Amirkabir University of TechnologyAUT Journal of Mechanical Engineering2588-29376420221201Hybrid Neural Network and Particle Swarm Optimization Model Applied to Assist Production Planning in a Large Petrochemical Plant491510496810.22060/ajme.2022.21146.6029ENAlirezaBehroozsarandDepartment of Chemical Engineering, Urmia University of Technology, Urmia, IranSeyyed SalarMeshkatDepartment of Chemical Engineering, Urmia University of Technology, Urmia, IranDavid . AWoodDWA Energy Limited, Lincoln, United KingdomJournal Article20220223Process and production planning play an important role in petrochemical production systems. Planning models are essential to optimize the combination of multiple non-linear production processes involved and therefore improve the commercial competitiveness of the such plant. Artificial neural networks offer an effective petrochemical plant planning tool, especially when configured in hybrid form as a back propagation artificial neural network coupled with an optimizer to assist with feature selection. A plant with eight feedstock inputs and thirteen petrochemical products is evaluated, firstly to show the capabilities of a basic backpropagation network model in predicting product outputs. The involvement of a particle swarm optimizer assists in filtering the dataset to remove outlying data records and identifying the input variables that are influential in determining specific product output volumes. The hybrid back propagation network-particle swarm optimization model assists by determining the logical relationship between input and output variables and expressing them in the form of an index matrix. The matrix leads to improved predictions of production outputs and faster convergence of the planning model. The modified back propagation network achieved maximum, minimum, and average relative errors of 59.1%, 0.0%, and 9.9%, respectively. Prediction errors in that range are considered acceptable for the collective production processes of a large-scale petrochemical complex evaluated with a nonlinear planning program.https://ajme.aut.ac.ir/article_4968_a48251d4c143adf4d4b657d5d82ee0ee.pdfAmirkabir University of TechnologyAUT Journal of Mechanical Engineering2588-29376420221201Accurate Estimating of Mechanical Properties of Austenitic Stainless Steels with Residual Stresses Using Indentation Technique511524483210.22060/ajme.2022.20715.6016ENFariborzBaratiDepartment of Mechanical Engineering, University of Zanjan, Zanjan, IranRasoulMoharramiDepartment of Mechanical Engineering, University of Zanjan, Zanjan, IranJournal Article20211027This study considers the accurate determination of the mechanical properties of austenitic steels containing equibiaxial residual stress by the spherical indentation technique. Many numerical simulations have been developed to evaluate the accuracy of the Kim and Lee methods. The results revealed that the Kim method evaluates a specimen's mechanical properties with higher accuracy than the Lee method. The Kim method was utilized in this paper to investigate the effect of residual stress on the accuracy of the indentation technique. The results of the study showed that residual stresses could lead to significant errors in the results of estimating the properties of materials like elasticity module, yield strength, and work hardening. By formulating the error changes as a function of work hardening and normalized residual stress, a method has been proposed to reduce the error. The proposed method has significantly mitigated the error in estimating the properties of materials with residual stress through the Kim method. Based on the results, the absolute value of errors has decreased from a maximum of 48% for , 33% for , and 39% for to 12%, 1%, and 3% respectively. Experimental tests on the stainless steel 321 sample were used to validate the results, and by comparing the numerical results, it was shown that a more accurate value for the properties of materials could be obtained using the proposed method.https://ajme.aut.ac.ir/article_4832_0a934ecab584f7a4cd0220a7caeccbcc.pdfAmirkabir University of TechnologyAUT Journal of Mechanical Engineering2588-29376420221201Stability Analysis of a Functionally Graded Carbon Nanotube Reinforced Composite Plate Integrated with Piezoelectric Layers under Supersonic Airflow525544487910.22060/ajme.2019.16343.5815ENMohammadHosseiniDepartment of Mechanical Engineering, Sirjan University of Technology, Sirjan, IranKazemMajidi-MozafariDepartment of Mechanical Engineering, Sirjan University of Technology, Sirjan, IranJournal Article20190515The dynamic and static instabilities of plates reinforced by carbon nanotubes which are fully covered by two piezoelectric layers subjected to supersonic airflow are investigated. For aero-elastic analysis of thin functionally graded carbon nanotube reinforced composite plate, classical plate theory, as well as first-order piston theory, has been applied. The effective material properties of functionally graded carbon nanotube-reinforced composite plates are evaluated based on the rule of mixture with consideration of efficiency parameter. Also, five various types of carbon nanotube distributions through the thickness direction are investigated. The distribution of electric potential across the piezoelectric thickness is assumed to be a quadratic function. Then, two kinds of electric boundary conditions such as open circuit and closed circuit are considered. The coupled governing electro-mechanical equations are derived by using Hamilton’s variation principle and electrostatic Maxwell’s equation. The partial differential governing equations are transformed into a set of ordinary differential equations by utilizing Galerkin’s approach. The result shows that the functionally graded carbon nanotube-reinforced composite plate integrated by two piezoelectric layers in open circuit condition has higher both flutter aerodynamic pressure and natural frequencies, in contrast with a similar plate in closed circuit conditions. In