Car Weight Research Articles

Heat Treatment Design for a QP Steel: Effect of Partitioning Temperature

Designing a new family of advanced high-strength steels (AHSSs) to develop automotive parts that cover early industry needs is the aim of many investigations. One of the candidates in the 3rd family of AHSS are the quenching and partitioning (QP) steels. These steels display an excellent relationship between strength and formability, making them able to fulfill the requirements of safety, while reducing automobile weight to enhance the performance during service. The main attribute of QP steels is the TRIP effect that retained austenite possesses, which allows a significant energy absorption during deformation. The present study is focused on evaluating some process parameters, especially the partitioning temperature, in the microstructures and mechanical properties attained during a QP process. An experimental steel (0.2C-3.5Mn-1.5Si (wt%)) was selected and heated according to the theoretical optimum quenching temperature. For this purpose, heat treatments in a quenching dilatometry and further microstructural and mechanical characterization were carried out by SEM, XRD, EBSD, and hardness and tensile tests, respectively. The samples showed a significant increment in the retained austenite at an increasing partitioning temperature, but with strong penalization on the final ductility due to the large amount of fresh martensite obtained as well.

Opportunities in Optimizing Car Door Weight

Car door is an important part that is used for the protection of passengers from side collisions and also for the comfort of entering and leaving the car. Car doors weigh around 2% of total car weight. Conventional car doors are made from steel as it is sturdy. But it also contributes to the increment of the car weight. As scientific researchers are getting more advanced, finding out new materials as a substitute for conventionally used steel becomes more evident. Advancement in manufacturing and joining technologies pave the way to encouraging us to search for new improvement opportunities in car door weight optimization. Side impact collision of a car is the most hazardous as it directly hits the driver which causes injuries or death all over the world. Vehicle is one the medium of the terribly hazardous crashes causing injuries and death annually around the word. In this research paper, the most important parameters including materials, loads, stresses and deformation were studied to find out opportunities of car door weight optimization. Reduction in car weight means less fuel consumption which enables automobile industries to reduce carbon emission levels of a car. But the safety of passengers is the main priority which demands a light-weight as well as strong material that can sustain collision impact. The aim of the report is to compare the structure of different materials used in car door with currently used material. The designing of the car door is done using computer-aided three-dimensional interactive application (CATIA) software. Impact analysis is conducted on the door using ANSYS Workbench software by varying the materials. S-glass epoxy UD alloys become promising substitutes because of their satisfactory mechanical properties and specifific strength.

High-strength steel components produced by hot metal gas forming

Advanced high-strength steels are promising materials for a variety of applications. They can be used in the automotive industry to reduce the car body weight and thus the fuel consumption as well. Very good mechanical properties can be obtained in martensitic steels by the quenching and partitioning process. Making complex-shaped parts using a single forming step is now possible with hot metal gas forming. Several heat treatment sequences were designed. One involved plain hardening to a temperature below the martensite start temperature. Another sequence was intended to explore the influence of the quenching and partitioning process. In this steel with a carbon content of 0.42%, tensile strengths in excess of 1800 MPa with elongations above 15% can be achieved.

Combined-cycle corrosion testing of steel/6000 series aluminum alloys joined by friction welding

Tailored blanks, especially semi-finished parts formed by welding steel and aluminum alloys, are being employed in the automobile industry to reduce the weight of automobiles. However, when dissimilar metals are welded, galvanic corrosion due to differences in ionization tendency occurs, decreasing the reliability of such welded products. In addition, the heat input when aluminum alloys are welded causes an aging problem. In this study, combined-cycle corrosion testing was performed for S45C/6000 series steel/aluminum alloys joined by friction welding. First, S45C steel pipes were joined to A6061-T6 and A6063-T6 aluminum alloy pipes by friction welding. Then, after combined-cycle testing, changes in appearance and joint strength were investigated as the number of cycles increased. In the natural aging test, test pieces were placed in a desiccator whose temperature was adjusted to about 20 °C with a humidity from 0 to 10 %. One piece was removed at predetermined time intervals and used in tensile testing. After tensile testing, fracture surfaces were observed with an optical microscope. For the S45C/A6061 friction- welded material, a decrease in tensile strength was found at the 36th cycle. It was confirmed that the strength of the S45C/A6063 friction-welded material decreased clearly at the 27th cycle. Any obvious changes in strength were not seen in specimens after 540 hours of natural aging.

