• Title/Summary/Keyword: Bending

Search Result 8,336, Processing Time 0.519 seconds

A Study on the Design and Development of Three Dimensional Bending Machine (3차원 Bending Machine 설계 및 개발에 관한 연구)

  • 이춘만;임상헌;김현진
    • Proceedings of the Korean Society of Precision Engineering Conference
    • /
    • 2004.10a
    • /
    • pp.1448-1451
    • /
    • 2004
  • This study is concerned about the design and development of three dimensional bending machine. The purpose of this study is design and development of three-dimensional bending machine by analysis of bending process and structural analysis simulation. The analysis is carried out by FEM simulation using DEFORM and CATIA V5 software. Based on this study, the three dimensional bending machine was developed. In order to evaluate a performance and reliability of the developed three dimensional bending machine, we used laser interferometer and three axial measuring system.

  • PDF

The Development of Inner Structure of Metallic Sandwich Plates for Bending (굽힘성형을 위한 금속 샌드위치판재의 내부구조재 개발)

  • Seong, D.Y.;Jung, C.G.;Yoon, S.J.;Shim, D.S.;Lee, S.H.;Ahn, D.G.;Yang, D.Y.
    • Transactions of Materials Processing
    • /
    • v.15 no.2 s.83
    • /
    • pp.126-131
    • /
    • 2006
  • Metallic sandwich plates are ultra-light materials not only with high strength and stiffness but also with other multifunctional physical properties. Inner dimpled shell structure can be fabricated by a piecewise sectional forming process, and then bonded with face sheets of the same material by resistance welding. Possible region for bending and limit radius of curvature are defined to compare the formability of sandwich plates. Tests have shown that sandwich plates with inner dimpled shell structure subject to bending have longer possible region for bending and smaller limit radius of curvature than other types of sandwich plates. The proposed inner dimpled shell structure is shown to have better formability of sandwich plates for bending than other types inner structures.

Strain characteristics of Ag sheathed Bi-2223 superconducting tapes according to bending mode (굽힘모드에 따른 Ag 시스 Bi-2223 초전도장척 테이프의 굽힘 변형률 특성)

  • Shin, H.S.;Choi, S.Y.;Ko, D.K.;Ha, H.S.;Ha, D.W.;Oh, S.S.
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
    • /
    • 2002.04a
    • /
    • pp.50-54
    • /
    • 2002
  • Influences of bending strain on the critical current ($I_c$) in Ag-sheathed Bi-2223 superconducting tapes at 77K were investigated. The effect of bending mode on the bending strain characteristics was discussed in viewpoints of sample geometry, n-value and damage morphology. Especially, in this paper, we reported the $I_c$ behavior in Ag alloy sheathed Bi-2223 multifilamentary superconducting tapes under hard bending. As a result, $I_c$ degradation behavior of the hard bending appeared remarkably than the case of easy bending, but it did not influence greatly on the n-value.

  • PDF

Effect of pre-bending on the properties of impact damage in CFRP laminates (CFRP적층판의 충격손상특성 및 손상거동에 미치는 초기굽힘의 영향)

  • 신형섭;서창민;황남성
    • Transactions of the Korean Society of Mechanical Engineers
    • /
    • v.18 no.5
    • /
    • pp.1144-1149
    • /
    • 1994
  • Damage caused in CFRP laminates by low energy impact of steel ball are investigated ultrasonically. Two types of laminated specimens having different stacking sequence are used as a target material. The effects of pre-bending on the behaviors of impact damage are specifically discussed. The initiation and progagation behaviors of delamination were largely dependent upon the bending rigidity of each specimen. Specimen C having higher bending rigidity produced larger delamination damage than the Specimen D having relatively low bending rigidity, however it was little for the Specimen C. Application of pre-bending increased the apparent bending rigidity of target during impacting, it produced delamination at lower impact energy level compared to the case of no preload.

The characteristics of bending collapse of aluminum/GFRP hybrid tube (알루미늄/GFRP 혼성튜브의 굽힘붕괴 특성)

  • 송민철;이정주
    • Proceedings of the Korean Society For Composite Materials Conference
    • /
    • 2000.11a
    • /
    • pp.84-87
    • /
    • 2000
  • Square tubes used for vehicle structure components have an important role on keeping its stiffness and preserving occupant safety in vehicle collision and rollover in which it experience axial collapse, bending collapse or both. Bending collapse, which absorbs kinetic energy of the impact and retains a survival space for the occupant, is a dominant failure mode in oblique collision and rollover. Thus, in this paper, the bending collapse characteristics such as the maximum bending moment and energy absorption capacity of the square tube replaced by light-weight material were evaluated and presented. The bending test of cantilever tubes which were fabricated with aluminum, GFRP and aluminum/ GFRP hybrid by co-curing process was performed. Then the maximum bending moment and the energy absorption capacity from the moment-angle curve were evaluated. Based on the test results, it was found that aluminum/ GFRP hybrid tube can show better specific energy absorption capacity compared to the pure aluminum or GFRP tube and can convert unstable collapse mode which may occur in pure GFRP tube to stable collapse mode like a aluminum tube in which plastic hinge is developed.

