Search for: carbon-fibers
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    Interface behavior between carbon-fiber polymer and sand

    , Article Journal of Testing and Evaluation ; Volume 44, Issue 1 , 2016 , Pages 385-390 ; 00903973 (ISSN) Toufigh, V ; Ouria, A ; Desai, C. S ; Javid, N ; Toufigh, V ; Saadatmanesh, H ; Sharif University of Technology
    ASTM International  2016
    Interface shear strength between soil and structural materials is dependent on the confining pressure. To increase the confining pressure, different methods of reinforcement and materials, such as carbon-fiber-reinforced polymer (CFRP) can be used. The shear strength of CFRP-improved soil is dependent on the interface properties of the soil and CFRP. The objective of this study is to investigate the interface properties (friction angle and adhesion) of sand and FRP experimentally using the direct shear test apparatus. To increase the surface roughness to improve the interface properties, a layer of sand was placed on saturated carbon fiber during the curing period [spark plasma sintering... 

    Highly efficient and stable perovskite solar cells based on a low-cost carbon cloth

    , Article Advanced Energy Materials ; Volume 6, Issue 20 , 2016 ; 16146832 (ISSN) Gholipour, S ; Correa Baena, J. P ; Domanski, K ; Matsui, T ; Steier, L ; Giordano, F ; Tajabadi, F ; Tress, W ; Saliba, M ; Abate, A ; Morteza Ali, A ; Taghavinia, N ; Grätzel, M ; Hagfeldt, A ; Sharif University of Technology
    Wiley-VCH Verlag  2016
    A low-cost carbon cloth is applied in perovskite solar cells (PSC) as a collector composite and degradation inhibitor. This study incorporates carbon fibers as a back contact in perovskite solar cells, which results in enhancement in all photovoltaic parameters. This material is suitable for large-scale fabrication of PSCs as it has shown an improved long-term stability when compared to the gold counterpart under elevated temperatures  

    Rapid manufacturing

    , Article Collaborative Engineering: Theory and Practice ; 2008 , Pages 127-152 ; 9780387473192 (ISBN) Asiabanpour, B ; Mokhtar, A. R ; Houshmand, M ; Sharif University of Technology
    Springer US  2008
    This chapter defines rapid manufacturing (RM) as a technique for manufacturing solid objects by the sequential delivery of energy and/or material to specified points in space. Current practice is to control the manufacturing process by using a computer-generated mathematical model. This chapter compares the large speed and cost advantages of RM to alternative polymer or metal manufacturing techniques such as powder metallurgy manufacturing or die casting. Moreover, the RM as an application of solid freeform fabrication for direct manufacturing of goods is addressed. Unlike methods such as computer numerical control (CNC) milling, these techniques allow the fabricated parts to be of high... 

    Behavior of square concrete columns strengthened with Carbon Fiber Reinforced Polymer (CFRP) strips

    , Article 1st International Conference on Concrete Repair, Rehabilitation and Retrofitting, ICCRRR 2005, Cape Town, 21 November 2005 through 23 November 2005 ; 2006 , Pages 471-473 ; 0415396549 (ISBN); 9780415396547 (ISBN) Taleie, S. M ; Moghaddam, H ; Sharif University of Technology
    Reinforced concrete columns with insufficient transverse steel reinforcement are not capable to dissipate seismic energy due to lack of necessary ductility. In this research, six RC columns with poor transverse reinforcements are tested under cyclic and axial loads as control columns and retrofitted ones. Prestressed and non-pre-stressed CFRP strips used as external transverse reinforcement to evaluate the benefits of active and passive confinement. Results indicate that additional confinement due to the use of CFRP strips enhances the strength, ductility and energy dissipation capacity of columns. The advantages of active confinement versus passive confinement are demonstrated too. © 2006... 

    Corrosion Resistance of Steel Reinforcement in Concrete Using Cellulose and Carbon Fiber Materials in Persian Gulf Water

    , M.Sc. Thesis Sharif University of Technology Gharaei, Pedram (Author) ; Zabihollah, Abolghasem (Supervisor) ; Shams, Mohammad Reza (Supervisor)
    Corrosion study of the reinforced concrete is one of the most commonly investigation for the construction in civil engineering. The corrosion of embedded steel for the structures in the marine area like the Persian Gulf Sea Water needed considerable attentions. Presence of chlorides and decrease of pH in pores reinforcement depth of concrete is a serious problem. Research the corrosion rate in reinforced concrete system using fibers with a rebar is investigated. Cellulose and Carbon fiber materials are used as inhibitors. The addition of small quantities of these materials into the concrete mixture, will change the concrete permeability and the corrosion resistance rate. Tests demonstrate... 

