• Title/Summary/Keyword: Velcro

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Seismic performance of RC-column wrapped with Velcro

  • Kwon, Minho;Seo, Hyunsu;Kim, Jinsup
    • Structural Engineering and Mechanics
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    • v.58 no.2
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    • pp.379-395
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    • 2016
  • A seismic strengthening method using Velcro is proposed to improve the seismic performance of columns in RC frame structures. The proposed method was evaluated experimentally using three fabricated RC specimens. Velcro was wrapped around the columns of the RC-frame specimen to prevent concrete spall falling. The reinforcing performance of the Velcro was determined from comparison of results on seismic performance (i.e., strength, displacement, failure mode, displacement ductility capacity and amount of dissipated energy). As the displacement of the reinforced specimens was increased, the amount of dissipated energy increased drastically, and the displacement-ductility-capacity of the reinforced specimens also increased. The final failure mode of RC frame structure was changed. As a result, it was concluded that the proposed seismic strengthening method using Velcro could be used to increase the displacement ductility of RC columns, and could be used to change the final failure mode of RC-frame structures.

Evaluation of Lateral Strength and Ductility of Velcro Reinforced RC Columns with Finite Element Analysis (유한요소해석을 통한 벨크로로 보강된 RC 기둥의 횡방향 강도 및 연성 능력 평가)

  • Kim, Sang-Woo;Kim, Kyeong-Min;Kim, Geon-Woo;Lee, Su-Young;Kim, Jin-Sup
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.25 no.4
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    • pp.12-19
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    • 2021
  • Recently, with frequent earthquakes around the world, research on seismic design and seismic reinforcement of reinforced concrete facilities has been actively conducted from earthquakes. In particular, columns, which are compressed members of reinforced concrete structures, are vulnerable to lateral forces caused by earthquakes, so an appropriate seismic reinforcement method is required. Therefore, this study intended to develop Velcro seismic reinforcement method that is quick and easy to construct. For the development of Velcro seismic reinforcement, the adhesion and tensile strength of the existing industrial velcro was improved. A direct tensile test was also conducted to compare the tensile performance of the newly-developed velcro seismic reinforcement to industrial one. In addition, numerical analysis was performed to predict the seismic performance of RC columns reinforced by industrial and newly-developed velcro. Based on the analysis results, the strength and ductility of the non-seismic and velcro-reinforced RC column were reviewed. The analysis confirmed that both the strength and ductility of non-seismic RC columns reinforced by industrial and newly-developed velcro increased, but the seismic performance of the newly-developed Velcro reinforcement is better than that of industrial velcro.

Experimental Study on the Performance Improvement of Velcro Reinforcement through Internal Filling (내부충진을 통한 벨크로 보강재의 성능향상에 대한 실험적 연구)

  • Jeong, Yeong-Seok;Kwon, Minho;Kim, Jin-Sup;Nam, Gwang-Sik
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.41 no.4
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    • pp.347-355
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    • 2021
  • During the earthquake, for multi-story structure, if the first floor is soft, the deformation will concentrate on that floor causing a serious damage to the column members which might leads to the collapse of the whole structure like Piloti structure during the Pohang earthquake in Korea. According to the 2016 National Disaster Management Research Institute's "Investigation of Seismic Reinforcement and Cost Analysis of Domestic Non-seismic Buildings", the rate of seismic resistance of private reinforced concrete buildings was 38.3 %. Among them, it was reported that the seismic-resistance ratio of the two to five-story structures was less than 50 %. Accordingly, the government is trying to improve the seismic rate through support projects, but the conventional seismic reinforcement methods are still expensive, and emergency construction is difficult. Therefore, in this study, the field applicability was evaluated by improving the reinforcement method using Velcro, which was developed through the research project of the Ministry of Land, Transport and Maritime Affairs in 2014. In order to improve the performance of the Velcro reinforcement method, introducing the initial tension of Velcro using high foaming rigid urethane filling between the Velcro and concrete of the columns was applied. Additionally, an experiment was conducted to evaluate the ductility of Velcro specimen from the concrete confinement effect. As a result, the ductility of the Velcro specimen was improved compare to Normal specimen. However, the energy dissipation capacity of VELCRO2 is better than VELCRO1, yet the maximum ductility of those two specimens did not show a significant difference. Therefore, the improvement of the internal filler material is still needed to have a better maximum ductility.

