Search for: polymer-matrix-composites
Total 47 records
Effect of particle size on the in vitro bioactivity, hydrophilicity and mechanical properties of bioactive glass-reinforced polycaprolactone composites [electronic resource], Article Journal of Materials Science and Engineering: C ; 10 October 2011, Volume 31, Issue 7, Pages 1526–1533 ; Bagheri, R ; Vossoughi, M ; Simchi, A. (Abdolreza) ; Sharif University of Technology
Polycaprolactone (PCL) composite films containing 5 wt.% bioactive glass (BG) particles of different sizes (6 μm, 250 nm, < 100 nm) were prepared by solvent casting methods. The ultra-fine BG particles were prepared by high-energy mechanical milling of commercial 45S5 Bioglass® particles. The characteristics of bioactive glass particles were studied by field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), dynamic light scattering (DLS), and X-ray diffraction (XRD) methods. In vitro bioactivity of the PCL/BG composite films was evaluated through immersion in the simulated body fluid (SBF). The films were analyzed by FE-SEM, energy dispersive...
Article Composites Science and Technology ; Volume 63, Issue 13 , 2003 , Pages 1931-1948 ; 02663538 (ISSN) ; Ghaffarian, S. R ; Karimian, S. M. H ; Sharif University of Technology
Elsevier BV 2003
Numerical simulation of resin transfer molding (RTM) is known as a useful method to analyze the process before the mold is actually built. In thick parts, the resin flow is no longer two-dimensional and must be simulated in a fully three-dimensional space. This article presents numerical simulations of three-dimensional non-isothermal mold filling of the RTM process. The control volume/finite element method (CV/FEM) is used in this study. Numerical formulation for resin flow is based on the concept of nodal partial saturation at the flow front. This approach permits to include a transient term in the working equation, removing the need for calculation of time step to track the flow front in...
Effect of nanoclays on the mechanical properties and durability of novolac phenolic resin/woven glass fiber composite at various chemical environments, Article Composites Part A: Applied Science and Manufacturing ; Vol. 63 , 2014 , pp. 149-158 ; ISSN: 1359835X ; Shojaei, A ; Sharif University of Technology
Both natural montmorilonite (CN) and organically modified montmorilonite (CB) improved significantly the mechanical performance of novolac phenolic resin (PF)/woven glass-fiber (GF) composites due to their nanodispersion and good interfacial interaction with the matrix. It was revealed that the incorporation of 2.5 wt% of the clays enhances the elastic modulus up to 38% for CN and 43% for CB. Aging of PF/GF composites at various aqueous solutions, i.e. water, brine and acidic environments, increased stiffness of the composite (∼100-250% increase in elastic modulus) due to possible secondary crosslinking caused by water molecules and hydroxyl groups of PF resin. However, aging led to the...
Article Journal of Reinforced Plastics and Composites ; Volume 26, Issue 8 , 2007 , Pages 743-760 ; 07316844 (ISSN) ; Adibnazari, S ; Sharif University of Technology
The efficiency of fiber/matrix interface bonding in composites has an important influence on their overall performance. This article deals with the simulation of interface imperfection effect as it grows under fatigue loading. The relations have been derived based on the constituents' properties for the primary damage mode in unidirectional composites and boundary conditions defined for elements of the micromechanics model. Conformation of model stiffness predictions with the best described residual stiffness model indicates the way to find the remaining constants in the simulated relation. Finally through this relation, cyclic corrected stress components in constituents could be determined....
Modification of nanostructure and improvement of mechanical properties of polypropylene/polyamide 6/layered silicate ternary nanocomposites through variation of processing route, Article Composites Part B: Engineering ; Volume 85 , February , 2016 , Pages 207-215 ; 13598368 (ISSN) ; Bagheri, R ; Sharif University of Technology
Elsevier Ltd 2016
Ternary nanocomposites of polypropylene/polyamide 6/layered silicate were prepared through three different processing procedures. X-ray diffraction and transmission electron microscopy were used to study the nanostructure of the samples, and tensile and impact strength measurements were conducted to assess the mechanical properties. It was shown that processing route has a significant effect on the delamination of clay platelets. Fully exfoliated nanostructure was achieved through a certain two-step processing route. Compatibilization of the blends affected microstructure as well as nanostructure. Mechanical properties were affected by changing the processing route, to a great degree....
