Decrease Vehicle Weight Research Articles

The Influence of High Temperature Ultrasonic Processing Time on the Microstructure and Mechanical Properties AZ91E Magnesium Alloy

The reduction of harmful greenhouse gas emissions can be realized by utilizing lightweight structural metals, such as magnesium (Mg). Magnesium alloys have the potential to replace higher-density aluminum and ferrous components in automotive and aerospace industries, thereby decreasing vehicle weight and the associated fuel requirements. However, their strength and ductility must be improved to ensure widespread application. This goal can be achieved through ultrasonic processing, a technique that is gaining popularity in the manufacturing of light alloys. In this study, the effects of high-intensity ultrasonic vibration on the microstructure and mechanical properties of AZ91E were investigated. The molten alloys were subjected to 60, 120, 180 and 240 s of sonication at a frequency and amplitude of 20 kHz and 30 µm, respectively. The resultant castings were characterized using optical microscopy, scanning electron microscopy and tensile testing. Sonication was found to improve the mechanical properties of the alloy relative to the base condition. The improvement was attributed to the refinement of the Mg grain structure, decreased area fraction and average size of the brittle Mg17Al12 eutectic phase, in addition to increased area fraction, homogenous distribution and spheroidization of the Mn-Al intermetallic phase. The refinement in microstructure was determined to be a result of improved nucleation and cavitation-induced undercooling of the melt as well as a finer grain size. Therefore, ultrasonic processing can enhance the viability of Mg alloys as engineering materials, offering important opportunities for the production of greener, light-metal components.

Ultrasonic Processing of Magnesium Alloy for Property Enhancement

The reduction of harmful greenhouse gas (GHG) emissions can be realized by utilizing lightweight structural metals, such as magnesium. Magnesium alloys have the potential to replace higher-density aluminum and ferrous components in automotive and aerospace industries, thereby decreasing vehicle weight and the associated fuel requirements. However, their strength and ductility must be improved to ensure widespread application. This goal can be achieved through ultrasonic processing in the molten state, a technique that is gaining popularity in the manufacturing of light alloys. In this study, the effects of high-intensity ultrasonic vibration on the microstructure and hardness of AZ91E Mg alloy was investigated. The molten alloys were subjected to sonication of varying durations, and the resulting castings were characterized using optical microscopy, scanning electron microscopy and hardness testing. Sonication was found to successfully increase the hardness of the alloy relative to the base condition. This improvement was attributed to the refinement of the magnesium grain structure as well as the Mg17Al12 and Mn-Al secondary phases in the sonicated alloys. The competitiveness of magnesium alloys can be significantly enhanced via ultrasonic processing, offering important opportunities for the production of greener, light metal components.

Optimization of Process Parameters in MIG Welding of Two Dissimilar Materials

MIG welding is used in automotive industries which helps in good opportunity to reduce production costs, decrease vehicle weight and improve the strength of sheet metal joining. In this project, the objective is to study welding parameters used in joining two dissimilar metals. Aluminum 6 series and aluminum 7 series with thickness both 6 mm was weld together using MIG welding with tailor welded blanks method. In this project the voltage(V), wire feed(F) and gas pressure(P) are maintained according to the material used for MIG welding. By using design expert software MIG welding parameters are optimized to obtain good tensile strength. Response surface methodology type is used to optimization to study the parameters of MIG WELDING.

Improvement of Die Corner Filling of Stepped Tubes Using Warm Hybrid Forming

Aluminum and magnesium alloys are of materials for decreasing vehicle weight and consequently reducing fuel consumption. However, forming limitations regarding their low formability at room temperature are found when being manufactured by conventional forming processes. For this reason, development of new forming techniques, such as warm tube hydroforming, is needed to overcome such limitations. In addition, production of parts with sharp corners is nearly impossible using conventional forming processes. This paper investigates the possibility of forming stepped tubes with high expansion ratio, sharp corner radii and precise geometric shape using a developed hybrid hydroforming and bending method. To assess tube formability, the bulge test was adopted with different forming temperatures and axial feeds. It is shown that using the feed of 35 mm and feed rate of 15 mm/min, a stepped tube with 47.6 % expansion ratio and corner filling ratio of about 100 % (part with sharp corners) could be achieved when adopting the developed hybrid hydroforming and bending method at 150 ᵒC.

Influence of Heat Treatment on Microstructure Stability and Mechanical Properties of a Carbide‐Free Bainitic Steel

Carbide‐free bainitic steels represent attractive candidates for the automotive industry to meet the conflicting requirements of increasing safety and decreasing vehicle weight. Their fine‐grained multi‐phase microstructure enables a well‐balanced combination of high strength and ductility. To identify and characterize all phases in dependence of the isothermal transformation temperature, metallographic and high‐resolution techniques are applied. The stability of the individual phases is evaluated based on their C concentration determined by atom probe tomography and, subsequently, linked to the mechanical properties.

