Composite Materials
Amirmehdi Mosaddeghi; Hamid Soleimanimehr; Ali Alinia ziazi
Abstract
As the smart materials, ionic polymer-metal composites (IPMCs), have a layered structure consisting of a polymeric membrane based on perfluorinated alkene, which is sandwiched between two noble metal-based electrodes, such as gold and platinum, and they can be bent significantly under applying a low-range ...
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As the smart materials, ionic polymer-metal composites (IPMCs), have a layered structure consisting of a polymeric membrane based on perfluorinated alkene, which is sandwiched between two noble metal-based electrodes, such as gold and platinum, and they can be bent significantly under applying a low-range of voltage. IPMCs are used in many applications, such as robotics, biomechanics, and medical purposes. In order to improve the performance of IPMC, in this article, three different anisotropic surface roughening methods with new and optimized fabrication instructions are used, and samples are compared. The experiments are applied to measure three main factors of IPMCs: displacement, blocking force, and lifetime. The results obtained from plasma samples show that the maximum displacement is 36.23 mm, the blocking force is 4.08 etching, 18 percent higher lifetime than micro sandblasting, and sandpaper under applying a voltage range between 1-7 V; as a result, the plasma etched IPMC sample has the most efficiency.
Composite Materials
Manoj Kumar Shukla; Kamal Sharma
Abstract
The synergetic effect of amine functionalized multiple graphene layers (AMGL) and multi-walled carbon nanotube (AMWCNT) nano-fillers mixed with epoxy resin is investigated on the particle size distribution (PSD) and tensile properties of hybrid composites. The hybrid composites with an equal ratio of ...
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The synergetic effect of amine functionalized multiple graphene layers (AMGL) and multi-walled carbon nanotube (AMWCNT) nano-fillers mixed with epoxy resin is investigated on the particle size distribution (PSD) and tensile properties of hybrid composites. The hybrid composites with an equal ratio of nano-fillers at a weight percent of 0.25, 0.50, 1, and 2 wt % are fabricated. The particle size analysis (PSA) is performed by the dynamic light scattering (DLS) technique and image analysis (IA) method; both verify PSD for composites. This is further verified by the analyses of scanning electron microscopy (SEM) images using Image J software. The optimum composite particle size of 6.8 µm and homogeneous mixture with a poly-dispersity index (PI) of 0.74 is investigated for a sample having filler content of 0.5 wt %. Tensile stress and elastic modulus is also found to be maximum at 0.5 wt %, which is 49.91 MPa of 2302 Mpa, respectively. The chemical composition of composite affecting its PSD is characterized by energy dispersive X-ray (EDX) process. Dimensional analysis of particle size in the domain of epoxy matrix provides deep insights to the researchers and may also provide them a direction for selecting an appropriate material for a particular application.
Composite Materials
Aidin Ghaznavi; Mohammad Shariyat
Abstract
Studying the behavior of sandwich panels is very important due to their widespread use in different industries. Therefore, over the past decades, various theories have been proposed to study the behavior of these panels. In this paper a higher order global-local theory with 3D equilibrium-based corrections ...
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Studying the behavior of sandwich panels is very important due to their widespread use in different industries. Therefore, over the past decades, various theories have been proposed to study the behavior of these panels. In this paper a higher order global-local theory with 3D equilibrium-based corrections is presented to study behavior of thick and thin sandwich plate with flexible and auxetic core. In addition to correcting the results with 3D elasticity equations, another important advantage of the presented theory is the ability to consider the transverse core deformation of the sandwich panels. It should be mentioned that to study the behavior of thick sandwich panels, especially with soft core, the existence of this feature is very necessary and has a great effect on the accuracy of the obtained results. Comparison of the obtained results with those existing in valid references showed that the formulation of the provided finite element had a very good accuracy even for thick and thin sandwich plates. Finally, the effect of different material and geometrical parameters on the behavior of sandwich plates are carefully investigated using the presented theory.
