• Title/Summary/Keyword: directional bending

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Fabrication and forming of metallic sandwich plates with bi-directional corrugated inner structure (두 방향 주름구조를 내부구조로 하는 금속 샌드위치 판재의 제작 및 성형)

  • Seong, D.Y.;Jung, C.G.;Shim, D.S.;Yang, D.Y.;Kim, J.Y.;Kim, J.H.;Chung, W.J.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2006.05a
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    • pp.281-284
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    • 2006
  • Metallic sandwich plates with hi-directional inner structure are important new structures for forming applications. Bi-directional corrugated inner structures with less than 25% of relative density are fabricated by piecewise sectional forming process and then bonded with two face sheets by adhesive bonding. Drawing and U-bending experiments have performed and shown that the radius of curvature of sandwich plates is 75mm and sandwich plates are bended 90 degrees without collapse of inner structures. Bi-directional inner structures are suggested to improve formability of sandwich plates for bending and drawing.

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Bending analysis of bi-directional functionally graded Euler-Bernoulli nano-beams using integral form of Eringen's non-local elasticity theory

  • Nejad, Mohammad Zamani;Hadi, Amin;Omidvari, Arash;Rastgoo, Abbas
    • Structural Engineering and Mechanics
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    • v.67 no.4
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    • pp.417-425
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    • 2018
  • The main aim of this paper is to investigate the bending of Euler-Bernouilli nano-beams made of bi-directional functionally graded materials (BDFGMs) using Eringen's non-local elasticity theory in the integral form with compare the differential form. To the best of the researchers' knowledge, in the literature, there is no study carried out into integral form of Eringen's non-local elasticity theory for bending analysis of BDFGM Euler-Bernoulli nano-beams with arbitrary functions. Material properties of nano-beam are assumed to change along the thickness and length directions according to arbitrary function. The approximate analytical solutions to the bending analysis of the BDFG nano-beam are derived by using the Rayleigh-Ritz method. The differential form of Eringen's non-local elasticity theory reveals with increasing size effect parameter, the flexibility of the nano-beam decreases, that this is unreasonable. This problem has been resolved in the integral form of the Eringen's model. For all boundary conditions, it is clearly seen that the integral form of Eringen's model predicts the softening effect of the non-local parameter as expected. Finally, the effects of changes of some important parameters such as material length scale, BDFG index on the values of deflection of nano-beam are studied.

형상기억합금 스프링을 이용한 2방향 BENDING 액츄에이터의 제작

  • 김명순;이승기;이상훈
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1995.10a
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    • pp.1071-1074
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    • 1995
  • This paper proposes two directional bending actator using three link, two shape memory alloys(SMA) of coil-type springs and two guide wires. By the heating of two SMA springs sequentially, the bending and stretching of the actuator is possible. Bending angle, force and repeated bending motion of actuator were measured and characterized. The performance of the actuator has been characterized for the possible application for catheter.

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Study on the Forming and Springback Analyses of a Precision Metal Bellows (정밀 금속 벨로우즈 성형 및 스프링백 해석)

  • 이상욱
    • Transactions of Materials Processing
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    • v.11 no.3
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    • pp.231-237
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    • 2002
  • The manufacturing of a metal bellows consists of the four main forming processes; deep-drawing, ironing, tube bulging and folding. Among these, the bulging and folding processes are critically important because the quality of metal bellows is greatly influenced by the forming conditions of these processes. In the present study, the finite element analysis technique is applied to the bulging and folding processes. The springback analysis is also called out. From the analysis results, it has been revealed that around the crown point the stress state is in one-directional tension and one-directional bending mode. Meanwhile, around the inner point of metal bellows it is in two-directional bending mode. It has also revealed that the thickness of metal bellows around the crown point is nearly uniform.

Dynamic Behavior Analysis of a Bridge Considering Nonlinearity of R/C Piers under Bi-Directional Seismic Excitations (R/C 교각의 비선형성을 고려한 교량시스템의 2방향 지진거동분석)

  • 김상효;마호성;이상우;강정운
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • 2001.04a
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    • pp.353-360
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    • 2001
  • An analysis procedure of 2-dimensional bridge dynamics has been developed by using force-deformation model, which simulates the pier motion under biaxial bending due to the bi-directional input seismic excitations. A three-dimensional mechanical model is utilized, which can consider the other major phenomena such as pounding, rotation of the superstructure, abutment stiffness degradation, and motions of the foundation motions. The bi-directional dynamic behaviors of the bridge are then examined by investigating the relative displacements of each oscillator to the ground. It is found that the nonlinearity of the pier due to biaxial bending affects the pier motions, but the global bridge behaviors are greatly governed by the pounding phenomena and stiffness degradation of the abutment-backfill system. Especially, the relative displacement of the abutment system (A2) with movable supports to the ground is increased about 30% due to the abutment stiffness degradation.