Experimental and Theoretical Investigation on the Frictional Performance of Friction Materials of Brake System, M.Sc. Thesis Sharif University of Technology ; Shojaei, Akbar
Various composite friction materials containing 40 vol.% organic binder (phenolic resin plus styrene-butadiene-rubber (SBR)) with varying phenolic-resin/SBR ratio were prepared. The content of phenolic resin in each composite was indicated by the resin value (RV) index ranging between 0-100%. The composites with RVs greater than 50% form resin-based friction materials in which the primary binder is the phenolic resin. For RVs less than 50%, the composites become the rubber-based materials where the primary binder is the SBR. The analysis of mechanical properties exhibited that the conformability of the composites increases upon incorporation of SBR. The frictional analysis revealed that type...
Investigation of flame retardancy and physical-mechanical properties of zinc borate and aluminum hydroxide propylene composites, Article Materials and Design ; Volume 29, Issue 5 , 2008 , Pages 1051-1056 ; 02613069 (ISSN) ; Rahimi, A ; Frounchi, M ; Radman, S ; Sharif University of Technology
Elsevier Ltd 2008
In this paper, the effects of flame retardant fillers mixture, zinc borate and aluminum hydroxide, on polypropylene including various ratios of their accumulated concentrations, have been studied. Maleic anhydrate grafted polypropylene and calcium stearate have been used to increase filler-matrix interactions and filler dispersion in matrix. Effects of filler types and their concentrations on fire resistibility of different composite samples have been determined via limiting oxygen index test method. Effects of foregoing parameters on the mechanical properties of prepared samples were also investigated. Recorded data shows that adding polypropylene, containing aluminum anhydrate lump,...
Article Metamaterials: Fundamentals and Applications, San Diego, CA, 10 August 2008 through 13 August 2008 ; Volume 7029 , 2008 ; 0277786X (ISSN) ; 9780819472496 (ISBN) ; 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...
Thermally conductive rubber-based composite friction materials for railroad brakes - Thermal conduction characteristics, Article Composites Science and Technology ; Volume 67, Issue 13 , 2007 , Pages 2665-2674 ; 02663538 (ISSN) ; Fahimian, M ; Derakhshandeh, B ; Sharif University of Technology
This study deals with the thermal conductivity of rubber-based composite friction materials used in railroad vehicles. Based on a commercially available railroad friction material, called here base material (BM), various friction materials containing different thermally conductive fillers (Cu, brass, Al, Al2O3 and talc) are fabricated and then their thermal conductivities are measured at various contents of the fillers. Addition of the thermally conductive fillers causes an increase in thermal conductivity of the friction material from 0.48 up to 5.8 W/m K, depending on the type and content of the filler. In addition, the experimental results reveal that the thermal conductivity of the...
Three-dimensional process cycle simulation of composite parts manufactured by resin transfer molding, Article Composite Structures ; Volume 65, Issue 3-4 , 2004 , Pages 381-390 ; 02638223 (ISSN) ; Ghaffarian, S. R ; Karimian, S. M. H ; Sharif University of Technology
A process cycle of resin transfer molding (RTM) consists of two sequential stages, i.e. filling and curing stages. These two stages are interrelated in non-isothermal processes so that the curing stage is dominated by the resin flow as well as temperature and conversion distributions during the filling stage. Therefore, it is necessary to take into account both filling and curing stages to analyze the process cycle accurately. In this paper, a full three-dimensional process cycle simulation of RTM is performed. Full three-dimensional analysis is necessary for thick parts or parts having complex shape. A computer code is developed based on the control volume/finite element method (CV/FEM)....
