Semnan UniversityMechanics of Advanced Composite Structures2423-48264220171101Dynamic Characteristics of Joined Steel and Carbon Fiber-Reinforced Plastic Tubes: Experimental and Numerical Investigation8897227710.22075/macs.2017.1526.1069ENM.ShakouriSemnan UniversityM.DanialiDepartment of Aerospace Engineering, Sharif University of TechnologyH. M.NavaziDepartment of Aerospace Engineering, Sharif University of TechnologyM. A.KouchakzadehDepartment of Aerospace Engineering, Sharif University of TechnologyJournal Article20160723The fundamental frequencies and mode shapes of steel and carbon fiber–reinforced plastic (CFRP) cylindrical shells with steel inserts were investigated using finite element analysis and modal testing. The free-free boundary condition was tested with modal testing using the roving hammer method and verified by finite element analysis using ABAQUS. The results show good agreement between the testing and finite element analysis in both natural frequencies and mode shapes. Then, the vibrational behavior of cylindrical shells with steel/CFRP lap joints for simply supported-free and clamped-free edge conditions was studied using the verified finite element modeling, and the effects of lengths and thicknesses of composite cylinders and steel inserts on the free vibration of joined steel/CFRP were investigated. The results show that the vibrational behavior of the CFRP shell and its dimensions has a major influence on natural frequencies and mode shapes of the joined shells.Semnan UniversityMechanics of Advanced Composite Structures2423-48264220171101Vibration Optimization of Fiber-Metal Laminated Composite Shallow Shell Panels Using an Adaptive PSO Algorithm99110262910.22075/macs.2017.1744.1087ENHadiGhashochi-BarghBuein Zahra Technical UniversityMohammad HomayounSadrAmirkabir University of TechnologyJournal Article20161117The paper illustrates the application of a combined adaptive particle swarm optimization (A-PSO) algorithm and the ﬁnite strip method (FSM) to the lay-up optimization of symmetrically fiber-metal laminated (FML) composite shallow shell panels for maximizing the fundamental frequency. To improve the speed of the optimization process, adaptive inertia weight was used in the particle swarm optimization algorithm to modify the search process. The use of the inertia weight provided a balance between global and local exploration and exploitation and resulted in fewer iterations on average to find an optimal solution. The fitness function was computed with a semi-analytical FSM. The number of layers, the fiber orientation angles, edge conditions, length/width (<em>a</em>/<em>b</em>) ratios, and length/radii of curvature (<em>a</em>/<em>R</em>) ratios were considered as design variables. The classical shallow shell theory (Donnell’s formulation) was applied to calculate the natural frequencies of FML cylindrical curved panels. A program using Maple software was developed for this purpose. To check the validity, the obtained results were compared with some other stacking sequences. The numerical results of the proposed approach were also compared with other algorithms, which showed that the A-PSO algorithm provides a much higher convergence and reduces the required CPU time in searching for a global optimization solution. With respect to the first natural frequency and weight, a bi-objective optimization strategy for the optimal stacking sequence of FML panels is also presented using the weighted summation method.Semnan UniversityMechanics of Advanced Composite Structures2423-48264220171101Open-Hole Size and Thermal Cycling Effects on Mass Loss and Surface Degradation of Polymer Matrix Composites111116263010.22075/macs.2017.1671.1089ENAhmad RezaGhasemiUniversity of KashanMahdiMoradiUniversity of KashanJournal Article20161126Degradation is a common problem for polymer matrix composites (PMCs) under low thermal cycling conditions. This paper investigates the effects of low thermal cycling on total mass loss (TML) and surface degradation of PMCs. Unnotched and open-hole specimens were weighed before and after low thermal cycling. The total mass loss and surface degradation of the specimens were studied over 250 cycles of 100˚C temperature difference. The experimental results showed that the mass loss linearly decreased during low thermal cycling. Also, it was found that laminates with