Semnan University PressMechanics of Advanced Composite Structures2423-48264120170401Synthesis and Characterization of Polymer/Nanosilicagel Nano-composites1850010.22075/macs.2016.500ENF.ShakooeeaFaculty of Materials and Metallurgical Engineering, Semnan University, Semnan, IranMardaliYousefpoarFaculty of Materials and Metallurgical Engineering, Semnan University, Semnan, IranMohammadTajaliFaculty of Materials and Metallurgical Engineering, Semnan University, Semnan, IranJournal Article20160628In this study, a polymer-silica nanocomposite using the sol-gel method was synthesized in three steps at room temperature. The nanocomposite material was formed with an organic compound (polyethylene glycol) and inorganic silica nanoparticles. Furthermore, the size and the distribution of nanoparticles in the polymer matrix were characterized by a transmission electron microscope (TEM). In addition, the refractometer analysis was used to measure the refractive index of the nanocomposite. Following that, Fourier transform infrared (FTIR) spectroscopy and small-angle X-ray diffraction and high X-ray diffraction have also used to characterize the polymer and the inorganic part of the nanocomposite. TEM studies showed the distribution of nanoscale silica particles of the size of 50-100 (nm) in the polymer matrix. Furthermore, the refractive index of the nanocomposite was measured about 1.4, which was very close to the refractive index of the natural lens (1.411). Additionally, the FTIR spectra showed OH groups in FTIR spectroscopy, which confirmed the hydrophilic property of silica nanoparticles and the two sharp peaks at the angles of 19° and 23° in the X-ray diffraction analyses, which were in the nature of the crystallinity of polyethylene glycol. Finally, the results showed the surface modification of nanoparticles and their incorporation in a polymer matrix, which led to the formation of the desired nanocomposite that was made of inorganic (silica nanoparticles) and an organic (polyethylene glycol) compound.https://macs.semnan.ac.ir/article_500_772032dbd6f3fa6b249633366b3de44f.pdfSemnan University PressMechanics of Advanced Composite Structures2423-48264120170401Distribution of Residual Stresses in Polymer Reinforced Carbon Nanotubes and Laminated Carbon Fibers91847610.22075/macs.2016.476ENAhmad RezaGhasemiUniversity of KashanMohammadMohammadi-FesharakiUniversity of KashanJournal Article20160723In this study, the distribution of residual stress in fiber-reinforced nanocomposites is investigated. Fiber-reinforced nanocomposite is composed of three substances: carbon fiber, carbon nanotube (CNT), and polymer matrix. Unit cells in hexagonal packing array with different arrays as unit cell, 3*3 and 5*5 arrays have been selected as suitable for finite element analysis of residual stresses. Radial and tangential residual stress have been determined in different directions by finite element analysis using ABAQUS commercial software for each phase individually. The effect of the CNTs’ various volume fractions (0%, 1%, 2%, and 3%) on residual stress distribution has been studied in different directions and compared to one another for each phase. Results show that the 3*3 unit cells arrays are suitable for modeling micro-residual stresses, and the results of this array are reliable. In addition, adding a 3% volume fraction of CNTs to the matrix is the best option for reduction of overall residual stresses with minimal fluctuation in local micro-residual stresses.https://macs.semnan.ac.ir/article_476_923c3b22a4f37795ee7ade15f4833926.pdfSemnan University PressMechanics of Advanced Composite Structures2423-48264120170401Study of Laminated Composite MEMS and NEMS Performance in Nano Metric Operations193149510.22075/macs.2016.495ENSadeghSadeghzadehSchool of new Technology, Iran University of Science and TechnologyMoharramHabibnejad KorayemIran University of Science and TechnologyAhmadHomayooniIran University of Science and TechnologyJournal Article20160812Precision of nano-metric operations is an important issue in nano-engineering studies. Several operative parameters might affect the quality of results. The parameters of the nano world are significant but not entirely controllable. However, the geometrical and mechanical properties of micro cantilevers are completely controllable. So, controlling the sensitivity of resulting image through t lamination design could be a proper approach. This paper analyses the effects of composite lamination on the performance of common Micro and Nano Electro Mechanical systems (MEMS and NEMS, respectively). Generalized Differential Quadrature (GDQ) and Generalized Differential Quadrature Element (GDQE) methods are used as semi-analytic solutions for regular and irregular domains, respectively. Validity, applicability and accuracy of the proposed approach are demonstrated and then the lamination effects on the nano-imaging and manipulation of nano particles by micro cantilevers are studied. This study shows that some laminations of micro cantilevers resulted in a better performance in nano-manipulation and imaging. Furthermore, clarifying the dependency of system sensitivity on the profile of the substrate is remarkable.https://macs.semnan.ac.ir/article_495_f35307a1fdd13aa89d258769c988f59b.pdfSemnan University PressMechanics of Advanced Composite Structures2423-48264120170401Improving Mechanical Properties of Nanocomposite-based Epoxy by High-impact Polystyrene and Multiwalled Carbon Nanotubes: Optimizing by a Mixture Design Approach3345227310.22075/macs.2017.1580.1076ENYasserRostamiyanDepartment of Mechanical Engineering, Sari Branch, Islamic Azad University, Sari, IranJournal Article20160903In the current study the influence of weight percentage of HIPS, weight percentage of CNT and hardener content on damping 1st and damping 2nd properties of epoxy/HIPS/CNT hybrid composite wase valuated. Mixture