Search for: reinforced-plastics
0.04 seconds
Total 111 records

    Environmental effects on the bond at the interface of fiber-reinforced polymer and masonry brick

    , Article Journal of Reinforced Plastics and Composites ; Volume 36, Issue 18 , 2017 , Pages 1355-1368 ; 07316844 (ISSN) Toufigh, V ; Yarigarravesh, M ; Mofid, M ; Sharif University of Technology
    This study examined the bond at the interface of masonry bricks and fiber-reinforced polymer when exposed to five environments. Three fabrics (aramid, carbon, and glass) and one type of epoxy resin were used. A total of 375 brick-fiber-reinforced polymer specimens were made using wet lay-up technic and exposed to chemical solutions at four pH values (2.5, 7, 10, and 12.5) and substitute seawater. The effect of dry heat on the bond at the interface was also investigated. Single-lap shear tests were then carried out on the samples after 2, 4, 6, 8, 10, and 13 weeks of exposure. The experimental results indicated that freshwater and seawater had a considerable effect on the bond strength of... 

    The effect of elevated temperatures on the tensile performance of GFRP and CFRP sheets

    , Article Construction and Building Materials ; Volume 190 , 2018 , Pages 38-52 ; 09500618 (ISSN) Jarrah, M ; Pournamazian Najafabadi, E ; Houshmand Khaneghahi, M ; Vatani Oskouei, A ; Sharif University of Technology
    Elsevier Ltd  2018
    In this study, the effects of fiber type (i.e., carbon and glass fibers) and intumescent paint on the tensile performance of fiber reinforced polymer (FRP) sheets at elevated temperatures are investigated. For this purpose, a series of tensile tests were conducted on the glass and carbon fiber reinforced polymer (GFRP and CFRP) sheets, with and without intumescent fire retardant paint, at different elevated temperatures. The studied temperatures ranged from 25 °C to 600 °C. Scanning electron microscopy was also used to examine the effects of elevated temperatures on FRP sheets and the fire protecting mechanism of the intumescent paint. Based on the test results, the tensile strength of the... 

    The tensile performance of FRP bars embedded in concrete under elevated temperatures

    , Article Construction and Building Materials ; Volume 211 , 2019 , Pages 1138-1152 ; 09500618 (ISSN) Pournamazian Najafabadi, E ; Vatani Oskouei, A ; Khaneghahi, M. H ; Shoaei, P ; Ozbakkaloglu, T ; Sharif University of Technology
    Elsevier Ltd  2019
    In this research, the mechanical properties of glass and carbon fiber reinforced polymer (FRP) bars with epoxy resin matrices embedded in concrete were investigated under an extensive range of elevated temperatures (i.e., 25–800 °C). Embedded FRP bars with various bar diameters were studied in order to determine bar diameter influence on the results. In addition, analysis of variance (ANOVA) was performed on the experimental results to investigate the contribution of exposure temperature and bar diameter to the tensile behavior of embedded in concrete FRP bars at elevated temperatures. The results show that the tensile strength of embedded FRP bars generally decreases with increasing... 

    Enhancement of bond characteristics of ribbed-surface GFRP bars with concrete by using carbon fiber mat anchorage

    , Article Construction and Building Materials ; Volume 134 , 2017 , Pages 507-519 ; 09500618 (ISSN) Ashrafi, H ; Bazli, M ; Vatani Oskouei, A. V ; Sharif University of Technology
    The bond of fiber-reinforced polymer (FRP) reinforcement is expected to be more sensitive to the strength and geometry of the ribs than conventional steel reinforcement. In this study, the effect of carbon fiber mat anchorage on the pullout behavior of glass fiber-reinforced polymer (GFRP) bars embedded in normal concrete is studied. The studied parameters were the compressive strength of the concrete (16 MPa, 24 MPa, and 37 MPa), and, the length and diameter of the anchorage. In total, 15 variables were studied. Ribbed GFRP bars with 10 mm nominal diameter and 80 mm embedment length, ld, (which is 8 times the bar diameter) were considered. Based on the results for concretes with the... 

    Intelligent control of an IPMC actuated manipulator using emotional learning-based controller

    , Article Metamaterials: Fundamentals and Applications, San Diego, CA, 10 August 2008 through 13 August 2008 ; Volume 7029 , 2008 ; 0277786X (ISSN) ; 9780819472496 (ISBN) Shariati, A ; Meghdari, A ; Shariati, P ; Sharif University of Technology
    In this research an intelligent emotional learning controller, Takagi- Sugeno- Kang (TSK) is applied to govern the dynamics of a novel Ionic-Polymer Metal Composite (IPMC) actuated manipulator. Ionic-Polymer Metal Composites are active actuators that show very large deformation in existence of low applied voltage. In this research, a new IPMC actuator is considered and applied to a 2-dof miniature manipulator. This manipulator is designed for miniature tasks. The control system consists of a set of neurofuzzy controller whose parameters are adapted according to the emotional learning rules, and a critic with task to assess the present situation resulted from the applied control action in... 