Article Wear ; Volume 274-275 , January , 2012 , Pages 286-297 ; 00431648 (ISSN) ; Shojaei, A ; Sharif University of Technology
Various composite friction materials containing 40. vol.% organic binder (phenolic resin plus styrene-butadiene-rubber (SBR)) with varying phenolic-resin/SBR ratio were prepared. The content of phenolic resin in each composite was indicated by the resin value (RV) index ranging between 0 and 100%. The composites with RVs greater than 50% form resin-based friction materials in which the primary binder is the phenolic resin. For RVs less than 50%, the composites become the rubber-based materials where the primary binder is the SBR. The analysis of mechanical properties exhibited that the conformability of the composites increases upon incorporation of SBR. The frictional analysis revealed that...
Fracture behavior dependence on load-bearing capacity of filler in nano- and microcomposites of polypropylene containing calcium carbonate, Article Materials and Design ; Volume 31, Issue 2 , 2010 , Pages 802-807 ; 02641275 (ISSN) ; Massoumi, I ; Khosh, R. L ; Bagheri, R ; Sharif University of Technology
The fracture toughness and deformation mechanism of PP/CaCO3 (15 wt.%) composites were studied and related to load-bearing capacity of the particles. To alter the load-bearing capacity of the particles, different particle sizes (0.07-7 μm) with or without stearic acid coating were incorporated. The fracture toughness of the composites was determined using J-Integral method and the deformation mechanism was studied by transmission optical microscopy of the crack tip damage zone. It was observed that the load-bearing capacity of the particles decreased by reduction of particle size and application of coating. A linear relationship between normalized fracture toughness and inverse of...
Processing and properties of nanofibrous bacterial cellulose-containing polymer composites: a review of recent advances for biomedical applications, Article Polymer Reviews ; Volume 60, Issue 1 , 2020 , Pages 144-170 ; Mahmoodi, A ; Mahmoudi, N ; Zandi, N ; Simchi, A ; Sharif University of Technology
Taylor and Francis Inc 2020
Bacterial cellulose (BC) is an extracellular natural polymer produced by many microorganisms and its properties could be tailored via specific fabrication methods and culture conditions. There is a growing interest in BC derived materials due to the main features of BC such as porous fibrous structure, high crystallinity, impressive physico-mechanical properties, and high water content. However, pristine BC lacks some features, limiting its practical use in varied applications. Thus, fabrication of BC composites has been attempted to overcome these constraints. This review article overviews most recent advance in the development of BC composites and their potential in biomedicine including...
The Effect of Structural Defects of Graphene Reinforced Polymer Nanocomposites on Mechanical Properties, M.Sc. Thesis Sharif University of Technology ; Naghd Abadi, Reza
Nanocomposites are widely used due to unique properties such as low density and high strength in many industries such as electronics, telecommunications, aerospaces, Petrochemicals and shipbuildings. Meanwhile, due to the importance of economic issues, polymer based nanocomposites are the most used type of nanocomposites. The purpose of this thesis is studing the structural defects of graphene-reinforced nanocomposite polymers on the mechanical properties of these materials. Defects created in nanocomposites can be divided into two categories after construction. The first category is the defects that are created in the graphene structure when it is synthsis, and the second happen at the...
Effects of Rolling Process on Mechanical Properties and Formability of Reinforced Polymeric Matrix with Stainless Steel Mesh as Cladding Composite Sheet, M.Sc. Thesis Sharif University of Technology ; Akbarzadeh, Abbas
In this study, the mechanical properties of composite sheet polymer matrix reinforced with steel mesh were investigated. This bonding was carried out by rolling of a three layers of steel mesh in between two composite polymer sheets. Then, the effective parameters of process; Sample maintenance temperature inside the furnace, reduction during rolling, rolling speed, rolling direction and Number of rolling passes were investigated to determine the optimized processing conditions. In this way, adding mesh to the polymeric matrix improves the strength and polymer / polymer bond in the sandwich structure. Placing the mesh in the sandwich structure converts the brittle behavior of the polymeric...
