Car Weight Research Articles

Overcoming the strength–formability trade-off in high strength steels via cryogenic treatment

High strength steels are becoming more important than ever before for automotive applications to reduce the weight of automobiles and to ensure the safety of passengers. Since increased strength usually results in degraded formability, however, cold forming of high strength steels into final shapes remains a challenge to both automotive manufacturers and suppliers. Here we report novel alloy and processing design concepts that can impart high strength to cold-formable steels, which deviates from the traditional approach of improving the formability of high strength steels. Such designed steel subjected to a designed processing route shows an excellent combination of formability and strength as well as crashworthiness, which is crucial for the safety of passengers in the automobiles. The alloy and processing design concepts used in the present study are based on the utilization of thermally induced austenite to martensite transformation, which imparts high strength to cold-formable austenite by cryogenic treatment.

A Study of Fabrication Method and Characterization of Jute fiber mat/Graphene/Multi wall carbon nanotube Reinforced Polymer Nanocomposite

Abstract: It is possible to lower the overall weight of automobiles in order to minimize waste of resources, enhance economic effectiveness, and optimize the performance of Vehicles. Currently, the utilization of composite materials rather than conventional materials is the primary significant way to reduce the weight of the automotive vehicles. Using polymer materials as a composite matrix in the industry may effectively decrease the quality of automobiles because strong moisture absorption characteristics, low impact and hardness properties than metal materials. It is well recognized that graphene is one of the strongest known materials, with exceptional toughness and electrical conductivity, and MWCNT also have exceptional mechanical properties and so in the polymer composite's mechanical and electrical characteristics may be improved significantly by dispersing graphene and MWCNT in polymer matrix. In the realm of materials, graphene/MWCNT-polymer composites are thus considered an excellent substitute of standard metal components in some applications. Current needs necessitate the use of hybrid materials of all varieties. The composites used in this research was created by hand layup process using LY556 epoxy resin and HY951 hardener, and the article examines the results of hybridization. Tests such as tensile, flexural, impact, and hardness indicate the attributes of all fabricated samples. The results of the test demonstrate that the (Jute Fibre Mat +Epoxy) composites with multi wall carbon nanotube MWCNT/Graphene in (1:5) ratio in sample 5 have considerably superior qualities than the other composites

The use of artificial intelligence methods in the analysis of the results of vehicle braking deceleration tests in the diagnostics of the braking system of a motor vehicle

The article presents the concept of using an artificial neural network to approximate the parameters describing the vehicle braking process, from the point of view of the application of this method in the diagnostics of the braking system. The artificial neural network of non-linear autoregression was used to approximate the dependence of the braking deceleration and the pressure in the braking system. The effectiveness of the neural network was checked depending on the number of neurons in its hidden layer and on the applied learning algorithm. The operation of the neural network was verified based on the actual braking processes of the Skoda Octavia, carried out with different dynamics, with different car weights and different tire inflation pressures. After verifying the neural network, it was used to approximate the braking deceleration values for the pressure values exceeding those present in the input data set. This action allows the analysis of the possibility of the vehicle obtaining a braking deceleration, which qualifies its braking system as efficient. Two concepts of using a neural network to solve this problem were analyzed. Conclusions related to the validity of the development of the discussed methods were drawn.

Effect of the combined centre of gravity height on the ride comfort of suspended monorail train under crosswinds

The combined centre of gravity (CCOG) height of a suspended monorail train may have a certain influence on the centrifugal forces acting on the train under crosswinds, and changes in centrifugal forces will further affect the dynamic interactions among the crosswind, the vehicle and the bridge subsystem. To investigate the effect of CCOG height on the dynamic behaviour of the train, this paper proposes an improved wind-vehicle-bridge coupling dynamics model considering the CCOG height for the suspended monorail system, in which the uneven passenger weight distribution is simulated with various vehicle parameters, and the aerodynamic wind forces acting on the running vehicles and bridge are simulated considering the effect of resultant wind yaw angle. The influences of passenger number, wind velocity, and vehicle speed on the dynamic behaviours of suspended monorail trains are also explored. The results indicate that the suspended monorail train has a certain self-balancing ability due to its unique structure type, which causes the lateral responses of the car body to attenuate with the increasing car weight. In addition, it is conservative to not consider the effect of CCOG height in the lateral ride comfort evaluation of the suspended monorail train subject to crosswinds.

