• 제목/요약/키워드: Bending

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형상기억합금을 이용한 bending 액츄에이터의 제작 및 컨트롤을 위한 기초실험 (Fabrication or Bending Actuator Using Shape Memory Alloy and Basic Experiment or Control)

  • 김명순;최낙빈;김대웅;이상훈;이승기
    • 대한의용생체공학회:학술대회논문집
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    • 대한의용생체공학회 1997년도 추계학술대회
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    • pp.497-500
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    • 1997
  • In this paper, we proposes a bending actuator using shape memory alloy coil-type springs. By the heating of two shape memory alloy coil-type springs sequentially, the bending and stretching motion of the actuator is possible. We measure the bending angle and repeated bending motion with the various currents. Furthermore, we control the bending angle of the 1 directional bending actuator with sensors. The performance of the actuator has been characterized or the possible application for catheter.

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스테인리스 판재의 굽힘공정에 관한 실험적 연구 (An Experimental Study on the Bending Process of Stainless Steel Sheets)

  • 김호윤;황범철;배원병;강충길;변천덕
    • 한국정밀공학회지
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    • 제16권2호통권95호
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    • pp.82-86
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    • 1999
  • An experimental study has been carried out to reduce bending load, surface roughness and springback in bending process of stainless steel sheets. A U-bending test has been performed to investigate appropriate process parameters for getting better surfaces and accurate dimensions of stainless steel products. In the test, selected process parameters are die material, lubricant, and die clearance. Die materials used in the test are STD11(HRC60), STD11(TiCN), and AMPCO. From the test results, we can suggest that AMPCO dies are most suitable for reducing bending load and surface roughness of stainless steel sheets. And STD11 dies are favorable for avoiding spring-back in the stainless steel sheet-bending.

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Analysis of dry friction hysteresis in a cable under uniform bending

  • Huang, Xiaolun;Vinogradov, Oleg
    • Structural Engineering and Mechanics
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    • 제2권1호
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    • pp.63-80
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    • 1994
  • A cable is considered as a system of helical wires and a core with distributed dry friction forces at their interfaces. Deformations of the cable subjected to a uniform bending are analyzed. It is shown that there is a critical bending curvature when a slip at the wire-core interface occurs. It originates at the neutral axis of the cross section of the cable and then spreads symmetrically over the cross section with the increase of bending. The effect of slippage on the cable stiffness is investigated. This model is also used to analyze a cable under the quasi-static cyclic bending. Explicit expression for the hysteretic losses per cycle of bending is derived. Numerical examples are given to show the influence of dry friction and helix angle on the bending stiffness and hysteretic losses in the cable.

A Study on the Bending and Seismic Performance of High Performance Cold Forming Composite Beam

  • Choi, Young Han;Kim, Sung Bae;Hong, Hyung Ju;Kim, Sang Seup
    • 국제강구조저널
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    • 제18권5호
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    • pp.1772-1783
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    • 2018
  • Nowadays, the researches about composite structure system are being implemented in various fields, and many steel structures are designed based on that. In this study, the bending and seismic performance of the newly developed high-performance cold forming composite beam are evaluated by several experiments. As a result of the bending performance test, the bending moment of beam was increased stably depending on the depth and plate thickness of beam, and it is considered that the bending moment can be evaluated by the equation of a composite beam design. As a result of the seismic performance test, it was verified that sufficient seismic performance was obtained despite the increase of a negative moment rebar and depth of beam. In addition, the nominal bending moment has obtained the strength above the plastic bending moment, and also the plastic rotation angle has satisfied the requirement of composite intermediate moment frame.

Characteristic responses of critical current in REBCO coated conductor tapes under tensile/compressive bending strains at 77 K

  • Diaz, Mark Angelo;Shin, Hyung Seop;Lee, Jae-Hun
    • 한국초전도ㆍ저온공학회논문지
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    • 제20권4호
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    • pp.31-35
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    • 2018
  • When REBCO coated conductors (CCs) are applied to superconducting devices such as coils and magnets, they are subjected to deformation in various modes such as compression/tension bending, uniaxial/transverse tension and torsion. Despite outstanding performances by REBCO CC tapes, their electromechanical properties have been evaluated primarily under uniaxial tension, therefore data about the critical current ($I_c$) response in the compressive strain region are lacking. In this study, the characteristic responses of $I_c$ in REBCO CC tapes under bending strains in the range from tensile to compressive were evaluated. The springboard bending beam was used, wherein the CC tape sample was soldered onto the surface of the springboard. A Goldacker-type bending test rig, which lacks a support holding the sample during testing, was used as a comparator. Degradation in $I_c$ behaviors, including strain sensitivity, in differently processed REBCO CC tapes were examined based on the test rig used.

가공면미세결함의 나노 인프로세스 측정을 위한 AFM시스템의 개발 (Development of an AFM-Based System for Nano In-Process Measurement of Defects on Machined Surfaces)

  • 권현규;최성대;박무훈
    • 대한기계학회논문집A
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    • 제26권3호
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    • pp.537-543
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    • 2002
  • This paper examines a new in-process measurement system for the measurement of micro-defects on the surfaces of brittle materials by using the AFM (Atomic Force Microscopy). A new AFM scanning stage that can also perform nano-scale bending of the sample was developed by adding a bending unit to a commercially available AFM scanner. The bending unit consists of a PZT actuator and sample holder, and can perform static and cyclic three-point bending. The true bending displacement of the bending unit is approximately 1.8mm when 80 volts are applied to the PZT actuator. The frequency response of the bending unit and the stress on the sample were also analyzed, both theoretically and experimentally. Potential surface defects of the sample were successfully detected by this measurement system. It was confirmed that the number of micro-defects on a scratched surface increases when the surface is subjected to a cyclic bending load.