smaller holes have higher percent mass loss than those with larger holes. Based on weight loss rates, a regression model is presented to evaluate the TML of laminated composite material samples. Also, under similar experimental conditions, the specimens exhibited 0.4% mass loss reduction after 250 cycles, and the incremental decrease of the hole diameter also decreased the TML. It was found that laminates with smaller holes have higher tensile strength variation than those with larger holes. The results showed that the incremental decrease of the hole diameter and number of cycles decreases the tensile strength of PMCs.Semnan UniversityMechanics of Advanced Composite Structures2423-48264220171101Numerical Simulation of a Hybrid Nanocomposite Containing Ca-CO3 and Short Glass Fibers Subjected to Tensile Loading117125262810.22075/macs.2017.1772.1092ENMinoo DokhtShokrianDepartment of mechanical engineering, University of TabrizKarimShelesh-NezhadDepartment of mechanical engineering, University of Tabriz, IranBehzadH SoudmandDepartment of mechanical engineering, University of Tabriz, IranJournal Article20161201The tensile properties of multiscale, hybrid, thermoplastic-based nanocomposites reinforced with nano-CaCO<sub>3</sub> particles and micro–short glass fibers (SGF) were predicted by a two-step, three-dimensionalmodel using ANSYS finite element (FE) software. Cylindrical and cuboid representative volume elements were generated to obtain the effective behavior of the multiscale hybrid composites. In the first step, the mechanical performance of co-polypropylene/CaCO<sub>3</sub> nanocomposite was analyzed. The thickness of the interphase layer around the nanoparticles was estimated by using differential scanning calorimetry data. In the second step, the nanocomposite (co-polypropylene/CaCO<sub>3</sub>) was considered as an effective matrix, and then the effect of micro-SGF inclusion on the corresponding effective matrix was evaluated. The FE and experimental stress-strain curves of multiscale, hybrid composites were compared at different weight fractions of the nanoparticle. The proposed two-step method can easily predict the tensile properties of multiscale, hybrid, thermoplastic-based nanocomposites.Semnan UniversityMechanics of Advanced Composite Structures2423-48264220171101Free Vibration Analysis of Size-Dependent, Functionally Graded, Rectangular Nano/Micro-plates based on Modified Nonlinear Couple Stress Shear Deformation Plate Theories127137262710.22075/macs.2017.1800.1094ENKoroshKhorshidiArak University0000-0002-7321-972XAbolfazlFallahArak UniversityJournal Article20161217In the present study, a vibration analysis of functionally graded rectangular nano-/microplates was considered based on modified nonlinear coupled stress exponential and trigonometric shear deformation plate theories. Modified coupled stress theory is a non-classical continuum mechanics theory. In this theory, a material-length scale parameter is applied to account for the effect of nanostructure size that earlier classical plate theories are not able to explain. The material properties of the plate were assumed to vary according to a power-law form in the thickness direction. The governing equation of the motion of functionally graded, rectangular nano-/microplates with different boundary conditions were obtained based on the Rayleigh-Ritz method using complete algebraic polynomial displacement and rotation functions. The advantage of the present Rayleigh-Ritz method is that it can easily handle the different conditions at the boundaries of moderately thick rectangular plates (e.g., clamped, simply supported, and free). A comparison of the results with those available in the literature has been made. Finally, the effect of various parameters, such as the power-law index, thickness-to-length scale parameter ratio <em>h/l</em>, and aspect ratio <em>a/b</em>, on the natural frequency of nano/micro-plates are presented and discussed in detail.Semnan UniversityMechanics of Advanced Composite Structures2423-48264220171101A Quasi-3D Polynomial Shear and Normal Deformation Theory for Laminated Composite, Sandwich, and Functionally Graded Beams139152262610.22075/macs.2017.10806.1105ENBharti M.ShindeDepartment of Civil Engineering, SRES’s Sanjivani College of Engineering, Savitribai Phule Pune University, Kopargaon-423603, Maharashtra, IndiaAtteshamuddin