Amirkabir University of TechnologyAUT Journal of Mechanical Engineering2588-29375420211201Suspension Design Optimization of a Hermetic Compressor for Improved Vibrational Behavior497510428310.22060/ajme.2021.19099.5932ENAliKoganiDepartment of Mechanical Engineering, University of Tehran, Tehran, IranFarzadA. ShiraziDepartment of Mechanical Engineering, University of Tehran, Tehran, IranMohammadMahjoobDepartment of Mechanical Engineering, University of Tehran, Tehran, IranJournal Article20201006Abnormalities in the vibrational behavior of driving motors and their side effects have always been a chief concern for home appliance manufacturers. Hermetic compressors used in refrigerators are no exception in this matter. As a single-piston reciprocating machine with a crankshaft driven by a simple rotor-stator system, compressors can have noticeable vibrational dissonances. The compressor’s vibration is considered as a source of noise that can be transferred to other parts of the refrigerator and disturbingly excite them. Despite multiple studies to isolate this vibration by removing or optimizing its pathways, the focus has never been directly on reducing the vibration of the main source. In this study, a 6 Degree of Freedom model of a refrigerator compressor is derived and then simulated in MATLAB-Simulink. The model is then verified with the computational results of an equivalent model made in ADAMS. All vibrating parts and their indexes are identified in order to design a new suspension system with improved vibrational behavior. A genetic algorithm is used to minimize an acceleration-based objective function considering six optimization variables including the stiffness parameters of springs and their arrangement. The optimized springs were built and tested under an actual compressor, and the time/frequency responses of the compressor were compared with the initial system. The results show the enhanced vibrational behavior of the compressor in its working frequency after optimization.https://ajme.aut.ac.ir/article_4283_b29244c9fb542c8b1cc3d616f0ec2a6d.pdfAmirkabir University of TechnologyAUT Journal of Mechanical Engineering2588-29375420211201Active Vibration Control of a Nonlinear System with Optimizing The Controller Coefficients Using Metaheuristic Algorithms511534444610.22060/ajme.2021.19740.5962ENMasoudAbdolMohammadiDepartment of Mechanical and Mechatronics Engineering, Shahrood University of Technology, Shahrood, Iran.HabibAhmadiDepartment of Mechanical and Mechatronics Engineering, Shahrood University of Technology, Shahrood, Iran.Seyyed MojtabaVaredi-KoulaeiDepartment of Mechanical and Mechatronics Engineering, Shahrood University of Technology, Shahrood, Iran.JavadGhalibafanDepartment of Electrical and Robotics Engineering, Shahrood University of Technology, Shahrood, IranJournal Article20210312An active vibration absorber is utilized in this study for a nonlinear system with unknown multi-harmonic frequency disturbance. At first, a function for disturbance force and its first and second derivatives are estimated. Then the position of the main system is controlled by feedback linearization and sliding mode controllers. A magnetic actuator is designed, which is controlled by a sub-controller. Liunberger observer estimates disturbance function, and the feedback linearization and sliding mode controllers regulate the main system's position. Metaheuristic algorithms obtain the controller's coefficients to minimize settling time and errors. Four different techniques, namely, Genetic algorithm, Particle swarm optimization, Simulated annealing, and Teaching-learning-based optimization, are utilized for the optimization process. A magnetic actuator is designed using Faraday and Lorentz's law for applying the controlling force to the system. Simulation results of the observer have been compared to real value, and the results show the excellent effect of active vibration absorbers on vibration suppression. Moreover, optimizing the controller coefficient shows an improvement in settling time and error. Comparing the algorithms, particle swarm optimization has the best cost function, where Teaching-learning-based optimization has the best-averaged results.https://ajme.aut.ac.ir/article_4446_1b2ae0f14b372127d767fff4c46e7877.pdfAmirkabir University of TechnologyAUT Journal of Mechanical Engineering2588-29375420211201Buckling Analysis of Stiffened Cross-Ply Laminated Conical Shells under Axial Compression Using Generalized Differential Quadrature Method535552423310.22060/ajme.2021.18820.5922ENMohammad AliKouchakzadehDepartment of Aerospace Engineering, Sharif University of Technology, Tehran, IranPeymanGholamiDepartment of Aerospace Engineering, Sharif University of Technology, Tehran, IranMeisamShakouriDepartment of Aerospace Engineering, Semnan University, Semnan, IranMohammadNoghabi3 Iran Space Institute, Tehran, IranJournal Article20200803This study aims to determine the global buckling load of stiffened composite conical shells under axial compression. Stringers stiffen the conical shells in