Logistics Business Model for Win-Win Strategy : Logister & Velcro Structure (윈윈전략을 위한 물류비즈니스 모델 : Logister와 벨크로 조직)

  • Paik, Si-Hyun
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.29 no.3
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    • pp.33-42
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    • 2006
  • From middle of 90's, SCM had emphasized the importance of connection of all companies which participate to a market, and outsourcing has emphasizes the slim structure of companies for pursing cost reduction and service improvement. But outsourcing as '2-1=1' and integration as '1+1=2' not adapt to the advanced market but return to the former state. Besides, it is impossible of subcontractors and logistics companies to execute these strategies which are win-win strategy and outsourcing. So many logistics companies have sharp competition in price recently. Therefore logistics companies have increased the need for a profitable business model and strategy. This paper researches the limitations of logistics market and redefines the role of logistics through the evolution of logistics. Also this paper proposes new role(Logister) and structure(Velcro structure) for not maker-oriented logistics but market-oriented logistics. The introductory case study will help to understand 2 terms(logister and velcro structure).

Construction Method Improvement of the FRP-plate Strengthening Method using the Velcro (벨크로를 이용한 FRP 플레이트 보강공법의 시공공법 개선)

  • Hong, Geon-Ho
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.12 no.6
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    • pp.225-232
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    • 2008
  • The object of this paper is to study the flexural strengthening effectiveness on the construction method of bonding of the FRP. The existing FRP flexural strengthening methods were divided into FRP sheet strengthening and FRP plate strengthening according to the FRP condition. For improving the existing construction method, this paper proposed the velcro type anchorage system for temporary bonding material, and flexural strengthening effects were tested. Test variables were bonding methods of the FRP strengthening materials, and total 4 specimens were tested. Following to the test results, it is shown that FRP-plate strengthening method using the velcro can get better workability than existing construction methods, and have excellent strengthening performance including flexural strength, stiffness, ductility and failure aspect.

Finite Element Analysis(fem) of The Fixed Position of the Velcro Band for the 3D Print Wrist Brace made using the Dicom File (CT Dicom 파일을 이용하여 제작한 3D Print 손목보호대용 Velcro band 고정위치의 유한요소해석(FEM))

  • Choi, Hyeun-Woo;Seo, An-Na;Lee, Jong-Min
    • Journal of the Korean Society of Radiology
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    • v.15 no.5
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    • pp.585-590
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    • 2021
  • Wrist braces are being used for patients with wrist trauma. Recently, many studies have been conducted to manufacture custom wrist braces using 3D printing technology. Such 3D printing customized orthosis has the advantage of reflecting various factors such as reflecting different shapes for each individual and securing breathability. In this paper, the stress on the orthosis by the number and position of Velcro bands that should be considered when manufacturing a 3D printing custom wrist brace was analyzed. For customized orthosis, 3D modeling of the bone and skin regions was performed using an automatic design software (Reconeasy 3D, Seeann Solution) based on CT images. Based on the 3D skin area, a wrist orthosis design was applied to suit each treatment purpose. And, for the elasticity of the brace, a wrist brace was manufactured with an FDM-type 3D printer using TPU material. To evaluate the effectiveness according to the number and position of the Velcro band of the custom 3D printed wrist brace, the stress distribution of the brace was analyzed by the finite element method (FEM). Through the finite element analysis of the wrist orthosis performed in this study, the stress distribution of the orthosis was confirmed, and the number and position of the orthosis production and Velcro bands could be confirmed. These experimental results will help provide quality treatment to patients.

A study on the mechanical properties of geosynthetic interface (토목섬유 접촉면의 역학적 특성에 관한 연구)

  • Nam, Yong;Kim, Gwang-Ho;Im, Jong-Chul;Ju, In-Gon;Kwon, Jeong-Geun
    • Proceedings of the Korean Geotechical Society Conference
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    • 2009.09a
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    • pp.1540-1549
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    • 2009
  • Shear properties of geosynthetic/geosynthetic and geosynthetic/soil were evaluated from direct shear tests. The type of geosynthetic is Velcro which is effective for geosynthetic interface and make up for the weakness of sandbag. In this study, the cohesion and the angle of internal friction of each interface was estimated. The test results showed that the cohesion and the angle of internal friction of the geosynthetics depended on the amount of normal stress, the type of the geosynthetics used, and combinations of the geosynthetics and soils. Finally, by comparing the apparent cohesion and the friction angle of the geosynthetics, the applicability to design was identified.