  • PDF

A Study on Characteristics of Bending Deformation in Cylindrical Die (원통형 다이를 이용한 굽힘의 변형특성에 관한 연구)

  • Kim, Yang-Woo;Lee, Dae-Su
    • Transactions of the Korean Society of Machine Tool Engineers
    • /
    • v.17 no.4
    • /
    • pp.59-66
    • /
    • 2008
  • This paper has proposed a new parameter to interpret the effects of plastic deformation in bending of strips in cylindrical die and punch. With reference to the parameter, we have provided an insight on the separation between strips and punches, the occurrence of the multi-point bending during the process of deformation, the final shapes of strips, and the springback ratios. Also using the parameter, we have considered the different effects between the bending deformation in the cylindrical die and the bending deformation due to pure bending.

The study of bending and buckling behavior of sandwich structure according to design parameter variation (설계변수 변화에 따른 샌드위치 구조물의 굽힘 및 좌굴 거동에 관한 연구)

  • 한근조;안성찬;안성찬;김진영
    • Proceedings of the Korean Society of Precision Engineering Conference
    • /
    • 1997.10a
    • /
    • pp.841-844
    • /
    • 1997
  • Sandwich structure is widely used in various fields of industry due to its excellent strength and stiffness compared with weight. We studied the buckling and bending behavior with respect to the variation of design parameters such as length, height, and thickness of honeycomb sandwich core. We found that as the density and the thickness of core become higher, the value of critical bucking load increased significantly. We found that the effect of bending stress due to critical buckling load resulted in high bending stress and the value of bending stress decreased in half according to the increase of length of core. The effect by bending stress is dominant above the portion of the intersection line between bending stress and the effect of buckling is dominant below the potion of it. We could get proper thickness ratio and density of core according to applied load conditions.

  • PDF

Bending Properties of ZnO Nanorod using Nano-Manipulator (나노조작기를 이용한 ZnO 나노막대 굽힘 물성 평가)

  • Jeon, Sang-Gu;Jang, Hoon-Sik;Kwon, Oh-Heon;Nahm, Seung-Hoon
    • Proceedings of the KSME Conference
    • /
    • 2008.11a
    • /
    • pp.260-263
    • /
    • 2008
  • The bending test of an individual ZnO nanorod was performed with a nano-manipulator and a force sensor inside the scanning electron microscope (SEM), and the bending properties of ZnO nanorod were also discussed. The ZnO nanorod used in this experiment was fabricated by means of solution base process. The force sensor used for bending test of ZnO nanorod was typed with cantilever. The force sensor was mounted on the nano-manipulator. The nano-manipulator was controlled and manipulated by a personal computer. The each end of an individual ZnO nanorod was attached on the rigid support and the tip of the force sensor with an electron beam exposure, and then the bending test was carried out by controlling of the nano-manipulator. The bending modulus of a ZnO nanorod was calculated at 69.35GPa after the bending test.

  • PDF

A Study on the Design of Three-Dimensional Bending Machine (3차원 Bending Machine 설계에 관한 연구)

  • Lee, Choon-Man;Lim, Sang-Heon;Park, Dong-Keun
    • Proceedings of the KSME Conference
    • /
    • 2003.11a
    • /
    • pp.1852-1857
    • /
    • 2003
  • This study is concerned about the development of three-dimensional bending machine for heat exchanger. Recently, three-dimensional bending is required for various heat exchanger. The purpose of this study is design of three-dimensional bending machine by analysis of bending process and structural analysis simulation. The analysis is carried out by FEM simulation using DEFORM and CATIA V5 software. The copper-tube is modeled by shell elements and the machine is modeled by placing proper shell and solid finite elements and fictitious mass properties to represent the real one. The final results of analysis are applied to the design of three-dimensional bending machine and the machine is successfully developed.

  • PDF

Static Bending 영향에 따른 Ti/Au의 전기적 특성 변화

  • Kim, Sang-Seop;Choe, Byeong-Deok
    • Proceedings of the Korean Vacuum Society Conference
    • /
    • 2014.02a
    • /
    • pp.370.2-370.2
    • /
    • 2014
  • 본 연구에서는 Bending 시간에 따른 Ti/Au의 전기적 특성 변화에 대한 실험을 진행하였다. 전기적 특성을 평가하기 위해 PET 기판 위에 Ti/Au을 Greek Bridge와 Line Bridge를 합친 Cross Bridge 형태로 증착하였고, Cross Bridge의 Line을 bending하여 시간 경과에 따른 정적인(static) bending 영향을 확인하였다. Bending은 0~100시간까지 진행하였고, Line의 width를 200, 400, 800, $1000{\mu}m$로 가변하여 시간에 따른 비저항의 변화를 측정하였다. 실험결과 Bending시간이 길어짐에 따라 비저항이 감소하였고, 일정시간에서 크게 감소하며, 그 이후에는 포화되는 경향을 보였다. 또한 Width가 증가함에 따라 비저항의 변화가 컸다. 800 um, $1000{\mu}m$에서는 bending 직후 비저항이 초기대비 약 90%까지 떨어졌으며 100시간 후에는 80%까지 감소하였다. 100시간 뒤 Width에 따라 초기대비 비저항이 78%~91%까지 감소하는 것을 확인하였다.

  • PDF