• Title/Summary/Keyword: Static behavior

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Anti-static behavior of Synthetic fabrics treated by anti-static agents (대전방지처리된 합성섬유의 대전성에 관한 연구)

  • Choi Suk-Chul;Kim Mi-Sung
    • Journal of the Korean Society of Clothing and Textiles
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    • v.11 no.1
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    • pp.51-62
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    • 1987
  • In this study, electrostatic behavior of polyester and nylon fabric treated with anti-static agents were investigated. The effects of the concentration of the agents and curing conditions on the electrostatic charge of the fabrics were studied. And washfastness, lightfastness and physicalproperties of the treated fabrics were also investigated. The results were as follows: 1) Polyethylene glycol alkylester was more effective in antistatic behavior than polyethylene laurylphosphate, and polyester is more effective in anti-static behavior than nylon. 2) Concentration of anti-static agents were suitable in concentration of $4\%$. 3) Glyoxal resin was more effective in anti-static behavior than melamine resin, and it was also good in the retaing anti-static behavior after treatments of lightfastness and washfastness. 4) As the condition of curing treatment, $190^{\circ}C$, 1min. for glyoxal resin and $130^{\circ}C$, 4min. for melamine resin is appropriate. 5) In comparison of anti-static behavior according to treating conditions, the simultaneous treatment was more effective than any other treatments. 6) Change of electrostatic charge of anti-static nylon cloths after treatments of lightfastness and washfastness increased greatly in above 10 laundering time and 20 fade-O-meter time. 7) In physical properties according to concentration of treating agents. decrease of physical properties scarcely appeared in concentration of treating agents $4\~5\%$.

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Analysis of Interrelationship between Undrained Static and Cyclic Shear Behavior for Nak-Dong River Sand (낙동강 모래의 비배수 정적 및 반복 전단거동 상호관계 분석)

  • Kim, Dae-Man;Kim, Byung-Tak
    • Journal of the Korean Geotechnical Society
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    • v.22 no.10
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    • pp.151-163
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    • 2006
  • This paper presents the interrelationship between undrained static and cyclic shear behavior. Laboratory works were performed through the undralned static and cyclic triaxial test using Nak-Dong River sand. And static triaxial test involved the triaxial extension test for comparison with cyclic shear behavior Cyclic triaxial test was performed with a variety of combination conditions of initial static shear stress $(q_{st})$ and cyclic stress $(q_{cy})$. In this result, the stress path of cyclic shear behavior was correspondent with static shear behavior passing the critical stress ratio (CSR) line because of the development of flow deformation. After that, a failure occurred according to failure line (FL) of static shear behavior. The stress path of cyclic shear behavior showed essentially the same with static shear behavior, although it appears a little different in test method.

An Investigation of Dynamic Characteristics of Structures in Optimization (동하중을 고려한 설계의 필요성에 관한 고찰)

  • Kang, B.S.;Kim, J.S.;Park, G.J
    • Proceedings of the KSME Conference
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    • 2004.04a
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    • pp.1011-1016
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    • 2004
  • All the loads in the real world are dynamic loads and it is well known that structural optimization under dynamic loads is very difficult. Thus the dynamic loads are often transformed to the static loads using dynamic factors. However, due to the difference of load characters, there can be considerable differences between the results from static and dynamic analyses. When the natural frequency of a structure is high, the dynamic analysis result is similar to that of static analysis due to the small inertia effect on the behavior of the structure. However, if the natural frequency is low, the inertia effect should not be ignored. Then, the behavior of the dynamic system is different from that of the static system. The difference of the two cases can be explained from the relationship between the homogeneous and the particular solutions of the differential equation that governs the behavior of the structure. Through various examples, the difference between the dynamic analysis and the static analysis are shown. Also the optimization results considering dynamic loads are compared with static loads.

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Axial Load Transfer Behavior of a Large Diameter Pile socketed into weathered rock (풍화암 소켓 대구경말뚝의 축하중 전이거동)

  • 정창규;임태경;황근배;최용규
    • Proceedings of the Korean Geotechical Society Conference
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    • 2002.10a
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    • pp.390-397
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    • 2002
  • In this study, static pile load tests with load transfer measurement for a pile socketed into weathered rocks were performed. Axial load transfers during static pile load test were measured and analyzed. Three large diameter piles socketed into weathered rock were behavior behaved as friction pile.

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Influence of shear deformation of exterior beam-column joints on the quasi-static behavior of RC framed structures

  • Costa, Ricardo J.T.;Gomes, Fernando C.T.;Providencia, Paulo M.M.P.;Dias, Alfredo M.P.G.
    • Computers and Concrete
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    • v.12 no.4
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    • pp.393-411
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    • 2013
  • In the analysis and design of reinforced concrete frames beam-column joints are sometimes assumed as rigid. This simplifying assumption can be unsafe because it is likely to affect the distributions of internal forces and moments, reduce drift and increase the overall load-carrying capacity of the frame. This study is concerned with the relevance of shear deformation of beam-column joints, in particular of exterior ones, on the quasi-static behavior of regular reinforced concrete sway frames. The included parametric studies of a simple sub-frame model reveal that the quasi-static monotonic behavior of unbraced regular reinforced concrete frames is prone to be significantly affected by the deformation of beam-column joints.

