• 제목/요약/키워드: Reinforced Cylinder

검색결과 81건 처리시간 0.018초

The Relationship between Splitting Tensile Strength and Compressive Strength of Fiber Reinforced Concretes

  • Choi, Yeol;Kang, Moon-Myung
    • 콘크리트학회논문집
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    • 제15권1호
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    • pp.155-161
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    • 2003
  • This paper presents experimental and analytical results of glass fiber-reinforced concrete (GFRC) and polypropylene fiber-reinforced concrete (PERC) to investigate the relationship between tensile strength and compressive strength based on the split cylinder test (ASTM C496) and compressive strength test (ASTM C39). Experimental studies were performed on cylinder specimens having 150 mm in diameter an 300 mm in height with two different fiber contents (1.0 and 1.5% by volume fraction) at ages of 7, 28 and 90 days. A total of 90 cylinder specimens were tested including specimens made of the plain concrete. The experimental data have been used to obtain the relationship between tensile strength and compressive strength. A representative equation is proposed for the relationship between tensile strength and compressive strength of fiber-reinforced concrete (FRC) including glass and polypropylene fibers. There is a good agreement between the average experimental results and those calculated values from the proposed equation.

Elastodynamic and wave propagation analysis in a FG graphene platelets-reinforced nanocomposite cylinder using a modified nonlinear micromechanical model

  • Hosseini, Seyed Mahmoud;Zhang, Chuanzeng
    • Steel and Composite Structures
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    • 제27권3호
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    • pp.255-271
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    • 2018
  • This paper deals with the transient dynamic analysis and elastic wave propagation in a functionally graded graphene platelets (FGGPLs)-reinforced composite thick hollow cylinder, which is subjected to shock loading. A micromechanical model based on the Halpin-Tsai model and rule of mixture is modified for nonlinear functionally graded distributions of graphene platelets (GPLs) in polymer matrix of composites. The governing equations are derived for an axisymmetric FGGPLs-reinforced composite cylinder with a finite length and then solved using a hybrid meshless method based on the generalized finite difference (GFD) and Newmark finite difference methods. A numerical time discretization is performed for the dynamic problem using the Newmark method. The dynamic behaviors of the displacements and stresses are obtained and discussed in detail using the modified micromechanical model and meshless GFD method. The effects of the reinforcement of the composite cylinder by GPLs on the elastic wave propagations in both displacement and stress fields are obtained for various parameters. It is concluded that the proposed micromechanical model and also the meshless GFD method have a high capability to simulate the composite structures under shock loadings, which are reinforced by FGGPLs. It is shown that the modified micromechanical model and solution technique based on the meshless GFD method are accurate. Also, the time histories of the field variables are shown for various parameters.

강섬유보강 폴리머침투 콘크리트 원통형구조의 충격거동 (Impact Behavior of Steel Fiber Reinforced Polymer-Impregnated Concrete Cylinder)

  • 변근주;정기영;김종우;심별;송하원
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 1995년도 봄 학술발표회 논문집
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    • pp.350-354
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    • 1995
  • This paper is about impact behavior of cylinder container, made of steel fiber reinforced polymer-impregnated concrete(SFPIC), for intermediate and low level radwaste disposal. In order to obtain the material properties of the SFPIC, steel ball impact tests were done to SFPIC beams and its simulation by finite element method was performed. By using the material properties in finite element impact analysis of the SFPIC concrete cylinder, we obtained impact behavior of the cylinder.

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경계요소법에 의한 콘크리트 원통형관의 파괴해석 (Fracture Analysis of Concrete Cylinder by Boundary Element Method)

  • 송하원;전재홍;변근주
    • 한국전산구조공학회:학술대회논문집
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    • 한국전산구조공학회 1995년도 가을 학술발표회 논문집
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    • pp.171-177
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    • 1995
  • Fracture mechanics does work for concrete, provided that one uses a proper, nonlinear form of fracture mechanics in which a finite nonlinear zone at fracture front is being considered. The fracture process zone is a region ahead of a traction-free crack, and the development of model of fracture process zone is most important to describe fracture phenomena in concrete. This paper is about fracture behavior of concrete cylinder under lateral pressure. Concrete cylinders were made of high strength normal connote, steel fiber reinforced concrete and steel fiber reinforced polymer-impregnated concrete and concrete and the fracture behavior such as cracking propagation and ultimate load are observed. The fracture process zone is modelled by a Dugdale-Barenblatt type model with linear tension-softening curve and are implemented to the boundary element technique for the fracture analyses of the cylinders. The experimental results are compared with analysis results and tension-softening curves for the steel fiber reinforced concrete and steel fiber reinforced polymer-impregnated concrete are obtained by back analyses.

