Showing 9 results for Sadeghi
R. Hosseini, M. Azadi, , , ,
Volume 5, Issue 4 (12-2015)
Abstract
In the present paper, the modal analysis on a full finite element model of an off-road vehicle. This vehicle was modeled in the CATIA software and then meshed in the HYPERMESH software. The free vibration analysis was conducted by the ABAQUS software. By applying an external displacement, the forced vibration analysis was also performed. As a result, natural frequencies and shape modes were extracted to detect critical regions. Then, some improvements were suggested to have better vibration behavior of the vehicle.
Sh. Chitsaz, H. Sadeghi Naeini, A. Nedayifard , H. Malekipour, A. Vahdad,
Volume 7, Issue 3 (9-2017)
Abstract
In this paper, the main objective is ergonomics evaluation of
automobile’s dashboard to devise suitable designs based on textures and
patterns. Undoubtedly appropriated dashboards' design based on textures
might be ended to more driving safety, in which the tactile-real and visualimplied
texture of a surface should be considered. In this study, data was
gathered by in-depth observation and questionnaires. Expert volunteers
who not only used their cars frequently, but also were fairly sensitive to the
effects of visual and tactile items in dashboard design automobile’s
manufacturers. Statistical data analyzing shows improving texture in
dashboard design has a significant influence on drivers'. The need to take
repeated glimpses in order to distinguish the operation of each button will
diminish, an issue significantly decreasing accident risk. The results show
the interaction between the product textures will be ended to users'
satisfaction and also product’s feature and performance. This study clarifies
the significance of dashboard texture, so industrial designers are expected
to work harder to make better use of textures in designing product elements.
S. Ali Mirmohammadsadeghi, Dr. Kamyar Nikzadfar, Nima Bakhshinezhad, Dr. Alireza Fathi,
Volume 8, Issue 3 (9-2018)
Abstract
In order to lowering level of emissions of internal combustion engines (ICEs), they should be optimally controlled. However, ICEs operate under numerous operating conditions, which in turn makes it difficult to design controller for such nonlinear systems. In this article, a generalized unique controller for idle speed control under whole loading conditions is designed. In the current study, instead of tedious time-consuming trial-and-error based methods, soft computing techniques are employed to tune a proportional-integral-derivative (PID) controller which controls idle speed of engine. Since model based design technique is employed, a mean value model (MVM) is taken advantage due to its evidenced merits. Moreover, a brief introduction to the selected meta-heuristics is given followed by a flowchart to show how the engine model is linked to the optimization algorithms. A set point of 750 rpm is fed to the system, and the weighted sum of the three characteristics of mean squared error, control energy, and percent overshoot of the control system is set to the problem objective function to be minimized. It is evidenced that of all the examined meta-heuristics, Bees Algorithm (BA) converges to a better solution. Finally, to consider the effectiveness of the developed optimal controllers in disturbance rejection, they are implemented to the engine MVM model. The results of the research indicate, all the four optimally designed control systems, albeit the intermediate superiority, are of conspicuous success in compensating for the input disturbances of the load torque.
Prof Majid Moavenian, Mr Sina Sadeghi Namaghi,
Volume 9, Issue 1 (3-2019)
Abstract
In order to improve the safety and longitudinal stability of a vehicle equipped with standard ABS system, this paper, analyzes the basic principles of vehicles stability and proposes a control strategy based on fuzzy adaptive control which will adjust PID gain parameters, using genetic algorithm. A linear three-degree-of-freedom (DOF) vehicle model was set up in Simulink and the stability test was conducted utilizing jointly a joint established simulation platform with CarSim.
For controlling the brake length, traditional controllers have difficulty in guaranteeing performance and stability over a wide range of parameter changes and disturbances. Therefore, a 2 level controller by providing a modified Sliding Mode Control (SMC) will be used. Using this approach the flexibility increased and brake length and rotor temperatures decreases significantly. This results improvement of the vehicle’s stability and brakes fatigue lifespan.