Effects of different process parameters on mechanical properties and microstructures of hot stamping boron steel

Hot stamping process has been increasingly used to produce automotive parts with ultra-high-strength property. Thus, increasing the crashworthiness of new generation vehicles and reducing car body weight could be simultaneously obtained. Taking boron steel B1500HS as the research object, this paper built a set of hot stamping experiment equipment that could monitor the temperature of sheet metal and die in real time. The initial forming temperature, contacting pressure, and pressure holding time in hot stamping process were examined under the condition of continuous hot stamping when the die temperature got into dynamic stability. The microstructures and mechanical properties including tensile strength, elongation, and hardness of stamped blank were used as quality evaluation indexes. For B1500HS boron steel sheets with the thickness of 1.2 mm, the optimal process parameter combination of hot stamping process comes true when the initial forming temperature is 800 °C, the contacting pressure is 20 MPa, and the pressure holding time is 10 s. The high-quality hot stamping parts with compact martensite phase could be finally obtained at the tensile strength of 1495 MPa, elongation of 7%, and hardness of 510 HV.

Optimization of process parameters of recycled carbon fiber-reinforced thermoplastic prepared by the wet-laid hybrid nonwoven process

The wet-laid hybrid nonwoven process can produce affordable carbon fiber-reinforced thermoplastic (CFRTP) because of its process simplicity, which can promote the application of CFRTP products in automobile weight reduction. The wet-laid hybrid nonwoven process involves two procedures, mainly: prepare preforms by a papermaking-like process and heat-molding compression. The parameters of heat-molding compression affect the quality of CFRTP directly, but there are not enough researches focusing on the effects of heat-molding compression parameters. This study aims to optimize the wet-laid hybrid nonwoven process to prepare recycled CFRTP. A proper carbon fiber content was determined firstly. Then, response surface methodology was used to optimize the heat-molding compression parameters. The effects of fiber length on composite properties were also investigated. The results showed that the fiber content of 30 wt% was the most suitable. The optimized heat-molding conditions were temperature, pressure, and time of 190°C, 2 MPa, and 10 min, respectively, leading to the lowest void content of 0.9%. CFRTP comprising carbon fibers with a length of 6 mm had the best properties, with the tensile strength of 59.34 MPa and flexural strength of 145.91 MPa.

A Study on the Resolution of Pin-dent Defects in Automotive Door Panels

The automotive customers have been down-gauging steel sheets for making door panels to reduce weight of the passenger cars and improve fuel efficiency under “Go Green” initiative. Tata Steel has been extending support in weight reduction initiative of the automakers through supplying thinner gauge interstitial free (IF) steel sheets. It was reported that in some cases, the thinner sheets could not withstand the intricate forming and stretching operation and resulted in pin-dent or press crack defect generation in deep drawn areas of the components. The defect was reported for the first time to TSL by auto customer, and in the sense, it was a unique defect. At times, the defect impacted 20–40% of deep drawn door components and led to a near line stoppage situation in the press shop. Representative samples containing the defects were collected from the site, and detailed investigation was carried out employing metallographic techniques such as scanning electron microscope (SEM) attached with energy-dispersive x-ray analysis (EDX). The investigation revealed non-metallic inclusions (NMI) to be the cause of such defects. A thorough process and data analysis was carried out to identify the sources of such inclusions and arrive at appropriate countermeasures to fix this problem. Subsequently, countermeasures were implemented in the steel manufacturing process, and such pin-dent defects were eliminated bringing much respite to the customer. The paper will highlight the systematic approach in dealing with the problem and successful resolution of the intriguing quality issue.

An Infrared local heat-treatment method to improve local formability of forming and trimming processes

This paper presents a local heat-treatment method to improve the local formability for stamping and trimming processes by using focused infrared (IR) rays. Although the demand of ultra-high strength steel (UHSS) has been increasing in order to reduce car weights, the low formability of the UHSS has been a limitation. In order to resolve the formability problem, heat treatment methods have been often studied, and the authors also have developed a local heat treatment method by using focused infrared (IR) rays for a decade. The difference of this method from the author’s previous works is that the new heat treatment is completed by the supplier. The supplier of the materials completes the local heat treatment on target areas of blanks where to improve the local formability, then stamping companies can conduct cold forming and trimming. The target material of this paper is a 1.5GPa steel, CR 1480M steel supplied by POSCO. This paper discusses the local formability change caused by the presented IR heat treatment.