design methodology was employed to generate mathematical models for predicting damping 1st and damping 2nd behaviors of new mentioned hybrid nanocomposite as function of physical factors and optimizing desired mechanical properties. The maximum and minimum values of damping 1st occurred in run numbers 7 and 1 and were 3.71%and 1.64 % respectively, moreover maximum and minimum values of damping 2nd occurred in coded levels 9 and 1 with the values of 4.25% and 1.82 % respectively. Results of analysis of variance showed that input variables had linear effect on both of the studied responses, also two component interactions X1*X2, X1*X3 and X2*X3 affected damping 1st and damping 2nd due to their obtained P-values. Optimization results described that the highest value for damping 1st and damping 2nd were 3.53% and 4.11% respectively.Coded values were HIPS= 0.222, CNT= 0.301 and hardener= 0.476 and corresponding mixture components were HIPS=4.18wt%, CNT= 1.12 wt% and hardener= 25.75phr respectively.https://macs.semnan.ac.ir/article_2273_3bd8f07ef567b8d24e0cd036d844fa64.pdfSemnan University PressMechanics of Advanced Composite Structures2423-48264120170401On the Buckling the Behavior of a Multiphase Smart Plate based on a Higher-order Theory475848510.22075/macs.2016.485ENSoheilRazaviYoung Researchers and Elite Club, Tabriz Branch, Islamic Azad University, Tabriz, Iran0000-0002-0281-9373Journal Article20160909Magneto-electro-elastic materials are multiphase smart materials that exhibit coupling among electrical, magnetic and mechanical energy fields. Due to this ability, they have been the topic of numerous research in the past decade. In this paper, buckling behavior of a multiphase magneto-electro-elastic rectangular plate with simply supported boundary conditions is investigated, based on Reddy’s higher-order shear deformation theory. Gauss’s laws for electrostatics and magnetostatics are used to model the electric and magnetic behaviors of the plate. The partial differential equations of motion are reduced to ordinary differential equations by using the Galerkin method. Then, the closed-form expression for the critical buckling load of the plate considered is obtained. Some examples are presented to validate the study and to investigate the effects of some parameters on the critical buckling loads of the multiphase magneto-electro-elastic rectangular plates. It is found that the buckling behavior of the magneto-electro-elastic plate is dominated by the elastic properties of the plate, and magneto-electric coefficients slightly increase the critical buckling load of the plate.https://macs.semnan.ac.ir/article_485_c868b22f717139ca4a769fdb3136f82c.pdfSemnan University PressMechanics of Advanced Composite Structures2423-48264120170401Free Vibration and Buckling Analyses of Functionally Graded Nanocomposite Plates Reinforced by Carbon Nanotube597349610.22075/macs.2016.496ENRasoolMoradi-dastjerdiYoung Researchers and Elite Club,Khomeinishahr Branch, Islamic Azad University, Khomeinishahr, IranHoseinMalek-MohammadiDepartment of Mechanical Engineering, Bu-Ali Sina University, HamedanJournal Article20161005This paper describes the application of refined plate theory to investigate free vibration and buckling analyses of functionally graded nanocomposite plates reinforced by aggregated carbon nanotube (CNT). The refined shear deformation plate theory (RSDT) uses four independent unknowns and accounts for a quadratic variation of the transverse shear strains across the thickness, satisfying the zero traction boundary conditions on the top and bottom surfaces of the plate without using shear correction factors. The motion equations are derived from Hamilton’s energy principle and Navier’s method is applied to solve this equation. The material properties of the functionally graded carbon nanotube reinforced composites (FG-CNTRCs) are assumed to vary along the thickness and estimated with the Mori–Tanaka approach. Effects on the natural frequency and critical buckling load of the FG-CNTRC plates by CNT volume fraction, CNT distribution, CNT cluster distribution, and geometric dimensions of the plate are investigated. Effects of loading conditions on the critical buckling load are also examined.https://macs.semnan.ac.ir/article_496_da40d6ffd5d8f34564ee36a6c5c7135b.pdfSemnan University PressMechanics of Advanced Composite Structures2423-48264120170401A Numerical and Analytical Solution for the Free Vibration of Laminated Composites Using Different Plate Theories7587227810.22075/macs.2017.1768.1090ENMohammad AminTorabizadehUniversity of Applied Science and TechnologyAbdolhosseinFereidoonUniversity of SemnanJournal Article20161127An analytical and numerical solution for the free vibration of laminated polymeric composite plates with different layups is studied in this paper. The governing equations of the laminated composite plates are derived from the classical laminated plate theory (CLPT) and the first-order shear deformation plate theory (FSDT). General layups are evaluated by the assumption of cross-ply and angle-ply laminated plates. The solver is coded in MATLAB. As a verification method, a finite element code using ANSYS is also developed. The effects of lamination angle, plate aspect ratio and modulus ratio on the fundamental natural frequencies of a laminated composite are also investigated and good agreement is found between the results evaluated and those available in the open literature. The results show that the fundamental frequency increases with the modular ratio and the bending-stretching coupling lowers the vibration frequencies for both cross-ply and angle-ply laminates with the CLPT. Also it is found that the effect of bending-stretching coupling, transverse shear deformation and rotary inertia is to lower the fundamental frequencies.https://macs.semnan.ac.ir/article_2278_4c7f1a6972cd9834d060b86b27244a48.pdf