Composite Materials
Nabard Habibi; Yasaman Ahmadi
Abstract
Water storage tanks are amongst the essential infrastructures, and the study of their natural frequencies plays a pivotal role in predicting and detecting dynamic behavior. Therefore, it helps to the uninterrupted operation of an industrial plant and the use of tank water in emergencies. This paper studies ...
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Water storage tanks are amongst the essential infrastructures, and the study of their natural frequencies plays a pivotal role in predicting and detecting dynamic behavior. Therefore, it helps to the uninterrupted operation of an industrial plant and the use of tank water in emergencies. This paper studies the influence of different shell materials, including steel, aluminum, and laminated composites with three types of different fiber orientations, on the natural frequencies of thin walled aboveground water storage tanks that have pinned boundary conditions at the base. Models investigated in this paper, either the roof is without an internal support structure or else a group of columns and radial beams are used for supporting it. These huge tanks had the height to diameter ratio of 0.4, and a water surface at 90% of the height of the tank's cylinder. The thicknesses of the cylindrical shells are tapered. The tanks without internal support included the vibrations that affect the cylinder mode shapes or the roof mode shapes or simultaneously both the cylinder and roof mode shapes. On the other hand, the mode shapes of the tanks with internal support affect predominantly only the cylinder. Among the studied tanks, the third type of composite tanks had the highest rigidity, and the first type of composite tanks had the lowest rigidity. The natural frequencies related to the first modes of vibrations for cylinder and roof shells with a wide range of circumferential wave numbers (n) and an axial halfwave (m) are studied.
Composite Materials
Meisam Shakouri; Hessam Sarvahed; H.M. Navazi
Abstract
Pressure vessels are used in a variety of applications in many engineering applications. The thin walled cylinders with torispherical heads have been widely used as pressure vessels in engineering applications. In this paper, the free vibration behavior of carbon fiber reinforced composite cylinders ...
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Pressure vessels are used in a variety of applications in many engineering applications. The thin walled cylinders with torispherical heads have been widely used as pressure vessels in engineering applications. In this paper, the free vibration behavior of carbon fiber reinforced composite cylinders ended with torispherical heads with various boundary conditions is investigated. The shape of a torispherical head is consists of a sphere of large radius and a much smaller minor radius at the knuckle. The numerical calculation with finite element method is obtained and the results were compared with the experimental data to confirm the accuracy of the numerical solution. The acceptable accordance between experimental and numerical results leads to use of numerical model instead of expensive experimental tests. In addition, the effects of the thickness of torispherical head and cylindrical section and the lengths of cylinder and torispherical head on vibrational behavior of the structure are studied.
Composite Materials
Hiral Parikh; Piyush Gohil
Abstract
As the fiber-reinforced polymer matrix composites give good strength and can work in rigorous environmental conditions, nowadays, more focus is given to study the behavior of these materials under different operating conditions. Due to the environmental concern, the focus on the natural fiber reinforced ...
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As the fiber-reinforced polymer matrix composites give good strength and can work in rigorous environmental conditions, nowadays, more focus is given to study the behavior of these materials under different operating conditions. Due to the environmental concern, the focus on the natural fiber reinforced polymer matrix composite is enhancing both in research and industrial sectors. Currently, the focus has been given to unifying solid fillers with the polymer matrix composite to improve their mechanical and tribo properties. Aligned to this, the present work discusses the effect of various weight fractions of fillers (Flyash, SiC, and graphite) on the frictional behavior of natural fiber (cotton) polyester matrix composites. The specimen prepared with a hand lay-up process followed by compression molding. A plan of experiments, response surface technique, was used to obtain a response in an organized way by varying load, speed, and sliding distance. The test results reveal that different weight concentration of fillers has a considerable result on the output. The frictional behavior of materials evaluated by general regression and artificial neural network. The validation experiment effects show the estimated friction by using the artificial neural network was closer to experimental values compare to the regression models.