TAILOR WELDED BLANKS

A Tailor Welded Blank (TWB) is a weld element where the welding is carried out between metals of two different elements. Tailor welded blanks (TWB’s) offer an excellent opportunity to reduce manufacturing costs, decrease vehicle weight and to improve the quality of sheet metal stampings and structural elements. Tailor Welded Blanks (TWBs) offer a means to address all of the concerns by reducing manufacturing costs, decreasing vehicle weight, improving crashworthiness, improving dimensional accuracy of the final part and increasing the corrosion resistance. A TWB is fabricated by welding together two or more sheets of metal of different thicknesses, material grades and/or coatings to produce a single blank, which is subsequently formed. Aluminum TWBs offer additional weight savings and would address the concerns of increased cost and decreased crashworthiness, which normally accompany Aluminum for steel material substitutions. While Aluminum TWBs are currently being implemented for less structural components such as deck lids and hoods, door inners and floor pans are being investigated as possible Aluminum TWB applications for the future. Like tailoring a shirt to suit the need of a person, a TWB is a weld designed to suit the applications. The application varies from strength to light metal. The applications of TWB are variant from the basic automobiles to that of space craft and structural elements.

A Software-Based Approach to Active Noise Control in Automobiles

Everyone wants a car that consumes less fuel. In fact, some studies indicate that car buyers now rank fuel economy as the top factor in choosing a new vehicle. To address this demand, as well as laws regulating fuel efficiency and carbon emissions, automakers have devised a variety of measures. These include variable cylinder management (i.e. deactivating cylinders under conditions of light engine load), operating the engine at lower RPM, and cutting back on passive damping materials to decrease vehicle weight.

Deposition and Characterization of HVOF Thermal Sprayed Functionally Graded Coatings Deposited onto a Lightweight Material

There is a significant interest in lightweight materials (like aluminum, magnesium, titanium, and so on) containing a wear resistance coating, in such industries as the automotive industry, to replace heavy components with lighter parts in order to decrease vehicle weight and increase fuel efficiency. Functionally graded coatings, in which the composition, microstructure, and/or properties vary gradually from the bond coat to the top coat, may be applied to lightweight materials, not only to decrease weight, but also to enhance components mechanical properties by ensuring gradual microstructural (changes) together with lower residual stress. In the current work, aluminum/tool-steel functionally graded coatings were deposited onto lightweight aluminum substrates. The graded coatings were then characterized in terms of residual stress and hardness. Results show that residual stress increased with an increase in deposition thickness and a decrease in number of layers. However, the hardness also increased with an increase in deposition thickness and decrease in number of layers. Therefore, an engineer must compromise between the hardness and stress values while designing a functionally graded coating-substrate system.

Effect of structural variables on automotive body bumper impact beam

Increasing fuel economy has been a central issue in the development of new cars, and one of the important strategies to improve fuel economy is to decrease vehicle weight. In order to obtain this goal, researchers have sought to make bumpers lighter without sacrificing strength, ability to absorb impact, or passenger safety. In this study, the effects of structural variables on the torsional stiffness of a body bumper impact beam were analyzed for possible weight reduction. To this end, the effects of variation of section height, increase of impact beam thickness and the addition of stays in a bumper impact beam were carefully investigated and compared. Among these, the most effective way to increase the torsional stiffness of the bumper impact beam was found to be increasing the section height. In addition, the potential for overall weight reduction of the impact beam was examined by comparing the crash capability of a bumper using conventional steels with that of high-strength steel (boron steel) with a tensile strength of 1.5 GPa. This analysis could serve as a guide to design for optimal bumper impact beam development.

Precipitation strengthening of the aluminum alloy AA6111

There is an increasing use of aluminum alloy sheet in automotive applications due to the desire to decrease vehicle weight. The current study provides a detailed quantitative study on precipitation strengthening in AA6111, which is the alloy of choice in North America for exposed body panels. Transmission electron microscopy was used to characterize the average size, the size distribution, the volume fraction, and the crystal structure of the hardening precipitates for aging at 180 °C (a) directly after solution treatment and (b) following 2 weeks of natural aging. The results indicate that both β″ and Q′ phases co-exist throughout the aging cycle with the relative amount of Q′ being increased both with increased aging time at 180 °C and when natural aging precedes aging at 180 °C. A strengthening model was developed which uses the size distribution and the volume fraction of precipitates as the primary inputs to predict the yield stress. An important feature of this model was that only one fitting parameter was necessary to give very good agreement with the experimental results.

A novel forming technology for tailor-welded blanks

A promising approach to reduce manufacturing costs, decrease vehicle weight, and improve the quality of automotive body components is through the use of tailor-welded blanks. This term refers to blanks where multiple sheets of material are welded together to create a single blank prior to the forming process. The welding process creates formability concerns in a traditional forming process due to material property changes in the weld and in the heat-affected zone adjacent to the weld. In this paper, a newly contrived clamping method along the weld line of the tailor-welded blank during forming is proposed. Numerical simulation results demonstrate the effectiveness and feasibility of the proposed technology, which reduced the maximum strains along the weld line by approximately one-fifth in the part examined.

Tractive and braking performance of a flexible tracked tractor moving up and down weak sloped terrain

The objective of this study is to analyse the tractive and braking performance of a tractor travelling up and down a weak silty loam sloped terrain. The effects of track belt size on terrain-track system parameters were investigated experimentally, and the force and energy balances were clarified for the actual flexible tracked vehicle. The flexibility of the track belt has been precisely analysed as a function of track tension, loading and reloading properties of terrain, and contact pressure distributions. The results show that the optimum effective driving (or braking) force decreases with the increase of slope angle due to the decreasing vehicle weight component, while the thrust (or drag) decreases and the compaction resistance increases. The contact pressure distribution under the flexible track belt shows a triangular wavy pattern having peak values under each track roller. The shear resistance distribution has positive and negative peak values for the driving and braking states, respectively.