Automotive Chassis Research Articles

True pinch mode of magnetorheological fluids

Abstract Magnetorheological (MR) fluids are representatives of smart materials. They react to magnetic fields by developing a yield stress. The effect has been employed in real-world applications such as automotive chassis systems or optical finishing. By convention, MR devices can be operated in at least one of the fundamental modes: flow, shear, squeeze, gradient pinch of which the former has been the least studied and understood. In pinch mode, the material in the flow channel is exposed to non-uniform magnetic fields in the direction parallel to fluid flow. As a result, only the volume of MR fluid near the channel walls are energized to modify the particular material property (yield stress). The result is the channel’s effective diameter change. The behavior of the material in pinch mode is unique and unseen in the other controllable fluids. To study the material’s characteristics in the specific mode, the authors developed a novel circuit concept for energizing the material in an effort to achieve the ’true-zero’ pinch mode magnetic behavior. Contrary to the existing pinch mode valve concepts, the concept valve allows to achieve zero magnetic flux density in the center of the flow channel regardless of the current level. To test the hypothesis a prototype valve was modeled, manufactured and tested across a range of external (flow rate, current/magnetic flux) stimuli. The obtained results yield sufficient evidence proven by results of magnetic simulations to support the underlying hypothesis. The experimental results illustrate the pinch mode type behaviour, i.e. the slope change in the pressure vs flow rate characteristics.

Construction of Fatigue Criteria Through Positive‐Unlabeled Learning

AbstractThe reliability of vehicles is a significant issue for automotive manufacturers, with mechanical fatigue representing a pivotal aspect of the design process. To accelerate the development of novel mechanical components, automotive manufacturers are increasingly employing numerical simulations with the objective of markedly reducing the number of prototype validation tests. This requires the utilization of efficient fatigue criteria capable of accurately identifying critical zones in numerical models. However, the current fatigue criteria frequently fail to demonstrate a satisfactory correlation with the results obtained from fatigue test rigs. In response, this paper proposes a probabilistic Dang Van criterion that accounts for variability in fatigue results within a multiaxial context. Additionally, a fatigue database comprising numerical results and test reports on automotive chassis components is introduced. A novel approach utilizing positive‐unlabeled learning is developed to enhance the predictive accuracy of the fatigue criterion. Its effectiveness is demonstrated through application to the fatigue database.

Comparative Analysis of Adaptation Behaviors of Different Types of Drivers to Steer-by-Wire Systems.

As one of the advanced automotive chassis technologies, the steer-by-wire system offers a high level of precision, responsiveness, and controllability in the driving experience. It can also adjust and optimize parameters to adapt to the preferences of different drivers. However, when faced with the steer-by-wire system, both experienced drivers and novice drivers are in the novice stage, exhibiting learning or adaptation behaviors when using this steering system. In this paper, a small-scale pilot evaluation was conducted by means of a questionnaire survey and driving-simulator experiment, and the learning behavior and adaptability of four experienced and four novice drivers to the steer-by-wire system were analyzed when using the traditional steering system. The study found that experienced drivers show significant changes in their adaptation to the steering system, mainly due to their habitual driving with traditional steering systems. In contrast, novice drivers show no significant changes in their adaptation to the steering system, which is attributed to their lack of driving experience and skills, resulting in less sensitivity to changes in the steering system. Additionally, the study found that novice drivers under the steer-by-wire system grasp control over speed and steering-wheel angle more quickly. This research provides a reference for improving drivers' learning and adaptation abilities to the steer-by-wire system and optimizing the design of the steer-by-wire system.

Superhydrophobic Surfaces Prepared from Columnar Units by Convenient Electrodeposition with Excellent Mechanical Stability Impact and Corrosion Resistance.