Composite Materials
Naser Kordani; Hamid Zalnezhad
Abstract
The most important reason for the design of curved tubes is increasing the heat transfer between the fluid and the wall which has provided many applications in various industries such as air conditioning, micro-electric, heat exchangers and etc. The aim of this study is numerical investigation of nano ...
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The most important reason for the design of curved tubes is increasing the heat transfer between the fluid and the wall which has provided many applications in various industries such as air conditioning, micro-electric, heat exchangers and etc. The aim of this study is numerical investigation of nano fluids flow in spiral tubes with injection of base fluid in different Reynolds numbers. According to, the effects of volume fraction, nanoparticle diameter, fluid injection, Reynolds number and spin effects on heat transfer and flow in the spiral tube are discussed. In this study, a mixture of water-Al2O3 is selected to model nano fluid flow in order to investigate the changes of the heat transfer rate by the injection of nanofluid to the base fluid in the spiral tube at different angles. The results show that by use of nanoparticles, the rotational effects of tube and the injection process increase the heat transfer performance. It was found that increasing the volume fraction has a direct effect on increasing the heat transfer coefficient. As the volume fraction increases from 2% to 8%, the heat transfer coefficient increases by 2%. In fact, the effect of nanoparticles on the thermal conductivity of the fluid causes this increase. Also, injection of fluid into the stream due to disturbance in the thickness of the boundary layer and the further mixing of the fluid layers which increases the heat transfer. 90-degree injection has the best effect. Cu2O3 –water nano fluid mixture has also been used. The results are presented in this paper and compared with the Al2O3 nano fluid model which indicates that the increase of heat transfer rate in Cu nano fluid was higher than aluminum nano fluid due to higher heat transfer capacity of Copper.
Composite Materials
Aidin Ghaznavi; Mohammad Shariyat
Abstract
In the present article, the dynamic behavior of sandwich plates with embedded shape memory alloy (SMA) wires is evaluated for two cases wherein (i) the stress-strain curve of the superelastic behavior of the SMA wires is symmetric and (ii) the mentioned curve is non-symmetric. A modified version of Brinson’s ...
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In the present article, the dynamic behavior of sandwich plates with embedded shape memory alloy (SMA) wires is evaluated for two cases wherein (i) the stress-strain curve of the superelastic behavior of the SMA wires is symmetric and (ii) the mentioned curve is non-symmetric. A modified version of Brinson’s constitutive model is proposed and used. The high non-linearity in the behavior stems from the SMA wires embedded in the sandwich plate. In this regard, in addition to the proposed advanced algorithm for the determination of the martensite volume fraction, a Picard iterative solution algorithm is used in conjunction with Newmark’s numerical time integration method for solving the resulting finite element equations. To improve the accuracy of the results, the variation of martensite volume fraction and material properties of individual points of the structure are updated continuously. Therefore, the kinetic equations of the phase transformation of the SMA are coupled with the motion equations, to accurately model the nonlinear behavior of the sandwich plate. For analysis of the thick sandwich plate, a higher-order global-local theory with novel 3D-equilibrium-based corrections is utilized. One of the features of this theory is the estimation capability of the nonlinear in-plane displacement components, and precise assessment of the transverse shear stresses through satisfying the continuity conditions of the shear stresses at the interfaces between layers. Another advantage of the proposed theory in comparison with the conventional approaches is the ability to simulate changes in the core thickness. This is especially important in cases where the core is relatively thick or soft.
Composite Materials
Hamed Khosravi; Reza Eslami-Farsani
Abstract
This work reports the high-velocity impact response of multiscale anisogrid composite (AGC) panels. The aim of the present study is to evaluate the influence of surface-modified multi-walled carbon nanotubes (S-MWCNTs) at different S-MWCNTs contents (0-0.5 wt.% at an interval of 0.1 wt.%) on the high-velocity ...
