• Title/Summary/Keyword: Mechanical engineering

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A Fault Isolation Filter Design Using Left Eigenstructure Assignment Scheme

  • Choi, Jae-Weon;Lee, Shi-Bok;Lee, Dae-Young;Park, Un-Sik;Suh, Young-Soo
    • Journal of Mechanical Science and Technology
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    • v.14 no.6
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    • pp.583-589
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    • 2000
  • This paper presents a novel fault isolation filter design method using left eigenstructure assignment scheme proposed by the first author et al. The proposed method shows good performance of fault isolation with an exact eigenstructure assignment and guarantees that the corrupted ${\gamma}$ faults can be isolated simultaneously when the number of available output measurements are equal to or larger than (${\gamma}+1$). A numerical example for the fault isolation filter is also included.

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Tribological Properties of Chemical Vapor Deposited Graphene Coating Layer (화학기상증착법에 의하여 제조된 그래핀 성장층의 기계적 마모 특성)

  • Lee, Jong Hoon;Kim, Sun Hye;Cho, Doo Ho;Kim, Se Chang;Baek, Seung Guk;Lee, Jong Gu;Kang, Junmo;Choi, Jae-Boong;Seok, Chang Sung;Kim, Moon Ki;Koo, Ja Choon;Lim, Byeong Soo
    • Korean Journal of Metals and Materials
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    • v.50 no.3
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    • pp.206-211
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    • 2012
  • Graphene has recently received high attention as a promising material for various applications, and many related studies have been undertaken to reveal its basic mechanical properties. However, the tribological properties of graphene film fabricated by the chemical vapor deposition (CVD) method are barely known. In this study, the contact angle and frictional wear characteristics of graphene coated copper film were investigated under room temperature, normal air pressure, and no lubrication condition. The contact angle was measured by sessile drop method and the wear test was carried out under normal loads of 660 mN and 2940 mN, respectively. The tribological behaviors of a graphene coating layer were also examined. Compared to heat treated bare copper foil, the graphene coated one shows a higher contact angle and lower friction coefficient.

Design and Manufacturing of Mechanical Metamaterials: A Review (기계적 메타물질 설계 및 제조방안)

  • Kim, Min-Kyeom;Kim, Seunghyun;Yun, Jae-Won;Jeong, Hyo Gyun;Kwak, Min-Jun;Ahn, Yea-Lin;Park, Chan-Wook;Kim, Youn-Chul;Suhr, Jonghwan
    • Composites Research
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    • v.34 no.4
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    • pp.199-211
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    • 2021
  • As an additive manufacturing achieves technological advances, it enables to manufacture complex structures with saving a cost and time. Therefore, metamaterials, which has geometric complexity, have gradually gathered attention due to the unprecedented properties: the unprecedented mechanical, thermal, electromagnetic, and optical properties. The metamaterials could exhibit a high potential in engineering applications, and thus it has been steadily investigated to design or/and develop novel metamaterials. Here, mechanical metamaterials, which had been reported, were reviewed to suggest the way to design and fabricate the metamaterials for industrial applications.

Formation of Metal Mesh Electrodes via Laser Plasmonic Annealing of Metal Nanoparticles for Application in Flexible Touch Sensors (금속 나노 파티클의 레이저 플라즈모닉 어닐링을 통한 메탈메쉬 전극 형성과 이를 활용한 유연 터치 센서)

  • Seongmin Jeong;Yun Sik Hwang;Yu Mi Woo;Yong Jun Cho;Chan Hyeok Kim;Min Gi An;Ho Seok Seo;Chan Hyeon Yang;Kwi-Il Park;Jung Hwan Park
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.37 no.2
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    • pp.223-229
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    • 2024
  • Laser-induced plasmonic sintering of metal nanoparticles (NPs) holds significant promise as a technology for producing flexible conducting electrodes. This method offers immediate, straightforward, and scalable manufacturing approaches, eliminating the need for expensive facilities and intricate processes. Nevertheless, the metal NPs come at a high cost due to the intricate synthesis procedures required to ensure long-term reliability in terms of chemical stability and the prevention of NP aggregation. Herein, we induced the self-generation of metal nanoparticles from Ag organometallic ink, and fabricated highly conductive electrodes on flexible substrates through laser-assisted plasmonic annealing. To demonstrate the practicality of the fabricated flexible electrode, it was configured in a mesh pattern, realizing multi-touchable flexible touch screen panel.

Effects of Rotor Misalignment in Airgap on Dynamic Response of an Eccentric Rotor in BLDC Motor

  • Kim, Tae-Jong;Kim, Kyung-Tae;Hwang, Sang-Moon;Park, No-Gill;Lee, Shi-Bok
    • Journal of Mechanical Science and Technology
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    • v.16 no.12
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    • pp.1576-1582
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    • 2002
  • Vibration of a BLDC motor is a coupled phenomenon between mechanical characteristics and magnetic origins which takes place through the motor airgap. When relative misalignment of a rotor in the airgap is introduced during assembly, the dynamic characteristics of the motor system are affected. The rotor-motor system used in a washing machine is modeled using FETM and magnetic forces in a BLDC motor with radial rotor eccentricity are determined analytically The transient whirl responses of a rotor system supported on two roller bearings with relative misalignment in the motor airgap are investigated by considering mechanical and magnetic coupling effects. Results show that rotor misalignment in the airgap considerably affects the vibration of the rotor-motor system.

Introduction to Autonomous Vehicle PHAROS (자율주행자동차 PHAROS)

  • Ryu, Jee-Hwan;Park, Jang-Sik;Ogay, Dmitriy;Bulavintsev, Segey;Kim, Hyuk;Song, Young-wook;Yoon, Moon-Young;Kim, Jea-Seok;Kang, Jeon-Jin
    • Journal of Institute of Control, Robotics and Systems
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    • v.18 no.8
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    • pp.787-793
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    • 2012
  • This paper introduces the autonomous vehicle Pharos, which participated in the 2010 Autonomous Vehicle Competition organized by Hyundai-Kia motors. PHAROS was developed for high-speed on/off-road unmanned driving avoiding diverse patterns of obstacles. For the high speed traveling up to 60 km/h, long range terrain perception, real-time path planning and high speed vehicle motion control algorithms are developed. This paper describes the major hardware and software components of our vehicle.

Development of Korean Maintainability-Prediction Software for Application to the Detailed Design Stages of Weapon Systems (무기체계의 상세설계 단계에 적용을 위한 한국형 정비도 예측 S/W 개발)

  • Kwon, Jae-Eon;Kim, Su-Ju;Hur, Jang-Wook
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.20 no.10
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    • pp.102-111
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    • 2021
  • Maintainability is a major design parameter that includes availability as well as reliability in a RAM (reliability, availability, maintainability) analysis, and is an index that must be considered when developing a system. There is a lack of awareness of the importance of predicting and analyzing maintainability; therefore, it is dependent on past-experience data. To improve the utilization rate, maintainability must be managed as a key indicator to meet the user's requirements for failure maintenance time and to reduce life-cycle costs. To improve the maintainability-prediction accuracy in the detailed design stage, we present a maintainability-prediction method that applies Method B of the Military Standardization Handbook (MIL-HDBK-472) Procedure V, as well as a Korean maintainability-prediction software package that reflects the system complexity.