Prof Majid Moavenian, Mr Sina Sadeghi Namaghi,
Volume 9, Issue 3 (9-2019)
Abstract
Most of drivers have to compensate small directional deviations from the desired driving path when disturbances such as crosswinds, overtakings, road irregularities and unintended driver inputs are imposed. These types of deviations have a tiring effect on driver and traffic’s safety and should be minimised. To increase the understanding the influence of vehicle’s properties in crosswind and overtaking conditions, specially vans and buses, and improving their safety, the vehicle was modeled using parameters based on real vehicle data for simulation in CarSim program. These parameters were validated or edited by simulation programs such as SOLIDWORKS, ADAMS/CAR ADAMS/CHASSIS and Well-known Calculation Software . A method for estimating the lateral error of vehicle due to original path in crosswind and overtaking conditions is also presented using Multi-Step Taguchi method in MINITAB. Dealing with limited but most effective factors of Vehicle’s Properties instead of large variety of them can be used for optimal vehicle’s design and propose ideal Crosswind Controllers
Mr Sina Sadeghi Namaghi, Mr Nima Sadeghi Namaghi,
Volume 9, Issue 4 (12-2019)
Abstract
Heavy articulated vehicles have low performance with respect to stability analysis due to their multifaceted geometry and dynamics especially when it comes to non-linear maneuvers. In this study in order to find out which statistical and dynamical factors have the most effect on stability of this type of vehicle without getting involve with their complex mathematical theory, combination of drive simulation and Taguchi method is used. Since the number and variety of factors are extensive, multi-step Taguchi method used. This method applied on values of modified rearward amplifications of each units of vehicle as a criterion of lateral stability. Results show the high effect of suspension and load geometry of Vehicle Units on lateral stability and safety.
Mr. Hamed Rahmanian, Dr. Alireza Sadeghi, Dr. Ali Asghar Ataee,
Volume 10, Issue 1 (3-2020)
Abstract
Application of Mg alloy parts in automotive industry is increasing to reduce weight and fuel consumption. One of the high potential parts for application of Mg alloys is the front seat frame. However, change of material is accompanied by change of manufacturing process and change of design for the seat frame. In the present research while keeping the reference overall ergonomic outline, a new substitute Mg alloy design was proposed, featuring a simple easy to manufacture Z profile. Next, a two-stage optimization technique (size and shape) is proposed for the Mg seat frame based on the stress and displacement criteria of standard test plans. The final optimized design is close to fully-stressed state and is 70% lighter than the reference steel backrest.
Shayan Sadeghi, Samane Ghandehariun,
Volume 10, Issue 3 (9-2020)
Abstract
A comparative full life cycle assessment of a gasoline vehicle and a fuel cell vehicle (FCV) with five different fuel cycles including steam methane reforming (SMR), coal gasification, photovoltaic (PV), solar thermal, and grid-based electrolysis is presented in this paper. The results show that the total greenhouse gas emissions (GHG) are mainly found in the materials production and the component manufacturing stages of the FCV. Among various hydrogen production methods, the FCV with PV electrolysis has the lowest GHG emissions of 0.13 kg CO2 eq./km. The total GHG emissions of the gasoline vehicle are estimated as 0.30 kg CO2 eq./km mainly from the operation stage. An uncertainty analysis is carried out to assess the effects of variations of different input parameters on the total emissions. With a 95% level of confidence, the total emissions of the FCV with PV electrolysis is 0.18±0.05 kg CO2 eq./km. The component manufacturing and assembly stage drives the total GHG emissions uncertainty the most.
Eng. Seyyed Ali Akbar Hashemi Milani, Dr. Reza Tavangar, Dr. Maziyar Azadbeh, Eng. Ibrahim Kahinpoor, Eng. Hossein Sadeghi-Nasab,
Volume 10, Issue 4 (12-2020)
Abstract
Drying temperature of the flux at normal atmosphere has a crucial role in brazing quality in automotive aluminum-based heat exchangers. Over the course of this research, NOCOLOK® flux consists of two phases of K2AlF5.H2O and KAlF4 with melting point around 580 °C was used. A flux slurry was applied on the base metal, and dried at 220, 300 and 380 °C in air. Mechanical assessment revealed that when flux dried at 300 °C, the joint withstands maximum shear stress of 44 MPa with complete bonding. At 220 °C and 380 °C, joint shear stresses are 34 MPa, 30 MPa respectively. 380 °C dry-off temperature under nitrogen gas improved shear strength to 39 MPa. Taking dry-off temperature as 300 °C the amount of defective heat exchangers was reduced from 6% to 2% on a daily basis.