longitudinal and rings in circumferential directions. The boundary conditions are assumed to be simply supported at both ends. At first, the equilibrium equations are obtained using the first-order shear deformation theory and the principle of minimum potential energy. Effects of stiffeners (longitudinal and circumferential directions) are considered using the smearing technique. The resulting equations are solved using the generalized differential quadrature method to obtain the critical buckling load. The acquired results are compared with the finite element method results and other researcher's results available in the literature, and good agreement is observed. The influence of the number of stiffeners and rings, length, radius, semi-vertex angle of the cone, and shear deformation on the shell's buckling behavior is studied. Finally, the optimum number of stiffeners (longitudinal and circumferential directions) to achieve the maximum global buckling load in a cross-ply composite conical shell with various stacking sequences for a specific weight and overall geometry is investigated.https://ajme.aut.ac.ir/article_4233_bc3d01d1ee99b5659789dfcbfe9375bb.pdfAmirkabir University of TechnologyAUT Journal of Mechanical Engineering2588-29375420211201Out of Plane Punch of Aluminum Hexagonal Honeycomb Using Flat Nose and Spherical Projectiles553570431710.22060/ajme.2021.18838.5924ENMohsenZarei MahmoudabadiDepartment of Mechanical Engineering, Amirkabir University of Technology, Tehran, IranMojtabaSadighiDepartment of Mechanical Engineering, Amirkabir University of Technology, Tehran, IranJournal Article20200806The energy absorption capacity of metal hexagonal honeycomb under out of plane local quasi-static loading is investigated, experimentally. Effects of geometrical parameters, such as the cell size and wall thickness of the honeycomb, projectile shape and projectile diameter, specimen height, and the loading speed on the perforated zone and the absorbed energy are studied. The perforated zone of the honeycomb has not perfectly the same shape of the projectile, but it can be assumed as a skew polygon or ellipse, extended in the direction of the honeycomb dual walls. Results show that changing the projectile shape from a flat nose to a sphere decreases the absorbed energy approximately to the half value. Multiplying the projectile diameter by two increases the mean crushing load of the metal hexagonal honeycomb less than four times. On the other hand, it was shown that the honeycomb local energy absorption capacity is not perfectly independent of sample height and loading speed. Furthermore, based on the modified Wierzbicki’s model in the global loading, a simple theoretical model for the estimation of the mean crushing load of a metal hexagonal honeycomb loaded by a flat projectile is presented. Good agreement between the theoretical and experimental results is illustrated. https://ajme.aut.ac.ir/article_4317_6f6af4cbde2f087ae8c1700459b1b775.pdfAmirkabir University of TechnologyAUT Journal of Mechanical Engineering2588-29375420211201A Review of the Different Standard Methods of Measuring the Tubular Braiding Angle571582431810.22060/ajme.2021.18787.5927ENGhazalGhamkharDepartment of Textile Engineering, Amirkabir University of Technology, Tehran, IranMajidSafar JohariDepartment of Textile Engineering, Amirkabir University of Technology, Tehran, IranHosseinHosseini ToudeshkyDepartment of Aerospace Engineering, Amirkabir University of Technology, Tehran, IranJournal Article20200820The simplicity of the braiding, wide variety and high strength of the braid structure are the factors that make this structure, i.e., braid, so essential. These factors also make this structure widely used in various industries, such as aerospace, automotive, medicine, and industrial products such as umbrella ropes, composite boosters, aircraft engine vanes, and medical implants. Therefore, studying the mechanical properties of this structure and obtaining products with desirable mechanical properties has been considered by researchers and the subject of many types of research. Due to the importance of the braiding angle and its relation with the mechanical properties of the braid structures as the fundamental parameter, this paper evaluates different methods of measuring the tubular braiding angles. The braiding angle measurement has been done using different methods. These methods include two general categories called computational methods and image processing techniques. The different methods of each category, their advantages and disadvantages are investigated separately, then the most accurate methods can be selected by users according to the available facilities. This paper aims to provide a comparative summary of different methods of measuring the tubular braiding angle. This innovative review of these methods allows researchers and manufacturers to select and use the most appropriate method with the highest accuracy according to their conditions and facilities.https://ajme.aut.ac.ir/article_4318_018c309946f76975bcd1278f1b73accd.pdfAmirkabir