Showing 341 results for Type of Study: Research
Mr Mahdi Soufizadeh, Dr Seyed Mehdi Mirmehdi,
Volume 13, Issue 4 (12-2023)
Abstract
The general public considers auto service operators to be experts in their work, and they use their advice and guidance when changing the oil. Therefore, due to the importance of this issue, during applied research conducted in a mixed (quantitative and qualitative) manner, an attempt was made to identify and prioritize factors affecting the offer of motor oil brands by Iranian auto services using the fuzzy Delphi technique. In terms of the research method, this research is considered descriptive-survey research, and its statistical population includes all the operators of Iranian auto services. The statistical sample of the research consists of 36 Iranian auto service operators who were selected as a cluster from all over Iran. In the following, after collecting data through semi-structured interviews and questionnaires and analyzing the information, it was determined that the engine oil quality factor is the most important in introducing the engine oil brand by the auto services, according to the experts present. Also, after the quality of the engine oil, the two factors of matching the engine oil with the technical specifications of the car and the timely delivery of orders from the manufacturing companies were placed in the second and third ranks of importance, respectively.
Dr Ali Farahbakhsh,
Volume 13, Issue 4 (12-2023)
Abstract
This paper presents a single layer circularly polarized (CP) antenna array based on gap waveguide (GW) technology for automotive radar applications. The antenna element is a curved slot that is cut into the top wall of a groove gap waveguide (GGW) structure. An 8×8 slot array antenna is constructed by combining eight sub-arrays of linearly arranged slots, using an 8-way power divider as the feeding network. The power divider and the transition from WR12 to GGW are also designed based on GW technology. The proposed antenna array operates in the frequency band from 76 GHz to 81 GHz, covering the automotive radar working bandwidth. The antenna has a maximum gain of 23.8 dBi and a minimum axial ratio of 0.5 dB. The antenna performance is verified by simulation using CST Microwave Studio.
Hamidreza Ghasempoor, Ali Keshavarzi, Hamed Saeidi Googarchin,
Volume 13, Issue 4 (12-2023)
Abstract
The utilization of adhesively bonded square sections (ABSS) serves to enhance energy absorption and specific energy absorption (SEA) when subjected to oblique loading. Finite element models utilizing LS-DYNA were constructed in order to examine the deformation mode and load-displacement characteristics of ABSS and hybrid aluminum/carbon fiber reinforced polymer models. Subsequently, an evaluation was conducted on the general parameter pertaining to crashworthiness and the capacity for absorption of energy. The results reveal that an increase in the quantity of Carbon Fiber Reinforced Polymer (CFRP) layers within the stacking sequence of [0,90] affords enhanced potential for energy absorption. Conversely, the stacking sequence of [90] exhibits an incongruity with this trend, and achieves superior energy absorption capacity with a count of 4 CFRP layers rather than 8.
The present study indicates that carbon fiber reinforced polymer (CFRP) possessing a stacking sequence of [90] exhibits superior energy absorption capacity under both axial and oblique loading conditions at an inclination angle of 10 degrees. In contrast, the use of eight layers of CFRP with a stacking sequence of [0, 90] is found to yield better performance in achieving both axial and oblique loading up to 10 degrees.