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This work reports the high-velocity impact response of multiscale anisogrid composite (AGC) panels. The aim of the present study is to evaluate the influence of surface-modified multi-walled carbon nanotubes (S-MWCNTs) at different S-MWCNTs contents (0-0.5 wt.% at an interval of 0.1 wt.%) on the high-velocity impact responses of E-glass/epoxy AGC. Surface modification of MWCNTs is confirmed by Fourier-transform infrared (FTIR) and thermogravimetric (TGA) analyses. AGC panels were fabricated via a manual filament winding technique. E-glass fiber roving and E-glass woven fabric are employed as reinforcing agents in ribs and skin, respectively. The impact test is done on the composite panels by a cylindrical projectile with a conical nose. The results showe that the highest enhancement in the impact characteristics is attributed to the panel containing 0.4 wt.% S-MWCNTs. Based on the analysis of fracture surfaces, enhanced interfacial fiber/matrix bonding is observed for the S-MWCNTs loaded specimen. Furthermore, the incorporation of MWCNTs leads to the reduced damaged area and enhanced tolerance of damage.
Composite Materials
Mahsa Gharechomaghlu; Hamed Mirzadeh
Abstract
A new computational method based on MATLAB was used to study the effect of different parameters on the homogeneity of composites produced by a severe plastic deformation technique known as accumulative roll bonding. For a higher number of passes, the degree of particle agglomeration and clustering decreased, ...
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A new computational method based on MATLAB was used to study the effect of different parameters on the homogeneity of composites produced by a severe plastic deformation technique known as accumulative roll bonding. For a higher number of passes, the degree of particle agglomeration and clustering decreased, and an appreciable homogeneity was obtained in both longitudinal and transverse directions. Moreover, it was found that the rolling temperature does not have any tangible effect on the distribution of particles. Furthermore, it was shown that while faster homogeneity can be obtained in the transverse direction by a cross accumulative roll bonding process, there is not any significant difference between homogeneity of particle distribution between this technique and other routes. In fact, after enough passes, the homogeneity level in all processing methods tends to a common value. Finally, the evolution of the mechanical properties of the composites sheets based on the work hardening, composite strengthening, grain refinement at high accumulative roll bonding cycles, and bonding between particles and the matrix was also briefly discussed.
Composite Materials
Erfan Mirshekari; Arash Reza
Abstract
In this work, transient dynamic stress concentration in a hybrid composite laminate subjected to a sudden internal crack is examined. It is assumed that all fibers lie in one direction and the applied load acts along direction of fibers. Two types arrangements are considered for the fiber; square and ...
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In this work, transient dynamic stress concentration in a hybrid composite laminate subjected to a sudden internal crack is examined. It is assumed that all fibers lie in one direction and the applied load acts along direction of fibers. Two types arrangements are considered for the fiber; square and hexagonal arrangement. Using shear lag model, equilibrium equations are deduced and upon proper application of initial and boundary conditions, the complete field equations are obtained using finite difference method. The results of dynamic effect of fiber breakage on stress concentration are well examined in presence of a second type fiber. These results are compared to those of their static values in both models. The effect of surface cracks on stress concentration, as a result of fiber breakage, is also examined. The values of dynamic stress concentrations is deduced and compared to those of a lamina. Also, the peak stress concentration during transition time for fibers to reach static equilibrium is calculated and compared with those of static values.
Composite Materials
Ali Akbar Azemati; Hossain Khorasanizadeh; Behzad Shirkavand Hadavand; Ghanbar Ali Sheikhzadeh
Abstract
One of the ways to waste energy in buildings is wasting it from the walls. For this reason, insulating materials are used to prevent the loss of energy in buildings. Typically, common insulations are high thickness and thin coatings are used less. The purpose of this research is to introduce nanocomposite ...