Application of Aluminum and ITS Alloys in the Automotive Industry With Special Emphasis PN Wheel Rims

The use of aluminum in modern cars began in the early 1970s, when under the pressure of the oil crisis, car manufacturers around the world began to reduce the weight of cars in order to achieve the lowest possible fuel consumption. The first applications of larger volumes were radiators, engine blocks and wheels. Meanwhile, in Europe, the average amount of consumed aluminum has continued to increase, reaching an average of 180 kg per car. Aluminum castings, forgings, sheets and extruded parts are used for a large number of car parts, including car bodies, chassis, suspensions, wheels and many others. The use of aluminum is also important for hybrid and battery electric cars. Due to the threat of global warming due to the greenhouse effect, it is very important to reduce the weight of the car by using aluminum, and thus fuel consumption.This paper explains why, now more than ever, vehicle weight reduction is necessary and how aluminum can be used to further improve the sustainability and safety of future generations of cars. Special attention is given to the use of aluminum for car wheels, which represent almost 15% of the average aluminum content in passenger cars.

Effects of fabrication method of composite yarn intermediate material and resin melt viscosity on the impregnation properties and mechanical properties of PA66 fiber and glass fiber composites

Continuous fiber-reinforced thermoplastic (c-FRTP) has received attention for reducing automobile weight. Hollow molded parts made by pultrusion molding of braided composites may improve the performance and reduce the weight of automotive parts. However, pultrusion molding of braided composites suffers from productivity problems. This research aimed to increase the productivity of pultrusion molding of braided fabrics to facilitate its practical application. The effects of the fiber intermediate fabrication method and the resin melt viscosity on the impregnation and mechanical properties of the composite were investigated. Glass fiber and polyamide 66 (PA66) were used as the fiber intermediates. Two types of fiber intermediates were used, one with interlace processing and one with the fibers lined up. PA66 fibers with high and low viscosity were used. A correlation was found between impregnation properties and mechanical properties of the molded products, which improved as the unimpregnated ratio decreased. Detailed observations revealed that impregnation of PA66 resin into glass fiber bundles started from interlaced points in the fiber intermediates introduced by interlace processing. Furthermore, low-viscosity PA66 resin had higher fluidity, which better promoted impregnation into glass fiber bundles. These results clarify design guidelines for fiber intermediates to realize better mechanical properties and shorter molding cycles.

Performance of Cell Phone Controlled Model Vehicle

The objective of the project was to construct a model car - using additive technology - which is connected to a phone via cordless communication. PLA was used as a material to print the units. The total weight of the model car is 690 grams including the electronic components. The power consumption and driving properties were measured under given circumstances. Based on our calculations, even in active use at its maximum speed of 5.16 km/h, the system is capable of at least 3.9 hours of operation, while full charging takes only 3 hours. As a result, with two battery units it can be operated continuously.

Linking Spectrograph to Mechanical and Physical Properties of X7475 Experimental Alloys Produced from Recycling Beverage Cans for Bumper Beam Applications

The automobile industry intends to consume more aluminium alloys in an effort to reduce the greenhouse emissions through the cut in the weight of the passenger cars. Experimental X7475 aluminium alloy is a good candidate to achieve this mission. Past efforts targeted at exploring the aluminium for bumper beam applications and even the recovery of aluminium from recycled beverage can (RBC) were not with the aim of upgrading the 3xxx to a novel 7xxx alloy. The wt. % of Zn was 5.0, 4.5 and 4.0, while Mg was left at 1.50, 1.25 and 1.00 wt. % with Mn at a peak of 0.075, 0.050 average and a least wt. % of 0.025. Alloys were homogenized and taken through annealing (O), natural aging (T4) and artificial aging (T6). The effect of hardening phases such as MgZn2 (ICDD 034-0457) due to heat treatments on the physical and mechanical properties of the new X7475 alloys was investigated. Formation of precipitates affected the density and hardness of the alloys produced via stir casting route. A least hardness of 63.40 Hv was observed in alloy H with a density of 2.7264 g/cm3 while the maximum of 113.06 Hv was recorded against alloy C in as-cast (AC). The result has contributed to the database of experimental alloys with the possibilities of producing a new material from RBCs for bumper beam applications. Future investigation should employ design of experiment (DOE) in optimization of the heat treatment for better mechanical properties.