Dr Mansour Baghaeian, Mr Khajeh Morad Sharghi,
Volume 13, Issue 4 (12-2023)
Abstract
| In this article, the effect of the usage of variable speed electric water pump on the cooling system of a type of passenger car engine has been investigated. The engine water circulation in most of today's cars uses a mechanical method, the power required for its circulation is provided by a belt with a ratio of 1:1 from the crankshaft. This action makes the changes of the water pump speed a function of the engine speed and there is no control over it. One way to solve this problem is to use an intelligent thermal management system. In this method, some components of the cooling system, including the electric water pump, are controlled based on the working conditions and engine temperature. In this research, GT Suite and Simulink software were used simultaneously, and for this purpose, the engine cooling circuit with a mechanical water pump was simulated in GT Suite software and the accuracy of laboratory values was verified in terms of heat transfer. Then the mechanical connection of the water pump was disconnected and the water pump circuit was controlled with an electric motor. In the next step, in order to obtain the control pattern, the electric water pump was replaced with the mechanical water pump in the simulation pattern. The results of the software and experimental simulations of the intelligent cooling system showed a 13.4% reduction in engine warm-up time. |
Mustafa Mirtabaee, Mohammad Abasi,
Volume 13, Issue 4 (12-2023)
Abstract
Protection of Armor Vehicles and military truck Occupants Against Explosion Mine and IED is the most important Parameter for comprehensive performance evaluation of armored vehicle. Armored Vehicle components Specifically Hull Floor Must be Able to Disperse Blast Shock Waves and Resist Against the structural Fracture. Analysis of the War Documents proves that flat hulls with thin-walled steel cannot resist against Anti-Tank Mines. In Recent years, development of V-shape Hull configurations Consider as an efficient Approach to improve Safety of armored vehicles. In the new generation of Armor Vehicle, Monocoque chassis combined with V-shape hull, But Replacement of All of the Old Armor Vehicle in the Defense Industry is not cost effective. So, there is an urgent need to develop the efficient strategy for enhancing the protection level of old armor vehicle. Since most of the armored vehicles used in the armies of different countries were designed and built in the past years, it is very likely that the safety standards have not been fully observed in them. Therefore, it is of great importance to provide a simple and low-cost plan for the reliable upgrade of such armored and logistics vehicles. In this article, by investigating the effect of placing V-shaped composite panels in three case studies, we were able to reduce the acceleration of the center of mass of the passenger compartment by approximately 7 times, in addition to reducing displacement by 50% on average. In addition, the explosion products were not able to penetrate into the cabin.
Dr. Pezhman Bayat, Dr. Peyman Bayat, Dr. Abbas Fattahi Meyabadi,
Volume 14, Issue 1 (3-2024)
Abstract
The hydrogen fuel cell is one of the latest technologies used in fuel cell electric vehicles (FCEVs), which uses hydrogen gas to supply the electrical energy needed by the electric engines. The proposed topology has boost function and uses a novel diodes and switches network, which leads to the creation of an integrated system with high efficiency and high voltage gain. Other advantages of the proposed converter are small size, low voltage and current stresses on all the components, less component count, continuous input current and light weight; which makes it more efficient compared to existing structures. In this regard, theoretical calculations and steady state analysis for the proposed system have been presented. Also, in order to verify the performance of the proposed converter, it has been simulated in the MATLAB/Simulink software environment at the rated power of 1kW, with an output voltage of 220V and an output current of 4.55A, and the results have been presented in detail. The peak efficiency of the proposed converter reached 97.4% at half power, and the efficiency at rated power was reported 96%. Moreover, in the proposed structure, the voltage stress of capacitors, diodes and switches reaches the maximum value of 63%, 83% and 41% of the output voltage, respectively; which are promising values. Finally, to verify the performance of the proposed converter and the relationships obtained, a 1kW prototype is built in the laboratory to demonstrate the efficiency of the proposed converter.
Dr Mohammad H. Shojaeefard, Dr Mollajafari Morteza, Mr Seyed Hamid R. Mousavitabar,
Volume 14, Issue 1 (3-2024)
Abstract
Fleet routing is one of the basic solutions to meet the good demand of customers in which decisions are made based on the limitations of product supply warehouses, time limits for sending orders, variety of products and the capacity of fleet vehicles. Although valuable efforts have been made so far in modeling and solving the fleet routing problem, there is still a need for new solutions to further make the model more realistic. In most research, the goal is to reach the shortest distance to supply the desired products. Time window restrictions are also applied with the aim of reducing product delivery time. In this paper, issues such as customers' need for multiple products, limited warehouses in terms of the type and number of products that can be offered, and also the uncertainty about handling a customer's request or the possibility of canceling a customer order are considered. We used the random model method to deal with the uncertainty of customer demand. A fuzzy clustering method was also proposed for customer grouping. The final model is an integer linear optimization model that is solved with the powerful tools of Mosek and Yalmip. Based on the simulation results, it was identified to what extent possible and accidental changes in customer behavior could affect shipping costs. It was also determined based on these results that the effective parameters in product distribution, such as vehicle speed, can be effective in the face of uncertainty in customer demand.