Regular array structures prepared by laser processing and three-dimensional printing have promising applications in building stable superhydrophobic structures. However, the size of the materials processed by these two methods is affected by the size of the processing equipment, which prevents the processing of large-size materials. In this paper, a columnar unit consisting of a spherical structure with similar mechanical stability to the array structure is designed and prepared for metal surface protection. A convenient electrodeposition method was used to deposit a layer of columnar micron-sized copper consisting of spheres on the surface of a 6061 aluminum alloy. Subsequently, modified ZrO2 nanoparticles and polytetrafluoroethylene (PTFE) were sprayed on the surface to form a superhydrophobic surface with synergistic columnar units and ZrO2 (CAZ). The structure was tested and found to have excellent mechanical stability, maintaining the superhydrophobic properties of the surface even after 200 abrasion cycles of 1000-grit sandpaper under a 500 g load. Moreover, the vertical deformation of the CAZ sample under normal pressure was increased by a factor of 4 compared to the original substrate. Importantly, in subsequent corrosion resistance tests, the CAZ samples showed a two-order-of-magnitude improvement in self-corrosion current density and impedance modulus at low frequencies compared to the original substrate. This strategy is an effective method for preparing mechanically stable superhydrophobic structures that are low-cost and large enough to provide long-term protection for metal surfaces. It is particularly suitable for surface protection of instruments and automotive chassis armor.

Design and Analysis of Heavy-Duty Vehicle Chassis

Automotive Chassis is the main body of a vehicle which act as a frame work for supporting the other part of vehicle. It should work on various parameter like shock, twist, vibration etc. it should have adequate bending stiffness for better handling characteristics. Stress and equilateral stress are basic characteristics for designing of a firm chassis. There are many industrialized sectors using truck as means of transportation for logistics, agricultures, factories and other industries. In this paper, three different material was adopted on the C-section truck frame design. ASTM A302, HSS 550 and ASTM A710 were structurally analysed on the heavy truck frame through finite element analysis. The results were compared and the best truck chassis material was identified with lower stress and deflection.

Integrated vehicle chassis fabricated by wire and arc additive manufacturing: structure generation, printing radian optimisation, and performance prediction

ABSTRACT In the automotive industry, the extended design and iteration cycles for integrated chassis typically span 2–3 years, creating a misalignment with swiftly changing market demands. Wire arc additive manufacturing (WAAM) technology presents a viable alternative, overcoming the limitations of conventional chassis production. Our holistic framework significantly condenses the design, optimisation, and validation stages for automotive chassis. Initially, a ground structure method is utilised to outline and generate a skeleton chassis. We then utilise the OpenCV image processing method to select a hollow skeleton chassis with minimal material occupancy (0.476) and suspension printing. Subsequently, we assess the influence of printing radian variations by the robotic arm on the microstructure and stress, employing a cellular automaton-finite element (CA-FE) model at the 150th and 200th layer benchmarks. A Kalman filter (KF) is also implemented to fine-tune the printing radian in regions with coarse grain structures and elevated solute concentrations. The process concludes with collision and modal simulation verifications of the skeleton chassis, affirming the optimisation's success. This streamlined methodology allows the completion of the chassis design and manufacturing cycle within a remarkably condensed time frame of one week, accelerating the development process by a factor of 120.

A Systematic Review and Future Development of Automotive Chassis Control Technology

Automotive chassis control technology plays a crucial role in ensuring the stability, performance, and safety of vehicles. This paper reviews and discusses automotive steering/braking/driving/suspension systems from perspectives of system composition, the state of the art, and key technologies. Detailed analysis is conducted on critical techniques related to system fault tolerance, road feel feedback, brake force distribution strategy, electric motors, and motor controllers. The development and application of automotive chassis control technology is in line with the goals and objectives for the advancement of the automotive industry in terms of innovation, safety, and environmental sustainability.

Research on multi-system integrated and coordinated control of automotive chassis

Abstract In this paper, we analyze automotive chassis system modeling and subsystem control to construct a nonlinear chassis system by analyzing the dynamics of the whole vehicle, handling process, and manufacturing process. Secondly, the integrated braking system decoupling controller is designed to control both friction and electromagnetic integrated brake systems effectively. Finally, the Simulink simulation model is integrated into Matlab software to conduct an imitation study of the control system. When the brake controller is activated, the findings show that the wheel’s slip rate drops to almost 0.2, which is close to the desired value. The vehicle’s braking distance with conventional braking is close to 40m, but it is reduced to about 30m under the action of the ABS system, which effectively shortens the braking distance and ensures the vehicle’s safety in braking.