Enhancement of resistance element welding of AA6061 to DP600 steel by using external magnetic field

The application of aluminum (Al)/steel hybrid structure has a broad prospect in automobile weight reduction. In this work, AA6061/DP600 steel was joined using a resistance element welding (REW) method to achieve high strength and plasticity. To modify the deviation of weld nugget and increase the diameter of nugget, annular permanent magnet was designed and used. The effect of external magnetic field on microstructure evolution and mechanical properties was investigated. An electromagnetic stirring effect was generated inside weld nugget, resulting in a larger bonding area between Q235 rivet and DP600 steel. Convection in weld nugget contributed to restraint of dendrite growth and changes in heat distribution, leading to grain refinement at weld nugget. The microstructure of weld nugget and heat affected zone (HAZ) was bainite in magnetically assisted resistance element welding (MA-REW) specimens. The microhardness distribution presented a symmetrical distribution in both horizontal and vertical direction of cross section while the highest microhardness value occurred in weld nugget. Compared to REW specimens, MA-REW specimens achieved improvement of 10.2 % in peak load and 26.8 % in displacement during the tensile test. When the welding current reached 11 kA, the fracture mode of MA-REW specimen transformed from interfacial fracture to button fracture. Enlarged weld nugget size and refined grains were responsible for the improved performance.

Dynamic Weighing to Improve Rail Freight Traffic Safety: A Case Study from the Czech Republic

Abstract Railway traffic safety is a decisive factor involved in any decision-making process in the railway transport, including the overall weight of cars, i.e., potential overloading. Overloaded rolling stock may cause many serious accidents. The presented article comprises two parts: the theoretical one explores the ways of progressive dynamic weighing of shipment. The practical part took place at Horní Dvořiště railway station, measuring the impact of the dynamic weighing on the decline in vehicular overloading.

Improved joint strength between friction-stir welded plates of Al alloy and thermoplastic vulcanizate

Nowadays, metal-polymer composites are used to reduce automobile's weight. However, welding nonpolar polymers to metals is difficult due to the lack of polar groups in molecular chains. The paper put forward an innovative strategy to solve this problem: by adding magnesium methacrylate (MDMA) changes the physical and chemical properties of polypropylene (PP)/ethylene-propylene-diene terpolymer (EPDM) TPV, which improves the compatibility of TPVs and metals. Moreover, the simulation experiments are carried out on plate vulcanization machine. It is found that the addition dosage and order of MDMA have a certain effect on the welding strength. Furthermore, friction stir welding (FSW) replicates the results of simulation experiments, and the ultimate tensile shear strength of P7-E3M1/aluminum alloy (AA6061-T6) reaches 24 MPa. Finally, the welding strength variation regularity with time shows that the properties of metal-TPVs become stable after 10 days. This work introduces a feasible and effective strategy that can be applied to weld various metals to polymers.

ОБ ОЦЕНКАХ РАБОЧИХ КАЧЕСТВ ПОГЛОЩАЮЩИХ АППАРАТОВ АВТОСЦЕПНОГО ОБОРУДОВАНИЯ ПОДВИЖНОГО СОСТАВА ЖЕЛЕЗНЫХ ДОРОГ

The study objective is to develop methods for performance evaluation of center coupler draft gears in various operating conditions. The problem to which the paper is devoted is to reduce the dynamic loading of the rolling stock by means of using efficient draft gears. The research methods on which this study is based are widely used in the dynamics of railroad cars. Typical modes of shunting impact of cars are considered, which are characterized by the highest level of forces in automatic couplings. The design schemes of impacts are considered as a system of connected material points. On the basis of D'Alembert's principle, differential equations of motion are made, and they are integrated by the Euler method. The novelty of the work is in developing an approach to evaluate the performance of draft gears using the proposed integrated evaluation. The results of the study are the nomographs of the effort in the draft gear, depending on car weight and the speed of impact. The conclusions of the study contain the evaluation of the results of applying the proposed approach, as well as recommendations on possible use of the proposed approaches.

