List of articles (by subject) composite materials
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Open Access Article
1 - Buckling Analysis of Discontinues Fractional Axially Graded Thin Beam with Piecewise Axial Load Function Rested on Rotational Spring Hinges
Abbas HeydariFunctionally Graded Materials (FGMs) can be described by continuous variation in structure and composition over volume, resulting in corresponding changes in the properties of the material. These kinds of materials are designed to achieve specific properties for specific MoreFunctionally Graded Materials (FGMs) can be described by continuous variation in structure and composition over volume, resulting in corresponding changes in the properties of the material. These kinds of materials are designed to achieve specific properties for specific applications. For the first time, the effects of stepwise fractional axial material gradation pattern and axial compressive load with piecewise function on buckling behaviour of Euler-Bernoulli beam rested on semi-rigid restraints are studied. It is worth mentioning that the more computational efforts are required to solve current problem with respect to the buckling problem of transversely graded beam due to discontinues material gradation especially in the axial direction, axial span-load with piecewise function and natural conditions of rotational spring hinges. The deflection continuity, natural equations as well as boundary conditions are written in the matrix form. The beam discretizing and nontrivial solution are employed to obtain buckling characteristic equation and matrix operations are used to calculate corresponding first mode shapes. Compatibility with various conditions and eliminating convergence drawbacks of conventional numerical tools are advantages of the proposed method. It is observed that the buckling load is decreased by increasing lengths of beam parts and increased by increasing rotational stiffness at semi-rigid supports. In the case of homogeneous beam, the result validity is proved by observing an excellent agreement between results of current work and well-known data in literature. Manuscript profile -
Open Access Article
2 - Free Vibration of Functionally Graded Epoxy/Clay Nanocomposite Beams based on the First Order Shear Deformation Theory
Mahdi Karami KhorramabadiThis paper deals with free vibration of epoxy/clay nanocomposite beams for functionally graded and uniformly distributed of Nanoclay with simply supported conditions at both ends. The specimens were prepared for uniformly distributed of Nanoclay with different Nanoparti MoreThis paper deals with free vibration of epoxy/clay nanocomposite beams for functionally graded and uniformly distributed of Nanoclay with simply supported conditions at both ends. The specimens were prepared for uniformly distributed of Nanoclay with different Nanoparticles weight percent (pure, 3 wt%, 5 wt% and 7 wt%) and functionally graded distribution. To apply the model of theoretical predictions for the Young modulus, the genetic algorithm procedure was employed for functionally graded and uniformly distributed epoxy/clay nanocomposites and then were compared with the experimental tensile results. The formulation for Young modulus includes the effect of nanoparticles weight fractions and it is modified for functionally graded distribution to take into account the Young modulus as a function of the thickness coordinate. The displacement field of the beam is assumed based on the first order shear deformation beam theory. Applying the Hamilton principle, the governing equations are derived. The influence of nanoparticles on the free vibration frequencies of a beam is presented. To investigate the accuracy of the present analysis, a compression study is carried out with the experimental free vibration results. The results have shown that there is high accuracy for the genetic algorithm procedure for theoretical predictions of the Young modulus and the free vibration frequencies for uniform distribution are generally lower than the corresponding value of the functionally graded distribution. Manuscript profile -
Open Access Article
3 - Vibration Analysis of Different Types of Porous FG Circular Sandwich Plates
Mohsen Rahmani Younes Mohammadi Farshad KakavandFor the first time, by applying a modified high order sandwich plates theory, vibration behaviour of two types of porous FG circular sandwich plates are investigated. In the first type, the face sheets and in the second one, the core is made of FGM which is modelled by MoreFor the first time, by applying a modified high order sandwich plates theory, vibration behaviour of two types of porous FG circular sandwich plates are investigated. In the first type, the face sheets and in the second one, the core is made of FGM which is modelled by power law rule that is modified by considering two types of porosity distributions. All materials are temperature dependent and uniform temperature distribution is used to model the effect of the temperature changing in the sandwiches. Governing equations are obtained by the Hamilton's energy principle and solved by Galerkin method for a clamped boundary condition. To verify the results, they are compared with FEM results obtained by Abaqus software and for special cases with the results in literatures. Manuscript profile -
Open Access Article
4 - Thermomechanical Properties of the Polymeric Nanocomposite Predicted by Molecular Dynamics