    Hot deformation behavior of P/M Al6061-20% SiC composite

    , Article 2006 Powder Metallurgy World Congress and Exhibition, PM 2006, Busan, 24 September 2006 through 28 September 2006 ; Volume 534-536, Issue PART 2 , 2007 , Pages 897-900 ; 02555476 (ISSN); 0878494197 (ISBN); 9780878494194 (ISBN) Asgharzadeh, H ; Simchi, A
    Trans Tech Publications Ltd  2007
    In the present work, hot workability of particulate-reinforced Al6061-20%SiC composite produced by direct hot extrusion technique was studied. Uniaxial hot compression test at various temperatures and strain rates was used and the workability behavior was evaluated from the flow curves and the attendant microstructures. It was shown that the presence of SiC particles in the soft Al6061 matrix deteriorates the hot workability. Bulging of the specimens and flow lines were observed, which indicates the plastic instability during hot working. Microstructure of the composites after hot deformation was found to be heterogeneous, i.e. the reinforcement clusters were observed at the flow lines. The... 

    Seismic performance of high-strength concrete square columns confined with carbon fiber reinforced polymers (CFRPs)

    , Article Canadian Journal of Civil Engineering ; Volume 32, Issue 3 , 2005 , Pages 569-578 ; 03151468 (ISSN) Hosseini, A ; Khaloo, A. R ; Fadaee, S ; Sharif University of Technology
    This paper presents the results of an experimental and analytical study on high-strength, reinforced-concrete (RC) columns with different levels of initial ductility enhanced with carbon fiber reinforced polymer (CFRP) wraps. Six square columns 260 mm wide and 1650 mm long were tested under constant axial load and reversed cyclic lateral load. The test specimens were divided into three groups. Groups I and II were designed and detailed according to the requirements of American Concrete Institute ACI318-02 for intermediate-moment frames. Group I was wrapped with CFRP, group II was control specimens, and group III was designed and detailed according to the requirements of ACI318-02 for... 

    Experimental investigation of square RC column strengthened with near surface mounted GFRP bars subjected to axial and cyclic lateral loads

    , Article Scientia Iranica ; Volume 20, Issue 5 , 2013 , Pages 1361-1371 ; 10263098 (ISSN) Dayhim, N ; Nicknam, A ; Barkhordari, M. A ; Hosseini, A ; Mehdizad, S ; Sharif University of Technology
    Sharif University of Technology  2013
    This article is intended to highlight the effectiveness of longitudinal Glass Fiber Reinforced Polymer (GFRP) bars in combination with GFRP sheets on the flexural capacity of Reinforced Concrete (RC) columns. Seven half-scale RC columns including five strengthened and two control unstrengthened specimens were experimentally tested under axial and cyclic lateral loads. The strengthened columns with two different longitudinal GFRP bar ratios were tested under three different axial load levels. The flexural strength and ductility parameters of the specimens were calculated by obtaining their deformations and measuring the loads from load cells. The experimental results indicate significant... 

    Parametric study of strain rate effects on nanoparticle-reinforced polymer composites

    , Article Journal of Nanomaterials ; Volume 2016 , 2016 ; 16874110 (ISSN) Soltannia, B ; Haji Gholami, I ; Masajedian, S ; Mertiny, P ; Sameoto, D ; Taheri, F ; Sharif University of Technology
    Hindawi Publishing Corporation  2016
    Crashworthiness, energy absorption capacity, and safety are important factors in the design of lightweight vehicles made of fiber-reinforced polymer composite (FRP) components. The relatively recent emergence of the nanotechnology industry has presented a novel means to augment the mechanical properties of various materials. As a result, recent attempts have contemplated the use of nanoparticles to further improve the resiliency of resins, especially when resins are used for mating FRP components. Therefore, a comprehensive understanding of the response of nanoreinforced polymer composites, subjected to various rates of loading, is of paramount importance for developing reliable structures.... 