In Situ Strain Distribution Measurement of Polyphenylene Sulfide-Aluminum Injection-Molded Direct Joints Using Synchrotron Radiation Microbeam X-ray Diffraction

Abstract The joining of dissimilar materials such as resin and metal has been attracting attention as a means of reducing the weight of automobiles. It is necessary to ensure that the dissimilar material joints are sufficiently strong and durable over time for practical use. Additionally, it is necessary to clarify the mechanisms that produce these properties. We fabricated direct joints of glass fiber-reinforced polyphenylene sulfide (GFRP) and unreinforced pure polyphenylene sulfide (PurePPS) that were injection molded onto aluminum (Al) with nanometer-scale surface irregularities. We used synchrotron microbeam X-ray diffraction to visualize the residual strain distribution at the jointed interface in a nondestructive, micrometer-resolution manner. While the GFRP-Al joint has a lower average tensile residual strain than the PurePPS-Al joint, its strain distributions are quite different. The residual strain distribution of the GFRP-Al joint was comparable to the orientation of glass fibers. The change in the strain distribution when tensile loading was applied in the elastic region was measured, indicating that the tensile strain at the jointed interface increased for PurePPS-Al. Our in situ microbeam X-ray diffraction method helps evaluate the strain at the interface, which is related to joint reliability.

New insights into the fracture behavior of advanced high strength steel resistance spot welds

While the automotive industry is striving for the reduction of car body weight to increase the fuel efficiency and to reduce CO2 emission without compromising the safety and crashworthiness of vehicles, a new generation of advanced high strength steels (AHSS) have emerged as excellent candidates to meet these requirements. However, their integration into the car body structure is associated with welding-related problems. This research utilizes a novel approach to establish a fundamental correlation between welding parameters, microstructure and mechanical performance of AHSS resistance spot welds. In-situ micro-cantilever bending experiments are executed and analyzed in a quantitative manner to evaluate the effect of texture and post-welding heat treatment on the local fracture toughness of spot welds. A striking finding is that, through a switch from single to double pulse weld scheme, the texture of martensite formed in the fusion zone becomes responsible for a significantly higher fracture toughness of the area in front of the pre-crack. In addition, it is found that paint baking heat treatment also results in a much enhanced fracture toughness through tempering of the martensitic microstructure. A quantitative correlation is made between the micro-scale fracture toughness and macro-scale mechanical performance of advanced high strength steel welds.

Hydrogen trapping and embrittlement in high-strength Al alloys

Ever more stringent regulations on greenhouse gas emissions from transportation motivate efforts to revisit materials used for vehicles1. High-strength aluminium alloys often used in aircrafts could help reduce the weight of automobiles, but are susceptible to environmental degradation2,3. Hydrogen ‘embrittlement’ is often indicated as the main culprit4; however, the exact mechanisms underpinning failure are not precisely known: atomic-scale analysis of H inside an alloy remains a challenge, and this prevents deploying alloy design strategies to enhance the durability of the materials. Here we performed near-atomic-scale analysis of H trapped in second-phase particles and at grain boundaries in a high-strength 7xxx Al alloy. We used these observations to guide atomistic ab initio calculations, which show that the co-segregation of alloying elements and H favours grain boundary decohesion, and the strong partitioning of H into the second-phase particles removes solute H from the matrix, hence preventing H embrittlement. Our insights further advance the mechanistic understanding of H-assisted embrittlement in Al alloys, emphasizing the role of H traps in minimizing cracking and guiding new alloy design.