    Increasing the interfacial adhesion in poly(methyl methacrylate)/carbon fibre composites by laser surface treatment

    , Article Polymers and Polymer Composites ; Volume 14, Issue 6 , 2006 , Pages 585-589 ; 09673911 (ISSN) Nematollahzadeh, A ; Mousavi, S. A. S ; Tilaki, R. M ; Frounchi, M ; Sharif University of Technology
    Rapra Technology Ltd  2006
    The impact strength of poly(methyl methacrylate)/caibon (long) fibre composites for denture prosthesis applications was improved by fibre surface treatment. The carbon fibre surfaces were modified by Nd:YAG laser irradiation at 1064 nm wavelength. Laser light intensity was adjusted at 100 mj per pulse that only changed the fibre surface roughness and did not lead to fibre rupture, as verified by scanning electron microscopy. Increased surface roughness of the fibres improved the adhesion of poly(methyl methacrylate) to the fibre surface. Adhesion between the fibres and poly(methyl methacrylate) was evaluated by a tear-off method and by scanning electron microscopy. The results also suggest... 

    Effect of short carbon fiber on thermal, mechanical and tribological behavior of phenolic-based brake friction materials

    , Article Composites Part B: Engineering ; Volume 168 , 2019 , Pages 98-105 ; 13598368 (ISSN) Ahmadijokani, F ; Shojaei, A ; Arjmand, M ; Alaei, Y ; Yan, N ; Sharif University of Technology
    Elsevier Ltd  2019
    The phenolic-based brake friction composites containing 0, 1, 2 and 4 vol% carbon fiber were fabricated in this study. Thermogravimetric analysis (TGA) revealed the adverse impact of carbon fiber on the thermal stability of the composites under air atmosphere. Differential scanning calorimetry (DSC) of the uncured samples indicated the positive impact of carbon fiber on the crosslink density of the phenolic resin. Viscoelastic results drawn from the dynamic-mechanical analysis (DMA) suggested that inclusion of carbon fiber increased the storage modulus and decreased the damping factor of the frictional composites. The tribological behavior of the specimens was assessed with a chase type... 

    Seismic behavior comparison of RC shear walls strengthened using FRP composites and steel elements

    , Article Scientia Iranica ; Volume 28, Issue 3 A , 2021 , Pages 1-27 ; 10263098 (ISSN) Habibi, O ; Khaloo, A ; Abdoos, H ; Sharif University of Technology
    Sharif University of Technology  2021
    This paper aims at investigating the seismic behavior of strengthened reinforced concrete (RC) shear walls using a 3D finite element analysis. A series of four different configurations of carbon fiber reinforced polymer (CFRP) composites and four different schemes of steel elements are utilized to compare the two methods of retrofitting RC shear walls with similar dimensions and reinforcement ratios. Nonlinear simulations of the RC shear walls are conducted under the action of lateral cyclic loading in ABAQUS Explicit software. In addition, the numerical modeling for RC walls strengthened by CFRP composites as well as steel elements are validated according to the previous experimental... 

    Investigation of the Role of Fiber Reinforcement on the Performance of Rubber Based Friction Material

    , M.Sc. Thesis Sharif University of Technology Arjmand, Mohammad (Author) ; Shojaei, Akbar (Supervisor)
    Friction composites, as a part of vehicle safety system, should hold some characteristics such as high wear resistance, low weight, durability, low noise, stable friction coefficient, availability and low price. It is very interested to use mixture of rubber and resin in friction materials to reach good properties of both rubber and resin simultaneously. This mixture is especially used in railway’s brake pads. Fibrous reinforcement is another important ingredient in friction composites. Asbestos used to be the most significant fibrous reinforcement due to its appropriate tribological specifications but the recent ban on asbestos by environmental protection agency has forced the friction... 

    Experimental Investigation on Debonding between FRP sheets and Structures

    , M.Sc. Thesis Sharif University of Technology Haghighi, Sina (Author) ; Toufigh, Vahab (Supervisor)
    This study has investigated the effects of different environmental conditions on the bond at the interface between two fiber reinforced polymer (FRP) layers. A total of 945 single lap splice coupons with three bond length were made using wet lay-up technic. There were used three unidirectional fabrics and one type of epoxy resin. A Uniaxial tensile test was performed on samples after 2, 4, 12, 20, 28, 36 and 48 weeks of exposure. Also series of test were conducted in order to determine the minimum lap splice length of single splice FRP samples. The experimental results indicated reduction of bond strength in glass specimens that was 17 % after 48 weeks of exposure while for same amount of... 