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Design rules of directional coupler optical switches in consideration of parasitic couplings in the input/output bending sections (Input/Output bending 영역에서의 parasitic coupling을 고려한 방향성 결합기 광 스위치의 설계 법칙)

  • 김동각;김창민
    • Journal of the Korean Institute of Telematics and Electronics D
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    • v.34D no.1
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    • pp.41-48
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    • 1997
  • Design rules of directional coupler optical switches are discussed in consideration of parasitic couplings in the bending section. The parasitic coupling phenomenon is analyzed based on the coupled-mode theory and the solutions are represented in the form of the transfer matrix. The modified switching conditions due to the parasitic coupling are derived and the resultant switching diagrams are illustrated. It is revealed that the parallel section's length needs to be adjustd less than the coupling length $l_c(=\pi/2\textsc{k}o)$ to obtain the desired crosstalk and that the adjustment depends on the strength of the parasitic coupling. However, it is discovered that, for weak parasitic coupling, the switching voltage does not need to be altered but may maintain the same value as if no parasitic coupling is taken into account.

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Bending and buckling of porous multidirectional functionality graded sandwich plate

  • Lazreg, Hadji;Fabrice, Bernard;Royal, Madan;Ali, Alnujaie;Mofareh Hassan, Ghazwani
    • Structural Engineering and Mechanics
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    • v.85 no.2
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    • pp.233-246
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    • 2023
  • Bending and buckling analysis of multi-directional porous functionally graded sandwich plate has been performed for two cases namely: FG skin with homogeneous core and FG core with homogeneous skin. The principle of virtual displacements was employed and the solution was obtained using Navier's technique. This theory imposes traction-free boundary conditions on the surfaces and does not require shear correction factors. The validation of the present study has been performed with those available in the literature. The composition of metal-ceramic-based FGM changes in longitudinal and transverse directions according to the power law. Different porosity laws, such as uniform distribution, unevenly and logarithmically uneven distributions were used to mimic the imperfections in the functionally graded material that were introduced during the fabrication process. Several sandwich plates schemes were studied based on the plate's symmetry and the thickness of each layer. The effects of grading parameters and porosity laws on the bending and buckling of sandwich plates were examined.

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

  • Kim, M.S.;Choi, N.B.;Kim, D.W.;Lee, S.H.;Lee, S.K.
    • Proceedings of the KOSOMBE Conference
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    • v.1997 no.11
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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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Development of a Wrist Bending Rehabilitation Robot with a Three-axis Force Sensor (3축 힘 센서가 적용된 손목 굽힘 재활로봇 개발)

  • Kim, Gab-Soon
    • Journal of Sensor Science and Technology
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    • v.25 no.1
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    • pp.27-34
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    • 2016
  • This paper describes the development of a rehabilitation robot that can provide wrist bending exercise to a severe stroke patient staying in a bed ward or at home. The developed rehabilitation robot has a three-axis force sensor which detects three directional force Fx, Fy, and Fz. The sensor measures a bending force (Fz) exerted on the wrist and the signal force (Fx and Fy) which can be used for the safety purpose. The robot was designed for severe stroke patients in bed, and the robot program was developed to perform a wrist bending rehabilitation exercise. In our tests including a nine-day experimental exercise, the developed force sensor-based robot operated effectively and safely.

Eringen's nonlocal theory for non-linear bending analysis of BGF Timoshenko nanobeams

  • Azandariani, Mojtaba Gorji;Gholami, Mohammad;Nikzad, Akbar
    • Advances in nano research
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    • v.12 no.1
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    • pp.37-47
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    • 2022
  • In this paper, the non-linear static analysis of Timoshenko nanobeams consisting of bi-directional functionally graded material (BFGM) with immovable ends is investigated. The scratching in the FG nanobeam mid-plane, is the source of nonlinearity of the bending problems. The nonlocal theory is used to investigate the non-linear static deflection of nanobeam. In order to simplify the formulation, the problem formulas is derived according to the physical middle surface. The Hamilton principle is employed to determine governing partial differential equations as well as boundary conditions. Moreover, the differential quadrature method (DQM) and direct iterative method are applied to solve governing equations. Present results for non-linear static deflection were compared with previously published results in order to validate the present formulation. The impacts of the nonlocal factors, beam length and material property gradient on the non-linear static deflection of BFG nanobeams are investigated. It is observed that these parameters are vital in the value of the non-linear static deflection of the BFG nanobeam.