Article Journal of Reinforced Plastics and Composites ; Vol. 33, Issue 17 , September , 2014 , pp. 1634-1643 ; ISSN: 07316844 ; Dadfar, M. R ; Zeraati, A. S ; Sharif University of Technology
In this study, the effect of carboxyl-terminated butadiene-acrylonitrile liquid rubber on fracture toughness of glass-reinforced epoxy composites has been investigated. Fracture toughness tests were conducted in modes I, II and different mixed mode ratios. The data obtained from these tests have been analyzed by using different methods. Results indicated that interlaminar fracture toughness of composite specimens improved considerably through addition of carboxyl-terminated butadiene-acrylonitrile in modes I, II and mixed mode. Interlaminar fracture surfaces of the specimens were also characterized by field emission scanning electron microscope
Article Applied Surface Science ; Volume 318 , 1 November , 2014 , Pages 90-94 ; ISSN: 01694332 ; Bagheri, R ; Shojaei, A ; Sharif University of Technology
X-ray diffraction and rheological measurements were used to characterize nanoparticle dispersion in LDPE/LLDPE/nanoclay hybrid nanocomposites. XRD patterns were interpreted with a novel distribution formula and rheological measurements were used to confirm the results. Results of these two methods indicated that increasing clay in all the prepared nanocomposites exhibited a significant improvement in filler-matrix interaction because of increasing the probability of polymer diffusion but further exfoliation need more compatibilizing situations. It seems that this mathematical method could be used for predicting the overall change in clay gallery d-spacing and the extent of...
An analytical solution to the elastic-plastic behavior of metal matrix composites under tensile loading, Article 29th Congress of the International Council of the Aeronautical Sciences, ICAS 2014 ; 2014 ; Mondali, M ; Abedian, A ; Sharif University of Technology
An analytical approach is proposed for studying the elastic-plastic behavior of short fiber reinforced metal matrix composites under tensile loading. In the proposed method, a micromechanical approach is employed, considering an axi-symmetric unit cell including one fiber and the surrounding matrix. First, the governing equations and the boundary conditions are derived and the elastic solution is obtained based on some shear lag type methods. A plastic deformation is considered for the matrix under each small tensile loading step. Then, applying the successive elastic solutions method, all the plastic strain terms are obtained for the matrix. Thereafter, the elastic-plastic stress transfer...
Article Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science ; Volume 227, Issue 10 , 2013 , Pages 2182-2194 ; 09544062 (ISSN) ; Mondali, M ; Abedian, A ; Sharif University of Technology
A new analytical formulation is presented to study the steady-state creep in short fiber composites using complex variable method. In this new approach, both the fiber and matrix creep at low stresses and temperatures. To analyze the crept fiber, a plane stress model was used. Important novelties of the present analytical method are determination of displacement rates with proper boundary conditions in the crept fibers and also using the complex variable method in creep analyzing. It is noteworthy that the method can be useful to study the creep behavior in polymeric matrix composites due to their high capability of creep. Moreover, another significant application of the present method is to...
Article Acta Mechanica ; Volume 224, Issue 4 , 2013 , Pages 789-809 ; 00015970 (ISSN) ; Naghdabadi, R ; Asghari, M ; Sharif University of Technology
In this paper, for obtaining an overall size-dependent yield function for nanocomposites containing aligned cylindrical nanofibers, the effects of interface residual stress and interface elasticity are taken into account within a micromechanical framework. Toward this goal, the modified Hill's condition is used, and then, in order to consider effects of the interface residual stress, strains are decomposed into two parts, a part due to the external loadings and the other due to the interface residual stress. Next, utilizing the field fluctuation method, an overall yield function containing effective elastic constants of the material is derived and then simplified for practical loading...