    Finite element analysis of a CFRP reinforced retaining wall

    , Article Geomechanics and Engineering ; Volume 10, Issue 6 , 2016 , Pages 757-774 ; 2005307X (ISSN) Ouria, A ; Toufigh, V ; Desai, C ; Toufigh, V ; Saadatmanesh, H ; Sharif University of Technology
    Techno Press 
    Soils are usually weak in tension therefore different materials such as geosynthetics are used to address this inadequacy. Worldwide annual consumption of geosynthetics is close to 1000 million m2, and the value of these materials is probably close to US$1500 million. Since the total cost of the construction is at least four or five times the cost of the geosynthetic itself, the impact of these materials on civil engineering construction is very large indeed. Nevertheless, there are several significant problems associated with geosynthetics, such as creep, low modulus of elasticity, and susceptibility to aggressive environment. Carbon fiber reinforced polymer (CFRP) was introduced over two... 

    Strengthening of metallic beams with different types of pre-stressed un-bonded retrofit systems

    , Article Composite Structures ; Volume 159 , 2017 , Pages 81-95 ; 02638223 (ISSN) Kianmofrad, F ; Ghafoori, E ; Elyasi, M. M ; Motavalli, M ; Rahimian, M ; Sharif University of Technology
    Elsevier Ltd  2017
    Unlike bonded retrofit systems, un-bonded systems do not need any surface preparation prior to bond application, which reduces the overall time and cost of a retrofit plan. Because the carbon fiber reinforced polymer (CFRP) plate in the un-bonded (tendon) systems is not bonded to a metallic substrate, different variants of the retrofit systems can be developed to ease application in the field. This paper presents four different variants of the prestressed un-bonded retrofit (PUR) systems: trapezoidal PUR (TPUR), triangular PUR (TriPUR), Flat PUR (FPUR), and Contact PUR (CPUR) systems. Analytical solutions based on the flexibility approach are developed to predict the behavior of the metallic... 

    Experimental and analytical evaluation of FRPs bonded to masonry-long term

    , Article Surface and Coatings Technology ; Volume 344 , 25 June , 2018 , Pages 729-741 ; 02578972 (ISSN) Yarigarravesh, M ; Toufigh, V ; Mofid, M ; Sharif University of Technology
    Elsevier B.V  2018
    This research investigated the long-term environmental effects on the bond at the interface between fiber-reinforced polymer (FRP) and a masonry brick. Seven types of FRP fabrics were used and placed on the masonry brick using the wet lay-up technique. Unidirectional and bidirectional fibers made of aramid, carbon, and glass and also combination of these fabrics were used. A total of 525 specimens were exposed to five chemical solutions with pH values of 2.5, 7, 10, 12.5 and substitution sea water for 1, 3, 6, 9 and 12 months. A chamber was also used to simulate the ultraviolent (UV) radiation on the specimens. A series of single-lap shear tests were performed on these specimens to determine... 

    Effect of thermal cycles on mechanical response of pultruded glass fiber reinforced polymer profiles of different geometries

    , Article Composite Structures ; Volume 223 , 2019 ; 02638223 (ISSN) Jafari, A ; Ashrafi, H ; Bazli, M ; Ozbakkaloglu, T ; Sharif University of Technology
    Elsevier Ltd  2019
    This study investigates the effect of Thermal cycles on the mechanical properties of GFRP pultruded profiles with different geometries. Bending specimens consisted of I-shaped and U-channel profiles that were tested in three-point bending along their both principal weak and strong axes, whereas box profiles and laminates were used in compression and tension tests, respectively. Each specimen was exposed to a range of thermal cycles, between −20 °C and 20 °C. The failure modes of the profiles were closely investigated at both major and minor scales. Results were analyzed using ANOVA to determine the influence of each factor and a model was developed to predict the strength retention of... 

    Seismic behavior of concrete moment frame reinforced with GFRP bars

    , Article Composites Part B: Engineering ; Volume 163 , 2019 , Pages 324-338 ; 13598368 (ISSN) Aliasghar Mamaghani, M ; Khaloo, A ; Sharif University of Technology
    Elsevier Ltd  2019
    In this research, four types of concrete moment frame were designed with glass fiber reinforced polymer (GFRP) bars according to ACI 440.1R-15 and the seismic behavior was assessed using pushover analysis. The frames were three and five stories with two and three bays. A computer code was developed to calculate the amount of fiber reinforced polymer bars in beams of the frames. In order to evaluate nonlinear behavior in plastic hinge regions, sections of beams and columns were analyzed on the basis of moment-curvature diagram and also P-M interaction curve for columns. Performance levels of frames were determined considering ATC-40 criteria. Behavior of concrete moment frames reinforced with... 