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Research on the Actual Condition of Shape and Material of Peanut-Shaped Cloth Diaper for Baby (유아용 땅콩형 천기저귀의 형태 및 소재에 관한 실태 조사)

  • Lee, Jung-Soon;Koo, Mi-Ran
    • Journal of the Korea Fashion and Costume Design Association
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    • v.12 no.3
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    • pp.57-71
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    • 2010
  • This study is to understand the actual condition of design and material of peanut-shaped diaper with looking at the types and characteristics of baby cloth diapers and domestic peanut-shaped diapers registered in the Patent Office. Furthermore, it is to suggest the basic data for designing more functional and comfortable cloth diapers. Here are the research result on the actual condition of design and material of baby cloth diapers. Firstly, 11 cloth diapers registered in the Patent Office can be divided into panty-shaped and straight line-shaped diapers. There are 7 kinds of panty-shaped cloth diapers which satisfy both the convenience of a disposable diaper and sanitation of a cloth diaper, and 4 kinds of straight line-shaped cloth diapers that minimize the weaknesses of existing cloth diapers. Secondly, domestic peanut-shaped cloth diapers can be divided into peanut-shaped, inserted, winged, velcro-attached diapers. Among 23 kinds of peanut-shaped cloth diapers from 16 companies, there are 12 kinds of peanut-shaped diapers which consist of layers of cloth to make peanut shape. There are 6 kinds of inserted diapers that insert extra diapers or handkerchiefs in between two sheets of cloth diapers and 3 kinds of winged diapers designed to shorten drying time with sawing only one side of several layered sheets. Also, there are 2 kinds of velcro-attached diapers that are removable according to the amount of excreta. Commonly used materials are cotton woven of diamond jacquard and knit of diamond Hole Stitch or Plain Stitch. And for handing the edge of diaper, the method of wrapping up the edge with cotton woven or knit bias is used.

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A Study on the Improvement Mechanical Properties of Geosynthetic Interface (토목섬유 접촉면의 역학적 특성 개선에 관한 연구)

  • Nam, Yong;Kim, Gwangho;Kwon, Jeonggeun;Im, Jongchul;Seo, Jeochan
    • Journal of the Korean GEO-environmental Society
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    • v.11 no.3
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    • pp.23-32
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    • 2010
  • In this study, Generally sandbag was used to reinforce slope or restore levee by using the in-situ material. To increase shear strength of sandbag, the Velcro system was effective for geosynthetic interface and make up for the weakness of shear strength between sandbag to sandbag. In this study, shear properties of geosynthetic-geosynthetic and geosynthetic-soil were evaluated from large scale direct shear tests. The cohesion and the angle of internal friction of each interface was evaluated. And laboratory model tests were performed to compare strength of reinforcement with strength of none reinforcement. As a result of this study, the cohesion and the angle of internal friction of each interface was increased, especially the cohesion was increased more than the angle of internal friction. Also according to the result of model test, the bearing capacity was increased by 20%.

A study on the fastening performance and finger function of the cerebral palsied (뇌성마비자의 의복여밈 수행능력과 수지기능)

  • 김순분;함옥상;서승록
    • Journal of the Ergonomics Society of Korea
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    • v.12 no.2
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    • pp.45-62
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    • 1993
  • This study was aimed to obtain the available information for the clothing constru- ction according to the traits of the cerebral palsied. For this purpose, their abilities of eleven methods seven of fastening performance and seven finger functions were tested and their correlationships were clarified. The results are as follows : 1. The length of time needed to perform each fastening method in descending order is as follows : small button > small snap > culumn button > large button > middle button > large snap > separating zipper > velcro. As the spastic has better function than the athetoid in the performance of all fastening methods, there was a significant difference between the types of handicap and between the handi- capped and the normal, except for velcro fastening style in which there was no significant differ- ence between the types of handicap. 2. In finger functions of the cerebral palsied, according to the types of handicap there was no significant difference among grip, palm fixation and hands coordination, howefer there were significant differences among pulp pinching, lateral pinching, finger rolling and lifting control. As to the correlation between the ability of fastening performance and finger function, there was a high significant correlation between the length of time needed to perform each fastenting and finger function of hands co ordination, and that of finger rolling; and there was a significant correlation between the length of time and pulp pinching, and laternal pinching.

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