Vehicle Body Research Articles

Bridge frequency extraction method based on contact point response of two-axle vehicle

Extracting bridge frequencies through the vehicle-bridge contact point response is more effective than that of the response of the vehicle body and wheels. However, when driving on uneven roads, the pitch effect caused by the vertical and rotational motion of the vehicle will affect the extraction of bridge frequencies. Therefore, this study establishes a two-axle vehicle model considering the suspension system and pitch effect. Meanwhile, general equations for calculating the contact point response related to the model are proposed. The accuracy of the equations is verified through numerical simulation. The result shows that extracting bridge frequencies through the contact point response is better than that of the wheel response. Three parameters, such as suspension damping, road surface roughness and vehicle speed are investigated to demonstrate the reliability of extracting bridge frequencies through the contact point response.

Conjugate heat transfer from a discrete-source heated plate by offset jet impingement

Convection/conduction simulations have been performed to determine flow and heat transfer phenomena in steady-state, for a plate carrying few embedded discrete heaters, exposed to by a turbulent offset cooling jet. This configuration is relevant, for example, in thermal design of vehicle body segments in aerodynamics conditions: when realized in certain alloys, their configuration will be determined based their discrete structural state prompted by supplied electrical heating. In order to approach an appropriate thermal design of the plate and obtain their precise state, the space of geometric and operating variables needs to be explored by a thorough parametric study based on the governing momentum and energy equations.In this paper, the interaction between the impinging boundary layer and the conductive effects produced by such discrete heaters is explored, giving rise to a conjugate heat transfer situation. With a flexible notation for discretized heating and temperature-dependent conduction, dimensionless heat transfer is discussed spanning the entire range of design parameters. Results report considerable variation in heat transfer: as an example, air jet over polypropylene plates brings about peak Nusselt numbers between 2000 and 4000 for an inclined configuration at Re≈1×106 based on nozzle width, with related strong temperature gradients that must be addressed during design, depending on discrete heaters' configuration and properties; whereas for alumina plates the peak Nusselt numbers fall down between 600 and 750, featuring much smoother temperature variations and consequent more stable structural states.

Estimation of turnout irregularities using vehicle responses with improved BiLSTM and Gaussian process regression

Railway turnout irregularities pose a safety risk, but existing detection methods using expensive trains with inertial navigation systems and laser measurement devices are cost-prohibitive and time-consuming for high-speed railways. This paper proposes a low-cost and real-time solution for estimating railway turnout irregularities using vehicle body acceleration, allowing for continuous monitoring of dynamic changes. A Bayesian-optimized improved bidirectional long short-term memory neural network model (BO-BiLSTM) was proposed in this paper, utilizing the vehicle's vertical and lateral acceleration as input to achieve point estimation of irregularities, with an estimation error approximately 50% lower than that of traditional recurrent neural networks. In addition, an interval estimation model combining BO-BiLSTM and Gaussian process regression (BO-BiLSTM-GPR) was proposed. Compared to the traditional interval estimation method Bootstrap, under the condition of narrow interval width, GPR ensures that over 90% of the measured values fall within the estimated interval and provides a better solution to the trade-off between interval estimation reliability and uncertainty.

In situ observation of electrochemical reaction of Zn primer steel plate in NaCl solution using confocal micro‐x‐ray fluorescence imaging

AbstractSteel plates have been widely used in bridges, vehicle bodies, guardrails, and so forth. Generally, to improve corrosion resistance, the surface of a steel plate is coated with a Zn layer. However, when the coated steel plate is scratched by external factors, the corrosion resistance decreases. Therefore, it is important to elucidate the elution processes of elements in coated layers and steel plates to develop new coated films and improve corrosion‐resistant techniques. During corrosion, an elution reaction between the coated metal and Fe (anodic reaction) and a reduction reaction of oxygen (cathodic reaction) occur. Confocal micro‐x‐ray fluorescence imaging was employed to visualize the elution processes at the anodic and cathodic steel plates. A Zn primer steel plate was scratched and then immersed in sodium chloride solution. The Zn elution process at the anodic side was observed when a constant current was applied to the two steel plates by a galvanostat. The Fe elution process did not occur, and we believe that the sacrificial protection of Zn inhibited the process. The elutions of Zn and Fe were not observed on the cathodic side of the steel plate. Using the proposed method, we successfully visualized the elemental distributions at the anodic and cathodic sides of the steel plates.