Majid Hadipeykani farshid Aghadavoudi Davood ToghraieA molecular dynamics simulation study is employed to investigate the elastic and basic thermal properties of thermoset polymer based nanocomposite sample reinforced by CNT. The COMPASS force filed was used to construct the simulation box. The simulation box contains the MoreA molecular dynamics simulation study is employed to investigate the elastic and basic thermal properties of thermoset polymer based nanocomposite sample reinforced by CNT. The COMPASS force filed was used to construct the simulation box. The simulation box contains the cured epoxy resin molecules obtained from cross linking process of DGEBA and DETA which were located around the CNT (10,10). NVT and NPT ensembles were performed to equilibrate the system and convergence of temperature, energy and density have been checked. The elastic constants of molecular sample of nanocomposite were determined based on stiffness matrix and compared with the molecular results of pure resin. The results show that the Young's modulus in the transverse direction of nanocomposite model is less than that in longitudinal direction indicating the transversely isotropic behaviour at atomic scale. Glass transition temperature (Tg) and coefficient of thermal expansion (CTE) were calculated through the linear fitting of density-temperature diagram for the CNT-reinforced nanocomposite model. Atomistic simulation results showed decrease in Tg and CTE comparing to the pure epoxy. Moreover, the simulation results were compared with the measured values and good agreements are observed. Manuscript profile -
Open Access Article
5 - Micro-Finite Element Model to Investigate the Mechanical Stimuli in Scaffolds Fabricated via Space Holder Technique for Cancellous Bone
Sayed Alireza Hashemi Saeid Esmaeili Mazyar Ghadirinejad Saeed Saber-Samandari Erfan Sheikhbahaei Alireza Kordjamshidi Amirsalar KhandanIn Osteoporosis, bone mechanical strength decreases and as a result, the risk of bone fracture increases. Osteoporosis is also referred as a "silent illness" since it usually develops asymptomatic until it breaks a long bone, like the femur. In recent years, porous scaf MoreIn Osteoporosis, bone mechanical strength decreases and as a result, the risk of bone fracture increases. Osteoporosis is also referred as a "silent illness" since it usually develops asymptomatic until it breaks a long bone, like the femur. In recent years, porous scaffolds have been utilized to repair damaged bone tissue. For bone tissue engineering, synthetic scaffolds should have acceptable mechanical properties, in addition to the required biological properties. In this regard, the finite element simulation is used to predict the mechanical properties of porous bone scaffolds as one of the most common methods for reducing the experimental tests, because the acquisition of mechanical properties of such scaffolds is very time-consuming and expensive. Due to the widespread use of hydroxyapatite (HA) in the manufacture of bone scaffold composites, the mechanical properties of HA-wollastonite scaffold composites are obtained by laboratory tests and finite element methods. Comparison of the simulation of finite element analysis (FEA) and the experimental results indicate the success of the FEA simulation. In conclusion, new finding satisfied expectations as being suitable for mechanical and biomaterial aspect of a porous scaffold which is proven by laboratory tests and FEA simulations. Due to that fact, the result of this study can be employed to obtain scaffolds well-suited for bone implementations. Manuscript profile -
Open Access Article
6 - Investigation of Adhesion Behavior of Aluminum Laminates /Carbon Fiber/ High Silica Fiber by Phenol Resins
kazem Salimi Alireza Naddaf Oskouei Rouhollah Hosseini Mohammad Javad ZeinalbeikFiber‐metal laminate is a material constituted of composite laminate and metal sheets, whose mechanical properties can be tailored by varying the thickness, the number of layers and bonding type. For this reason, in this research, strength test, adhesion test and flux t MoreFiber‐metal laminate is a material constituted of composite laminate and metal sheets, whose mechanical properties can be tailored by varying the thickness, the number of layers and bonding type. For this reason, in this research, strength test, adhesion test and flux test for a sandblasted and etched aluminum sheet that contained a seven-layer composite with 2 types of adhesion treatment (phenol adhesive/resin of composite material) and front side composite layup (High-silica/High-silica+Carbon) were investigated. It was found that the above-mentioned factors influenced the flexural strength of FML; precisely, the presence of an adhesive layer between the composite plies and the metal sheet made the flexural strength decrease, while this mechanical parameter increased passing from two metal sheets to only one. The results show that the presence of carbon layer has led to the greatest increase in strength due to strong bonding. Also, the results of the flux test show that the behavior of the two samples is very close to each other. Manuscript profile -
Open Access Article
7 - Investigation on Failure Loads and Failure Modes for Two Parallel Pin-Loaded Holes Made from Unidirectional Glass-Epoxy Nanoclay Laminates
