• Title/Summary/Keyword: fiber model

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Nonlinear Failure Analysis of Reinforced Concrete Structures using Fiber Model (파이버모델에 의한 철근콘크리트 구조물의 비선형 파괴해석)

  • 송하원;김일철;변근주
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 1998.04a
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    • pp.127-134
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    • 1998
  • The objectives of this paper is to analyze the reinforced concrete structures by using fiber model. In this study, the fiber modeling techniques including modeling of support conditions are studied. In order to verify the modeling techniques, analysis results obtained for reinforced concrete cantilever beam and reinforced concrete T-girder bridge under cyclic loading are compared with experimental results from full scale test. From the comparison, it is shown that the modeling techniques in this study can be well applied to the nonlinear failure analysis of reinforced concrete structures with porper modifications.

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Investigation of elasto-plastic seismic response analysis method for complex steel bridges

  • Tang, Zhanzhan;Xie, Xu;Wang, Yan;Wang, Junzhe
    • Earthquakes and Structures
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    • v.7 no.3
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    • pp.333-347
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    • 2014
  • Multi-scale model can take both computational efficiency and accuracy into consideration when it is used to conduct elasto-plastic seismic response analysis for complex steel bridges. This paper proposed a method based on pushover analysis of member sharing the same section pattern to verify the accuracy of multi-scale model. A deck-through type steel arch bridge with a span length of 200m was employed for seismic response analysis using multi-scale model and fiber model respectively, the validity and necessity of elasto-plastic seismic analysis for steel bridge by multi-scale model was then verified. The results show that the convergence of load-displacement curves obtained from pushover analysis for members having the same section pattern can be used as a proof of the accuracy of multi-scale model. It is noted that the computational precision of multi-scale model can be guaranteed when length of shell element segment is 1.40 times longer than the width of section where was in compression status. Fiber model can only be used for the predictions of the global deformations and the approximate positions of plastic areas on steel structures. However, it cannot give exact prediction on the distribution of plastic areas and the degree of the plasticity.

Crack and Deformation Behaviors of Steel Fiber Reinforced Concrete Slab Model Specimens Using Domestic Steel Fiber (국내 강섬유를 사용한 강섬유보강 콘크리트 슬래브 모델의 균열 및 변형특성)

  • 박승범;홍석주;이봉춘;조춘근
    • Proceedings of the Korea Concrete Institute Conference
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    • 1999.04a
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    • pp.319-324
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    • 1999
  • This study is to investigate the properties on the load-deflection and fracture behaviors of the steel fiber reinforced concrete(SFRC) slab model specimens, Steel fibers of indent, crimp, and end hook shape were considered to reinforce the matrix under various mixing conditions and proportions. Initial cracking load, maximum load, and energy absorption capacity(load carrying capacity) of SFRC panel specimen increased with increase of steel fiber contents. And the plain concrete slab was fractured abruptly after maximum load but SRFC slabs were fractured smoothly by steel fibers in concrete matrix operated as cracking resistance force after maximum load. Indent, crimp and end hook shape steel fibers were effective in reinforcing the matrices but end hook type fiber were superior to indent and crimp type fibers.

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Load Carrying Capacity and Deformation Properties of Steel Fiber Reinforced Concrete Slab Model Utilizing Waste Glass by Fine Aggregates (폐유리를 잔골재로 활용한 강섬유보강 슬래브모델의 내력 및 변형률특성)

  • 박승범;김경훈;이봉춘;이준;정명일
    • Proceedings of the Korea Concrete Institute Conference
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    • 2003.05a
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    • pp.385-390
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    • 2003
  • As growing of industrialization and increasing of population, the quantities of waste glasses are rapidly growing in the earth. It cause some problems such as the waste of natural resources and environmental pollution. In this context, recycling waste glass as a material of concrete has a great advantage environmentally and economically. This study is aimed to investigate the effect of load and deflection on fiber reinforced concrete slab model utilizing waste glass by fine aggregates. The flexural strength of the concrete including waste glass increased considerably, as the inclusion rate of steel fiber were increased. And the first crack load, maximum load and energy absorption capacity increased remarkably as the inclusion rate of steel fiber were increased. Therefore, in this study we confirmed the possibility of application for the usage of waste glass to the steel fiber reinforced concrete.

