List of Articles

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  1 - Finite element modeling of a pavement piezoelectric energy harvester
  Ehsan Latifi Pakdehi Ali Akbar Pasha Zanoosi
  One of the best methods to achieving renewable and clean energy is piezoelectric energy harvesters (PEHs), which convert mechanical and vibration energy into electrical energy. These generators appeared after the special and unique capabilities of piezoelectric and vibr More

  One of the best methods to achieving renewable and clean energy is piezoelectric energy harvesters (PEHs), which convert mechanical and vibration energy into electrical energy. These generators appeared after the special and unique capabilities of piezoelectric and vibration to electrical energy can be directly converted. The use of these generators is seen in many fields including the use of roads and bridges to convert vibrations caused by the vehicles in to electrical energy and other thing. In this study a piezoelectric energy harvester with the feature of parallel piezoelectric connections was computer simulated using a finite element method. In a computer simulation unlike laboratory method that can only analyze one form of a system, different states and situations of factors can be simulated. In this study, to achieve an optimal state of power and output voltage of an existing PEH, the effects and behaviors of different parameters such as forces, frequencies, temperatures, housing dimensions, piezoelectric materials and the presence of isolators have been investigated. In addition, to obtain the significance of these factors, using the analysis of variance method, the importance and effectiveness of each of these parameters has been investigated. The results revealed that increasing the amount of force and frequency and decreasing the temperature increases the output voltage of this kind of PEH. Changing the dimensions of the housing if its area is constant, does not change the output result and the use of isolators reduces the output voltage. The effect of these parameters is compared to previous studies and the results are presented. Manuscript profile
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  2 - Prediction of Heating Energy Consumption in Houses via Deep Learning Neural Network
  Newsha Valadbeygi Ali Shahrjerdi
  This paper presents a novel model for prediction of energy consumption and heat transfer in houses on the basis of neural network by the use of experimental dataset of some cities of Iran for the learning process. To this end, a deep learning neural network (DNN) is des More

  This paper presents a novel model for prediction of energy consumption and heat transfer in houses on the basis of neural network by the use of experimental dataset of some cities of Iran for the learning process. To this end, a deep learning neural network (DNN) is designed by means of real set of data as input. In order to evaluate the proposed network, the predicted results are compared with the results obtained from the practical schemes. The comparison approved the effectiveness and feasibility of the suggested network in prediction of energy consumption and heat transfer with a low error for regression. Manuscript profile
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  3 - Department of Mechanical Engineering, Islamic Azad University, Roudehen Branch Tehran, Iran
  S.M.M. Shafiei H. Raeisifard
  Plasma-assisted chemical vapor deposition method was used to construct a diamond-like carbon coating on aluminum substrate 6061-T6. Sedimentation was carried out using CH4 as a process gas at different temperatures of 250-300 Celsius with constant flow rate and power. R More

  Plasma-assisted chemical vapor deposition method was used to construct a diamond-like carbon coating on aluminum substrate 6061-T6. Sedimentation was carried out using CH4 as a process gas at different temperatures of 250-300 Celsius with constant flow rate and power. Raman spectroscopy was used to describe these samples. Raman analysis of DLC coatings at different temperatures has been done in detail for two different wavelengths of stimulation of 514 and 785 nm and the results are shown in this paper. Peak changes were observed in both D and G peaks of Raman spectrum with increasing sediment temperature, indicating the formation of compressive strain in DLC coatings at high temperatures. Scattering is observed at both D and G peaks for different wavelengths of excitation, indicating that the DC coating is hydrogenated. It seems that the degree of hydrogenation of DLC coating decreases due to sediment temperature. The study of nano-indentation with increasing sediment temperature shows a marginal increase in hardness. Manuscript profile
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  4 - Free Vibration Analysis of Sandwich Plates with FGM Face Sheets and Temperature-Dependent Properties of the Core Materials
  Y. Mohammadi
  In this paper, the free vibration of sandwich plates with power-law FGM face sheets in various thermal environments is performed by high-order sandwich plate theory. The material properties of the core, such as Young’s modulus, density, thermal expansion coefficie More

  In this paper, the free vibration of sandwich plates with power-law FGM face sheets in various thermal environments is performed by high-order sandwich plate theory. The material properties of the core, such as Young’s modulus, density, thermal expansion coefficient and Poisson’s ratio, are assumed to be temperature dependent by nonlinear function of temperature [1]. The material properties of the FGM face sheets are assumed to vary continuously through the thickness according to a power law distribution in terms of volume fractions of the constituents [2]. The governing equations of motion in free natural vibration are derived using Hamilton’s principle [3]. A new approach is used to reduce the equations of motion from twenty three equations to eleven equations and then solve them. The new solution approach consists of isolating six of the unknowns in the displacements of the face sheets using the compatibility equations, followed by isolating the additional six Lagrange multipliers using the equations of the face sheets, finally, the isolated unknowns are substituted into the eleven equations of the core. Both un-symmetric and symmetric sandwich plates are considered in this analysis. Good agreement is found between theoretical predictions of the fundamental frequency parameters and the results obtained from other references for simply supported sandwich plates with functionally graded face sheets. The results show that the fundamental frequency parameters (ω ̅ ) increases by increasing the volume fraction index (κ). Also, the effect of temperature on the value of fundamental frequency parameters decreases with increases in the FGM face sheets thickness. The results also revealed that as the side-to-thickness ratio (b⁄h), the core-to-face sheet thickness ratio (h_c⁄h_t ) and temperature changes, have a significant effect on the fundamental frequency parameters. Manuscript profile
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  5 - Investigation of Failure Mechanism in Earth Dam upon Triggered Liquefaction
  Farzad Peyman
  The behavior of the earth-dam body as a soil structure made of cohesive soil in the core and non-cohesive soil as the core supports, including water interaction upstream through earthquake upon multi-line constitutive equations, is the aim of this paper. A multi-plane m More