Seied Isa Koranian, Mahdi Gholampour, Hamid Mazandarani,
Volume 14, Issue 1 (3-2024)
Abstract
Harnessing nanomaterials and the piezo-phototronic effect, we engineered a high-performance ultraviolet (UV) photodetector (PD), unveiling a new frontier in optoelectronics. This novel device seamlessly integrates zinc oxide nanorods (ZnO NRs) onto a flexible polyethylene terephthalate- indium tin oxide (PET-ITO) substrate through a straightforward and efficient hydrothermal process. This unique nanostructure design outshines its competitors, producing significantly higher current under UV illumination despite a comparable detection area. The plot thickens with the intriguing "piezo-phototronic effect," where applying pressure under UV light amplifies the current and overall device efficiency. This groundbreaking discovery paves the way for cutting-edge optoelectronic applications, where nanomaterials and the piezo-phototronic effect join forces to redefine performance.
Mr Seyed Amir Mohammad Managheb, Mr Hamid Rahmanei, Dr Ali Ghaffari,
Volume 14, Issue 1 (3-2024)
Abstract
The turn-around task is one of the challenging maneuvers in automated driving which requires intricate decision making, planning and control, concomitantly. During automatic turn-around maneuver, the path curvature is too large which makes the constraints of the system severely restrain the path tracking performance. This paper highlights the path planning and control design for single and multi-point turn of autonomous vehicles. The preliminaries of the turn-around task including environment, vehicle modeling, and equipment are described. Then, a predictive approach is proposed for planning and control of the vehicle. In this approach, by taking the observation of the road and vehicle conditions into account and considering the actuator constraints in cost function, a decision is made regarding the minimum number of steering to execute turn-around. The constraints are imposed on the speed, steering angle, and their rates. Moreover, the collision avoidance with road boundaries is developed based on the GJK algorithm. According to the simulation results, the proposed system adopts the minimum number of appropriate steering commands while incorporating the constraints of the actuators and avoiding collisions. The findings demonstrate the good performance of the proposed approach in both path design and tracking for single- and multi-point turns.
Mr. Nasrollah Taghizadeh, Dr. Mohsen Esfahanian,
Volume 14, Issue 1 (3-2024)
Abstract
Due to the importance of vehicle weight reduction which can reduce fuel consumption and air pollution, changes are made in vehicles. In heavy trucks with payload limitations, a lighter trailer can provide higher load-carrying capacity and more economical benefits. Composite materials are a good candidate for material exchange due to their resistance to various conditions and low weight compared to steel. In this paper, the trailer material made of steel will be replaced by composite so that strength density will remain the same. For this purpose, the finite element method is used for static and dynamic analyses. At first, the model of a two-axle trailer is developed using SolidWorks software. Then, using standard loading and failure theories (Tsai-Hill, Tsai-Wu), the number of composite layers and their suitable angles are selected for the chassis. Finally, the loaded trailer's static, modal, and dynamic analysis are performed using the finite element method with a composite material. Results show that 17 layers of polymer composite with glass fibers with 0-0 angle can reduce 17.7 percent weight.
Dr Mohammad Shirzadifar, Dr Javad Marzbanrad,
Volume 14, Issue 1 (3-2024)
Abstract
The corrugated composite plates have wide application to improve the energy absorption and failure behavior of panel structures. The roof panel of the bus could benefit from the use of these structures to reduce impact failures in rollover accidents. The aim of this paper is to design a new configuration of bus roof panels stiffened with multi-layer semi-circular corrugated CFRP plates to minimize structure failure during rollover accidents. An analytical failure equation of Tsai-Hill index for the new proposed panel subjected to dynamic impact loading has been derived. The failure equation was validated using FEM methods and digital image correlation impact tests. According to the roll over impact situation, the multi-layered semi-circular corrugated woven CFRP roof panel displays a positive failure behavior of 89%.