Prediction of Self-Loosening Mechanism and Behavior of Bolted Joints on Automotive Chassis Using Artificial Intelligence

The tightening torque values considered in the assembly of vehicle subparts are of great importance in terms of connection safety. The torque value to be selected is different for each bolted joint type with respect to mechanical features. While the tightening torque value is an important indicator, the bolt preloading value is always a more reliable parameter in terms of whether a secure tightening can be achieved or not. For this reason, when it is desired to create reliable joints, the preloading value that the tightening torque input will create on the connection package should be calculated well. This study presents an integrated approach using Taguchi method (TM) and neural network (NN) to predict the self-loosening mechanism of bolted joints in automotive chassis engine suspension connections. External loading acting on the joints of the engine suspension was collected from bench tests. NN was applied to establish the relationship between controlled factors and loosening rate. The results showed that the proposed approach can be used to predict mechanism of self-loosening and behavior of bolted joints without additional tests, and it is possible to make predictions with very low error rates using artificial intelligence techniques.

Control of four-wheel steering vehicles based on composite model free observer

Four-wheel steering (4WS) is an advanced technology for automotive chassis, which is more flexible and redundant than conventional front wheel steering. For a 4WS vehicle, the accuracy and stability of steering control must be guaranteed, so the main difficulty is the model nonlinearity during driving. To deal with the problems, a novel composite model free observer (CMFO) is designed. The nominal parameters are used to model the 4WS vehicles, and the data-driven method is used to improve observation accuracy. Then a CMFO based controller is designed to control the lateral dynamics of 4WS vehicles. The stability of the proposed control scheme is proved by theoretical derivation, and experiments are carried out to compare the performance between the CMFO based controller, model free adaptive controller (MFAC) and linear quadratic regulator (LQR). The mean absolute error (MAE) values of CMFO are reduced by 75.56% and 44.49% compared with those of LQR and MFAC, respectively.

Ultrasonic Spot Weld inspection system based on Industrial Robotic, Artificial Intelligence and Artificial Vision

Nowadays, spot welding is still one of the most frequently used techniques for bonding metal plates, for example, in an automotive chassis between 3000 and 4000 spot welds can be found. Using this technique is possible to obtain at a low cost, easily automated and versatile welds with high quality and speed of operation but, the inspection and quality control process needs to be improved so that it is possible to reach automatic systems that allow maximizing the speed of inspection and guarantee, in turn, the repeatability and accuracy of the results, eliminating possible deviations introduced by the operator. In this paper an inspection system, based on the ultrasonic propagation, is described. The main challenges faced are presented, such as the location of the spot weld, using artificial vision, the definition and positioning of the probes until a reliable signal, and the final analysis through a development based on artificial intelligence. The results achieved in real parts, have shown that this robotic system, has a better defect detection capacity than the systems currently on the market, and is applicable to the inspection on assembly lines, optimizing not only the inspection times but also improving the results and therefore the quality of the process.

SIMULATION OF STRESS ANALYSIS FOR MULTIPLE TRUSS STRUCTURES FOR DUAL SEATED ROLL CAGE CHASSIS

In recent years, automotive chassis has developed tremendously. This includes the roll cage chassis type which has a higher centre of gravity. This will require an optimum number of truss members to ensure the rigidity and safety of the chassis and user. This research paper aims to analyse the roll cage chassis frame using static analysis simulation by removing truss members at the bottom of the chassis for each design. Carbon steel was employed for all chassis designs. Then, static analysis simulation was done using Autodesk Inventor 2023. From the static analysis, a load equal to 6300 N was applied to the chassis. The safety factor, von Misses stress, 1st principal stress, and 3rd principal stress were analysed and compared for each of the designs. The result shows that the lowest safety factor starting from Design 1, Design 2 and Design 3 with the values of 2.13, 1.85, and 3.24, respectively. For the 1st principal stress, the values are 97.39 MPa, 329.5 MPa, and 104 MPa for Design 1, Design 2, and Design 3, respectively. This result is good as the ultimate strength of carbon steel is 695 MPa. While for the 3rd principal stress, the values are 20.2 MPa, 96.4 MPa to 37.6 MPa for Design 1, Design 2, and Design 3, respectively. In conclusion, removing a few truss members will affect the static analysis performance. It is determined that Design 2 has an optimum truss members number compared to the other two designs.