The Behavior and Estimated Stiffness Rubber Pad for Disk Bearing (디스크 받침용 고무패드의 거동 및 강성추정)

  • Cho, Sung-Chul;Choi, Eun-Soo;Park, Joo-Nam;Kim, Man-Cheol
    • Proceedings of the KSR Conference
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    • 2009.05a
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    • pp.599-605
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    • 2009
  • The aim of the present study is the characteristics of bridge rubber pads and suggested how to determine the stiffness the pads. A disk bearing is operated as an elastic bearing in the vertical direction and is composed of a Polyether Urethane (polyurethane) disk for elastic support and Polytetrafluoroethylene (PTFE) to accommodate movement. Static tests are conducted in a laboratory to determine the static behavior of a Polyurethane disk. Finite Element (FE) analysis is also performed to verify the static performance. For dynamic behavior, four disk bearings having the identical Polyurethane disk used in the static tests are installed in a full size railway bridge and tested under a running locomotive. From the tests results, the static and dynamic stiffness of disk bearings are estimated and compared with each other. In the procedure to estimate the stiffness of a pad, the dead load(pre-load) of a bridge and live load of a vehicle are considered.

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On the Description of Constrained Static Behavior of Continuous System

  • Eun, Hee-Chang;Lee, Min-Su;Bae, Chung-Yeol
    • Architectural research
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    • v.9 no.1
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    • pp.39-45
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    • 2007
  • The static behavior of continuous system is described by the elastic curve method or is approximately analyzed by a finite element method to be modeled as a discrete system. If a continuous system is constrained by linear constraints which restrict its static behavior, its behavior can be approximately described by the finite element method. It is not easy to describe the constrained behavior by continuous coordinate system. Starting from the generalized inverse method provided by Eun, Lee and Chung, this study is to expand the equation to the continuous systems, to perform the structural analysis of the beam under a uniform loading with interior spring supports, and to investigate the validity of the proposed method through applications.

Laminate composites behavior under quasi-static and high velocity perforation

  • Yeganeh, E. Mehrabani;Liaghat, G.H.;Pol, M.H.
    • Steel and Composite Structures
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    • v.22 no.4
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    • pp.777-796
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    • 2016
  • In this paper, the behavior of woven E-glass fabric composite laminate was experimentally investigated under quasi-static indentation and high velocity impact by flat-ended, hemispherical, conical (cone angle of $37^{\circ}$ and $90^{\circ}$) and ogival (CRH of 1.5 and 2.5) cylindrical perforators. Moreover, the results are compared in order to explore the possibility of extending quasi-static indentation test results to high velocity impact test results in different characteristics such as perforation mechanisms, performance of perforators, energy absorption, friction force, etc. The effects of perforator nose shape, nose length and nose-shank connection shapes were investigated. The results showed that the quasi-static indentation test has a great ability to predict the high velocity impact behavior of the composite laminates especially in several characteristics such as perforation mechanisms, perforator performance. In both experiments, the highest performance occurs for 2.5 CRH projectile and the lowest is related to blunt projectiles. The results show that sharp perforators indicate lower values of dynamic enhancement factor and the flat-ended perforator represents the maximum dynamic enhancement factor among other perforators. Moreover, damage propagation far more occurred in high velocity impact tests then quasi-static tests. The highest damage area is mostly observed in ballistic limit of each projectile which projectile deviation strongly increases this area.

Effects of fines content on void ratio, compressibility, and static liquefaction of silty sand

  • Lade, Poul V.;Yamamuro, Jerry A.;Liggio, Carl D. Jr.
    • Geomechanics and Engineering
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    • v.1 no.1
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    • pp.1-15
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    • 2009
  • Many aspects of the behavior of sands are affected by the content of non-plastic fine particles and these various aspects should be included in a constitutive model for the soil behavior. The fines content affects maximum and minimum void ratios, compressibility, shear strength, and static liquefaction under undrained conditions. Twenty-eight undrained triaxial compression tests were performed on mixtures of sand and fine particles with fines contents of 0, 10, 20, 30, 50, 75, and 100% to study the effects of fines on void ratio, compressibility, and the occurrence of static liquefaction. The experiments were performed at low consolidation pressures at which liquefaction may occur in near-surface, natural deposits. The presence of fines creates a particle structure in the soil that is highly compressible, enhancing the potential for liquefaction, and the fines also alter the basic stress-strain and volume change behavior, which should be modeled to predict the occurrence of static liquefaction in the field. The void ratio at which liquefaction occurs for each sand/fines mixture was determined, and the variation of compressibility with void ratio was determined for each mixture. This allowed a relation to be determined between fines content, void ratio, compressibility, and the occurrence of static liquefaction. Such relations may vary from sand to sand, but the present results are believed to indicate the trend in such relations.

Fracture properties and tensile strength of three typical sandstone materials under static and impact loads

  • Zhou, Lei;Niu, Caoyuan;Zhu, Zheming;Ying, Peng;Dong, Yuqing;Deng, Shuai
    • Geomechanics and Engineering
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    • v.23 no.5
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    • pp.467-480
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    • 2020
  • The failure behavior and tensile strength of sandstone materials under different strain rates are greatly different, especially under static loads and impact loads. In order to clearly investigate the failure mechanism of sandstone materials under static and impact loads, a series of Brazilian disc samples were used by employing green sandstone, red sandstone and black sandstone to carry out static and impact loading splitting tensile tests, and the failure properties subjected to two different loading conditions were analyzed and discussed. Subsequently, the failure behavior of sandstone materials also were simulated by finite element code. The good agreement between simulation results and experimental results can obtain the following significantly conclusions: (1) The relationship of the tensile strength among sandstone materials is that green sandstone < red sandstone < black sandstone, and the variation of the tensile sensitivity of sandstone materials is that green sandstone > red sandstone > black sandstone; (2) The mainly cause for the difference of dynamic tensile strength of sandstone materials is that the strength of crystal particles in sandstone material, and the tensile strength of sandstone is proportional to the fractal dimension; (3) The dynamic failure behavior of sandstone is greatly different from that of static failure behavior, and the dynamic tensile failure rate in dynamic failure behavior is about 54.92%.