Seied Isa Koranian, Mahdi Gholampour, Hamid Mazandarani,
Volume 14, Issue 2 (6-2024)
Abstract
Fueled by their potential for energy harvesting, ZnO nanorods (NRs) have sparked considerable enthusiasm in the development of piezoelectric nanogenerators in the last decade. This is attributed to their exceptional piezoelectric properties, semiconducting nature, cost-effectiveness, abundance, chemical stability in the presence of air, and, the availability of diverse and straightforward crystal growth technologies. This study explores and compares the piezoelectric properties of two promising nanostructured ZnO architectures: thin films deposited via radiofrequency (RF) magnetron sputtering and well-aligned nanorod arrays grown using a hydrothermal process. Both structures are fabricated on flexible polyethylene terephthalate (PET) with an indium tin oxide (ITO) electrode (PET-ITO substrate), presenting valuable options for flexible piezoelectric devices. By directly comparing these distinct morphologies, we provide insights into their respective advantages and limitations for energy harvesting and sensor applications. The investigation into the piezoelectric properties of ZnO NRs involved the construction of an actual piezoelectric nanogenerator. This device demonstrated a direct correlation between applied mechanical forces and the resultant voltage outputs. It was observed that when the same external force was applied to both devices, the ZnO NRs-based piezoelectric nanogenerator (PENG) exhibited a higher output voltage compared to the other device.
Mr. Milad Arianfard, Dr. Abbas Soltani,
Volume 14, Issue 2 (6-2024)
Abstract
In this paper, the strength of the gear shifting blocker for Peugeot gearbox is investigated. A hardened steel sheet is used inside the plastic part of shifting blocker to strengthen it. According to the feedback from the customer that this part fails in some conditions, some suggestions for its improvement are presented. In this research, two proposed correction designs are presented to increase the strength of the gear shifting locker by changing on the considered steel sheet. Abaqus software has been used to model the gear shifting blocker and analyze the stress of parts by finite element method. In order to validate the analytical results and choose the proper proposed design to strengthen the blocker part, some experimental tests are performed on the tension-compression test device. By comparing the results of the numerical analysis, it can be observed that the first and second modification designs have improved the stresses of blocker plastic part by 18% and 45%, respectively.
Mr. Alireza Azarm, Dr. Mohsen Esfahanian, Mr. Hosein Hamidi Rad,
Volume 14, Issue 2 (6-2024)
Abstract
The objective of developing kinetic energy recovery systems for vehicles is to repurpose energy otherwise dissipated during braking. Brake energy recovery and storage are achieved through two broad methods: electrical and mechanical, contingent on the energy storage type and the traction system's operational approach. Utilizing a rotating flywheel emerges as a practical, cost-effective, safe, and environmentally friendly means of storing energy, offering an extended service life. This study, synthesizing insights from various theories, aims to devise a prototype brake energy recovery system compatible with Samand car, employing the flywheel tank. Additionally, considerations for the power transmission system and clutch involve designing their type and dimensions, taking many factors into account for the selection. The initial design undergoes simulation and evaluation using MATLAB_SIMULINK and the ADVISOR plugin. The investigation delves into the influence of various design parameters on the efficiency of the system. Subsequently, attempts are undertaken to clarify the factors contributing to varied outcomes. The simulation results indicate a notable decrease in fuel consumption and emissions for a Samand car during urban driving cycles characterized by frequent braking. This improvement is realized through the utilization of a steel flywheel with an incomplete cone geometry and a specified radius. Suggestions are put forth for refining the controller to potentially enhance reductions in fuel consumption and pollution.