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The Impregnation of Thermoplastic Resin into a Unidirectional Fiber Bundle (열가소성 수지 복합재료에서의 수지 함침)

  • Kim, Tae-Uk;Jeon, Ui-Jin;Lee, U-Il
    • 한국기계연구소 소보
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    • s.18
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    • pp.163-168
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    • 1988
  • Impregnation of molten thermoplastic resin into continuous unidirectional fiber bundles was investigated. The degree of impregnation is defined as the ratio between the number of impregnated fibers and the total number of fibers of a bundle. The degree of impregnation was modeled as a function of time, impregnation pressure, temperature and tow size assuming the radial inward flow through the fiber bundle is governed by the Darcy's law. The permeability was assumed to be constant. Experiments were performed to evaluate the validity of the medel. Today's T300 graphite fiber bundles and Polyetheretherketone(PEEK) resin was used. A fiber bundle and resin powder were put into a mold and pressure and temperature were applied. After a predetermined time, the sample was taken out and microphotographs of the cross-section were taken. From the microphotographs, the number of impregnated fibers was counted and then the degree of impregnation was determined. Experiments were also performed for different tow sizes. Good agreements were found between the model and the experiments rendering a confidence in the model.

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Simulation of Pervaporation Process Through Hollow Fiber Module for Treatment of Reactive Waste Stream from a Phenolic Resin Manufacturing Process (페놀수지 생산공정에서 배출되는 반응성 폐수처리를 위한 중공사막 모듈 투과증발 공정모사)

  • C. K Yeom;F. U. Baig
    • Membrane Journal
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    • v.13 no.4
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    • pp.257-267
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    • 2003
  • For the treatment of reactive phenolic resin waste, a simulation model of pervaporative dehydration process has been developed through hollow fiber membrane module. Some of basic parameters were determined directly from dehydration of the waste liquid through a flat sheet membrane to get realistic values. The simulation model was verified by comparing the simulated values with experimental data obtained from hollow fiber membrane module. Hollow fiber membranes with active layer coated on inside fiber were used, and feed flew through inside hollow fiber. Feed flow rate affected membrane performances and reaction by providing a corresponding temperature distribution of feed along with fiber length. Feed temperature is also a crucial factor to determine dehydration and reaction behavior by two competing ways; increasing temperature increases permeation rate as well as water formation rate. Once the permeate pressure is well below the saturated vapor pressure of feed, permeate pressure had a slightly negative effect on permeation performance by slightly reducing driving force. As the pressure approached the vapor pressure of feed, dehydration performances declined considerably due to the activity ratio of feed and permeate.

Development of Multiplexing Model for Moire-Fringe-Based Fiber Optic Sensor (무아레 프린지 기법 적용 광섬유 센서를 위한 다점 측정 모델의 개발)

  • Kim, Dae-Hyun;Lee, Yeon-Gwan;Kim, Chun-Gon
    • Journal of the Korean Society for Nondestructive Testing
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    • v.30 no.1
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    • pp.36-45
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    • 2010
  • This paper shows a multiplexing technique to maximize the application of a moire-fringe based fiber optic sensor to lots of structure. Especially, a novel fringe-based fiber optic sensor was proposed to overcome the difficulty of multiplexing of a previous moire-fringe-based fiber optic sensor. The novel fringe-based fiber optic sensor is composed of a single reflective fringe and two optical fibers. Therefore, the multiplexing is easily realized because of the simplicity of optic structure inside the sensor. This paper also proposed four models of the multiplexing techniques. The models are based on a wavelength division multiplexing(WDM) technique and a time division multiplexing(TDM) one. Basically, the models would be profitable for a general extrinsic fiber optic sensor such as the fringe-based fiber optic sensor. Finally, the real optic system was manufactured by using the proposed model and successfully examined to prove the feasibility of the model for the application.