sajjad dehghanpour keivan hosseini safari Farzan Barati Mohammadmahdi AttarPurpose of this study is to obtain failure modes and failure loads of two Parallel pin loaded holes in unidirectional glass fibre/epoxy by adding nanoclay in the absence of nanoclay composite laminates using finite element analysis; the results are validated through exp MorePurpose of this study is to obtain failure modes and failure loads of two Parallel pin loaded holes in unidirectional glass fibre/epoxy by adding nanoclay in the absence of nanoclay composite laminates using finite element analysis; the results are validated through experiment. The geometrical parameters studies in this survey include the distance between the diameter of the hole (e/d) and the free edge of specimen, the distance between two holes-to-hole diameter (M/d). The samples were exposed to constant speed tensile loading. The results showed that by adding nanoclay, failure load increases and failure modes varies from shear out to bearing failure. Furthermore, increasing distance from the free edge of the pin centre’s increases load bearing capacity of two type of composite materials and changes the failure mode from shear to the bear, it increases and decreases the distance from canter’s of pin in layers with and without nanoclay particles, respectively and changes failure mode from shear to bear mode. In order to find morphology of specimens and dispersion quality, Scanning Electron Microscope (SEM) was used. For predicting failure load and differentiating failure modes, Tsai-hill failure criteria associated with material property degradation is used. Experimental and FEM results indicate importance of considering the impact of e/d and M/d ratios in the design of two Parallel pin joints. ANSYS was used to carry out numerical simulation and the results denote a good agreement between numerical and experimental results. In this study, by designing an experimental and numerical procedure to estimate the effect of nanoclay, on failure mode and failure load of typical composite material, glass-epoxy, we could illustrate that adding nanoclay brought with it improvement of shear and tensional strength of glass-epoxy about 10 %. Manuscript profile -
Open Access Article
8 - Study on the Wettability and Optical Properties of Polydimethylsiloxane-SiO2 Nano-composite Surfaces
Reza Abedinzadeh Hamid Shirian Janan ParhizkarIn this paper, the effects of different weight percentages of silica nano-particles on the wettability and optical properties of polymer based surfaces were investigated. The Polydimethylsiloxane (PDMS)-SiO2 nano-composites containing 0.5, 1, 2, 3 and 4 wt% silica were MoreIn this paper, the effects of different weight percentages of silica nano-particles on the wettability and optical properties of polymer based surfaces were investigated. The Polydimethylsiloxane (PDMS)-SiO2 nano-composites containing 0.5, 1, 2, 3 and 4 wt% silica were prepared and coated on the fabric surfaces by immersion technique at the ambient conditions. Then, the characterization of nano-composite coated samples was carried out by water contact angle technique, scanning electron and atomic force microscopes and diffuse reflectance spectroscopy. It was found that increasing the silica content caused to increase the water contact angle of sample to 158° which results in an improvement in the water repellency property. This can be due to the aggregation of silica nano-particles which led to higher surface roughness of sample. The AFM and SEM images validated the results of surface roughness. However, Silica-PDMS composite coated sample exhibited a lower transmittance value (57%) in comparison to the uncoated sample (90%). This can be ascribed to the light scattering by silica nano-particles. Manuscript profile -
Open Access Article
9 - Fabrication of Aluminum/Gr Composites and Investigation of its Tribological and Wear Properties
Mohammad Heydari ViniNowadays metal matrix composites are popular in many industries due to their desirable properties. Severe plastic deformation techniques usually are popular to fabricate metal matrix composites. In this study and as its novelty, Al/Gr composites have been manufactured v MoreNowadays metal matrix composites are popular in many industries due to their desirable properties. Severe plastic deformation techniques usually are popular to fabricate metal matrix composites. In this study and as its novelty, Al/Gr composites have been manufactured via a new novel technique, powder metallurgy and press bonding process. Then, as a function of Gr as additive part in this study, tribological, mechanical and microstructure properties of Al/Graphite composites were studied. The tribo surface and microstructure of composites have been investigated more over using SEM microscopy. The density and wear rate of samples increased and the hardness and friction coefficient decrease and by increasing the Gr content. Results showed that addition of Gr into Al matrix can improve the tribological properties of composite. Manuscript profile -
Open Access Article
10 - Dynamic Analysis of Carbon Nanotube-Reinforced Multilayer Composite Plates
Jamshid Ebrahimi Jafar Eskandari Jam Reza Azarafza Mohsen Heydari Beni Majid Eskandari ShahrakiThe paper studied the analysis of vibrations of rectangular carbon nanotube-reinforced composite plates. To this end, a three-layer nanocomposite plate - two layers with the targeted distribution of carbon nanotubes as FG-X at the top and bottom and a layer without an a MoreThe paper studied the analysis of vibrations of rectangular carbon nanotube-reinforced composite plates. To this end, a three-layer nanocomposite plate - two layers with the targeted distribution of carbon nanotubes as FG-X at the top and bottom and a layer without an amplifier in the middle of the plate - were analyzed. The governing equations for this problem are based on First-order Shear Deformation Theory (FSDT). The distribution of nanotubes on these plates is as targeted FG-X. The effect of various types of SWCNTs distributions in the direction of thickness on the vibrational behavior of nanocomposite plates was examined. The effective properties of nanocomposite materials Functionally Graded Carbon Nanotube-Reinforced Composite (FG-CNTRC) were estimated using the rule of mixtures. Detailed parametric studies were performed to determine the effects of the volume fraction of carbon nanotubes and the thickness-to-length ratio of the plate on the natural frequency responses and the shape of the plate mode. The equations obtained in this problem were coded in MATLAB software, the nanocomposite plate was modelled in ABAQUS software, and the comparison of the results obtained from the numerical solution with ABAQUS software showed relatively right consistency with the results obtained from the analytical solution. Manuscript profile -