addition, the result elucidated that the stability region increase as the piezoelectric thickness increases.https://ajme.aut.ac.ir/article_4879_606c90a06173d69682feb83037a68fec.pdfAmirkabir University of TechnologyAUT Journal of Mechanical Engineering2588-29376420221201Influencing Parameters on Tensile Modulus Characterization of Unidirectional Composite Laminates Using Digital Image Correlation Technique545560489010.22060/ajme.2022.20714.6015ENAmirrezaZarei AzizDepartment of Mechanical and Energy Engineering, Shahid Beheshti University, Tehran,RoohollahSarfaraz KhabbazDepartment of Mechanical and Energy Engineering, Shahid Beheshti University, Tehran,Journal Article20211027Digital image correlation as a well-established strain measurement technique is commonly employed for material characterization purposes. However, several parameters should usually be decided by users to attain accurate results with minimum processing time while there are few definite recommendations for the selection of these parameters. In the present study, the optimum setting of digital image correlation parameters is examined in order to minimize the processing time and sensitivity to the selection of parameters, and practical directions are advised to improve the efficiency of the technique. The performance of a typical analysis for the derivation of strain field and measurement of tensile modulus of a unidirectional carbon/epoxy composite laminate subjected to monotonic loading is experimentally assessed. The influence of setting parameters on the accuracy of measurement and the computational time required for the process is examined. The mutual influence of these parameters is also analyzed and discussed. Comparison of results shows the sensitivity of outputs to the selection of investigating parameters i.e. subset radius, subset spacing, and region of interest. The results show that an efficient gain from the maximum available region of digital images reduces the sensitivity of the analysis to these parameters. Moreover, the error introduced to the results is slightly increased by the increase of subset spacing while this influence can be diminished by enlarging the subset radius. https://ajme.aut.ac.ir/article_4890_060afc8a563aaccd288f98b7c8723b61.pdfAmirkabir University of TechnologyAUT Journal of Mechanical Engineering2588-29376420221201Transient Response of Laminated Composite Curved Beams with General Boundary Conditions under Moving Force561578491510.22060/ajme.2022.20787.6020ENAliAhmadiDepartment of Mechanical Engineering, University of Mazandaran, Babolsar, Iran.0000-0002-9609-3875MaryamAbediDepartment of Mechanical Engineering, University of Mazandaran, Babolsar, Iran.0000-0002-1766-1601Journal Article20211124Vibrational analysis of beams has been an important subject for many years. Despite the wide applications of curved beams, especially laminated composite curved beams, less attention has been paid to this subject. In this study, the transient response of the laminated composite curved beam due to a moving force with constant velocity for different boundary conditions has been obtained. By employing Hamilton’s principle, the equations of motion along with the corresponding boundary conditions of the beam are determined. The finite element method is employed to solve these equations. Using the eigenvalue technique, the vibrational characteristics of the beam are calculated. Results for the free and forced vibration of the beam have been compared against available data in the literature and the three-dimensional model in ANSYS. The effects of different parameters such as the geometry of the beam, fibers orientation, and boundary conditions on the transient response of the beam have been investigated. It has been shown that beam with cross-ply layups has lower values of transient deflection compared to the angle-ply layups. Also, the anti-symmetric cross-ply beam has more deflection with respect to the symmetric one.https://ajme.aut.ac.ir/article_4915_e4a86b0d7bf4c46d7d550a92b0b2fcae.pdfAmirkabir University of TechnologyAUT Journal of Mechanical Engineering2588-29376420221201Numerical Evaluation on Blood Rheological Behavior in a Realistic Model of Aneurysmal Coronary Artery579596495610.22060/ajme.2022.20917.6025ENAshkanRafieiDepartment of Mechanical Engineering, Razi University, Kermanshah, IranMaysamSaidiDepartment of Mechanical Engineering, Razi University, Kermanshah, Iran0000-0001-7423-334XJournal Article20211223The aim of this study is to evaluate the blood rheological behavior within a coronary artery aneurysm in detail. The three-dimensional model was reconstructed from computed tomography angiography images of a 43-year-old man with a coronary artery aneurysm on the bifurcation. First, the effects of blood dynamic viscosity on the hemodynamic characteristics in the aneurysmal coronary artery were studied. Then, a comparison between Newtonian and non-Newtonian viscosity models was carried out using four non-Newtonian blood models, namely the Carreau, Modified Casson, Cross, and Carreau-Yasuda models. The results have been presented in the form of velocity contours, streamlines, pressure drop variation, wall shear stress, and oscillatory shear index. The outcomes showed that a 20% change in the Newtonian blood viscosity leads to almost up to 12% alters in the aneurysm wall shear stress and nearly 15-18% changes in the value of the other sections. The decrement of the blood viscosity declines the aneurysm rupture risk by reducing blood pressure and wall shear stress. Additionally, among studied viscosity models, the Modified Casson model predicts the highest value of average wall shear stress in all parts except for the aneurysm, whereas, the highest value in the aneurysm is related to the Carreau model, close to 5.3% greater than the Modified Casson. Moreover, the average wall shear stress in the Newtonian state is the lowest in comparison with non-Newtonian models.https://ajme.aut.ac.ir/article_4956_d80b7040b773199015de6d3b4293c8ff.pdf