Contact interface fiber section element: shallow foundation modeling

  • Limkatanyu, Suchart;Kwon, Minho;Prachasaree, Woraphot;Chaiviriyawong, Passagorn
    • Geomechanics and Engineering
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    • v.4 no.3
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    • pp.173-190
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    • 2012
  • With recent growing interests in the Performance-Based Seismic Design and Assessment Methodology, more realistic modeling of a structural system is deemed essential in analyzing, designing, and evaluating both newly constructed and existing buildings under seismic events. Consequently, a shallow foundation element becomes an essential constituent in the implementation of this seismic design and assessment methodology. In this paper, a contact interface fiber section element is presented for use in modeling soil-shallow foundation systems. The assumption of a rigid footing on a Winkler-based soil rests simply on the Euler-Bernoulli's hypothesis on sectional kinematics. Fiber section discretization is employed to represent the contact interface sectional response. The hyperbolic function provides an adequate means of representing the stress-deformation behavior of each soil fiber. The element is simple but efficient in representing salient features of the soil-shallow foundation system (sliding, settling, and rocking). Two experimental results from centrifuge-scale and full-scale cyclic loading tests on shallow foundations are used to illustrate the model characteristics and verify the accuracy of the model. Based on this comprehensive model validation, it is observed that the model performs quite satisfactorily. It resembles reasonably well the experimental results in terms of moment, shear, settlement, and rotation demands. The hysteretic behavior of moment-rotation responses and the rotation-settlement feature are also captured well by the model.

Modified K&C Model for Numerical Analysis of Steel-Fiber-Reinforced Concrete Structure (강섬유 보강 콘크리트 구조물의 해석을 위한 K&C모델의 보정)

  • Park, Gang-Kyu;Lee, Minjoo
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.34 no.2
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    • pp.85-91
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    • 2021
  • This paper introduces a modified Karagozian & Case concrete model (K&C model) for the numerical analysis of a steel-fiber-reinforced concrete (SFRC) structure subjected to projectile impact. The original K&C model was calibrated to consider the effects of steel fibers accurately by modifying the strength surfaces and input parameters. Single element tests were then conducted and compared with uniaxial and triaxial compressive data to verify the modified model. With the application of a dynamic increase factor, the finite element model of the SFRC structure subjected to projectile impact was constructed. Thereafter, the applicability of the modified material model was examined by comparisons with the experimental results.

Investigations on the tensile strength of high-performance fiber reinforced concrete using statistical methods

  • Ramadoss, P.;Nagamani, K.
    • Computers and Concrete
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    • v.3 no.6
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    • pp.389-400
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    • 2006
  • This paper presents the investigations towards developing a better understanding on the contribution of steel fibers on the tensile strength of high-performance fiber reinforced concrete (HPFRC). An extensive experimentation was carried out with w/cm ratios ranging from 0.25 to 0.40 and fiber content ranging from zero to 1.5 percent with an aspect ratio of 80. For 32 concrete mixes, flexural and splitting tensile strengths were determined at 28 days. The influence of fiber content in terms of fiber reinforcing index on the flexural and splitting tensile strengths of HPFRC is presented. Based on the test results, mathematical models were developed using statistical methods to predict 28-day flexural and splitting tensile strengths of HPFRC for a wide range of w/cm ratios. The expressions, being developed with strength ratios and not with absolute values of strengths and are applicable to wide range of w/cm ratio and different sizes/shapes of specimens. Relationship between flexural and splitting tensile strengths has been developed using regression analysis and absolute variation of strength values obtained was within 3.85 percent. To examine the validity of the proposed model, the experimental results of previous researchers were compared with the values predicted by the model.