University of TechnologyAUT Journal of Mechanical Engineering2588-29375420211201A Novel AA3105-Sic Composite Fabrication Method583598434010.22060/ajme.2021.19162.5934ENMerajHoushyarDepartment of Mechanical Engineering, Babol Noshirvani University of Technology, Babol, IranSalmanNourouziDepartment of Materials Engineering, Babol Noshirvani University of Technology, Babol, IranHamedJamshidi AvalDepartment of Materials Engineering, Babol Noshirvani University of Technology, Babol, IranJournal Article20201020Conventional methods of composite production using friction stir processing are simple, rapid, and economical. However, homogenizing the reinforcing particles in the processing zone is very difficult. In addition, this method mainly focuses on surface composite production, while obtaining bulk composites is still challenging. This study investigates the production of AA3105-SiC aluminum matrix composite using the sandwich method as the manufacturing process. The SiC particles were applied through spraying as a layer between AA3105 aluminum sheets. Then, the effect of friction stir processing parameters is investigated. The results indicate an enhanced degree of stirring and plastic deformation following increasing the rotational to translational speed ratio (w / v), which leads to homogenization of the particle distribution in the aluminum matrix. By increasing the <em>w</em> / <em>v</em> ratio, the distribution coefficient decreases from 0.58 to 0.21, which indicates an improvement in the distribution of particles in the matrix. The friction stir processing using the sandwich method significantly improves the mechanical properties of the AA3105-SiC bulk composite compared with the processed samples without reinforcement, with a maximum increase of 192 % in ultimate tensile strength and 273 % in toughness at 1600 rpm and 31.5 mm/min.https://ajme.aut.ac.ir/article_4340_e748592031d275e5d07affa5244e4b4c.pdfAmirkabir University of TechnologyAUT Journal of Mechanical Engineering2588-29375420211201Optimum Diameter and Location of Pipes Containing Phase Change Materials in a Channel in Latent and Sensible Heat Transfer599616431510.22060/ajme.2021.18362.5896ENJavadRostamiDepartment of Mechanical Engineering, Razi University, Kermanshah, Iran0000-0002-0568-8428Journal Article20200504In this paper, two pipes containing phase change materials, located perpendicular to the flow direction in a channel, are simulated numerically to find out their best diameter and location (their distances from the walls) in the convective heat transfer behavior. The governing equations have been solved by the semi-implicit method for pressure linked equations. In the first part, the phase change material is in the phase change (isothermal state) process, and the best location and diameter of the pipes are defined. In the second part, for obtained best size and location obtained in the first part, depending on the phase change material to the fluid special heat capacity ratio, the duration of the after-melting process, and reaching the final equilibrium state of the phase change material has been determined. The results of the first part show the best geometrical parameter depends on the Reynolds and the Prandtl numbers. Results of the second part show, the time at which the temperature of the pipes (phase change material) reaches 99% of the temperature of the inlet flow, depends on the special heat capacity ratio. Also, the best non-dimensional diameter of pipes is 0.153 for <em>Re</em>=500 and 0.165 for <em>Re</em>=700 in different Prandtl numbers and the best non-dimensional distance of the pipes from the wall is between 0.15-0.175 for different Reynolds and Prandtl numbers.https://ajme.aut.ac.ir/article_4315_c20280077dfb05285846c8c3ab8c4620.pdfAmirkabir University of TechnologyAUT Journal of Mechanical Engineering2588-29375420211201Multi-Objective Optimal Design of an Organic Rankine Cycle Plate Heat Exchanger with Phase Change617638433210.22060/ajme.2021.19168.5935ENMahmoodNorouziDepartment of Mechanical Engineering, Shahrood University of Technology, Shahrood, Iran.RezaMahmoodi TarghiDepartment of Mechanical Engineering, Shahrood University of Technology, Shahrood, Iran.Seyed MajidHashemianDepartment of Mechanical Engineering, Shahrood University of Technology, Shahrood, Iran.Seyyed AmirrezaVaziriDepartment of Mechanical Engineering, Shahrood University of Technology, Shahrood, IranOsmanAnwar BegDepartment of Aeronautical and Mechanical Engineering, Salford University, Manchester, UkJournal Article20201024In this study, a multi-objective optimization method founded on genetic algorithms is implemented to obtain optimized geometrical parameters for the plate heat exchanger configuration which causes pressure drop minimization and overall heat transfer coefficient maximization. This heat exchanger is basically designed as an evaporator of Organic Rankine Cycles by considering R123 as the working fluid. It is supposed that water vapor with entrance temperature of is deployed as hot fluid. A