A hybrid multi-stage decision-making method with probabilistic interval-valued hesitant fuzzy set for 3D printed composite material selection

The 3D printed composite material selection is of great interest due to its extensive application prospect and can be considered as a challenging multiple-criteria decision making (MCDM) issue. The hesitation and uncertainty of experts are difficult to measure, and the high degree of interaction among criteria is often overlooked in the decision process. In addition, composites are required to serve in harsh environments for various mechanical and industrial fields, resulting in the degradation of mechanical properties. In this study, a hybrid multi-stage decision-making method is developed to conduct 3D printed composite material selection in harsh environments. The theory of probabilistic interval-valued hesitant fuzzy set (PIVHFS) is proposed to characterize the decision-making information of experts, which can effectively quantify the assessment in uncertain environments. An integrated method that combines Choquet fuzzy integral and Shapley value is proposed to obtain the weight vector of criteria, which can reflect the mutual influence between criteria and their overall importance. The final decision-making result and the optimal alternative can be calculated by the PIVHFS-based Tomada de Decisão Interativa Multicritério and Technique for order preference by similarity to an ideal solution (TODIM-TOPSIS) method. An empirical application, i.e., 3D printed composites in the background of automotive chassis, is applied to validate the application of the proposed method. Comparative analysis, sensitivity analysis, and managerial implications are also conducted to illustrate the validity of the method. This paper provides a valuable tool for addressing the material selection issue of 3D printed composites from a multi-criteria perspective.

On the Use of a Hybrid Metallic-Composite Design to Increase Mechanical Performance of an Automotive Chassis

Thanks to the introduction of high-performance composite materials, 'metal replacement' approaches are successfully gaining ground even in the most challenging engineering applications. Among these, one of the most recent application challenges is improving the driving range of Battery Electric Vehicles (BEVs) by adopting innovative materials to lighten the mass of structural components, thus reducing energy requirements and enabling the use of smaller and less expensive batteries. Hence, in the present work, the employment of laminated composite panels in an electric minibus chassis is investigated as an effective way to reduce the global mass of the chassis’ structure and, at the same time, to increase its structural performances in terms of torsional stiffness and crashworthiness. By replacing specific steel tubulars with carbon-fiber-reinforced polymer (CFRP) laminated composite structures, different chassis configurations were numerically developed and detailed simulations to compare both masses and mechanical responses were carried out. The paper proves that with this approach it is possible to lighten the chassis up to 9%, while achieving a 7% increase in torsional stiffness and a 9% increase in Specific Energy Absorption (SEA).

Influence of Loading Sequence Effect on Cyclic Hysteresis Characteristics of an Al–Mg–Si Alloy

The alloy materials of automotive chassis are subjected to sequential time-varying loads due to road unevenness. The continuous change of the loading mode and the stress ratio leads to cyclic plasticity of the material, which induces cyclic hardening. The estimation of hardening effects seriously affects the structural's fatigue properties. Therefore, herein, a hardening model and the corresponding fatigue life prediction model are proposed. Then, the loading sequence effect's influence on an Al–Mg–Si alloy's cyclic hysteretic characteristics is analyzed. The steering knuckle is taken as the verification object. The acquired load spectrum is transformed into three sequential forms according to the equivalent damage principle for the verification test. The test results verify the conjecture of the loading sequence effect and confirm the accuracy of the proposed prediction model.

Weight Optimization of Chassis of an Automotive Vehicle using ANSYS

The objective of this paper is to find out the most favourable material and immensely fitted cross-section for TATA 11O9 TRUCK ladder chassis. This research aims to optimize the weight of the chassis. For this we have taken three materials like structural steel, carbon fiber and Aluminium silicon carbide metal matrix composite. The automotive chassis is the vehicle's base, providing strength and support to the numerous body sections such as suspension, engine, power train, and so on. Recent advancements in the realm of automobiles have expanded rapidly, particularly in the current context. Problem faced by modern days vehicle is the heavy weight. So here we try to decrease the weight of chassis frame by using various method and increase the strength, efficiency of chassis. Reducing the weight of chassis results in increase in performance of vehicle, reduce fuel consumption, less wear and tear of tire. The designing of the chassis is done on software SOLIDWORKS and further analysis is done on ANSYS19.2. The current chassis mass with traditional material is 1560 Kg which is made up of structural steel, whereas the chassis mass with Aluminium carbide metal matrix composite material is 523.45 Kg. According to the analysis, the chassis mass has been reduced by 66.44%, which would eventually hinder the vehicle's performance.

