focus is on the influence of the oscillation of the moving load and the problem parameters such as the cylinder's thickness/radius ratio on the critical velocities. At the same time, the dependence between the interface stresses and load moving velocity under various frequencies of this load, as well as the frequency response of the mentioned stresses under various load velocity are investigated. In particular, it is established that oscillation of the moving load can cause the values of the critical velocity to decrease significantly and at the same time the oscillation of the moving load can lead to parametric resonance. It is also established that the critical velocity decreases with decreasing of the cylinder's thickness/radiusratio.

Establishing a stability switch criterion for effective implementation of real-time hybrid simulation

  • Maghareh, Amin;Dyke, Shirley J.;Prakash, Arun;Rhoads, Jeffrey F.
    • Smart Structures and Systems
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    • v.14 no.6
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    • pp.1221-1245
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    • 2014
  • Real-time hybrid simulation (RTHS) is a promising cyber-physical technique used in the experimental evaluation of civil infrastructure systems subject to dynamic loading. In RTHS, the response of a structural system is simulated by partitioning it into physical and numerical substructures, and coupling at the interface is achieved by enforcing equilibrium and compatibility in real-time. The choice of partitioning parameters will influence the overall success of the experiment. In addition, due to the dynamics of the transfer system, communication and computation delays, the feedback force signals are dependent on the system state subject to delay. Thus, the transfer system dynamics must be accommodated by appropriate actuator controllers. In light of this, guidelines should be established to facilitate successful RTHS and clearly specify: (i) the minimum requirements of the transfer system control, (ii) the minimum required sampling frequency, and (iii) the most effective ways to stabilize an unstable simulation due to the limitations of the available transfer system. The objective of this paper is to establish a stability switch criterion due to systematic experimental errors. The RTHS stability switch criterion will provide a basis for the partitioning and design of successful RTHS.

Mechanical Properties of Dissimilar Friction Welded Steel Bars in Relation to Post Weld Heat Treatment (이종 마찰용접 강봉재의 후열처리에 따른 기계적 특성)

  • Kong Yu-Sik;Kim Seon-Jin
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.30 no.4 s.247
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    • pp.402-408
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    • 2006
  • Dissimilar friction welding were produced using 15(mm) diameter solid bar in chrome molybedenum steel(KS SCM440) to carbon steel(KS S45C) to investigate their mechanical properties. The main friction welding parameters were selected to endure good quality welds on the basis of visual examination, tensile tests, Vickers hardness surveys of the bond of area and H.A.Z and microstructure investigations. The specimens were tested as-welded and post-weld heat treated(PWHT). The tensile strength of the friction welded steel bars was increased up to 100% of the S45C base metal under the condition of all heating time. Optimal welding conditions were n=2,000(rpm), $P_1=60(MPa),\;P_2=100(MPa),\;t_1=4(s),\;t_2=5(s)$ when the total upset length is 5.4 and 5.7(mm), respectively. The peak of hardness distribution of the friction welded joints can be eliminated by PWHT. Two different kinds of materials are strongly mixed to show a well-combined structure of macro-particles without any molten material and particle growth or any defects.

An Easy-to-Use Three-Dimensional Molecular Visualization and Analysis Program: POSMOL

  • Lee, Sang-Joo;Chung, Hae-Yong;Kim, Kwang S.
    • Bulletin of the Korean Chemical Society
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    • v.25 no.7
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    • pp.1061-1064
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    • 2004
  • Molecular visualization software has the common objective of manipulation and interpretation of data from numerical simulations. They visualize many complicated molecular structures with personal computer and workstation, to help analyze a large quantity of data produced by various computational methods. However, users are often discouraged from using these tools for visualization and analysis due to the difficult and complicated user interface. In this regard, we have developed an easy-to-use three-dimensional molecular visualization and analysis program named POSMOL. This has been developed on the Microsoft Windows platform for the easy and convenient user environment, as a compact program which reads outputs from various computational chemistry software without editing or changing data. The program animates vibration modes which are needed for locating minima and transition states in computational chemistry, draws two and three dimensional (2D and 3D) views of molecular orbitals (including their atomic orbital components and these partial sums) together with molecular systems, measures various geometrical parameters, and edits molecules and molecular structures.

Extraction of electrical parameters as a function of post-annealing in organic solar cells (유기 태양전지의 후열처리온도에 따른 전기적 Parameter들의 추출)

  • Kim, Dong-Young;Kim, Ji-Hwan;Lee, Hye-Jee;Kim, Hae-Jin;Sohn, Sun-Young
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2009.06a
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    • pp.460-461
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    • 2009
  • We studied the effects of post-annealing treatment on poly(3-hexylthiophene)(P3HT, donor):[6,6]-phenyl $C_{61}$ butyric acid methyl ester(PCBM, acceptor) blend film as an active layer in the organic solar cells(OSCs). For the formation of the active layer, 3 wt.% P3HT:PCBM solution in chlorobenzene were deposited by spin-coating method. In order to optimize the performance of OSCs, the P3HT crystallization and the redistribution of PCBM cluster at P3HT:PCBM composition as a function of post-annealing condition from room temperature to $200^{\circ}C$ were measured by the Hall effect and the UV-vis Spectrophotometer. We thought that the improved efficiency in the OSCs with post-annealing treatment at $150^{\circ}C$ can be explained by the efficient separation or collection of the photogenerated excitons at donor-acceptor interface by P3HT crystallization.

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Feature extraction and Classification of EEG for BCI system

  • Kim, Eung-Soo;Cho, Han-Bum;Yang, Eun-Joo;Eum, Tae-Wan
    • Proceedings of the Korean Institute of Intelligent Systems Conference
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    • 2003.09a
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    • pp.260-263
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    • 2003
  • EEC is an electrical signal, which occurs during information processing in the brain. These EEG signals has been used clinically, but nowadays we are mainly studying Brain-Computer Interface(BCI) such as interfacing with a computer through the EEG controlling the machine through the EEG The ultimate purpose of BCI study is specifying the EEG at various mental states so as to control the computer and machine. A BCI has to perform two tasks, the parameter estimation task, which attemps to describe the properties of the EEG signal and the classification task, which separates the different EEC patterns based on the estimated parameters. First, we have to do parameter estimation of EEG to embody BCI system. It is important to improve performance of classifier, But, It is not easy to do parameter estimation by reason of EEG is sensitivity and undergo various influences. Therefore, this research should do parameter estimation and classification of the EEG to use various analysis algorithm.

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Failure Characteristics of Foundation System Reinforced with Stone Columns (쇄석말뚝으로 보강된 기초시스템의 파괴 거동)

  • Shin, Bang Woong;Bae, Woo Seok
    • Journal of the Korean GEO-environmental Society
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    • v.2 no.3
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    • pp.71-80
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    • 2001
  • The quantitative analysis of bearing capacity with stone column-mat is not ease because the bearing capacity of stone column is affected by so many parameters. The bearing capacity of stone column is mainly governed by horizontal resistance along the interface with soil. Also, this foundation system is affected by geometric factors such as column spacing, embedment ratio and failure surface inclination. Therefore, in this study, critical length and the effect of failure surface inclination was studied with single and group end bearing stone columns by loading tests. Results of model tests are compared to the present theoretical methods and are examined with FEM analysis.

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