Automotive Science and Engineering
Volume:3 Issue: 1, Winter 2013

Turning of hardened steels using a single point cutting tool has replaced the cylindrical grinding now as itoffers 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 cylindricalgrinding. In order to obtain desired surface quality by machining, proper machining parameters selection isessential. This can be achieved by improving quality and productivity in metal cutting industries. Thepresent study is to investigate the effect of machining parameters such as cutting speed, feed and depth ofcut 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 isselected for experimental planning and the analysis of variance (ANOVA) has been employed to analyzethe 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 cutcuttingspeed (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. surfaceroughness has been modeled using multiple regression analysis.

Material properties and geometry are two important design parameters which their effects should beconsidered in a crashworthiness analysis. In this paper, the axial impact of metallic and hybrid energyabsorbing thin-walled tubes with poly-gonal cross-section is simulated using LS-DYNA software. Thecombined effects of changing the geometry and material properties on the mass specific energy absorption(MSEA) as well as the mean and maximum crush forces are investigated. To compare the results, allmetallic tubes have identical thickness, length, and circumference. The hybrid tubes are made of the samemetallic tubes which are reinforced with special composite overlays. These materials are intentionallyselected in such a way that the effects of yield strength and Young’s modulus can be separatelyinvestigated. The results show that, in contrast with the current belief, there are some metallic and hybridtubes with non- circular cross-section shapes, which have better mass specific energy absorptioncapabilities than the circular ones during the impact.

In the present paper, a complete literatures review of thermal barrier coating applications in diesel enginesis performed to select a proper type and to find coating effects. The coating system has effects on the fuelconsumption, the power and the combustion efficiency, pollution contents and the fatigue lifetime of enginecomponents. Usually there are several beneficial influences by applying ceramic layers on the combustionchamber, including the piston, the cylinder head, the cylinder block, intake and exhaust valves by using aplasma thermal spray method. Several disadvantages such as producing nitrogen oxides also exist when acoating system is used. In this article, all effects, advantages and disadvantages of thermal barrier coatingsare investigated based on presented articles.

In this paper, a method based on binary-coded genetic algorithm is proposed to explore an optimization method, for obtaining an optimal elliptical tank. This optimization method enhances the rollover threshold of a tank vehicle, especially under partial filling conditions. Minimizing the overturning moment imposed on the vehicle due to c.g. height of the liquid load, lateral acceleration and cargo load shift are properly applied. In the process, the width and height of tanker are assumed as constant parameters. Additionally, considering the constant cross-sectional area, an optimum elliptical tanker of each filling condition is presented to provide more roll stability. Moreover, the magnitudes of lateral and vertical translation of the cargo within the proposed optimal cross section under a constant lateral acceleration field are compared with those of conventional elliptical tank to demonstrate the performance potentials of the optimal shapes. Comparing the vehicle rollover threshold of proposed optimal tank with that of currently used elliptical and circular tank reveals that the optimal tank is improved approximately 18% higher than conventional one.

The objective of this study was to develop a numerical model for the prediction of temperature distribution,effective plastic strain distribution, and especially material flow in friction stir welding of copper plates.The DEFORM-3D software was used by incorporating a lagrangian incremental formulation. Threedimensionalresults of the material flow pattern which were extracted using the point tracking are in goodagreement with the experiment. It was shown that the main part of material flow occurs near the topsurface. Material near the top surface at the behind of tool stretches from retreating side towards advancingside which leads to non-symmetrical shape of the stir zone. The stir zone shape in FSW of copper alloys,which was predicted by simulation, does not lean completely towards any sides of welding line.

In this study, stability control of a three-wheeled vehicle with two wheels on the front axle, a three-wheeledvehicle with two wheels on the rear axle, and a standard four-wheeled vehicle are compared. For vehicledynamics control systems, the direct yaw moment control is considered as a suitable way of controlling thelateral motion of a vehicle during a severe driving maneuver. In accordance to the present availabletechnology, the performance of vehicle dynamics control actuation systems is based on the individualcontrol of each wheel braking force known as the differential braking. Also, in order to design the vehicledynamics control system the linear optimal control theory is used. Then, to investigate the effectiveness ofthe proposed linear optimal control system, computer simulations are carried out by using nonlinear twelvedegree-of-freedom models for three-wheeled cars and a fourteen-degree-of-freedom model for a fourwheeledcar. Simulation results of lane change and J-turn maneuvers are shown with and without controlsystem. It is shown that for lateral stability, the three wheeled vehicle with single front wheel is more stablethan the four wheeled vehicle, which is in turn more stable than the three wheeled vehicle with single rearwheel. Considering turning radius which is a kinematic property shows that the front single three-wheeledcar is more under steer than the other cars.

Running the industrial components at a proper temperature is always a big challenge for engineers. Internalcombustion engines are among these components in which temperature plays a big role in theirperformance and emissions. With the development of new technology in the fields of ‘nano-materials’ and‘nano-fluids’, it seems very promising to use this technology as a coolant in the internal combustionengines. In this study, a nano-fluid (Al2O3-Water/Ethylene Glycol (EG)) is used as an engine coolant alongwith an optimized heat exchanger to reduce the warm-up timing. The effect of nano-fluid concentration isconsidered here by using their corresponding governing equations, such as momentum and energy. Theengine coolant thermal behavior calculation is carried out based on the lumped method. The obtainedresults indicated that using different percentage of nano-fluid mixtures (by volume), such as Al2O3-Water/EG as engine coolant enhances the heat transfer coefficient and reduces the warm-up timing which,in turn, results in reduced emissions and fuel consumption.