Online hydrodynamic forces estimation system based on the artificial lateral line system

Vehicles that operate beneath or on the surface of water (e.g., boats, remotely operated vehicles, unmanned underwater vehicles, etc.) are subjected to external hydrodynamic forces and require an online hydrodynamic observer for precise autonomous control. The accurate calculation of current forces requires accurate sensor data and computational fluid dynamics, which impose a huge computational burden and cannot be applied in the real-time control of such vehicles. Fish can accurately perceive the effects of ocean currents, a function that can be achieved through an artificial lateral line system. In this study, an online hydrodynamic observer is proposed that uses an artificial lateral line system to estimate the resultant forces acting on water vehicles in real time for the autonomous control of the vehicle. A small three-layer artificial neural network is used to construct the hydrodynamic observer to evaluate various hydrodynamic forces in the form of a six-axis resultant force, such as the damping effects of currents and effects of wind and waves. In this study, an artificial lateral line system is designed for vehicles of any geometry. The system consists of a multipressure sensor array, data acquisition unit, and computational unit. Each pressure sensor is packaged as a separate unit that can be assembled on the surface of an underwater robot. These pressure sensors measure the pressure changes caused by the ocean current forces, while the data acquisition unit collects, collates, and sends the pressure sensor and attitude and heading reference system (AHRS) data to the processing unit. The processing unit uses an artificial neural network to estimate the ocean current forces acting on the vehicle body coordinate system based on the pressure sensor array, and converts them into the inertial reference system in the geoid based on the data acquired from the AHRS. This study explores the effects of the number of sensors and their locations on the accuracy of the estimated results. It investigates whether a scale factor can be used to estimate other available observers of the same size and geometry to enable the rapid deployment of artificial lateral devices to different vehicles. To evaluate the generalization performance of the proposed hydrodynamic observer, tests were conducted in dynamic water environments, such as rivers and oceans.

Numerical Simulation of Hatchback Car with Modified Vehicle Design for the Improvement of Fuel Consumption

The continuous demand and fuel depletion in the automobile industries cause a reduction in fuel consumption, especially in a car which is a classic problem to focus on vehicle body design. The formation of drag force in the car body demands tractive force and significantly affects the engine performance and fuel consumption rate which is not advisable for enhancing aerodynamic efficiency. This paper discusses the methodology to reduce the fuel consumption rate in hatchback cars using a ‘basebleed method’. The hatchback car model with and without basebleed is numerically simulated for the various speed to study the aerodynamic coefficients. The numerical simulation is performed with the k-ε turbulence model for predicting the wake region of both car models with and without basebleed. The numerical study witnessed the hatchback car model with basebleed arrived 6% reduction in the coefficient of drag (CD) compared to without basebleed, which results in a reduction of fuel consumption rate of up to 4.33 %. The research evidence that the stability of the car is not affected while using this basebleed drag reduction method and it is studied from the resultant parameters such as coefficient of lift (CL) and coefficient of side force (CS) and for the varying yaw angle (φ). Further, the research recommends the integration of basebleed at the underbody structure in Hatchback cars to improve the engine fuel consumption without affecting its stability.

Comparative Study on Finite Element Analysis and Performance Test for Structural Safety Evaluation of Mountain Tram Vehicle Body in Sharp Curve Traffic System

Comparative Study on Finite Element Analysis and Performance Test for Structural Safety Evaluation of Mountain Tram Vehicle Body in Sharp Curve Traffic System

Analysis of the influence of track irregularity on high-speed train ride comfort

The vibration of high-speed trains induced by track irregularities is a main factor affecting ride comfort. Especially, the long-wavelength track irregularities can reduce the passengers’ ride comfort by increasing the vibration of the high-speed trains. A three-dimensional human body model coupled to a vehicle body and tracks is established to form a coupled human-seat-vehicle-track system for investigating the influence of the long-wavelength track irregularities on ride comfort. The parameters of the seated human model are determined by measurement based on the multi-island GA method. The coupled model is then used to evaluate the ride comfort of high-speed trains using ISO 2631 under the excitation of the track longitudinal level irregularities. The effects of primary, secondary suspension, and seat support vertical stiffness and damping on ride comfort are analysed. The results show that the track's longitudinal irregularities lead to high human body vibration levels and large ride comfort indices (lower ride comfort), especially when the irregularity excitation frequency is near the natural frequency of the high-speed train. The passengers’ ride comfort is more sensitive to the vertical secondary suspension stiffness than the other suspension parameters.

Enhanced Modeling of Crumple Zone in Vehicle Crash Simulation Using Modified Kamal Model Optimized with Gravitational Search Algorithm

The effectiveness of a vehicle crash system depends on how well it can simulate the behavior of a real vehicle in a crash scenario and accurately identifies the correct working limits of the model parameters, including mass, spring, and damper. Therefore, this study explores the modelling vehicle front crumple zone to represent the behaviors of real crash scenario. The modelling process using Kamal approach is used to develop a precise vehicle crash model for analyzing the impact of a collision on both the vehicle and its passengers. In this study, a complex mass-spring-damper system representing the front crumple zone of an actual car is re-designed to modify the existing vehicle crash model. The gravitational search algorithm (GSA) is implemented in the simulation model's code to obtain optimized values of damping coefficient (c) and spring constant (k). The simulation results show that the deformation response of crumple zone and the deceleration response of vehicle body match the experimental results, indicating the model's accuracy. Additionally, this study investigates the effects of varying the GSA parameters' number of agents (N), the beta parameter (β), and the gravitational constant (G) to improve the model's accuracy by minimizing the root mean square error (RMSE) between model response and crash test data. The optimal GSA parameter chosen in this study were N = 50, β = 0.3, and G = 20 with the lowest RMSE of 22.3874, 22.26664, and 23.86638 respectively.

