Automotive Science and Engineering
Volume:7 Issue: 3, Summer 2017

In this paper, a three-axle bus rollover threshold and the effective parameters are studied. The rollover threshold is a speed that automotive is passing without occurring rollover. The objective is a determination of the heavy vehicle rollover critical speed while turning. For this purpose, a three-axle bus is studied. The dynamic equations related to rollover is extracted, and then rollover criterion, which is LTR (Load Transfer Ratio) in this paper, is obtained. The governing equations are simulated in MATLAB software and then the effect of the parameters such as steering rate, road curvature radius, road bank slope and automotive effective parameters on the rollover critical speed is studied. Prior to the investigation of these parameters, due to validation of the simulation model in MATLAB, a three-axle bus with specific parameters values is placed under various maneuvers with different conditions in TruckSim software then results are recorded. In order to validate, these results are compared with the results which are achieved from MATLAB. After validation, the relation between effective parameters in rollover stability and vehicle speed for desire maneuvers is obtained and it is illustrated in form of function. The results of this research work can be used in road threshold speed without huge computation costs and expensive tests.

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.

This paper presents a force field concept for guiding a vehicle at a high speed maneuver. This method is  similar to potential field method. In this paper, motion constrains like vehicles velocity, distance to obstacle and tire conditions and such lane change conditions as zero slop condition and zero lateral acceleration are discussed. After that, possible equations as vehicles path are investigated. Comparing advantages and disadvantages of 7th, 11th degree and a few other equations, followed by single mass and bicycle models lead to an improved method, which is presented in this paper.

This paper studies the longitudinal control of a group of vehicles following a lead vehicle. A  neighbor based upper level controller is proposed by considering communication delay and actuator lag. Constant spacing policy is used between successive vehicles. Two different approaches based on Lyapunov-Razumikhin and Lyapuniv-Krassovski theorems are presented to stability analysis of closed loop dynamic. By simulation studies, it will be shown that the second approach is less conservatism than the first one. We consider the bidirectional leader following (BDLF) topology for inter-vehicle communication. Based on this structure, some sufficient conditions assuring string stability of platoon is derived. At the end of paper, four different scenarios are presented to study the robustness of algorithm against communication delay, actuator lag, disturbance, heterogeny and communication losses.

In this paper we aim to develop a predictive combustion model for a turbocharged engine in GT-Power software to better simulate engine characteristics and study its behavior under variety of conditions. Experimental data from combustion was initially being used for modelling combustion in software and these data were used for model calibration and result validation. EF7-TC engine was chosen for this research which is the first turbocharged engine designed and developed by IKCO and IPCO in Iran. After analyzing necessary theories for predictive combustion model and required steps for calibration of CombSITurb model in software, one final set of multipliers were calculated based on different sets derived for each engine speed and engine operation was simulated with this combustion model. In addition to improved predictability of engine model, comparing results of predictive model with non-predictive model shows better accuracy especially at lower engine speeds and less tolerance of results for each engine speed.

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.