Automotive Science and Engineering

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Parametric design optimization of an automotive body crashworthiness improvement is presented. The thicknesses of parts are employed as design variables for optimization whose objective is to increase the maximum deceleration value of the vehicle center of gravity during an impact. Using the Taguchi method, this study analyzes the optimum conditions for design objectives and the impact factors and their optimal levels are obtained by a range analysis of the experiment results. A full frontal impact is implemented for the crashworthiness simulation in the nonlinear dynamic code, LS-DYNA. The controllable factors used in this study consist of the six inside foreheads structural parts, while design parameters are relevant thicknesses. The most interestingly the maximum deceleration of the vehicle center of gravity is reduced by 20% during a full frontal impact while several parts experience mass reduction.

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Turning of hardened steels using a single point cutting tool has replaced the cylindrical grinding now as it offers attractive benefits in terms of lower equipment costs, shorter set up time, fewer process setups, higher material removal rate, better surface quality and elimination of cutting fluids compared to cylindrical grinding. In order to obtain desired surface quality by machining, proper machining parameters selection is essential. This can be achieved by improving quality and productivity in metal cutting industries. The present study is to investigate the effect of machining parameters such as cutting speed, feed and depth of cut on surface roughness during dry turning of hardened AISI 4340 steel with CVD (TiN+TiCN+Al2O3+ZrCN) multilayer coated carbide inserts. A full factorial design of experiment is selected for experimental planning and the analysis of variance (ANOVA) has been employed to analyze the significant machining parameters on surface roughness during turning. The results showed that feed (60.85%) is the most influencing parameter followed by cutting speed (24.6%) at 95% confidence level. And the two-level interactions of feed-cutting speed (F*V), depth of cut-feed (D*F) and depth of cutcutting speed (D*V) are found the significant effects on surface roughness in this turning process. Moreover, the relationship between the machining parameters and performance measure i.e. surface roughness has been modeled using multiple regression analysis.

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In this paper, the development and optimization of Power Distribution Control Strategy (PDCS) have been performed for a Hybrid Energy Storage Systems (HESS) of a Series Hybrid Electric Bus (SHEB). A common PDCS is based on the use of Ultra-Capacitor (UC) pack. A new simple PDCS is developed as a battery based one. For the battery based PDCS, four parameters are introduced for tuning the PDCS performance. The Design of Experiment (DoE) method is utilized to optimize the parameters of the battery based PDCS for the driving cycles and the vehicle controllers. The results show the optimized battery based PDCS performance for some cases are better than the UC based PDCS performance. Vice versa, for some cases the performance of the UC based PDCS is better than the battery based PDCS. Finally, the costs rising from the HESS (about 66%) is reasonable when considering the over double increase in the battery life-time when using an appropriate PDCS.

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Nowadays, automakers have invested in new technologies in order to improve the efficiency of their products. Giant automakers have taken an important step toward achieving this objective by designing continuously variable transmission systems (CVT) to continuously adapt the power of the engine with the external load according to the optimum efficiency curve of engine and reducing fuel consumption beside, making smooth start up and removing the shock caused by changing the gear ratio and making more pleasurable driving. Considering the specifications of one of Iranian automaker products (the Saipa Pride 131), a CVT with a metal pushing belt and variable pulleys have been designed to replace its current manual transmission system. The necessary parts and components for the CVT have been determined and considering the necessary constraints, its mechanism and components have been designed.

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Robust control design of vehicles addresses the effect of uncertainties on the vehicle’s performance. In present study, the robust optimal multi-objective controller design on a non-linear full vehicle dynamic model with 8-degrees of freedom having parameter with probabilistic uncertainty considering two simultaneous conflicting objective functions has been made to prevent the rollover. The objective functions that have been simultaneously considered in this work are, namely, mean of control effort (MCE) and variance of control effort (VCE).The nonlinear control scheme based on sliding mode has been investigated so that applied braking torques on the four wheels are adopted as actuators. It is tried to achieve optimum and robust design against uncertainties existing in reality with including probabilistic analysis through a Monte Carlo simulation (MCS) approach in multi-objective optimization using the genetic algorithms. Finally, the comparison between the results of deterministic and probabilistic design has been presented. The comparison of the obtained robust results with those of deterministic approach shows the superiority robustness of probabilistic method.