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One of the ways to waste energy in buildings is wasting it from the walls. For this reason, insulating materials are used to prevent the loss of energy in buildings. Typically, common insulations are high thickness and thin coatings are used less. The purpose of this research is to introduce nanocomposite thin polymer coatings and its effect on thermal conductivity. For achieving this, chemically modified nano zirconium oxide and nano aluminum oxide in three different weight percentages (1, 3, and 5%) were used in polyurethane matrix for preparing nanocomposite coatings. To study thermal conductivity, the metallic plates are coated with prepared nanocomposites and the thermal conductivity of the samples was measured. The results show that by adding zirconium oxide and aluminum oxide nanoparticles in polyurethane matrix, the thermal conductivity of coatings in all three weight percentages compared to the coating without nanoparticles, decreased. The lowest thermal conductivity was found for 5% nano aluminum oxide composition, which, compared to the conductivity of the pure polyurethane resin, has decreased about 40% that leading to a decrease in the surface heat flux.
Composite Materials
Reza Eslami-Farsani; Hamed Khosravi
Abstract
In the present study, multiscale nanosilica/E-glass/epoxy anisogrid composite panels were investigated for flexural properties as a function of nanosilica loading in the matrix (0, 1, 3 and 5 wt.%). The surface of the silica nanoparticles was firstly modified with 3-glycidoxypropyltrimethoxysilane (3-GPTS). ...
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In the present study, multiscale nanosilica/E-glass/epoxy anisogrid composite panels were investigated for flexural properties as a function of nanosilica loading in the matrix (0, 1, 3 and 5 wt.%). The surface of the silica nanoparticles was firstly modified with 3-glycidoxypropyltrimethoxysilane (3-GPTS). The fourier transform infrared (FTIR) spectroscopy revealed that the organic functional groups of the silane were successfully grafted on the surface of the nanoparticles. It was illustrated that flexural properties of the composite panel loaded from the skin side can be significantly enhanced by incorporating silica nanoparticles. The use of 3 wt.% nanosilica was the most effective in increasing the load bearing capacity and energy absorption value, while the specimen containing 5 wt.% nanosilica demonstrated the highest flexural stiffness. From the results obtained for the anisogrid panels loaded from the skin side, it was found that these structures displayed excellent damage resistance which is represented by their energy absorption capability. Moreover, a significant portion of energy absorbed after the primary failure at the peak load. Finally, the results correlated well with the observation of field emission scanning electron microscopy (FESEM) micrographs where the nanocomposite panels exhibited higher degree of fiber-matrix interfacial strength and also enhanced matrix characteristics, imparted by the incorporation of surface modified silica nanoparticles.
Composite Materials
A. Niknami; M. Shariyat
Abstract
In the present research, in contrast to the available papers, not only the superelasticity but also the shape memory effects are taken into account in determination of the impact responses. At the same time, in addition to modifying Brinson’s model for the shape memory alloys (SMAs), to include ...
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In the present research, in contrast to the available papers, not only the superelasticity but also the shape memory effects are taken into account in determination of the impact responses. At the same time, in addition to modifying Brinson’s model for the shape memory alloys (SMAs), to include new parameters and loading events, and Hertz contact law, distributions of the SMA phases are considered to be both localized and time-dependent. Furthermore, effects of the impact-induced heat generation and mechanical energy on the resulting histories of the martensite phase volume fraction, stress-strain, temperature, lateral deflection, and contact force are investigated. The generated heat in the SMA wires during the impact is determined through using a Helmholtz free energy function including the latent heat of the phase transformation. The resulting governing equations are solved by the finite element method. The nonlinear refined constitutive laws are solved through a return-mapping Newton-Raphson procedure. Results reveal that incorporation of the heat generation effects is significant in medium/high-velocity impacts or when the stress field is almost uniform.
Composite Materials
S. Khalilpourazary; N. Payam
Abstract
Warpage and shrinkage control are important factors in proving the quality of thin-wall parts in injection modeling process. In the present paper, grey relational analysis was used in order to optimize these two parameters in manufacturing plastic bush of articulated garden tractor. The material used ...