Open Access Article
11 - Design and Fabrication of a Composite Energy Absorber
Hamid Reza Shalian Mohammad Hossein Alaee Jafar Eskandari Jam Mohsen Heydari Beni Majid Eskandari Shahraki Naser AsiabanIn this paper, the quasi-static test and the damage of the thin-walled composite cylinder were numerically simulated using ABAQUS. Then, a comparison was made between the results of this simulation and those obtained from experimental studies followed by their validatio MoreIn this paper, the quasi-static test and the damage of the thin-walled composite cylinder were numerically simulated using ABAQUS. Then, a comparison was made between the results of this simulation and those obtained from experimental studies followed by their validation. In the next step, several parameters affecting the energy absorption rate including outer diameter-to-cylinder height ratio, thickness-to-outer diameter ratio, and angle of damage initiation mechanism were selected. They were optimized by modelling different states in ABAQUS. The number of tests is reduced by the design of experiments using response surface methodology and the optimal specimen is extracted by this software. Finally, optimum adsorbent is fabricated and tested. Considering enhanced energy absorption, increased mean reaction force, and reduced initial maximum force, the optimal design parameters include the inner diameter-to-cylinder height ratio of 0.2, thickness-to-inner diameter ratio of 0.1, and angle of damage initiation mechanism of 45°. Manuscript profile -
Open Access Article
12 - Experimental and Numerical Study of Lateral Loadings on the Composite Tubes with SMA and Aluminum Wires and Without Wire
sajjad dehghanpour Mohsen RahmaniIn this paper, crushing length, deformations and energy absorption of thin walled square and rectangular composite tubes which are reinforced with Aluminium and SMA wires and without wire have been investigated under a quasi-static lateral load, both experimentally and MoreIn this paper, crushing length, deformations and energy absorption of thin walled square and rectangular composite tubes which are reinforced with Aluminium and SMA wires and without wire have been investigated under a quasi-static lateral load, both experimentally and numerically. To experimental study, square and rectangular composite tubes have been fabricated with SMA wire, Aluminium wire and without wire. To validate the results, a finite element model is constructed and analysed under the same conditions by using FEM27 and LS-DYNA software packages for composite tubes with Aluminium wire and without wire. The numerical results are in a good agreement with the experimental data. The results show that section geometry and the types of reinforcement wires have a considerable effect on the energy absorption. Rectangular cross-section samples with SMA wires have the most energy absorption capacity. Manuscript profile -
Open Access Article
13 - Design and Analysis of Metal-Composite Vessel under Internal Pressure
Ghasem Amraee Rad Gholamhossien RahimiThis paper, firstly, investigates the behavior of a pressure vessel designed based on the netting analysis method. Then, the strain measurement result performed to examine the behavior of the vessel is presented. It has been observed that the reverse strain is occurred MoreThis paper, firstly, investigates the behavior of a pressure vessel designed based on the netting analysis method. Then, the strain measurement result performed to examine the behavior of the vessel is presented. It has been observed that the reverse strain is occurred at the joint of the vessel cylindrical area and its head. To inspect the experimental data, the ABAQUS software (finite-element) was deployed. The simulation results turned out to be in good consistency with the experimental data. Later, to design the vessel, Von Mises and Tsai Wu criterion were used for liner and composite layers, respectively. The design results showed that the netting analysis method is not optimal and leads to increase in the cost and weight of the vessel. In addition, investigating the vessel behavior indicated that using softer liner results in more exploit of the composite properties which in turn, can bring better performance in special applications. The good consistency between the experimental and simulation results proved that the complexity involved in the design of pressure metal-composite vessels can be greatly reduced through employing finite-element simulation methods. Manuscript profile -
Open Access Article
14 - Frequency Analysis of Ring-Stiffened Composite Cylindrical Shell using Experimental, Analytical and Finite Element Methods
