• 제목/요약/키워드: Mechanical engineering

검색결과 42,680건 처리시간 0.096초

Passive seismic protection systems with mechanical metamaterials: A current review

  • Guevara-Corzo, Jeffrey J.;Begambre-Carrillo, Oscar J.;Garcia-Sanchez, Jesus A.;Sanchez-Acevedo, Heller G.
    • Structural Engineering and Mechanics
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    • 제82권4호
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    • pp.417-434
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    • 2022
  • In this work, a review of mechanical metamaterials and seismic protection systems that use them is carried out, focusing on passive protection systems. During the last years, a wide variety of classical systems of seismic protection have demonstrated to be an effective and practical way of reducing the seismic vulnerability of buildings, maintaining their health and structural integrity. However, with the emergence of metamaterials, which allow obtaining uncommon mechanical properties, new procedures and devices with high performance have been developed, reducing the seismic risk through novel approaches such as: seismic shields and the redirection of seismic waves; the use of stop band gaps and the construction of buried mass resonators; the design of pentamodal base isolators. These ideas are impacting traditional areas of structural engineering such as the design and building of highly efficient base isolation systems. In this work, recent advances in new seismic protection technologies and researches that integrate mechanical metamaterials are presented. A complete bibliometric analysis was carried out to identify and classify relevant authors and works related with passive seismic protection system based on mechanical metamaterial (pSPSmMMs). Finally, possible future scenarios for study and development of seismic isolators based on mechanical metamaterials are shown, identifying the relevant topics that have not yet been explored, as well as those with the greatest potential for future application.

혈액펌프 성능평가를 위한 실험장치 구성 (An Experimental Setup for Measuring the Performance of Blood Pumps)

  • 김성길;홍석빈;김태홍;김원정;강성원;강신형;허남건
    • 한국유체기계학회 논문집
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    • 제19권6호
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    • pp.55-60
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    • 2016
  • We present an experimental setup for measuring the mechanical performance of centrifugal blood pumps. Using a 3D printer to construct supporting parts and magnetic couplings, we developed the measurement setup that can be used for various types of blood pumps. The experimental setup is equipped with sensors to measure a variety of mechanical characteristics of blood pumps including pressure, flow rate, torque, temperature, and rotating speed. Our experimental measurements for two commercial blood pumps are consistent with data provided by manufacturers, which indicates that the our setup offers the accurate measurements of blood pump performance. Utilizing the experimental setup, we tested aqueous glycerin solutions mimicking the density and viscosity of blood, which enabled us to predict the difference in operations using water and blood.

Error Analysis of a Parallel Mechanism Considering Link Stiffness and Joint Clearances

  • Park, Woo-Chun;Song, Jae-Bok;Daehie Hong;Shim, Jae-Kyung;Lim, Seung-Reung;Kyungwoo Kang;Park, Sungchul
    • Journal of Mechanical Science and Technology
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    • 제16권6호
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    • pp.799-809
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    • 2002
  • In order to utilize a parallel mechanism as a machine tool component, it is important to estimate the errors of its end-effector due to the uncertainties in parts. This study proposes an error analysis for a new parallel device, a cubic parallel mechanism. For the parallel device, we consider two kinds of errors. One is a static error due to link stiffness and the other is a dynamic error due to clearances in the parts. In this study, we propose a stiffness model for the cubic parallel mechanism under the assumption that the link stiffness is a linear function of the link length. Also, from the fact that the errors of u-joints and spherical joints are changed with the direction of force acting on the link, they are regarded as a part of link errors, and then the error model is derived using forward kinematics. Lastly, both the error models are integrated into the total error, which is analyzed with a test example that the platform moves along a circular path. This analysis can be used in predicting the accuracy of other parallel devices.

연마불균일도에 영향을 미치는 패드 표면특성에 관한 연구 (The Effect of Pad Surface Characteristics on Within Wafer Non-uniformity in CMP)

  • 박기현;박범영;정재우;이현섭;정석훈;정해도;김형재
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
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    • pp.38-39
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    • 2005
  • We have investigated the effect of the pad surface characteristics such as roughness, groove density and wear of pad on within wafer non-uniformity(WIWNU) in chemical mechanical polishing(CMP). We found that WIWNU increases as pad surface roughness($R_{pk}$; Reduced peak height) increases in an early stage of polishing. But after polishing time goes to a certain extent, WIWNU decreases as uniformity of pad surface roughness. Also, groove of pad has effect on relative pad stiffness although original mechanical properties of pad are unchanged by grooving. WIWNU decreases as relative pad stiffness decreases. In addition, conditioning process causes non-uniform wear of pad during in CMP. The profile of pad wear has a significant effect on WIWNU.

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MEMS CMP에서 모니터링 시스템을 이용한 슬러리 특성 (The Surry Characteristic Using Monitoring System in MEMS CMP)

  • 박성민;정석훈;박범영;이상직;정원덕;장원문;정해도
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2006년도 하계학술대회 논문집 Vol.7
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    • pp.573-574
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    • 2006
  • The planarization technology of Chemical-mechanical polishing(CMP), used for the manufacturing of multi-layer various material interconnects for Large-scale Integrated Circuits (LSI), is also readily adaptable as an enabling technology in MicroElectroMechanical System (MEMS) fabrication, particularly polysilicon surface micromachining. However, general LSI device CMP has partly distinction aspects, the pattern scale and material sorts in comparison with MEMS CMP. This study performed preliminary CMP tests to identify slurry characteristic used in general IC device. The experiment result is possible to verify slurry characteristic in MEMS structure material.

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