  The behavior of the earth-dam body as a soil structure made of cohesive soil in the core and non-cohesive soil as the core supports, including water interaction upstream through earthquake upon multi-line constitutive equations, is the aim of this paper. A multi-plane mechanism-based approach is successfully employed for assigning post-liquefaction displacement of earth-dam structures. This approach is derived from total stress procedures with two major advantages:1) the triggering and post-liquefaction responses have been multi-lined into one analysis.2) the modeling of post-liquefaction element behavior is greatly improved.To sum up, a multi-plane-based framework is employed. The strength effects on integrated sampling planes and the resultant of this simulated multi-lined behavior are implemented for each finite element gauss point. This multi-plane-based model can also predict the effects of induced and inherent anisotropy plus the rotation of principal stress/strain axes through the plastic behavior of both cohesive and non-cohesive soils.The approach is presented through the simulation of the case history as the response of the lower San Fernando dam to the 1971 San Fernando earthquake. The magnitude and pattern of the predicted displacements are shown to be in good agreement with the measured values Manuscript profile
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  6 - Vortex-induced energy harvesting of an elliptic blade in high-Reynolds lid-driven cavity flow
  Ali Akbar Hosseinjani Ghasem Akbari
  Lid-driven cavity flow is characterized by large-scale energetic eddies which are potential for energy harvesting purposes. The present article deals with numerical study of vortex-induced autorotation of an elliptic blade hinged at the center of a lid-driven cavity.Imm More

  Lid-driven cavity flow is characterized by large-scale energetic eddies which are potential for energy harvesting purposes. The present article deals with numerical study of vortex-induced autorotation of an elliptic blade hinged at the center of a lid-driven cavity.Immersed boundary method is utilized to solve the governing equations for this moving boundary problem. Four different blade dimensions are considered at a fairly high-Reynolds number to evaluate the impact of various vortex types and flow unsteadiness on the blade dynamics. Small-amplitude fluttering, clockwise autorotation and counter-clockwise autorotation are three dominant modes observed at various configurations and different temporal stages. The average-length blade is equally characterized by vortices at both directions, and consequently experiences a fluttering mode. In contrast, short (long) bladeis mainly affected by one dominant vortex type, leading to steady autorotation in counter-clockwise (clockwise) direction. At stable autorotation of blade in both directions, regular cyclic temporal oscillations are observed in the rotational speed, which are due to cyclic evolution of the near-blade vortices and their alternating moment applied to the blade. Manuscript profile
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  7 - Analysis of Free Vibration Sandwich Panels with trapezoidal Corrugated Core Based on Galerkin Method
  Arman Gholamreza BanadCooki J.Rezaei Pazhand
  The purpose of this paper is to evaluate the free vibration of sandwich panels with corrugated core using the element-free Galerkin method and based on the first-order shear deformation theory (FSDT).The sandwich panels' free vibrations with corrugated core consist of t More

  The purpose of this paper is to evaluate the free vibration of sandwich panels with corrugated core using the element-free Galerkin method and based on the first-order shear deformation theory (FSDT).The sandwich panels' free vibrations with corrugated core consist of two sheets above and below the panels, and a corrugated core in middle of these panels. The core equals to orthotropic sheet and the two panels equal to isotropic sheet. Dynamic equations of the members are obtained through FSDT. The present research applies Galerkin numerical element less method to solve equations of the problems. This method uses the functions of minimum moving squares. The model is simulated in cosmos software; the results are compared with the results of present papers, and show the accuracy of the method applied in the present paper. Manuscript profile
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  8 - Chaos and Bifurcation in Roto-Translatory Motion of Gyrostat Satellite
  Seyed Mahdi Abtahi Seyed Hosein Sadati
  The chaotic dynamics of Roto-Translatory motion for a triaxial Gyrostat satellite is considered in this study based on the Hamiltonian approach. Higher complexity in the coupled spin-orbit equations motivates the reduction of the Hamiltonian in the study of this nonline More

  The chaotic dynamics of Roto-Translatory motion for a triaxial Gyrostat satellite is considered in this study based on the Hamiltonian approach. Higher complexity in the coupled spin-orbit equations motivates the reduction of the Hamiltonian in the study of this nonlinear system. This reduction is done by the use of the Deprit canonical transformation developed here by the new Serret-Andoyer variables used as rotational and translational variables. The results obtained from the Hamiltonian reduction can be written as a perturbed equation near Integrable-Hamiltonian form, where the perturbed part of the equations consists the orbital and gravity gradient effects. Increasing the perturbation parameter causes the trajectories of the system to pass throughout heteroclinic bifurcation zone introducing chaos in the system. Also heteroclinic bifurcation and transversally stable and unstable manifolds are mathematically proven using Melnikov method. Through the Melnikov integral, the bounded variations in the design parameters are determined so as to prevent the system from a chaotic behavior. The simulation results based on the numerical methods such as the time series responses, trajectories of phase portrait, Poincare section, and Lyapunov exponent criterion quantitatively verify chaos in the system in the presence of perturbation influences.. Manuscript profile