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Warpage and shrinkage control are important factors in proving the quality of thin-wall parts in injection modeling process. In the present paper, grey relational analysis was used in order to optimize these two parameters in manufacturing plastic bush of articulated garden tractor. The material used in the plastic bush is Derlin 500. The input parameters in the process were selected according to their effect on shrinkage and warpage values, melt temperature, mold temperature, injection rate, injection pressure, and packing pressure. Then, the Taguchi method was applied to design the experiments, and through the use of Mold Flow software injection molding process was simulated based on these experiments and the input parameters. Based on the results obtained from the simulation, the input parameters were analyzed in three levels using grey relational analysis. Then, analysis of variance and confirmation tests were carried out on the output of grey relational analysis to predict the optimum values of the input parameters and to calculate the dimensional changes of the plastic bush. Gaining these values, the plastic bush sample was manufactured, and its 3D point cloud model was generated by a scanner. At the end, by generating 3D solid model of the plastic bush its dimensional features were studied. The comparison of the warpage and shrinkage values between grey relational analysis and 3D CAD model indicates the precision of the method in controlling and measuring these two parameters.
Composite Materials
Y. Bayat; H. Ekhteraei Toussi
Abstract
In many cases, a torsional shaft may be a thick-walled radially inhomogeneous cylindrical object. The hollow shafts made of functionally graded materials (FGMs) are such kind of compositions which were studied in this paper. Cylindrical FG shafts are composed of ceramic and metallic parts with power ...
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In many cases, a torsional shaft may be a thick-walled radially inhomogeneous cylindrical object. The hollow shafts made of functionally graded materials (FGMs) are such kind of compositions which were studied in this paper. Cylindrical FG shafts are composed of ceramic and metallic parts with power function distribution across the radial direction. The ceramic phase is isotropic elastic and the metallic phase was elastic-plastic. In this paper, the volume fraction-based elastic–plastic mixture rule of renowned Tamura–Tomota–Ozawa (TTO) was used to model the behavior of the composite material. The elasto-plastic torsion problem was modeled and solved analytically. The results were compared with the simulations of ABAQUS and the accuracy of the solutions was evaluated. Depending on the thickness and level of inhomogeneity, different modes of yielding were obtained. The results showed that plastic zone could occur at the inner or outer surfaces or simultaneously at both surfaces; even it may start in-between the thickness. Moreover, the influence of material inhomogeneity and thickness of shaft upon the plastic zone development were studied and discussed.
Composite Materials
Y. Bayat; M. Alizadeh; A. Bayat
Abstract
In this paper, a general solution for torsion of hollow cylinders made of functionally graded materials (FGM) was investigated. The problem was formulated in terms of Prandtl’s stress and, in general, the shear stress and angle of twist were derived. Variations in the material properties such as ...
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In this paper, a general solution for torsion of hollow cylinders made of functionally graded materials (FGM) was investigated. The problem was formulated in terms of Prandtl’s stress and, in general, the shear stress and angle of twist were derived. Variations in the material properties such as Young’s modulus and Poisson’s ratio might be arbitrary functions of the radial coordinate. Various material models from the literature were also used and the corresponding shear stress and angle of twist were individually computed. Moreover, by employing ABAQUS simulations, finite element results were compared with the analytical ones.
Composite Materials
S. Mohammadi*; F. Abdi
Abstract
In the presented work, sulfur concrete and rubber were used for producing functionally graded materials (FGM). The physical and mechanical properties of sulfur concrete and rubber were changed continuously across the thickness. On one side, there was just rubber and, on the other, there was pure sulfur; ...
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In the presented work, sulfur concrete and rubber were used for producing functionally graded materials (FGM). The physical and mechanical properties of sulfur concrete and rubber were changed continuously across the thickness. On one side, there was just rubber and, on the other, there was pure sulfur; the properties of each substance were moved to reach another. This kind of material was constructed by applying mechanical pressure on all layers together and heating in a casting die. Thus, it is essential to consider the quantity of sulfur and rubber at each layer and the rule obeyed by physical and mechanical properties. In the drop test, it was found that the elastic impact coefficient changed from sulfur concrete around 50% to rubber around near zero. It seems that, by changing some parameters like combination percentage or layers' thickness, it is possible to optimize the FGM.