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Excavators are heavy construction equipment consisting of a boom, dipper (or stick), bucket and cab on a rotating platform known as the "house". In this paper the hydraulic shovel excavator is analyzed through the D-H method. The shovel working device with the bucket capacity of 36m3 is optimized. The determination of the objective function, variables and constraints are described in detail. The position of optimized shovel is achieved. Also Bucket trajectory and envelope drawing are designed. These are carried on the analysis and comparison. Optimum design is proved rationality.

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Due to the extensive use of cars and progresses in the vehicular industries, it has become necessary
to design vehicles with higher levels of safety standards. Development of the computer aided design and
analysis techniques has enabled employing well-developed commercial finite-element-based crash
simulation computer codes, in recent years. The present study is an attempt to optimize behavior of the
structural components of a passenger car in a full-frontal crash through including three types of energy
absorptions: (i) structural damping of the car body, (ii) viscoelastic characteristics of the constituent
materials of the bumper, and (iii) a proposed wide tapered multi-cell energy absorber. The optimization
technique relies on the design of experimental (DOE) method to enables finding the absolute extremum
solution through the response surface method (RSM) in MINITAB software. First, the car is modeled in
PATRAN and meshed in ANSA software. Then, the full-scale car model is analyzed in ABAQUS/CAE
software. The optimization has been accomplished through a multi-objective function to simultaneously,
maximize the observed energy and minimize the passenger’s deceleration. Results are verified by the
experimental results and effects of using non-equal importance coefficients for the absorbed energy and
passenger’s deceleration in the multi-objective function are also evaluated. Influence of the optimized
parameters on the frontal crash behavior of the vehicle body structure and passenger’s deceleration is
investigated, too.

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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.  

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Brake system performance significantly affects safety, handling and vehicle dynamics. Therefore, the objective of this paper is to discuss brake system characteristics and performance and component design parameters. We perform a detailed study of a specific brake system designed for Mercedes-AMG SLC-43, considering component design parameters and operational points, and finally conduct the vehicle braking system layout design. To this end, brake force and torque calculations and power dissipation modelling is performed. Then, ventilated brake discs are designed for the front and rear brakes. A main goal of the present article is to apply digital logic method to the material selection procedure among the candidate material proposed for brake components and rank the materials according to performance indices. The performance indices of five candidate materials were calculated and compared to select the best option for application in the brake disc. Finally, the calculations of the brake pedal, booster, cylinder, hoses and tubes are obtained.

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Nowadays, lightweight automotive component design, regarding fuel consumption, environmental pollutants and manufacturing costs, is one of the main issues in the automotive societies. In addition, considering safety reasons, the durability of the automotive components, as one of the most important design requirements should be guaranteed. In this paper, a two-step optimization process including topology and shape optimization of an automotive wheel, as one of the most significant chassis components, is studied. At first, topology optimization method with volume and fatigue life constraints is used to obtain the optimal initial lightweight design, followed by shape optimization technique to improve the fatigue life. The results show 31.841% weight and 33.047% compliance reduction by topology and also 652.33% average minimum fatigue life enhancement, by the shape optimization. Therefore, the proposed two-step optimization method is qualified in designing the lightweight automotive wheel. The method used in this study can be a reference for optimization of other mechanical components.

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Hardware implementation of the Plug-in hybrid electric vehicles (PHEVs) control strategy is an important stage of the development of the vehicle electric control unit (ECU). This paper introduces Model-Based Design (MBD) approach for implementation of PHEV energy management. Based on this approach, implementation of the control algorithm on an electronic hardware is performed using automatic code generation. The advantages of the MBD in comparison with the traditional methods are the capability of eliminating the manual coding complexities as well as compiling problems and reducing the test duration. In this study, hardware implementation of a PHEV rule-based control strategy is accomplished using MBD method. Also, in order to increase the accuracy of the results of the implementation, the data packing method is used. In this method, by controlling the primer and end data of the data packet transferred between the electronic board and the computer system, the noisy data is prevented from entering. In addition, to verify the performance of the implemented control strategy, hardware-in-the-loop (HIL) simulation is used with the two frequency rates. The results show the effectiveness of the proposed approach in correct and rapid implantation procedure.