S.SayyadDepartment of Civil Engineering, SRES&#039;s College of Engineering, Savitribai Phule Pune University, Kopargaon,-423601Journal Article20170309Bending analyses of isotropic, functionally graded, laminated composite, and sandwich beams are carried out using a quasi-3D polynomial shear and normal deformation theory. The most important feature of the proposed theory is that it considers the effects of transverse shear and transverse normal deformations. It accounts for parabolic variations in the strain/stress produced by transverse shear and satisfies the transverse shear stress-free conditions on the top and bottom surfaces of a beam without the use of a shear correction factor. Variationally consistent governing differential equations and associated boundary conditions are obtained by using the principle of virtual work. Navier closed-form solutions are employed to obtain displacements and stresses for the simply supported beams, which are subjected to sinusoidal and uniformly distributed loads. Results are compared with those derived using other higher-order shear deformation theories. The comparison validates the accuracy and efficiency of the theory put forward in this work.Semnan UniversityMechanics of Advanced Composite Structures2423-48264220171101Mesh-free Dynamic Analyses of FGM Sandwich Plates Resting on A Pasternak Elastic Foundation153168262410.22075/macs.2017.11043.1107ENRasoolMoradi-dastjerdiYoung Researchers and Elite Club,Khomeinishahr Branch, Islamic Azad University, Khomeinishahr, IranHamedMomeni-KhabisiDepartment of Mechanical Engineering, University of Jiroft, Jiroft, IranRaminBaghbaniDepartment of Water Engineering, Isfahan University of Technology, Isfahan, IranJournal Article20170413This study analyzes the free vibration, forced vibration, resonance, and stress wave propagation of orthotropic sandwich plates made of functionally graded materials (FGMs). Dynamic analyses are conducted using a mesh-free method based on first-order shear deformation theory and the shape functions constructed using moving least squares approximation. The sandwich plates are rested on a Pasternak elastic foundation and subjected to periodic or impact loading and essential boundary conditions, which are imposed through a transfer function method. The sandwich plates are assumed to be composed of a homogeneous orthotropic core and two orthotropic FGM face sheets made of two orthotropic materials. The volume fractions of the materials are varied smoothly along the thickness of the face sheets. The convergence and accuracy of the applied method are demonstrated, after which numerical analyses are conducted to investigate the effects of elastic foundation coefficients, material distributions, geometrical dimensions, time-dependent loading, and boundary conditions on the vibrational and dynamic characteristics of the orthotropic FGM sandwich plates.Semnan UniversityMechanics of Advanced Composite Structures2423-48264220171101Using the Taguchi Method for Experimental and Numerical Investigations on the Square-Cup Deep-Drawing Process for Aluminum/Steel Laminated Sheets169177258310.22075/macs.2017.11051.1108ENMasoudMahmoodiMechanical Engineering Dept. Semnan University, Semnan, IranHabibSohrabiMechanical Engineering Dept. Semnan University, Semnan, IranJournal Article20170415The effects of input parameters on the square-cup deep-drawing process for a two-layer aluminum/steel laminated sheet were investigated. Each layer was 0.7 mm thick, and the input parameters covered in the investigation were punch nose radius (PR), die shoulder radius (DR), the clearance between a punch and die (CPD), blank holder force (BHF), and layer arrangement (LA). The effects of the input parameters on wrinkling and thinning defects were determined by finite element simulation and Taguchi’s design of experiments. Experimental tests were conducted to validate the finite element analysis results. Results indicated that the parameter exerting the greatest effect on thinning defects was PR, followed by LA relative to the other parameters. BHF had the highest influence on the wrinkle height of the two-layer aluminum/steel sheet. Optimization was conducted, and the optimum input parameter values that caused the least wrinkling and thinning defects were 5.35 mm for DR, 8.35 mm for PR, 6000 N for BHF, and 1.3 t for CPD.