• Title/Summary/Keyword: Stiffness improvement

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New Concept of Stiffness Improvement in Paper and Board

  • Seo, Yung B.
    • Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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    • pp.168-182
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    • 2001
  • A new concept of stock preparation for the increase of bending stiffness in paper and board was proposed. The 'stiff' fibers, which were mechanically not treated or treated slightly to remove fiber curls, were combined with extensively refined fibers (ERF) to produce higher stiffness papers than those where the whole fibers were refined. The combination of 'stiff' fibers and extensively refined fibers produced higher stiffness at the same tensile strength than the control furnish, in which all the fibers are refined together. In this concept, the fibers from recycled papers could be as much useful as the virgin fibers as long as they are stiff enough or they can produce highly bondable fiber fractions by extensive refining. Use of the concept in real paper mill needs considerations such as increase of refining energy, slower drainage, and added drying burden, but savings of wood fibers, utilization of more recycled fibers, and increase of physical properties may offset the negative concerns. The success of this concept implementation in mills, therefore, depends on the wood fiber market around the mills and the proper decision making for the papermakers about how to apply this concept.

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New Concept of Stiffness Improvement in Paper and Board

  • Seo, Yung B.
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.34 no.5
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    • pp.63-69
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    • 2002
  • A new concept of stock preparation for the increase of bending stiffness in paper and board was proposed. The "stiff" fibers, which were mechanically not treated or treated slightly to remove fiber curls, were combined with extensively refined fibers (ERF) to produce higher stiffness papers than those where the whole fibers were refined. The combination of "stiff" fibers and extensively refined fibers produced higher stiffness at the same tensile strength than the control furnish, in which all the fibers are refined together. In this concept, the fibers from recycled papers could be as much useful as the virgin fibers as long as they are stiff enough or they can produce highly bondable fiber fractions by extensive refining. Use of the concept in real paper mill needs considerations such as increase of refining energy, slower drainage, and added drying burden, but savings of wood fibers, utilization of more recycled fibers, and increase of physical properties may offset the negative concerns. The success of this concept implementation in mills, therefore, depends on the wood fiber market around the mills and the proper decision making for the papermakers about how to apply this concept. apply this concept.

Static and Dynamic Weak Point Analysis of Spindle Systems Using Bending Curve (굽힘곡선을 이용한 공작기계 주축의 정적 동적 취약부 규명)

  • 이찬홍;이후상
    • Journal of the Korean Society for Precision Engineering
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    • v.15 no.12
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    • pp.188-193
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    • 1998
  • This paper describes static and dynamic weak point analysis of spindle systems to eliminate high concentrated bending point on spindle and improve total stiffness of spindle systems. The weak point analysis is based on the evaluation of bending curves of spindles. For static weak point analysis the bending curve is derived from static deflection curve and for dynamic weak point analysis it is derived from the mode shape curves in consideration of the transfer function at exciting point. The validity of the weak point search methodology is verified by comparison of the static deflection, the natural frequency and the dynamic compliance between the original and the improved spindle.

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A Study for Stiffness Improvement Method with Use of Filled Concrete in Continued Steel Box Girder Bridge (강상자형 연속교에서 콘크리트재를 이용한 부모멘트 구간의 강성향상공법)

  • 구민세;이호경
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • pp.69-78
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    • 1999
  • The stiffness of slab concrete section is not considered as effective in the existing method of construction for continued steel box girder bridge. Using lifting system and filled concrete, it is possible to make stiffness of slab concrete section effective and improve stiffness of negative moment section. It was proved that the stress of upper flange in positive moment is significantly lower than case of existing method through the stress comparison. This stress difference made possible to rearrange flange thickness and as the result of this rearrangement, the amount of steel and height of girder can be reduced up to 13.23% and 11.5%.

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THICKNESS OPTIMIZATION OF AN AUTOMOBILE BODY FOR NATURAL FREQUENCY MAXIMIZATION

  • Panganiban, Henry;Jang, Gang-Won;Chung, Tae-Jin;Choi, Young-Min
    • Proceedings of the KSME Conference
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    • pp.572-577
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    • 2007
  • The paper presents design optimization of an automobile body for dynamic stiffness improvement. The thicknesses of plates making-up the monocoque body of an automobile were employed as design variables for optimization and the objective was to increase the first torsional and bending natural frequencies. By allotting one design variable to each plate of the body, compared to previous works based on element-wise design variables, design space of optimization was reduced to a large extent and numerical instabilities such as checkerboard pattern was efficiently evaded. The method resulted to a considerable amount of increase in the automobile body's torsional and bending natural frequencies. Considering manufacturability of the optimized result, the converged values of plate thicknesses were approximated to commercially-available values by appropriately reflecting their design sensitivities.

