• Title/Summary/Keyword: Bending

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Proposal of bulged-type abrupt bend structure with low bending loss (굽음손실이 적은 Bulged형 Abrupt Bend 구조의 제안)

  • 한상필;김창민
    • Journal of the Korean Institute of Telematics and Electronics D
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    • v.34D no.8
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    • pp.71-79
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    • 1997
  • Bulged-type bends with low bending loss are newly proposed, and the FD-BPM is made use of for designing optimum structure. How to evaluate bending loss of conventional bends and how to improve the bending structure based on the phase compensation concept are described in genral. Besides simulation results for the bulged-type bends, results for the coupled-type bends and the chamfered-type bends show the most superior performance in terms of not only the bending loss but also the design tolerance.

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Effect of Interlining Adhesion on the Bending Behavior of Wool Fabrics (부착 심지에 의한 모직물의 굽힘특성 변화)

  • 서문호;이승윤
    • Textile Science and Engineering
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    • v.40 no.3
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    • pp.238-249
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    • 2003
  • Interlinings have been known to improve garment smoothness and silhouette by increasing fabric stiffness. The objective of this study is understanding the effort of the interlining on the bending rigidity of composite fabrics. Through extended experiments and analysis of composite fabrics prepared from woolen fabrics and spunlaced non-woven interlinings, it can be concluded that the major sources for the composite fabric bending rigidity enhancement are thickness and the non-linear tensile stress strain characteristics of both materials. However, interlayer bonding material exhibits a significant role generating anisotropic behavior of composite fabric bending.

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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Change of Lumbar Spine and Hip Joint Flexion Angles During Forward Bending of the Trunk Using Manual Facilitation and a Stick (도수 촉진과 막대를 이용한 몸통의 전방 굴곡 운동에 따른 요추와 고관절 굴곡 각도의 변화)

  • Choung, Sung-Dae;Park, Kyue-Nam;Hong, Ji-A;Cho, Min-Sue;Son, Dong-Hwi;Cynn, Heon-Seock
    • Physical Therapy Korea
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    • v.18 no.1
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    • pp.57-63
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    • 2011
  • The purpose of this study was to identify the effects of manual facilitation and a stick on lumbar and hip joint flexion angles in subject with lumbar flexion syndrome during forward bending from a sitting position. Fifteen subjects with lumbar flexion syndrome were recruited for this study. As a pretest, all subjects performed three repetitions of bending the trunk forward until the tips of their fingers touched the target bar. After this pretest, the subjects practiced the forward bending of the trunk 10 times, using either manual facilitation or a stick. Then, as a posttest, all subjects repeated the pretest procedure. The flexion angles of lumbar spine and hip joint during forward bending in a sitting position were measured using a three-dimensional motion analysis system. A paired t-test was used to determine the statistical differences between pre-test and post-test flexion angles and pre- and post-test flexion angle differences between forward bending with manual facilitation and forward bending with a stick. The level of statistical significance was set at p=.05. The results of the study showed that the angle of the lumbar flexion decreased significantly and the bilateral hip flexion angle increased significantly when performing forward bending with stick and manual facilitation. Furthermore, the angle of lumbar flexion decreased significantly and the angle of bilateral hip flexion increased significantly in forward bending with a stick compared to forward bending with manual facilitation. The findings of this study indicate that both forward bending with manual facilitation and sticks could be used to prevent excessive lumbar flexion and increase hip flexion, and that forward bending with a stick is more effective than forward bending with manual facilitation for inducing lumbar spine and hip joint angle changes.

Influence of bending strain on $I_c$ Degradation Behavior in YBCO Coated Conductor Tapes processed using RABiTS/MOD

  • Shin, Hyung-Seop;Dizon, John Ryan C.;Bonifacio, Rolly;Park, Jeong-Soo
    • Progress in Superconductivity and Cryogenics
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    • v.9 no.2
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    • pp.11-14
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    • 2007
  • The critical current, $I_c$, degradation behaviors with bending strain were investigated in a commercially available YBCO coated conductor tape. In particular, the strain reversibility of $I_c$ and the influence of repeated bending on $I_c$ have been studied. Also, repeated bending at 77 K was done in order to understand the Ie behavior under cyclic bending strains. A reversible behavior of $I_c$ has been found up to a high bending strain of 1.60% for the RABiTS/MOD processed CC sample with copper reinforcement. Under repeated bending, the Ie showed a 95% $I_c$ retention up to 100 cycles for bending strains of 1.0% or less. The n-value behavior showed a good agreement with the $I_c$ degradation behavior, representing that any cracking did not occur on the YBCO film resulting from the reinforcement provided by the copper stabilizers.