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Tensile damage of reinforced concrete and simulation of the four-point bending test based on the random cracking theory

  • Chang, Yan-jun;Wan, Li-yun;Mo, De-kai;Hu, Dan;Li, Shuang-bei
    • Computers and Concrete
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    • 제30권4호
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    • pp.289-299
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    • 2022
  • Based on the random cracking theory, the cylinder RVE model of reinforced concrete is established and the damage process is divided into three stages as the evolution of the cracks. The stress distribution along longitude direction of the concrete and the steel bar in the cylinder model are derived. The equivalent elastic modulus of the RVE are derived and the user-defined field variable subroutine (USDFLD) for the equivalent elastic modulus is well integrated into the ABAQUS. Regarding the tensile rebars and the concrete surrounding the rebars as the equivalent homogeneous transversely isotropic material, and the FEM analysis for the reinforced concrete beams is conducted with the USDFLD subroutine. Considering the concrete cracking and interfacial debonding, the macroscopic damage process of the reinforced concrete beam under four-point bending loading in the simulation. The volume fraction of rebar and the cracking degree are mainly discussed to reveal their influence on the macro-performance and they are calibrated with experimental results. Comparing with the bending experiment performed with 8 reinforced concrete beams, the bending stiffness of the second stage and the ultimate load simulated are in good agreement with the experimental values, which verifies the effectiveness and the accuracy of the improved finite element method for reinforced concrete beam.

Geometrically nonlinear dynamic analysis of FG graphene platelets-reinforced nanocomposite cylinder: MLPG method based on a modified nonlinear micromechanical model

  • Rad, Mohammad Hossein Ghadiri;Shahabian, Farzad;Hosseini, Seyed Mahmoud
    • Steel and Composite Structures
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    • 제35권1호
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    • pp.77-92
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    • 2020
  • The present paper outlined a procedure for geometrically nonlinear dynamic analysis of functionally graded graphene platelets-reinforced (GPLR-FG) nanocomposite cylinder subjected to mechanical shock loading. The governing equation of motion for large deformation problems is derived using meshless local Petrov-Galerkin (MLPG) method based on total lagrangian approach. In the MLPG method, the radial point interpolation technique is employed to construct the shape functions. A micromechanical model based on the Halpin-Tsai model and rule of mixture is used for formulation the nonlinear functionally graded distribution of GPLs in polymer matrix of composites. Energy dissipation in analyses of the structure responding to dynamic loads is considered using the Rayleigh damping. The Newmark-Newton/Raphson method which is an incremental-iterative approach is implemented to solve the nonlinear dynamic equations. The results of the proposed method for homogenous material are compared with the finite element ones. A very good agreement is achieved between the MLPG and FEM with very fine meshing. In addition, the results have demonstrated that the MLPG method is more effective method compared with the FEM for very large deformation problems due to avoiding mesh distortion issues. Finally, the effect of GPLs distribution on strength, stiffness and dynamic characteristics of the cylinder are discussed in details. The obtained results show that the distribution of GPLs changed the mechanical properties, so a classification of different types and volume fraction exponent is established. Indeed by comparing the obtained results, the best compromise of nanocomposite cylinder is determined in terms of mechanical and dynamic properties for different load patterns. All these applications have shown that the present MLPG method is very effective for geometrically nonlinear analyses of GPLR-FG nanocomposite cylinder because of vanishing mesh distortion issue in large deformation problems. In addition, since in proposed method the distributed nodes are used for discretization the problem domain (rather than the meshing), modeling the functionally graded media yields to more accurate results.