컨테이너 운반선 해치-커버 제작시 전 굽힘 변형 거동에 관한 연구 (Behavior of Global Bending Distortion of Hatch-cover in Container Carrier during Fabrication Process)

  • 이동주;김경규;신상범
    • Journal of Welding and Joining
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    • 제28권4호
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    • pp.41-48
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    • 2010
  • The purpose of this study is to establish the control method of the global bending distortion caused by fabrication process of hatch-cover in a container ship. In order to do it, the transitional behavior of global bending distortion in the deck of hatch-cover during fabrication process was measured by 3-dimensional measuring instrument. From the results, the principal factor controlling the global bending distortion was identified as the bending moment associated with the longitudinal shrinkage force and transverse shrinkage caused by welding and flame heating and the change of the centroid axis of hatch-cover in each fabrication process. Therefore, in this study, with the predictive equations of the longitudinal shrinkage force and transverse shrinkage caused by welding and flame heating and the simplified thermo elastic method, the predictive method for the global bending distortion was established and verified by comparing with the measured result. Based on the results, the amount of reverse bending distortion of main stiffeners was determined to prevent the global bending distortion of hatch-cover.

매크로 벤딩 측정을 위한 금속 모세관 결합 광섬유 센서 (Fiber-optic macro-bending sensor aided by metal capillary)

  • 백승인;정윤찬;이병호
    • 한국광학회지
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    • 제12권4호
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    • pp.289-293
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    • 2001
  • 금속 모세관을 이용하여 일반적인 단일모드 광섬유를 결합함으로써 매크로 벤딩(macro bending)을 측정할 수 있는 광섬유 센서를 제작하였다. 매크로 벤딩에 의한 곡률 반지름이 감소함에 따라 각도 정렬 오차가 증가하여 투과되는 빛의 에너지가 감소하게 되므로 매크로 벤딩을 측정할 수 있었다. 측정 범위는 곡률 반지름 20mm에서 85mm의 영역이었다. 사용한 광섬유 격자의 중심 파장은 각각 1543.3 nm, 1549.5nm이고 최대 벤딩 손실을 -11.19dB였다. 이 센서와 광섬유 브래그 격자를 이용하여 다중점 측정이 가능함을 보였다.

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한국산 옻나무의 휨 및 종압축 강도적 성질(I) (The Bending and Compression Strength Properties in Rhus verniciflua(I))

  • 변희섭;시마다 마사히로;후시타니 마사미
    • 목재공학
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    • 제24권1호
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    • pp.95-99
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    • 1996
  • The bending and compression strength properties of two types Rhus verniciflua specimens, which made of no heat-treated wood and heat-treated wood for urushiol extraction, were measured. The heat-treated specimens were finger-jointed with either resorcinol-phenol or polyurethane resin adhesives, and the vertical type bending strength property was also measured in these specimens. The results obtained are as follows ; 1. The correlation coefficient between the compression strength and specific gravity in the specimens of no heat-treated and heat-treated wood was high. However there was no difference in compression strength property as affected by heat treatment. 2 The correlation coefficient between the bending strength and specific gravity in the specimens of no heat-treated and heat-treated wood was also high. However, there was no difference in bending strength property as affected by heat treatment. 3 The bending test showed high correlation between modulus of elasticity and modulus of rupture for the specimens made of no heat-treated and heat-treated wood. However, there was no difference in bending strength property between the specimens made of heat-treated and no heat-treated wood. 4. The efficiencies of bending strength test on the finger-jointed specimens of heat-treated wood with resorcinol-phenol and polyurethane resin adhesives were 0.85, 0.81. respectively.

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미드솔의 경도 및 두께가 스포츠화의 굽힘 특선에 미치는 영향 (The Effects of Hardness and Thickness of Midsole on the Bending Properties of Footwear)

  • 박차철
    • Elastomers and Composites
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    • 제41권2호
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    • pp.125-130
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    • 2006
  • 폴리우레탄(PU)과 폴리에틸렌비닐아세터이트(EVA) 미드솔이 스포츠화의 굽힘 강성에 미치는 영향을 이해하기 위하여 두께와 경도가 다른 중창으로 스포츠화를 제조하여 중창이 스포츠화의 굽힘특성에 미치는 영향을 고찰하였다. 스포츠화의 굽힘 모멘트는 굽힘 각도 $19^{\circ}$에서 나타나기 시작했으며, 이 초기 굽힘각도는 중창의 경도나 두께에 무관한 것으로 나타났다. 중창의 경도 및 두께가 증가함에 따라 스포츠화의 굽힘 모멘트의 값은 현저하게 증가하는 경향을 나타내었다. 발포체 시트나 미드솔 자체만으로 비교하였을 때보다 스포츠화의 굽힘 강성이 미드솔의 두께나 경도 등 신발의 설계에 따라 더욱 크게 영향을 받는 것으로 나타났다.