Near-surface characterization using a roadside distributed acoustic sensing array

Due to the broadband nature of distributed acoustic sensing (DAS) measurement, a roadside section of the Stanford DAS-2 array can record seismic signals from various sources. For example, it measures the earth's quasistatic deformation caused by the weight of cars (less than 0.8 Hz) as well as Rayleigh waves induced by earthquakes (less than 3 Hz) and by dynamic car-road interactions (3–20 Hz). We directly utilize the excited surface waves for shallow shear-wave velocity inversion. Rayleigh waves induced by passing cars have a consistent fundamental mode and a noisier first mode. By stacking dispersion images of 33 passing cars, we obtain stable dispersion images. The frequency range of the fundamental mode can be extended by adding the low-frequency earthquake-induced Rayleigh waves. Due to the extended frequency range, we can achieve better depth coverage and resolution for shear-wave velocity inversion. To assure clear separation from Love waves and to align apparent and true phase velocities, we choose an earthquake that is approximately in line with the array. The inverted models match those obtained by a conventional geophone survey, performed using active sources by a geotechnical service company contracted by Stanford University, from the surface to about 50 m. To automate the VS inversion process, we introduce a new objective function that avoids manual dispersion curve picking. We construct a 2D VS profile by performing independent 1D inversions at multiple locations along the fiber. From the low-frequency quasistatic deformation recordings, we also invert for a single Poisson's ratio at each location along the fiber. We observe spatial heterogeneity of both VS and Poisson's ratio profiles. Our approach is less expensive than ambient field interferometry, and reliable estimates can be obtained more frequently because no lengthy crosscorrelations are required.

Materials for lightweight electric motors – a review

Electric motors are widely used in automobiles and large electric vehicles would be introduced in market in the near future to reduce global warming. Reduction in electric motor weight also reduces the overall weight of automobiles. The use of fiber-reinforced polymer materials reduces the weight of electric motors. Lightweight electric motors promote energy savings owing to the reduction of self-weight. Researchers all over the World are trying to make all parts of electric motors using lightweight materials. This review paper presents the outcome of research carried out by researchers from Germany and UK. Fiber reinforced plastics (FRP) reduce weight and increase mechanical and electrical properties. Phenolic composite materials gave promising results due to its electrical insulation properties and corrosion resistance. Thermosets do not swell when they are exposed to chemicals unlike thermoplastics. Aluminium matrix composites (AMC) are used to improve the motor efficiency resulting in a considerable weight reduction. Electric motors have 90 percent or above, which means that a high mechanical energy is derived from electrical energy. The remaining electrical energy is converted into heat. To prevent overheating, the heat is conducted through housing to a cooling jacket having cold water. Researchers have replaced the circular wire by rectangular flat wire that can be coiled tightly on the stator. Newer cooling concepts are developed for making housings using polymer materials. Carbon fiber reinforced materials with metal pins are used for reducing weight and to increase thermal conductivity. Use of high modulus fibers increase damping properties and reduce noise produced by electric motors. Comparisons between electric motors made of lightweight materials and traditional metals in terms of weight, efficiency, cooling rate are presented.

Study on the Effect of Bleaching Treatment on the Mechanical Properties of Kenaf Fibers

Automotive industries are trying to reduce the weight of cars by replacing parts that are made of steel and aluminum with lighter material but equally strong. It is an emerging trend in these industries to utilize polypropylene reinforced with natural fiber as the alternative lightweight material. PP-natural fiber composite is projected to have market growth with compound annual growth rate (CAGR) of 9.5% within 2018-2025. Blending PP with natural fiber is a challenging process considering these two materials are not compatible enough to produce composite with desired mechanical properties. Prior treatment to the fiber is required to improve its compatibility with PP with cautionary that it does not degrading the mechanical strength of the fiber. The aim of this work was to study the effect of chemical treatment on Kenaf fiber to the tensile strength of the fiber. Kenaf fiber was bleached with NaClO solution at various concentration (1-10% v/w), temperature (25-55°C), and duration (1-6 hours). The effect of bleaching treatment to the chemical structure and the tensile strength of the fiber was analyzed using FTIR and UTM respectively. This study showed that the fiber with highest tensile strength was the one that treated with NaClO solution with concentration 1% v/w, at 25°C for 1 hour. This treatment removed impurities for the surface and reduced some amorphous part of the fiber. However further increasing NaClO concentration, mixing temperature and duration will damage the cellulose chain in Kenaf fiber which will decrease the mechanical strength of the fiber.

Analysis of Skid and Rolling Vehicle

Daihatsu Taft Hiline is one of the cars that are widely used for out-of-town travel, to improve the performance of the car in the field, modified cars, modifications made namely the elevation of the car body. The elevation of the car results in a shift in the center of gravity, so that the stability of the car changes. Changing the stability of the car results in skid conditions and the condition of the car rolling. Data processing calculations using the Vehicle Dynamics Turn method, where previously performed calculations to get the car data, car height, car weight, and the location of the center of gravity. Then do skid analysis and rolling to find out the vehicle dynamics that occur in the vehicle. The calculation result of the maximum speed allowed so as not to skid is 66.16 Km / h and the maximum speed allowed so as not to roll is 32.21 Km / h.