Research on parameter estimation methods of fatigue life distribution model of automotive chassis parts

The reliability assessment of fatigue life of automotive chassis parts is an important part of automobile safety. The fatigue endurance tests of automotive half-axles were carried out. The three-parameter Weibull distribution model was established according to the fatigue life distribution of samples. Using the right approximation method and the genetic algorithm to estimate three parameters of the distribution model and a comparative analysis was made. The results show that the initial life unreliability estimated by the median rank in the right approximation method had a large deviation from the true value, which may cause the iterative algorithm fall into the local optimal solution and affect the estimation accuracy. Therefore, a new parameter estimation method based on dual genetic algorithm was proposed. The newly proposed dual genetic algorithm not only improves the iteration speed, but also improves the accuracy of parameter estimation, which provides new ideas and theoretical basis for reliability assessment of mechanical components.

Dynamic Tests of Formula SAE Car Bodies

Palermo University (Italy) does not participate directly in the FSAE competition, but lets its students compete "virtually" by organizing laboratories and working groups in order to design and simulate a car chassis that meets the regulations, of Formula Student in particular. These works, which flow into the students' graduate theses, are often placed together with a view to continuity and constant optimization and improvement. The purpose of this paper is to pick up the work done in the design of an automotive chassis, and to carry it out by shifting the focus no longer on the static resistance of the structure, but on the influence it has on the dynamic behavior of the vehicle. To do this, a long work of reconstruction of past models was carried out, adding to them what was necessary to complete the definition of an equivalent vehicle, and using materials and technologies used in the automotive industry. The subsequent series of simulations on three vehicles with different chassis and the comparison of the results have shown how at present the aluminum alloy frame is the preferable one over the steel and carbon alloy one.

Properties of Hybrid Aluminium-Steel Joints Made by Resistance Spot Welding

Resistance spot welding has significant role in the joining technologies of automotive industry. In the recent period there were some rival technologies, but resistance spot welding remains important. This has numerous reasons however mass production is one of the main motivations. The applied base materials both steel and aluminium develop rapidly. The dual-phase (DP) steels with different strength are typical in the automotive chassis, and the high strength aluminium alloys also continuously spread. These special material combinations mean new challenges for joining technologies, sometimes hybrid aluminium - steel joints should be prepared. In this paper hybrid joints between DP800 steel and 5754-H22/6082-T6 sheets were prepared. The microstructural and strength properties of the joints were investigated and compared. An intermetallic compound was formed between the dissimilar sheets during welding which is basically determine the joint properties.

Investigation of Dynamic Factors in Different Sections of HVC by Static and Free Vibration Modal Analysis

One of the essential purposes of the automotive chassis is to maintain the vehicle's shape and bear the various loads applied to the vehicle. When a heavy-duty vehicle, e.g., a truck, travels on the road, the chassis is subject to vibrations produced by surface roughness and excitation due to the vibration of body parts. The present study aims to design, model, and perform a static structural & vibrational modal analysis on a commercial vehicle (Truck) chassis considering both conventional Structural steel and P100/6061 Al Metal Metrix Composite (MMC) using ANSYS CFX to determine the strength of chassis with transverse sections. Free vibrational modal analysis determines the mass participation factor and resonance frequency for square section and C section, respectively, for both materials using the finite element technique. It was observed that the use of the C section causes an increase in deformation for all the natural frequencies, which is not preferred. The high mass participation factor along the x-direction signifies that any external excitation along this direction would likely cause resonance and amplitude build-up. The C section profile of the chassis shows 1.69% higher deformation than the square section in both cases; hence it is not desirable for the design.