Scope of Carbon Fibre-Reinforced Polymer Wheel Rims for Formula Student Racecars: A Finite Element Analytical approach

Wheel rims are vital components critical to the safety of an automobile. Conventional wheel rims have utilized monolithic materials like aluminium and magnesium alloys in replacement to heavier steel rims. To reduce the weight of the formula car, lightweight composite wheel rims with higher stiffness are explored in the current work. Composite wheel rims are still in their nascent stage for commercial automotive applications, although they are commonly seen more in motorsports. The factors like complex design, high cost, and difficulty in fabrication are some of the demerits of composite wheel rims. Formula Manipal racing has been building race cars for Formula India events for over 13 years, on which aluminium wheel rims were standardly fitted. In the current work, the design and finite element analysis of carbon fibre wheels rims were undertaken to replace the aluminium wheel rims after a thorough consideration of other potential materials also. The modelling was carried out on CATIA3DX®, and finite element analysis was carried out using the ANSYS COMPOSITE PREP/POST (ACP)® module for laminate stackup and structural analysis tools for mechanical response. From the studies, the carbon fibre rims reduced the weight significantly by 42% while improving the factor of safety by 41% as compared to the current aluminium wheel rims while thermally outperforming magnesium and titanium alloys.

Study of the efficiency of brake shoes

Brake shoes are used as the main means for securing trains and for reducing the speed of rail cars. The design of brake shoes was invented about 100 years ago and has not changed principally until now. One of the main disadvantages of brake shoes is the formation of sliders on the wheelsets. This leads to the need to replace wheelsets, which, in turn, leads to a significant increase in the cost of cargo transportation. This paper provides a study of the efficiency of the brake shoes when they are used at hump yards to reduce the speed of movement. For the study, a simulation model of the movement of the cut on brake shoes was developed. The paper provides a mathematical apparatus for simulation modeling. It was concluded that the effectiveness of the brake shoes depends on the number of cars in the cut and the weight of the first car in the cut. With an increase in the number of cars in a cut, the effectiveness of the brake shoe decreases. In cases where the first car in the cut will have the smallest weight of all cars, the efficiency of the brake shoe will be insufficient to stop the rolling stock. The paper also compares the effectiveness of the new Retarder Stopper with brake shoes.

Deformation behavior of bolted thin plates subjected to shear load.

The use of non-ferrous metal materials is promoted as a means of reducing the weight of automobiles toward the realization of a sustainable society. Due to the low Young's modulus of non-ferrous metals, it is important to optimize the stiffness of the structure, especially the structure of the joints and the number of joints for stress concentration. So far, it has been suggested that when the load limit is exceeded, slippage occurs between the test plates and the bolt deforms S-shape. This time, the deformation state of the bolt was investigated by FEM, and it was confirmed that the bolt was actually deformed S-shape. Furthermore, it was found that the inclination of the bolt head and the nut part differed depending on the constraint conditions, and that the slip did not return even after unloading.