Effects of Visual Biofeedback on Movement Patterns of Neck Lateral Bending and Muscle Activation of Sternocleidomastoid During Neck Rotation in Adults with Forward Head Posture (전방머리자세를 가진 성인들에게 목 돌림 수행 시 시각적 생체되먹임 적용이 목의 가쪽 굽힘 움직임 패턴과 목빗근 근활성도에 미치는 영향)

  • Yang, No-Yul;Oh, Jae-Seop
    • Journal of the Korean Society of Physical Medicine
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    • v.9 no.4
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    • pp.425-432
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    • 2014
  • PURPOSE: The purpose of this study was to investigate that the differences in sternocleidomastoid muscle activity, neck rotation angle, neck lateral bending angle and neck lateral bending onset time between conditions with and without visual biofeedback during neck rotation. METHODS: Ten male and four female adults with condition of forward head posture were recruited in this study. Subjects conducted to left and right maximal neck rotation under the conditions with and without visual biofeedback. During neck rotation, kinematic data of neck rotation, neck lateral bending movement, and electromyography activities of bilateral sternocleidomastold muscles were collected. Differences in dependent variables between conditions with and without visual biofeedback were analyzed using paired t-test. RESULTS: There were significant decreases in lateral bending angle, while lateral bending movement onset time was delayed significantly when applying visual biofeedback (p<.05). However, there were no significant differences in the activation of left and right sternocleidomastoid muscles and neck rotation angle between conditions with and without visual biofeedback (p>.05). CONCLUSION: These findings suggest that visual biofeedback may be effective for axial rotation of cervical spine during neck rotation in adults with forward head posture.

A Study on Extru-Bending Process Extrusion Bending Machine (열간금속 압출굽힘기를 이용한 금속곡관의 압출굽힘가공에 관한 연구)

  • 박대윤;진인태
    • Transactions of Materials Processing
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    • v.11 no.3
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    • pp.262-268
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    • 2002
  • The bending process for the rectangular and circular curled tube can be developed by the hot metal extrusion machine with the multiple punches moving in the different velocity. The bending phenomenon has been known to be occurred by the different of velocity at the die exit. The difference of velocity at the die exit section can be obtained by the different velocity of billets through the multi-hole container and by the cohesion of billet Inside the porthole die chamber. The bending phenomenon can be controlled by the two variables, the one of them is the difference of velocity at the die edit section by the different velocity of billets through the multi-hole container The other is the difference by the different hole diameter The results of the experiment show that the rectangular curved tube can be formed by the extrusion process, that the curvature of the curved product can be controlled by the velocity of punch and the diameter of container hole, that the defects such as the distortion of section and the thickness change of the wall of tube and the folding and wrinkling of thin tube did not happen after the extra-bending processing by the extrusion bending machine.

Efficient Methods of Prediction Incorporating Equivalent Models for Elasto-Plastic Bending Behavior of Metallic Sandwich Plates with Inner Dimpled Shell Structure (등가형상을 이용한 딤플형 금속 샌드위치 판재의 효율적 굽힘 거동 예측)

  • Seong D. Y.;Jung C. G.;Yoon S. J.;Yang D. Y.
    • Transactions of Materials Processing
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    • v.14 no.8 s.80
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    • pp.718-724
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    • 2005
  • An efficient finite element method has been introduced for analysis of metallic sandwich plates subject to bending moment. A full model 3-point bending FE-analysis shows that the plastic behavior of inner structures appears only at the load point. The unit structures of sandwich plates are defined to numerically calculate the bending stiffness and strength utilizing the recurrent boundary condition for pure bending analysis. The equivalent models with the same bending stiffness and strength of full models are then designed analytically. It is demonstrated that the results of both models are almost the same and the FE-analysis method incorporating the equivalent models can reduce the computation time effectively. The dominant collapse modes are face buckling and face yielding. Since the inner dimpled structures prevent face buckling, sandwich plates with inner dimpled shell structure can absorb more energy than other types of sandwich plates during the bending behavior.

Process Development of Constant Curvature Extrusion for Aluminum Alloy (알루미늄 합금의 일정 곡률 압출공정 개발)

  • Joe, Y.J.;Lee, S.K.;Oh, K.H.;Park, S.W.;Kim, B.M.
    • Transactions of Materials Processing
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    • v.16 no.7
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    • pp.555-560
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    • 2007
  • This paper shows some achievements at bending of extruded aluminum profiles during the extrusion process. The conventional process for the production of bent profiles involves a successive extrusion, stretching, and bending of the profiles. Conventional bending methods can not meet demands far precision and cost-effective production in some cases, due to cross sectional deformation, irregular decrease of tube wall thickness and a complication of the process design. An estimation of spring-back required for precision of the bending radius can not always be achieved by the over bending of the profile. Since the profile is hot during the bending process, the spring-back phenomenon can be avoided. This means that an additional bending process is not necessary. Consequently, flexible bending can be achieved with cost reduction and quality improvement. Experimental tests were completed to study the relationship between curvature radius of profile and position of guide on the extrusion for vehicle bumper. A7108 is applied as a billet material in order to increase strength. The overall correlation between the experimental and numerical results is good. It is therefore concluded that the present method provides an efficient means for the constant curvature extrusion process.