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Thin-walled structures play an important role in absorbing the energy in a low impact crash of vehicles up to saving lives from high impact Injury. In this paper, the thin-walled columns by using a hybrid Design of Experiments (DOE) and Ant Colony Algorithm (ACO) has been optimized. The analysis of the behavior of the nonlinear models under bending load is done using finite-element software Abaqus. The objective is to study the performance geometrically parameters of the columns using DOE-ACO approach.
DOE method is being applied to determine the effects of cross-sections, material, and thickness on the energy absorption; and the ACO method is used for finding more accurate thickness on energy absorption. Four types of thin-walled cross-sections, i.e., circle, ellipse, hexagon, and square are used in this study. The optimized results of DOE method show that aluminum alloy (Al-6061) and high strength low alloy steel (HSLA) square columns have a higher energy absorption in comparison with the other cross-sections. However, the amount of absorbed energy in two types of columns is equal but, 50 percent weight reduction may be seen in Al-6061 columns. The columns are re-optimized by ACO to find the best thickness in the last step.
In the following, by topology optimization participation, a new plan is proposed by the same thickness and 50% less weight, that has a higher crashworthiness efficiency by increasing SAE more than 70%. As a result of this plan is bridging the gap between standard topological design and multi-criteria optimization.
 

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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.

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Go-karts are popular sport mini-car in western countries, and there are gaining prominence in developing countries such as Nigeria. Its performance is determined by the chassis design and the braking system is its lifeline. Because of the lack of a suspension system and differentials, a good chassis must be able to bend and twist.
This Go-kart is powered by a Yamaha Vino Automatic Petrol 2-stroke Engine that generates approximately 4.1kw of power at 9018rpm. It boasts slick tyres for increased grip and a hydraulic disc brake for smooth and effective braking in both wet and dry conditions. The focus of this paper is on the braking system and material characterization of its structural members
Simulation static study with Autodesk Inventor yielded the following results: Mass Density 281.550 lbmass/ft3 Yield Strength 40.000 ksi Ultimate Tensile Strength 50.000ksi. Design calculations were performed, and the best possible result was obtained. Ergonomics, safety, cost of manufacturing, and reliability are all considered.

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Electric vehicles are attaining significant attention recently and the current legislation is forcing the automotive industry to electrify the productions. Regardless of electric energy accumulation technology, drive technology is one of the vital components of EVs. The motor drive technology has been mainly developed based on the application which required position/velocity control. In automotive application, however, torque control is an important aspect since the drivers have already used to drive the vehicle based on torque control approach in traditional powertrain system. In this article, a model-based approach is employed to develop a controller which can guarantee the precise control of the induction motors torque for a micro electric vehicle (EV) application regardless of operating conditions. The implementation of the control drive was conducted in MATLAB/Simulink environment, followed by Model In the Loop simulation and testing at various test conditions to confirm the robustness of the developed drive. Direct Torque Control (DTC) with optimum voltage vector selection method is employed to control the motor torque that requires fewer power electronics to process its operation and hence lowers the cost of implementation. The result shows the practicality of the designed control system and its ability to track reference torque commands. Vitally, the controlled approach shows fair abilities to control IMs to produce torque at both the motoring and regenerative modes which is a highly important requirement in electrical propulsion powertrains. Furthermore, the controller’s response time was within the industrial standard range which confirms its suitability for industrial implementation at low cost.

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The braking system has always been considered one of the most significant vehicle subsystems since it plays a key role in safety issues. To design such a complex system, modeling can be a helpful tool for designers to save time and costs. In this paper, the hydraulic braking system of a B-Class vehicle was modeled by simulating the relationship between brake components such as pedals, boosters, main cylinders, and wheel cylinders, with the vehicle dynamics by using the existing models of the tire and their dynamic relationships. The performed modeling was compared with the results of a concerning vehicle's direct movement. The results of this comparison showed that our modeling is very close to the experimental data. The braking distance parameter was selected to examine the effects of each braking component on the vehicle dynamics. The results of investigating the effect of different parameters of the braking system on the dynamic behavior of the vehicle indicated that the main cylinder diameter, the diameter of the front and rear wheels’ brake cylinders, the effective diameter of the front disk, and the diameter of the rear drum are the most effective design parameters in vehicle's braking system and optimal results are obtained by applying changes to these parameters.