ПІДВИЩЕННЯ ПАЛИВНОЇ ЕКОНОМІЧНОСТІ АВТОМОБІЛЯ ЗА РАХУНОК ВИБОРУ ОПТИМАЛЬНОЇ МАСИ АВТОПОЇЗДА

The article considers the influence of the mass of a road train on its fuel economy. 241 The object of research is road vehicles that are in operation. Research method – analysis of fuel efficiency of cars. The purpose of the work is to determine measures to increase the efficiency of vehicle use by reducing fuel consumption. When transporting goods by road, the issue of substantiation of the mass of road trains and their fuel consumption is relevant. When carrying out transportation, the fuel consumption of a road train is influenced by many factors, the main of which are: the weight of the road train, road conditions and traffic regime. The following indicators can be used to assess the efficiency of car use: amount of fuel per 100 km; amount of fuel per 1 tkm, etc. But the most objective indicator is the specific fuel consumption Qp, ie fuel consumption per 1 km, attributed to the unit of transport productivity of the road train, Pi (tkm / h). Calculations performed on the example of road trains in the tractors KrAZ-260 and IVECO-190.48 show that the specific fuel consumption on the route Qpp with a total coefficient of resistance in the range Ψp = 0.04-0.06 at a load weight Mv = 40t is 0.8 and 0.8 ml, respectively. (tkm / year)), and at Mv = 70t, Qpp = 8.5 and 2.5 (ml / (tkm / year)). The calculation of fuel consumption depending on the equipped weight of cars of different brands is compared, comparing KrAZ-6510 and DAF-2700 cars. To reduce the curb weight, you must, first of all, carefully analyze the layout and mass characteristics of all components and units, widely use lightweight and high-strength materials. The results of the article can be used in the operation and improvement of car design.KEY WORDS: CAR EQUIPMENT, FUEL ECONOMY, MOVEMENT RESISTANCE, FUEL CONSUMPTION, EFFICIENCY OF OPERATION

Dynamic displacement response analysis of bridge in the impact vibration of slight and frequent vehicle bump

To study the impact of vehicle moving on bridge, the bump occurring under the determined limit conditions of vehicle from no bump to the beginning of bump was named as slight and frequent vehicle bump. With a 1/4 simplified vehicle model and the Euler-Bernoulli bridge model, the required minimum impact height for the bump and the effect of bump impact on the vertical dynamic mid-span displacement response of bridge were figured out in different vehicle speed, axle load and wheel diameter. The simulation analysis by ANSYS software, with HSFLD242 unit simulating air inside the tire and MASS21 simulating the car weight held by tires, verified the results of the minimum impact height. The effect of bump impact on the vertical dynamic mid-span displacement response of bridge was also verified by observation using the TCQN-6A bridge deflection detector on the mid-span dynamic deflection of a 25-metre simply supported beam bridge.

Features of braking of multi-axle vehicles depending on the layout of their axles

Problem. For an hour, in the scientific-methodical recommendations of the ship-experts, it is installed in the scientific-technical literature of the day-to-day parameters of galvanizing of vantage, bug-capable transport equipment, so that it is inaccurate to introduce autotransport equipment for the eastern part to inaccurate zasob_v unique road transport suit. Goal. The value of the function of galvanizing large transport bridges on the basis of the coordinates of the position to the center of the heavy transport, realizable values, which are realized between the tires and the supporting surface, as well as the support for the rear axle of the transport bridges. Methodology. The approaches adopted in the work to solve this goal are based on the theoretical foundations of braking multi-axle vehicles, the scientific provisions of elastic deformations of pneumatic tires of automobile wheels, geometric and weight parameters of a wheeled vehicle. Results. The equations that allow to calculate the value of the braking coefficient of multi-axle vehicles based on the coordinates of the position of the center of gravity, the realized couplings between the tires and the bearing surface, as well as the load distribution between the respective front and rear axles of the vehicle. Rivnyannya is assigned, which allow the positioning of the coordinates to the center of the car of a multi-axle wheeled transport vehicle for both front and rear axles. The calculation schemes of the position of the coordinates of the center of mass for two-axle, three-axle and four-axle with different axle layout are presented in graphical form, which give a general idea of the mass distribution between the front and rear axles of the vehicle. Originality. Presented in a graphical view of the layout of the positioning of the coordinates to the center of the car for a two-axle, three-axle and one axle with a small layout of the bridges, which give a far-reaching display of the space between the front and rear axles of the transport vehicle. Practical value. The results can be recommended by the experts-auto technicians in the development of technical capabilities for the drivers of vantage transport means, uniqueness of the road-transport usability.