터널 폼 공법에서 강제양생이 콘크리트강도에 미치는 영향 (Effect of a Heated Curing on Concrete Compressive Strength for Tunnel Form Construction)

  • 이충우;이광수;신성우
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 1993년도 가을 학술발표회 논문집
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    • pp.232-236
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    • 1993
  • The Tunnel Form(T/F) system instead of traditional euro form has been tried to reduce construction duration and to improve concrete quality in reinforced concrete wall type apartment construction. To find the relationship for concrete compressive strength between cylinder mold and slab, the different curing locations of concrete cylinder mold in the room have been investigated. The test results showed that the compressive strength of the cylinder concrete with middle-upper location in the room was most near concrete compression strength with respect to slab concrete strength.

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강/복합재 이중구조 실린더 설계를 위한 유한요소 해석 (Finite Element Analysis for the Design of Fiber Reinforced Metal Cylinder)

  • 김태환;김위대;정철곤
    • Composites Research
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    • 제26권1호
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    • pp.7-13
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    • 2013
  • 본 연구에서는 특수강과 복합재료를 사용한 이중구조 실린더의 설계를 위한 해석에 대해서 기술하였다. 특수강과 복합재의 이중구조는 제품의 특성에 적합한 물성을 유지하면서도 무게를 절감해 줄 수 있으며, 이로 인해 고탄성 저중량을 필요로 하는 각종 지상무기 산업분야와 항공분야, 스포츠 관련 분야 등에 점차 확대 적용되고 있다. 따라서 본 연구에서는 하나의 설계에 복합재의 적층각, 종류 등을 바꾸어 가며 이중구조의 설계에 가장 적합한 복합재 적용 방법을 찾기 위해 해석을 실시하였다. 또한 해석의 결과 값들의 비교를 통해 본 연구 설계목표에 가장 알맞은 복합재 적용 방법을 제시하였다.

Fiber Reinforced Framework를 이용한 Implant 수복증례 (Implant Restorations Using Fiber Reinforced Framework)

  • 송호용;이양진;조리라
    • 대한심미치과학회지
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    • 제10권2호
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    • pp.21-30
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    • 2001
  • Fiber reinforced materials have favorable mechanical properties. Moreover, the strength to weight ratios of this material is superior to those of most alloys. Comparing to the metals, it showed many other advantages as well, including non-corrosiveness, translucency and easy repair characteristic. Since, it has the potential for the chair-side and laboratory fabrication, it is not surprising that fiber reinforced composites offer the potential for use in various applications in dentistry. To make the well-fitted restorations, Fiber reinforced composite (FRC) has been suggested as an alternative framework material for the implant supported fixed prosthesis. Two fixed partial denture fabrication procedures were tried. Vectris fiber was pressed to the EsthetiCone gold cylinder on the implant positioned cast. And then, Targis were added on it. In the other method, we used the customized component using UCLA abutment. The beads for retaining the Vectris fiber were added on the abutment. If careful laboratory and clinical techniques were done, these two techniques would fulfill the demands of the esthetics and strength.

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Transient heat transfer analysis of functionally graded CNT reinforced cylinders with various boundary conditions

  • Moradi-Dastjerdi, Rasool;Payganeh, Gholamhassan
    • Steel and Composite Structures
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    • 제24권3호
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    • pp.359-367
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    • 2017
  • In this work, transient heat transfer analysis of functionally graded (FG) carbon nanotube reinforced nanocomposite (CNTRC) cylinders with various essential and natural boundary conditions is investigated by a mesh-free method. The cylinders are subjected to thermal flux, convection environments and constant temperature faces. The material properties of the nanocomposite are estimated by an extended micro mechanical model in volume fraction form. The distribution of carbon nanotube (CNT) has a linear variation along the radial direction of axisymmetric cylinder. In the mesh-free analysis, moving least squares shape functions are used for approximation of temperature field in the weak form of heat transform equation and the transformation method is used for the imposition of essential boundary conditions. Newmark method is applied for solution time depended problem. The effects of CNT distribution pattern and volume fraction, cylinder thickness and boundary conditions are investigated on the transient temperature field of the nanocomposite cylinders.