Mr. Mohammad Zarei-Jelyani, Mr. Amirhossein Salehi, Dr. Mohsen Babaiee, Dr. Mohammad Mohsen Loghavi,
Volume 14, Issue 2 (6-2024)
Abstract
The global transition towards renewable energy necessitates efficient energy storage solutions to address the intermittency of renewable sources. Lithium-ion batteries (LIBs), widely utilized in electric vehicles (EVs) for their high energy density and efficiency, yet their performance at low temperatures remains a challenge. This study investigates the influence of electrolyte solvent composition on LIB performance under low-temperature conditions. Three electrolytes were studied: a standard electrolyte (STDE) comprising 1 M LiPF6 in ethylene carbonate (EC) and diethyl carbonate (DEC), a low-temperature electrolyte (LTE) consisting of 1 M LiPF6 in EC, ethyl methyl carbonate (EMC), and ethyl acetate (EA), and a long-cycle-life electrolyte (LCLE) containing 1 M LiPF6 in EC/EMC. The EIS results revealed significant differences in resistance values among the electrolytes at varying temperatures. Specifically, at 0 °C, the STDE exhibited a charge transfer resistance (Rct) of 1055.3 Ω and a solid electrolyte interface resistance (RSEI) of 803.4 Ω, whereas the LTE showed a substantially lower Rct of 507.4 Ω and RSEI of 64.2 Ω, indicating superior low-temperature performance. Similarly, at -20 °C, the Rct values for STDE, LTE, and LCLE were 8878.6 Ω, 854.2 Ω, and 15622 Ω, respectively, with corresponding RSEI values of 172.1 Ω, 92.4 Ω, and 2364 Ω. Notably, the addition of EA in the LTE formulation contributed to enhanced low-temperature performance, likely by lowering the overall viscosity of the electrolyte mixture and improving ionic mobility. This study demonstrates the critical role of solvent composition, particularly EA, in optimizing LIB performance for cold climate applications.
Fatemeh Ganjali, Dr Hadi Arabi, Dr Shaban Reza Ghorbani, Dr Nasrin Azad,
Volume 14, Issue 2 (6-2024)
Abstract
High-entropy oxides (HEOs) are single-phase crystal structures composed of multiple metal elements that provide great potential for energy storage applications due to the synergistic effect of various metal species. They are considered effective anode materials for high-performance lithium-ion batteries (LIBs) because of their structural stability, high electronic conductivity, and ability to create anode materials with novel structures using several elemental compounds. Because the effects of different types of electrochemically active elements on the properties of anode materials are unknown, it is necessary to develop HEOs and investigate their properties. Herein, to explore the electrochemical properties of HEOs by changing the content of cations with various mechanisms for storing lithium, we prepared three samples of HEOs with spinel structure using the solid-state method, one of which is equimolar ((MgNiTiFeZn)0.6O4) and two numbers are near-equimolar ((Mg0.6Ni0.6Ti0.3Fe0.9Zn0.6)O4 and (Mg0.6Ni0.6Ti0.3Zn0.9Fe0.6)O4)). For structural properties determination, X-ray diffraction analysis was used. The results confirmed the formation of three single-phase high-entropy oxides.
Electrochemical tests indicated the structural stability of three compounds of high entropy oxides, and the composition of (MgNiTiFeZn)0.6O4, relative to the others, has better rate capability (163 mAhg−1 at 1000 mAg–1) and higher discharge capacity (220 mAhg−1 at 200 mAg–1) after 200 cycles.
Dr Moslem Mohammadi Soleymani, Benyamin Sohrabinejad, Dr Aliakbar Majidi Jirandehi,
Volume 14, Issue 2 (6-2024)
Abstract
In the automobile sector, stainless steel and resistance spot welding (RSW) are often used. In this work, RSW was used to join five samples of 316L stainless steel joints at currents of 15, 20, 25, 30, and 35 kA while the heat input parameters varied. The welded joints' microstructure, hardness, and mechanical properties were examined and evaluated. The base metal, heat-affected zone (HAZ), and weld areas' microstructures were all examined using optical microscopy. The mechanical characteristics of the joints were assessed using room-temperature tensile-shear testing and hardness testing. The microstructure findings revealed ferrite in many weld regions and an austenitic structure overall. In the samples with welding currents of 15, 20, 25, 30, and 35 kA, the average hardness of the weld zone was 329, 258, 251, 238, and 235 Vickers, in that order. The hardness of the weld zone exhibited an inverse connection with the welding current, as an increase in welding current resulted in a drop in the resistance spot welded area's hardness. Furthermore, when heat input increased, the hardness of the HAZ reduced and increased relative to the 316L steel. The joint strength of the RSW increased with increasing welding current, as demonstrated by the tensile-shear test results for all five welded samples with varying currents. As a result, the samples with 30 and 35 kA currents failed at the weld with a force greater than 3 kN, while the other samples with lower welding currents had a failure force of less than 2 kN.