    Effect of Carbon Fiber on Frictional and Wear Properties of Automotive Brake Pads

    , M.Sc. Thesis Sharif University of Technology Ahmadi Joukani, Farhad (Author) ; Shojaei, Akbar (Supervisor)
    In the recent decade, composites have been used in safety system of automobiles due to important characteristics such as high wear resistant and durability, low weight and also low noise pollution, stable friction coefficient, availability and low cost. In recent years, composites have attracted the attention of brake pads manufacturers because of their appropriate thermal and mechanical properties. Fibers play an important role in these material. Carbon fiber due to its features such as high strength, acceptable module, proper heat transfer coefficient and excellent resistant against thermal degradation has been considered by the experts but there is not any comprehensive research on... 

    Modeling of the Behavior of Prestressed Concrete Column Confined by CFRP Composites

    , M.Sc. Thesis Sharif University of Technology Yazdani, Mohammad (Author) ; Kazemi, Mohammad Taghi (Supervisor)
    Because of mistakes in the design and calculation, incoherence between construction and design, structural changes, changes in loads and also damages caused by the passage of the time, concrete structures need to be improved and strengthened. Polymeric sheets reinforced by fibers (FRP), according to their appropriate characteristic, are more efficient for strengthening concrete structures. Most studies on confined columns refers to confined RC columns with FRP and less mentioned about prestressed columns. In this study, the behavior of prestressed columns is analyzed by modeling a case of prestressed column in a nonlinear analysis software. Samples of confined concrete columns with CFRP and... 

    Exact formulations of non-linear planar and spatial Euler-Bernoulli beams with finite strains

    , Article Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science ; Volume 226, Issue 5 , 2012 , Pages 1225-1236 ; 09544062 (ISSN) Abedinnasab, M. H ; Zohoor, H ; Yoon, Y. J ; Sharif University of Technology
    Using Hamilton's principle, exact equations of motion for non-linear planar and spatial Euler-Bernoulli beams are derived. In the existing non-linear Euler-Bernoulli beam formulations, some elastic terms are dropped by differentiation from the incomplete Green-Lagrange strain tensor followed by negligible elastic deformations of cross-sectional frame. On the other hand, in this article, the exact strain field concerning considerable elastic deformations of cross-sectional frame is used as a source in differentiations. As a result, the achieved closed-form equations are exact and more accurate than formerly reported equations in the literature. Moreover, the applicable dynamic model of... 

    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... 

    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... 

    A data mining approach to compressive strength of CFRP-confined concrete cylinders

    , Article Structural Engineering and Mechanics ; Volume 36, Issue 6 , Dec , 2010 , Pages 759-783 ; 12254568 (ISSN) Mousavi, S. M ; Alavi, A. H ; Gandomi, A. H ; Arab Esmaeili, M ; Gandomi, M ; Sharif University of Technology
    In this paper, compressive strength of carbon fiber reinforced polymer (CFRP) confined concrete cylinders is formulated using a hybrid method coupling genetic programming (GP) and simulated annealing (SA), called GP/SA, and a robust variant of GP, namely multi expression programming (MEP). Straightforward GP/SA and MEP-based prediction equations are derived for the compressive strength of CFRP-wrapped concrete cylinders. The models are constructed using two sets of predictor variables. The first set comprises diameter of concrete cylinder, unconfined concrete strength, tensile strength of CFRP laminate, and total thickness of CFRP layer. The most widely used parameters of unconfined concrete... 

    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... 

    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... 

    High-Performance fiber-shaped flexible asymmetric microsupercapacitor based on ni(oh)2 nanoparticles-decorated porous dendritic ni-cu film/cu wire and reduced graphene oxide/carbon fiber electrodes

    , Article ACS Sustainable Chemistry and Engineering ; Volume 6, Issue 11 , 2018 , Pages 14574-14588 ; 21680485 (ISSN) Shahrokhian, S ; Naderi, L ; Mohammadi, R ; Sharif University of Technology
    American Chemical Society  2018
    Miniaturization of electronic devices with portable, flexible and wearable characteristics created a great demand for high-performance microscale energy storage devices with lightweight and flexible properties. Among the energy storage devices, wire-shaped supercapacitors (WSSCs) have recently received tremendous attention due to their tiny volume, wearability, high flexibility and potential applications in the next-generation portable/wearable electronic devices. Herein, we successfully fabricated a porous dendritic Ni-Cu film on Cu wire substrate (CWE) for fabrication of high-performance wire-type supercapacitors. The porous structure with dendritic morphology provides a high surface area,...