Hadi Salimi Ali Davar Mohsen Heydari Beni Jafar Eskandari Jam Majid Eskandari ShahrakiIn this paper, free vibration of laminated composite cylindrical shells reinforced with circumferential rings, are investigated with experimental, analytical and finite element methods and natural frequencies are obtained. The analysis is carried out for clamp-free and MoreIn this paper, free vibration of laminated composite cylindrical shells reinforced with circumferential rings, are investigated with experimental, analytical and finite element methods and natural frequencies are obtained. The analysis is carried out for clamp-free and clamp-clamp boundary conditions and the results are compared with each other. To solve the problem, the equilibrium Equations of motions are written according to the classical shells theory and after simplification, the structural stiffness and mass matrices and the frequency Equation are derived using Galerkin method. The results obtained in this paper, are compared with the results available in the literatures, and the results of experimental and finite element methods and good agreement is observed. Manuscript profile -
Open Access Article
15 - Numerical and Experimental Static Bending Analysis of Composite Sandwich Panels with Grid-Stiffened Cores Before and After Transverse Impact Loading
Ali Asghar Davoodabadi Ali Davar Mohsen Heydari Beni Jafar Eskandari JamNowadays grid structures are considered as one of the most useful composites because of their various applications. Since grid structures are vulnerable to impact loads, they should be investigated under such loadings. The present paper studies the low-velocity impact l MoreNowadays grid structures are considered as one of the most useful composites because of their various applications. Since grid structures are vulnerable to impact loads, they should be investigated under such loadings. The present paper studies the low-velocity impact loading of sandwich panels with grid-stiffened cores using both experimental and numerical simulations. In addition to the impact behaviour and the resultant damage of the sandwich panels, the behaviour of these structures under three-point bending was studied before and after the impact loading. The results were provided for impact and bending loadings separately. Then the effect of impact loadings on bending strength was investigated and it was found that the impact loading decreases the bending strength. A consistency between numerical and experimental results was also observed, which confirms the applicability of the Finite Element Method (FEM) in simulating the behaviour of such structures under impact and bending loads, while saving lots of time, efforts and costs. Manuscript profile -
Open Access Article
16 - Fabrication, Testing and Analysis of Composite Lattice Panels Under Three-Point Bending Load
Mahdi Farhadi Ali Davar Mohsen Heydari Beni Jafar Eskandari JamThanks to their high strength-to-weight ratio, lightweightness, and excellent energy absorption, composite lattice panels can be used in the aerospace, marine, automotive, and other industries. These structures can be used as an alternative to string-reinforced structur MoreThanks to their high strength-to-weight ratio, lightweightness, and excellent energy absorption, composite lattice panels can be used in the aerospace, marine, automotive, and other industries. These structures can be used as an alternative to string-reinforced structures, honeycomb (core) sandwich panels, and aluminum grid structures. In this paper, a composite lattice panel is first fabricated from glass/epoxy by hand lay-up method using a silicon rubber mold. In this method, a Kagome composite lattice panel with twelve layers of resin-impregnated fibers was fabricated during a continuous process. After fabrication, the test panel was shown under three-point bending and failure modes. Also, a numerical simulation of three-point bending was performed in ABAQUS software. Then, the simulation results were compared with those of the experimental test, indicating a good convergence between the experimental test results and the finite element ones up to the point of failure. Due to changes in directions of force, these structures have a high ability to withstand damage, and therefore, continue to withstand the load after the failure of one or more ribs. Also, there is no sudden and sharp drop in the load-bearing capacity of the structure despite the force being maximized, which can be attributed to the high energy absorption of such structures. Instead, the force decreases slowly with fluctuations, and the structure continues to absorb energy until final failure. Therefore, such lightweight structures can be used in applications where energy absorption is of great importance. Manuscript profile -
Open Access Article
17 - Dynamic Response of FGM Plates Under Blast Load
reza azarafza puya pirali Ali Davar majid ghadimiThe present study investigates the deformation of FGM plates under blast load. Hamilton's principle is used to obtain the dynamic Equations. The two constituent phases, ceramic and metal, vary across the wall thickness according to a prescribed power law. Boundary condi MoreThe present study investigates the deformation of FGM plates under blast load. Hamilton's principle is used to obtain the dynamic Equations. The two constituent phases, ceramic and metal, vary across the wall thickness according to a prescribed power law. Boundary conditions are assumed to be Simply Supported (SS). The type of explosive loading considered is a free in-air spherical air burst and creates a spherical shock wave that travels radially outward in all directions. For the pressure time of the explosion loading, Friedlander’s exponential relation has been used. In order to determine the response analytically, the stress potential field