Mr Amirhossein Jazari, Prof Ayat Gharehghani, Mr Soheil Saeedipour,
Volume 14, Issue 3 (9-2024)
Abstract
A novel liquid cooling system for pouch-type lithium-ion batteries (LIBs) is proposed by focousing on uniform temperatue disturbution and effective heat dissipation. The system utilizes a michrochannel cold plate with an innovative coolant disturbution design. This study proposes a novel microchannel disturbution path design with each microchannel dimensioning 1 mm2 and embeded in the battery's ciritical region to enhance the thermal contact among the LIB and the microchannels. This study aims to simulate and evaluate the performance of cooling system under varius Iranian environmental conditions (Tehran, Shiraz, Isfahan, and Bandar Abbas) and operational parametrs (channel pattern, flow rate) to achieve optimal battery temperature and reduce energy consumption.
Javad Marzbanrad, Zahra Taghizade, Mohammad Yaghoobian,
Volume 14, Issue 3 (9-2024)
Abstract
A bus experiences various loads during operation, stressing its structural components and causing noise, vibrations, and strains. To withstand these stresses, components must have sufficient stiffness, strength, and fatigue properties. In this study, the CAD model of a bus was created in SolidWorks and meshed using HyperMesh. A modal analysis conducted in HyperMesh verified the model's integrity, welding joint accuracy, and suitability for further analysis. A HyperMesh solver performed bending and torsional analyses. The torsional and bending stiffness of the bus body was calculated based on these results. Previous research primarily focused on stress and displacement, neglecting torsional and bending stiffness analysis for three-axle buses. This study addresses this gap, providing industry engineers with insights into acceptable torsional and bending stiffness for intercity buses. This knowledge supports the design of buses with adequate braking and turning capabilities. Additionally, the research contributes to bus body optimization efforts. In subsequent studies, scientists can experiment with various materials and models of various bus structure beam profiles.
Seyed Reza Hosseini, Mahdi Moghimi, Norouz Mohammad Nouri,
Volume 14, Issue 3 (9-2024)
Abstract
The impact of a supercooled droplet on a surface is a primary challenge of many industrial and aeronautical processes. However, in some cases, such as frost formation on vehicle windshields or wind turbine blades, the supercooled droplet collision does not occur in stagnant air. In this study, for the first time, the effects of the air transverse flow (ATF) on the thermal-fluid behavior of a supercooled droplet were investigated numerically. Also, different patterns of a superhydrophobic pillared surface were used in 24 three-dimensional simulations in ANSYS Fluent software. The volume of fluid method is chosen for the simulation of the multiphase flow. The freezing model is improved by the supercooling temperature consideration method. The results show that the ATF velocity reduces the separation time exponentially and helps the droplet bounce from the surface before freezing inception. However, the excessive increase in ATF velocity has the opposite effect and may prevent the droplet from detaching the surface due to notable drag. The best value of the ATF velocity is obtained to be 8 m/s , which reduces the separation time exponentially from 16.3 ms to 12.5 ms for a cold surface with a simple pillar pattern. The separation time is entirely affected by the simulation conditions and varies from 11.85 ms to 29.2 ms . The maximum spreading factor, despite the separation time, is seriously influenced by the void fraction percentage of different pillared surfaces and varies from 1.53 to 1.69.