multi-objective optimization method founded on genetic algorithms is implemented to optimize geometrical parameters for the heat exchanger configuration which leads to pressure drop minimization and overall heat transfer coefficient maximization. Two objective functions are conflicting with each other that both single and two-phase flow scenarios are also addressed. In the present optimization method, a Pareto solution is used which permits the derivation of a mathematical relation between the two objective functions simultaneously and yields the optimal geometrical parameters for heat exchangers subjected to constraints associated with the Pareto optimal set. A detailed sensitivity analysis has been conducted for each geometrical parameter and the effects of each parameter on key design characteristics have been evaluated. Both objective functions of the overall heat transfer coefficient and the total drop are reduced, by increasing the ports’ diameter and, due to increasing the thickness of each plate inside the plate heat exchanger, the two-sheet spacing will naturally reduce.https://ajme.aut.ac.ir/article_4332_94e477525f7547aa1d072e4665d8aa06.pdfAmirkabir University of TechnologyAUT Journal of Mechanical Engineering2588-29375420211201Series Flat Plate Pulsating Heat Pipe: Fabrication and Experimentation639654435210.22060/ajme.2021.19402.5947ENAmir HassanEkramiDepartment of Mechanical Engineering, University of Kashan, Kashan, IranMajidSabzpooshaniDepartment of Mechanical Engineering, University of Kashan, Kashan, IranMohammad BehshadShafiiDepartment of Mechanical Engineering, Sharif University of Technology, Tehran, IranJournal Article20201225Pulsating Heat Pipes have recently become popular due to their capability in removing heat at higher rates, over short or long distances. Their passive operation and relative ease of manufacturing have been added to their popularity. In this study, a combination of two flat plate pulsating heat pipes in series configuration is proposed and their thermo-hydraulic behavior is investigated experimentally in vertical bottom heated mode. The series configuration provides the possibility of heat removal from the heat source within longer distances at acceptable efficiencies. Fluid type, filling ratios, and input powers were the factors chosen to study their influence on the operation of the setup. The results showed that the 60% filling ratio for the water filled channel together with the 40% filling ratio for the methanol filled channel present the lowest thermal resistance in the range of considered input powers. It was observed that for all of the filling ratio combinations used, the methanol channel started oscillation before the water channel and it presented lower thermal resistance as compared with the water channel. The experimental results demonstrated that the dominant hydrodynamic fluid pattern is slug flow with the pulsation of fluid columns together with sporadic circulation at higher input power rates.https://ajme.aut.ac.ir/article_4352_50780efd3991f8254b47d237324bf5c2.pdfAmirkabir University of TechnologyAUT Journal of Mechanical Engineering2588-29375420211201Investigation of Gas Radiation Effect on Thermal Behavior of Solar Gas Heaters under High Irradiation655668439110.22060/ajme.2021.19585.5954ENS. A.Gandjalikhan NassabDepartment of Mechanical Engineering, Shahid Bahonar University of Kerman, Kerman, IranMaryamMoein AddiniDepartment of Mechanical Engineering, Shahid Bahonar University of Kerman, Kerman, IranJournal Article20210205Based on the global consensus on mitigation of greenhouse gas and human footprint as well as improvement of engineering application sustainability, the mission of this study dedicated to the numerical simulation of plane solar gas heaters under different solar irradiation for both radiating and non radiating working gases. In numerical simulation, the continuity and momentum equations for the gas flow were solved by the finite volume method (FVM) using the SIMPLE algorithm, and the energy equation for the forced convection gas flow coupled with the conduction equation for solid parts have been solved by the finite difference method (FDM). The intensity of radiation in participating gas flow was computed by numerical solution of the radiative transfer equation (RTE) with the discrete ordinate method (DOM). It is seen thatl that increasing in gas optical thickness causes significant reduction in temperature difference between the absorber plate and flowing gas, especially at high solar irradiation. In the cases of using radiative gas with optical thickness of 0.2, instead the non participating gas, numerical results show 55%, 64% and 77% improvement in the gas temperature increase along the heater under the incidence of 900 W/m^2, 1100 W/m^2 and 1400 W/m^2, respectively. This makes the heat transfer more reversible that leads to high performance. Comparison between the present numerical results with experimental data shows good consistency.https://ajme.aut.ac.ir/article_4391_1ab642d7ffcbe50838b06eebf29f1477.pdf