function is considered. Using the Galerkin method, the final Equations are obtained as nonlinear and nonhomogeneous second-order differential Equations. The effect of temperature including thermal stress resultants and different parameters on the dynamic response have been investigated. Results have been compared with references and validated. Results showed that the amplitude of the center point deflection of the FGM plate is less than the pure metal plates when exposed to blast load, by increasing the volumetric index percentage of FGM, center point deflection is increased and in the FGM plates, deformation of symmetrical plates is smaller than the asymmetric plates. Also by applying the damping coefficient of the FGM plates, the amplitude of center point deflection is reduced, and by increasing the aspect ratio of the FGM plate, its center point deflection against explosion waves is reduced and by considering the effects of thermal resultant forces and moments, center point deflection is increased. Manuscript profile -
Open Access Article
18 - Analysis of FGM Cylindrical Shell under Impact Loading of Explosion
reza azarafza puya pirali Ali JavadiDue to the increasing application of Functionally Graded Materials (FGM) shells, it seems necessary to investigate their behaviour under different loads. Therefore, in this paper, the dynamic response of functionally graded materials cylindrical shells under explosive l MoreDue to the increasing application of Functionally Graded Materials (FGM) shells, it seems necessary to investigate their behaviour under different loads. Therefore, in this paper, the dynamic response of functionally graded materials cylindrical shells under explosive load has been investigated with analytical and simulation methods. LS-DYNA software is used in the simulation method. In analytical solution, vibration of composite circular cylindrical shells is investigated based on the first-order deformation shell theory. The boundary conditions are assumed to be fully simply supported. The dynamic response of composite shells is studied under blast loading. The modal technique is used to develop the analytical solution of composite shell. The solution for the shell under the giving loading condition can be found using the convolution integral. Material properties are assumed to be graded in the thickness direction according to Reddy function. A FGM cylindrical shell is made up of a mixture of ceramic and metal. Results show that the effect of explosion is such that it has the greatest effect on the inner layer and with increasing thickness to the outside of the shell this effect decreases and when the maximum deflection occurs, the dynamic velocity is zero. Also, it was observed that with increasing length, the radial deflection increases due to increasing the distance from the support to the center of the shell. Manuscript profile -
Open Access Article
19 - Influence of Al2O3 Additive on Mechanical Properties of Wollastonite Glass-Ceramics
Monavvar Rahimi Babak Sadeghi Maryam Kargar RaziIn this paper, wollastonite glass-ceramics and composites of wollastonite glass– ceramics with 2.5, 5, 10 and 20 weight percent alumina with an average size of 2 microns and also wollastonite glass-ceramics with 2.5, 5, and 10 percent alumina with an average size MoreIn this paper, wollastonite glass-ceramics and composites of wollastonite glass– ceramics with 2.5, 5, 10 and 20 weight percent alumina with an average size of 2 microns and also wollastonite glass-ceramics with 2.5, 5, and 10 percent alumina with an average size of 40 nanometers were produced without pressure by Sintering and their physical properties (e.g. bulky density, the percentage of linear shrinkage and relative density) were measured. Sinter operation in the temperature range of 1030-1170 °С was performed for 3 hours. Existing phases in composites by X-ray Diffraction (XRD) and their structure were examined by Scanning Electron Microscopy (SEM) and while measuring mechanical properties of composites such as flexural strength, hardness and compared fracture toughness with base glass ceramic was performed. Results indicate that adding 2.5 percent micron-sized alumina to wollastonite glass-ceramics decreases the flexural strength from 8.01±120 to 10.26±50 MPa and its fracture toughness declines to 0.8±0.74, while by adding 2.5 percent nano-alumina to wollastonite glass – ceramics, the flexural strength increases from 8.01±120 to 20.7±133 MPa and its fracture toughness improves up to 1.40±10. Manuscript profile -
Open Access Article
20 - Behavior of Lightweight Smart Sandwich Panels Subjected to Tensile and Bending Loads- An Experimental Study
sameera Khalili s. Mohammad Khalili Reza Eslami Farsani Puneet MahajanIn this research work, sandwich composite panels made by fiber metal laminate (FML) as the facesheets and polymer foams as the core material are investigated in tensile and bending loads. To change or enhance the behaviour of sandwich panels in tensile and bending loads MoreIn this research work, sandwich composite panels made by fiber metal laminate (FML) as the facesheets and polymer foams as the core material are investigated in tensile and bending loads. To change or enhance the behaviour of sandwich panels in tensile and bending loads, shape memory alloy wires with pseudoelastic behaviour are also embedded in between FML layers in facesheets. The shape memory wires are also pre-strained in the FML facesheets of sandwich panels. To study the tensile and flexural properties of sandwich panels with smart FML facesheets three types of sandwich panels are considered and made including