Finite element analysis of Epoxy/E-Glass composite material based mono leaf spring for light weight vehicle

A great deal of work is put into decreasing the fuel consumption of automotive vehicles, which may be accomplished by reducing the bulk of the vehicles. One component that may be explored is the leaf spring, which is extensively utilized in many sorts of cars, including electric ones. For the leaf spring, four distinct materials are considered: standard steel, Epoxy/E-Glass UD composite, Epoxy/E-Glass Wet composite, and Epoxy/S-Glass UD composite. The FEA study executed with the help of the ANSYS finite element code. Firstly, the 3-D model of the leaf spring with different thickness varying from 15mm to 65mm is designed using SolidWorks software which is then imported to the ANSYS software for the static analysis. Along with this, the finite element analysis under full load on 3-D composite multi leaf spring model is executed using ANSYS 2020 R1 by taking three different materials and then the result for the different static behaviour of the leaf spring are compared for all the materials assigned. In this paper we describe design and analysis of composite leaf spring. The leaf spring model used for this purpose is a rear leaf spring used in MAHINDRA “MODEL-COMMANDER 650 DI”. When compared to traditional steel, the mass of hybrid composite material is 62% lower. Hybrid composite materials have 36% lower equivalent (Von-Mises) stress than steel. Utlimately, the hybrid composite material may be employed as a leaf spring, decreasing the total weight of automobiles.

Friction welding of pure titanium-AZ31 magnesium alloy: Characterization and simulation

Friction stir welding (FSW) is a solid-state joining process that is still effectively utilized for joining Mg alloys, Ti alloys, and many other similar and dissimilar materials. Application and dissimilar joining of titanium to magnesium are very attractive in the automobile industry due to the reduction in automobile weight and fuel consumption. In this study, parameter optimization of friction welding on the shear strength of pure commercial titanium to AZ31 magnesium alloy joint by response surface methodology (RSM) was carried out. Rotation speed, friction pressure, and forging pressure on three levels were considered as the variable parameters in welding for a friction time of 4 s and a fixed forge time of 8 s. The torsion test results showed that the best shear strength (103.285 MPa) is related to the sample with optimum parameters, namely, a friction pressure of 50 MPa, forging pressure of 40 MPa, and rotation speed of 1300 rpm. Analysis of variance (ANOVA) was used to investigate the capability of the expanded model. The ANOVA results also showed that among the parameters, rotation speed and friction pressure significantly affect the shear strength. The reason is that high rotation speed and friction pressure can result in rapid transformation for achieving axial displacement stability and escalation of temperature.

POSSIBLE OPTION FOR CALCULATING VEHICLE VIBRATIONS

Determination of the loads on the elastic elements of the car suspension is a necessary part of the overall calculation of the car as a complex technical system. Considerable attention is paid to this issue both in fundamental works on automobiles and in educational literature. The authors of works devoted to the problem of car vibrations, in most cases, vibrations are considered from the point of view the smoothness of the movement of the car, which is quite logical because the smoothness of the ride determines many indicators of movement and, first of all, the physical well-being of the driver and passengers as well as the safety of transported fragile goods. In this case, the car is considered as a system with several masses connected by elastic elements. This approach requires reducing the masses and stiffnesses of elastic elements to specific points of the vehicle structure, compiling several differential equations of mass motion and, accordingly, significantly complicates solving a problem that is not always required by specific design problems. This article presents a variant of calculating dynamic loads based on a single-mass dynamic system, in which the sprung masses are considered as a single mass concentrated in the center of mass of the body and resting on elastic suspension elements. The solution of the dynamic problem in this case is much simpler, and the results solving a problem that is not always required by specific design problems. This article presents a variant of calculating dynamic loads based on a single-mass dynamic system, in which the sprung masses are considered as a single mass concentrated in the center of mass of the body and resting on elastic suspension elements. The solution of the dynamic problem in this case is much simpler, and the results of the solution may well satisfy the requirements for the accuracy of calculations, since end obtaining specific formulas for the dynamic factor of the loads on the vehicle structure depending on the speed of the vehicle hitting an obstacle. In addition, knowledge of the maximum deformation of the elastic elements of the suspension makes it possible to optimally determine the required depth of the wheel arches of the car, to calculate the required stiffness of the elastic elements of the axles of the car in accordance with the parts of the weight of the entire car falling on them. Keywords: automobile, elastic elements, vibrations, loads.