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Evaluation of Structural Capacity for Concrete Beams Reinforced Simultaneously with GFRP and Steel rebar (GFRP와 철근 보강근으로 복합 휨보강된 보 시험체의 구조성능 평가)

  • Sim, Jong-Sung;Park, Cheol-Woo;Oh, Hong-Seob;Ju, Min-Kwan;Lim, Jun-Hyun
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.518-521
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    • 2006
  • The purpose of this study is to evaluate structural performance of concrete beam reinforced simultaneously with GFRP and steel rebar. Because the GFRP has lower elastic modulus than steel or CFRP, serviceability for concrete structure can be an issue. According to the test result, the hybrid reinforced specimen showed better stiffness improvement than the specimen reinforced with only GFRP rebar. From an additional research on design parameter and reliability analysis, the field adaptability can be proved.

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Improvement of Fire Resistance and Impact Sound Insulation Performance for Timber Framed Floor by Installation of Isolated Ceiling (분리된 천정의 설치를 통한 목구조 바닥의 내화성능 및 충격음 차단성능 향상)

  • Park, Joo-Saeng;Kim, Se-Jong;Lee, Sang-Joon
    • Journal of the Korea Furniture Society
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    • v.24 no.4
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    • pp.426-432
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    • 2013
  • Fire resistance and impact sound insulation tests were performed for a floor assembly, of which stiffness was reinforced by shortening the span of floor joists by installing glulam beam additionally in the middle or one thirds of the original span, and which an additional ceiling component was installed apart from floor structure. By applying the isolated ceiling, timber framed floor showed 1 hour of fire resistance even in case that dead load was increased by considering cement mortar layer for radiant floor heating. Insulation performance against light and heavy impact sound was improved significantly by applying the sound absorbing layer of big mass and high elasticity in addition to the stiffness improvement and isolated ceiling.

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A Study on Torsional Stiffness Improvement of a Vehicle (자동차의 비틀림 강성 향상에 관한 연구)

  • 임기창;임석현
    • Fire Science and Engineering
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    • v.11 no.1
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    • pp.47-54
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    • 1997
  • Using high tensile steel plate makes the vehicle body stiffness lower even though it can lessen the fuel consume rate in application of weight reduction. The crack which happens arround vehicle window glass is brought about due to fatigue with low torsional stiffness. The paper presents a most suitable way to increase torsional stiffness using elasticity theory. Also the result of this study shows good agreement with FEM and experiments. We used a passenger car for calculation in this paper. Because we can apply the result of this study to fire engine as well as passenger car.

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Effect of Fabric Softner on the Absorbency, Stiffness and Antistatic Properties of Fabrics. (유연제 사용에 따른 직물의 흡수성.유연성.대전성 변화에 관한 연구)

  • 김언아
    • Journal of the Korean Home Economics Association
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    • v.31 no.2
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    • pp.189-203
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    • 1993
  • The objective of this study was to investigate the changes of the fabric absorbency, stiffness and antistatic property by using a fabric softner at laundering. The samples selected in this study were cotton and polyester fabrics. The cotton fabric was treated with 1/2 times(0.035%), 1 time(0.07%), 3 times(0.21%) and 10 times(0.7%) of the commercially suggested concentration (0.07%) of the fabric softner. And polyester fabric was done at 1 time(0.07%) of that. In order to examine the effect of the fabric by using a fabric softner, the abstraction of a surface active agent and quantitative analysis was performed by using a UV/VIS Spectroscopy and the correlations among the absorbency, stiffness and antistatic property was analyzed. The results obtained from this study were as follows; 1. In the cotton fabric, fabric softner gave the degradation of absorbency, and stiffness improvement was not shown by repeated fabric softner on the cotton fabric. 2. In the polyester fabric, the absorbency increased and the stiffness in creased very slightly. Specially, it is desirable to use fabric softner on the polyester due to improvement of antistatic property.

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A study on the Properties for Structural Behavior of High-Performance Concrete Filled Square Steel Tube Columns -The Behavior Properties by Loading Conditions- (고성능 콘크리트를 충전한 각형강관 기둥의 구조적 거동 특성에 관한 연구 -재하조건별 거동특성-)

  • Park, Jung Min;Lee, Sung Jo;Kim, Wha Jung
    • Journal of Korean Society of Steel Construction
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    • v.10 no.2
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    • pp.177-186
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    • 1998
  • The concrete filled steel tubular column have to superior in compressive load carrying capacity, compared with same section typed hollow steel tube column, and have many excellent structural properties, such as stiffness improvement by filled concrete, improvement of ductility by reinforced effect of local buckling, and the like. However, it has not clear the effect of interaction between steel tube and filled concrete, stress portion ratio and fracture mechanism of concrete. This study investigated to structural properties for high strength concrete filled steel tube column by loading conditions through a series of experiments. Especially, this study investigated the properties of structural behaviors for concrete filled steel tube column stress ratio by loading conditions and failure mechanism of filled concrete.

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