panels without shape memory alloy wire, panels with shape memory wires with 0% tensile pre-strain, and panels with shape memory wires with 5% tensile pre-strain for the same cross section. By placing SMA wires in the FML, the strength and stiffness of the smart sandwich specimens are increased significantly in tensile and bending loads. However, the effect of pre-straining the SMA wires is more predominant on stiffness of the specimens. The tensile and flexural toughness or energy absorption is much higher in case of the specimen with 5% pre-strained SMA wires. At the expenses of adding the SMA wires in the sandwich structures, the densities of various specimens are changed by nearly 1% to 5% for various specimens, but a significant increase in mechanical properties such as the strength and particularly the stiffness and toughness were achieved by the present lightweight smart sandwich structures. Manuscript profile -
Open Access Article
21 - Numerical Investigation of the Grid Geometry Effect on the Modal Response and Buckling of Grid-Stiffened Composite Conical Structure
Mohammad Reza Zamani Mohsen Zaretabar Hossein Parsa Mohsen Heydari BeniThis study aims to the investigation of the effect of grid geometry on the modal response and buckling strength of a composite conical lattice structure under static axial loading by Finite Element Method (FEM). For this purpose, four structures with similar geometry ha MoreThis study aims to the investigation of the effect of grid geometry on the modal response and buckling strength of a composite conical lattice structure under static axial loading by Finite Element Method (FEM). For this purpose, four structures with similar geometry have been designed through four grid structures. Abaqus finite element software has been used for modeling and analyzing the structures. The experimental results of Zamani and Ahmadifar study [1] have been used to validate the results of FEM. Given the results of numerical and experimental analysis, there is an accordance between the results and the FEM efficiency. The results show the contiguous natural frequency of the structures so that their negligible difference is due to the variations of structures’ weight and stiffness. Changing the grid does not affect the shape of the modes. The isogrid bears a higher buckling loading than the anisogrid. Reducing the rib angle is an effective parameter, which increases the buckling loading on the structure. Although peripheral ribs play a role in load bearing, adding their numbers increases the total weight of the structure, therefore, it has no significant effect on increasing the stability of the structure. Manuscript profile -
Open Access Article
22 - Effect of CaCO3 Nanoparticles on Vibrational Damping Behavior and Static Mechanical Properties of Polypropylene Composite Plates: An Experimental Investigation
Mahdi Rahmani Armen Adamian Ahmad Hosseini-SianakiIn this research, the effect of CaCO3 nanoparticles was experimentally investigated on vibrational damping behavior and static mechanical properties of polypropylene (PP). Hammer tests along with modal analysis were carried out to evaluate the forced vibration behavior MoreIn this research, the effect of CaCO3 nanoparticles was experimentally investigated on vibrational damping behavior and static mechanical properties of polypropylene (PP). Hammer tests along with modal analysis were carried out to evaluate the forced vibration behavior of composite plates under one edge clamped support conditions while tensile tests were performed to assess the static mechanical properties. A comparison of the results showed an increment in the static mechanical properties of nanocomposites by increasing the nanoparticles content in the PP matrix. Composite with 10 wt.% nanoparticles showed the highest rise in Young’s modulus (39.71 %) compared to pure PP. An increment in Young’s modulus and stiffness led to an increasing trend in the damped natural frequencies of the nanocomposites so that the composite with 10 wt. % nanoparticles showed the highest damped natural frequency augmentation (23.6 %, 36.78 %, and 252.62 %) compared to pure PP in the first three modes. In addition, an enhancement in the nanoparticles content of the PP matrix led to an increasing trend in damping ratios of the nanocomposites such that the composite with 10 wt. % nanoparticles in the first mode (28.99 %) and composite with 7.5 wt. % nanoparticles in the second and third modes (418.66 % and 9.93 %) showed the highest rise in damping ratio compared to pure PP. Increasing damping ratios can be due to the proper dispersion of nanoparticles in the matrix and consequently energy dissipation of the stick-slip mechanism between the matrix and nanoparticles. Moreover, high nanoparticle contents had destructive effects on both the static and dynamic behavior of the composites. Manuscript profile -
Open Access Article
23 - Investigating the Effect of Process Parameters on Reducing the Peeling Stress in Adhesive Joints of Composite Materials