    Effect of fibers configuration and thickness on tensile behavior of GFRP laminates subjected to elevated temperatures

    , Article Construction and Building Materials ; Volume 202 , 2019 , Pages 189-207 ; 09500618 (ISSN) Jafari, A ; Bazli, M ; Ashrafi, H ; Vatani Oskouei, A ; Azhari, S ; Zhao, X. L ; Gholipour, H ; Sharif University of Technology
    Elsevier Ltd  2019
    This study was aimed at gaining an improved understanding of the behavior of glass fiber-reinforced polymer laminates at elevated temperatures by means of testing laminate specimens with unidirectional, woven, and randomly distributed (chopped strand mat) fibers. The testing parameters were temperature, the type of fiber, and the thickness of the laminates. The failure modes of the specimens and their elasticity moduli at ambient temperature were investigated, and analysis of variance was conducted to determine the contribution of each parameter to the behavioral test results. The findings showed that among the parameters, an increase in temperature exerted the strongest effect on the... 

    Damage behavior of fiber reinforced composite plates subjected to drop weight impacts

    , Article Composites Science and Technology ; Volume 66, Issue 1 , 2006 , Pages 61-68 ; 02663538 (ISSN) Hosseinzadeh, R ; Shokrieh, M. M ; Lessard, L ; Sharif University of Technology
    Fiber reinforced materials are widely used in many industrial structures including automotive, aviation, and civil due to their lower weights compared to metal structures. Full-composite body structures, especially in automotive and aviation applications, are becoming a proper replacement for current metal ones. For this reason, damage of such structures subjected to impact is a crucial case study in current research. The typical types of damages are mainly caused during production, repair, maintenance, or by particle crashes during function, and collisions between different structures. In this paper, four different fiber reinforced composite plates are studied after being impacted by a... 

    Investigation of Dynamic Behavior of Concrete Slabs Reinforced with GFRP Bars and Prestressed Concrete Slabs under Impact Loading

    , Ph.D. Dissertation Sharif University of Technology Sadraie, Hamid (Author) ; Khaloo, Alireza (Supervisor)
    Prestressed and reinforced concrete slabs are common structural elements that could be exposed to impact loading. Although, use of reinforced concrete slabs and utilization of Fiber Reinforced Polymer (FRP) as alternative to traditional steel reinforcement slabs are growing, but the influence of various parameters on their response under impact loads is not properly evaluated. In addition, studies on steel reinforced concrete slabs have been found in literature, but investigation of prestressed slabs and GFRP reinforced concrete slabs under impact load is limited. This study investigated the effect of rebar’s material, amount and arrangement of reinforcements, concrete strength and slab... 

    Strengthening Reinforced Concrete Deep Beams Using FRP Systems

    , M.Sc. Thesis Sharif University of Technology Mesgarian, Iman (Author) ; Kazemi, Mohammad Taghi (Supervisor)
    In recent years, the development of the plate bonding repair technique has been shown to be applicable to many existing strengthening problems in the building industry. This technique may be defined as one in which composite sheets or plates of relatively small thickness are bonded with an epoxy adhesive to, in most cases, a concrete structure to improve its structural behaviour and strength. The sheets or plates do not require much space and give a composite action between the adherents. The old structure and the new bonded-on material create a new structural element that has a higher strength and stiffness than original one. According to the available methods of analysis and design for... 

    A Study on the Effect of Different Lubrication Methods on Surface Integrity and Tool Wear during Ultrasonic-Assisted Milling of CFRP

    , M.Sc. Thesis Sharif University of Technology Amirnia, Mahan (Author) ; Akbari, Javad (Supervisor)
    The aim of this study was to compare the effect of different cooling conditions (dry, flood, mql) on machined surface parameters (smoothness and protrusion of fibers) and tool erosion in carbon fiber reinforced plastic composite materials (CFRP) in the presence of ultrasonic vibrations or without it. Is. Today, carbon fiber reinforced plastic composite materials or CFRP have become one of the most widely used materials in industry due to their strength and light properties. For example, these materials have been used in the manufacture of products from commercial aircraft to shoes, tennis rackets, golf clubs, fishing rods, etc. The combination of carbon fibers woven with resin in alternating... 

    Fabrication and Investigation of Structure and Mechanical Properties of Bagasse Fibers Reinforced PP: Role of Alkalization and Calcium Carbonate Filler

    , M.Sc. Thesis Sharif University of Technology Asgharpour, Ali (Author) ; Bagheri, Reza (Supervisor)
    The consumption of plastics in the world is increasing and this is accompanied by the challenges of production from oil products and carbon footprint, waste production and environmental issues. The solutions to these challenges are material recycling and the production of biocompatible plastics. Polypropylene is a widely used polymer that is commonly used in conjunction with reinforcements such as fiberglass. Natural fibers can be substituted to increase the biocompatibility of the composite, which, despite its many advantages, presents challenges. The most important challenge is the poor adhesion of the fibers and the matrix due to the hydrophilicity of natural fibers and hydrophobicity of...