Influence of the charge materials on the quality of cast wheel rims made from AK7 alloy

The widespread use of aluminum and alloys based on it in mechanical engineering is determined by high values of specific strength, increased corrosion resistance, as well as the ability to damp vibrations and high energy absorption. These indicators are especially important in the production of cars, as these alloys can reduce product weight and, as a result, the amount of fuel consumed. Reduced weight of cars can reduce harmful emissions into the environment and reduce the pressure on the road surface. Currently, AK7 cast aluminum alloy is the standard alloy for making rims. To obtain an alloy with the necessary properties, it is necessary to take into account the quality of the used charge materials. First of all, this applies to foundry alloys, which are used for alloying and alloy modification. In the study, we studied AlSi10 pig foundry alloy and AlTi5B1 foundry alloy rod.

A semi-convex function for both constant and time-varying moving force identification

In recent years, many moving force identification (MFI) methods have been proposed to monitor moving forces indirectly from structural responses. However, the prior knowledge about moving forces has not been reasonably considered in the existing methods, so the identified moving forces are not accurate enough. To improve the accuracy of MFI results, a novel MFI method is proposed based on a semi-convex function in this study. Firstly, a model of a simply-supported beam subjected to moving forces is taken as an example to establish the relationship between moving forces and structural responses. Then, the prior knowledge that time-varying force component of a moving force usually fluctuates around its static weight in the time domain is adopted. Thus, the moving force is decomposed into constant and time-varying force components. The constant force component is unchanged over time and the time-varying force component is changed over time. Based on this prior knowledge, a semi-convex function is defined for MFI, which is inspired by an alternating iterative method (AIM) and regularization techniques. As a result, the semi-convex function is solved by the AIM, so the constant and time-varying force components can be respectively obtained through iterations, and the moving forces are identified from structural responses. Finally, to evaluate the effectiveness of the proposed method, both numerical simulations and experimental verifications are carried out. The identified results show that the proposed method can further improve the MFI results by comparing with the L2 regularization and the moving average Tikhonov regularization. The characteristics of the identified moving forces are consistent with that described in the given prior knowledge. Moreover, the proposed method can provide a good ability to estimate the total weight of the model car.

Association between Different Modes of Travelling and Adiposity in Chilean Population: Findings from the Chilean National Health Survey 2016-2017.

Background: Active travel has been suggested as a feasible way of increasing physical activity levels. Although international studies have demonstrated its effect over different health outcomes and adiposity, there is still limited evidence on this topic in developing countries, such as Chile. Aim: To investigate the associations between different types of travelling and markers of obesity in the Chilean adult population. Methods: 5411 participants from the Chilean National Health Survey 2016–2017 (CNHS) were included in this study. Active travel was assessed using a questionnaire. Car commuters, public transport (PT), walking and cycling were the four forms of travelling assessed. Bodyweight, body mass index and waist circumference were used as markers of adiposity. Results: Compared to car travellers, body weight, WC and BMI levels were lower for PT walking and cycling travellers. The odds for obesity (Odds ratio (OR): 0.41 (95% CI: 0.28; 0.61 p ≤ 0.001) were lower for walking and the odds (OR: 0.56 (95%CI: 0.35; 0.89 p = 0.014) for central obesity were significantly lower for cyclist in comparison to car travellers. Additionally, participation in any form of active travel (walking or cycling) was low, with only 20.9% of the population reporting being active travellers. Conclusion: Active travel, such as walking and cycling, was associated with lower adiposity levels in the Chilean adult population. Promoting active travel could be a feasible strategy to tackle the high prevalence of obesity and physical inactivity in the Chilean population.

Correlation Between Car Size, Weight, Power, and Vowel Quality in Model Names

Abstract This paper focuses on the practical application of the theory of sound symbolism in brand name development and examines which of the two phonetic dimensions of vowel articulation, the vertical articulatory scale or the horizontal one, is utilised to a higher degree in communicating the size of a vehicle to customers. The methodology used in previous studies on size-sound symbolism did not make it possible to separate the two aspects of vowel articulation. In the present paper, these dimensions were categorised by the use of quantitative methods. Each Received Pronunciation vowel was assigned a numerical value separately on both scales. Then, the correlations between the values obtained for horizontal and vertical articulation of the vowels present in the names of cars sold in Great Britain and the physical attributes of the respective vehicles such as size, weight, and power were calculated. The final results reveal that it is only the vertical scale of vowel articulation which is utilised to signal the physical characteristics of the vehicles examined in this project. Although these findings refer directly to British English, they may also have more universal implications for the theory of magnitude sound symbolism.