Saeed Yaghoubi Mohammad Shishehsaz Kiamehr RouzbakhshzadehJoints are considered the weakest part of an engineering structure and failure usually occurs in this region, firstly. One of the main factors in the rupture of adhesive joints is the normal stresses between the layers created by the presence of an out-of-center load an MoreJoints are considered the weakest part of an engineering structure and failure usually occurs in this region, firstly. One of the main factors in the rupture of adhesive joints is the normal stresses between the layers created by the presence of an out-of-center load and bending moment. The present research work has focused on the influence of parameters including the adhesive zone length, adhesive and adherend layer thickness on reducing the amount of normal interlayer stress in a single-lap adhesive joint. Optimization of parameters have been done using BA and PSO optimization algorithm. The distribution of normal and shear stresses are based on two-dimensional elasticity theory that includes the complete stress-strain and strain-displacement relations for the adhesive and adherends. The results obtained from current research revealed that by optimization of mentioned parameters, the value of peeling stress is significantly reduced. Although increasing in Young’s modulus of adhesive layer leads to an increase in normal stress of the joint, it creates a more uniform stress distribution at the edges. The outcomes also revealed that increasing the length of the joint zone and the thickness of adherends can improve the interlayer normal stress in the adhesive joint. Manuscript profile -
Open Access Article
24 - Experimentally Designed of PVC/NiAl2O3/AlF3 Nanocomposite by Sol-Gel Method
Elinaz Ahmadian Maryam Kargar Razi Babak Sadeghi Mahbobeh NakhaeiIn this study, we have synthesized nano Aluminum Fluoride (nAF) nanoparticles by the sol-gel method and studied the nano-sized morphology of crystals. In the other section, the PVC/NiAl2O3/AlF3 (nPNA) nanocomposite was successfully prepared and characterized by FT-IR, a MoreIn this study, we have synthesized nano Aluminum Fluoride (nAF) nanoparticles by the sol-gel method and studied the nano-sized morphology of crystals. In the other section, the PVC/NiAl2O3/AlF3 (nPNA) nanocomposite was successfully prepared and characterized by FT-IR, and HRTEM techniques. FTIR peaks of the PVC and nPNA have been shown spherical shape of PVC and also spherical shapes nanoparticles of nPNA loaded on PVC. A solvothermal method has been successfully introduced and applied for catalyst efficiency. This nanocomposite was used for the removal of Congo red dye. For this purpose, the morphology and the structure of crystals have been changed by modification on precursor gel. Meanwhile, precursor gel preparation and the interaction on the nano-sized area have been studied. This study exhibited that PVC/NiAl2O3/AlF3 (nPNA) nanocomposite is an effective catalyst for the synthesis of some organic derivatives. The results show that the as-prepared nanocomposite is an efficient catalyst and that PVC/NiAl2O4/AlF3 nanocomposite can be used in the next-generation of some organic reactions and faster production of various materials. Manuscript profile -
Open Access Article
25 - Finite Element Analysis of the Impact Behavior of Sandwich Panels with Nanocomposite Face sheet (Epoxy/ Fiberglass/Nanosilica)
Arash Azadi Mahdi Karami Khorramabadi Maziar Mahdipour JalilianIn this research, the impact behavior of nanocomposite sandwich panels with epoxy/fiberglass/nanosilica face sheet were assessed by the finite element method. In the first step, the mechanical properties of the nanoparticle-containing composite should be obtained. A uni MoreIn this research, the impact behavior of nanocomposite sandwich panels with epoxy/fiberglass/nanosilica face sheet were assessed by the finite element method. In the first step, the mechanical properties of the nanoparticle-containing composite should be obtained. A unit cell of fabric was designed in Catia software and placed within the designed polymeric matrix. The mechanical properties of this unit cell were defined as a new matrix and the nanoparticles were randomly dispersed in the new matrix using a Python code. The elastic properties of the modeled nanocomposite were obtained using Abaqus software via applying periodic boundary conditions based on the mean volumetric stress. In the next step, the sandwich structure was subjected to impact loads at various speeds and contact force-time diagrams were plotted using Abaqus software. The modeled results were compared with the known experimental data which showed a high accuracy in predicting the mechanical properties and impact behavior of the nanocomposite sandwich structures. Manuscript profile -
Open Access Article
26 - Non-Destructive Assessment of Concrete Quality Produced with Riverbed Sand and Drainage Sand as Fine Aggregates
Aderemi__A__Alabi Alabi Ayobami__Eniola__Agboola Agboola Joseph__Olawale__Akinyele Akinyele Victor MakindeIn this work, the effect of fine aggregates from two different sources on the quality and strength of concrete was determined using UPV measurements. The concrete samples were produced using a nominal mix ratio of 1: 1½: 3 and water-cement ratio of 0.55, with three diff MoreIn this work, the effect of fine aggregates from two different sources on the quality and strength of concrete was determined using UPV measurements. The concrete samples were produced using a nominal mix ratio of 1: 1½: 3 and water-cement ratio of 0.55, with three different aggregate sizes (3/8, ½ and ¾ inches) of granite mixed separately with sand obtained from Ogun river and a local drainage in Abeokuta, Southwestern, Nigeria. UPV was measured through each sample on days 1, 7, 14, 21 and 28 after curing using Pundit lab+ equipment. Comparison of the actual compressive strength and estimated compressive strengths from equations generated for each sample type using the crushed samples on the 7th and 28th days respectively shows that most estimations were within the acceptable ±20% variation. Results show that there is no significant difference between the samples made from using either of the two fine aggregates. Manuscript profile