Energy absorption and toughness analysis on FSW butt joint of AA 5052 and AA 5083

Friction Stir Welding (FSW) is an efficient and effective welding method with good-quality welds. Aluminum Alloy (AA) has been widely used for various automotive needs, including in vehicle manufacturing. AA series 5XXX is a type of material used for vehicle manufacturing because it has good strength properties even after the joining process. A similar butt joint using the FSW method was carried out on material AA 5052 and AA 5083. The results of the welding were then given radiographic testing to determine the general condition of the welds. The impact test was carried out according to the procedures standard of ASTM on the welding results to analyze the energy absorption and toughness properties of welds by getting the impact value of the welded joint, and then looking for the quantity ratio to the impact value of the base material. After that, the results and discussion were obtained that the welded areas showed different impact strength and absorbed energy value, which is compared to the base material the range is below with a decrease in value of between 34% and 68% of the initial toughness strength of the parent material. The reduction in toughness strength can be attributed to the influence of mechanical properties during the welding process. Nevertheless, the welds demonstrated good quality and integrity, highlighting FSW's efficacy in joining aluminum alloys. This research significantly contributes to comprehending the energy absorption and toughness analysis of FSW butt joints in aluminum alloys, crucial for vehicle body technology applications.

Pengaruh Pengerolan Alur Pelat Heksagonal Terhadap Frekuensi Pribadinya Dalam Kondisi Bebas-Bebas

Public interest in pick-up cars as a means of transportation for transporting goods has continued to increase lately because they are considered more flexible for transporting raw materials, workshop products and agricultural products and are capable of being operated on urban and rural roads that have different road roughness, as well as in very high traffic conditions. Plate panels that must be used in pick-up vehicles need to be designed as thin as possible but have high stiffness and natural frequency so that they are more efficient in fuel use and able to withstand vibrations that occur during driving. This study aims to determine the natural frequency that occurs in the plate panel profile for vehicle bodies resulting from the cold rolling process. The galvanized steel plates used are 0.6 and 0.8 mm thick. The natural frequency test method is used with free boundary conditions, where the conditioning plate is suspended by a rope. The natural frequency test tool used is the vibroport 80 at an existential pressure of 10 grams, with the hammer hitting the centre of the panel and the sensors being positioned at 0 and 90 degrees. Based on the test results that have been carried out, the panel specimen with a thickness of 0.8 mm obtained the highest natural frequency value of 922.5 Hz, while for a plate thickness of 0.6 mm, the highest value was only 816.25 Hz. However, the two groups of specimens with plate panel thicknesses of 0.6 and 0.8 mm because of rolling experienced an average increase in natural frequency, reaching 2.3 – 2.5 times when compared to the flat plates without the rolling process. The conclusion is that as the natural frequency value increases, the plate panel stiffness also increases.

Dynamic Suspension Utilizing PID Control with MATLAB

This research paper proposes a PID controlled electromagnetic actuator design for active suspension system. In this method the ride profile is an unknown disturbance and we only measure the vertical displacement of the vehicle body caused by irregular ride profile. The simulation result show that proposed control can achieve better suspension performance and requires less information, also achieves better traction after encountering irregularities on the road.

A study of vehicle lateral position characteristics and passenger cars' special lane width on expressways

AbstractLane width is crucial for traffic safety management. Previous studies have shown that inappropriate width will lead to an increase in accident probability and unsafe driving behaviors. However, there have been limited studies on determination method of special lane width for different models, especially for passenger cars. To tackle this problem, the lateral driving behavior characteristics of the expressway need to be clarified. This work aims to obtain the appropriate lane width according to the vehicles' width and lateral position characteristics. In this study, the lane lateral residual width (the distance between the vehicle body's contour and the lane marking on the same side) and the lateral safety margin are extracted as characterization indices of vehicle lateral characteristics from natural driving trajectory data of expressways. The effect of vehicle type, driving speed, and lane position on the expressway's trajectory behavior is investigated. The results show that the utilization rate of lane width is higher in the outer lane compared to the inner lane. As driving speed increases, vehicles in the inner and middle lanes exhibit shy away effect, moving away from obstacles. Substantial variations exist in the lateral width of lanes among different vehicle types. When driving in the same lane, passenger cars' lane lateral residual width that is 0.4–0.5 m wider than that of heavy vehicles. The recommended lane width for the safe operation of trucks on expressways is 3.75 m. After a comprehensive analysis of vehicle width, trajectory oscillation, and lateral safety margin, this study proposes a minimum lane width of 3.25 m and a recommended general width of 3.5 m for a passenger car‐only expressway. This study holds great significance in enhancing road safety and provides a valuable theoretical foundation for the design of lane width in a passenger car‐only expressway.

Combined Estimation of Vehicle Dynamic State and Inertial Parameter for Electric Vehicles Based on Dual Central Difference Kalman Filter Method

Distributed drive electric vehicles (DDEVs) possess great advantages in the viewpoint of fuel consumption, environment protection and traffic mobility. Whereas the effects of inertial parameter variation in DDEV control system become much more pronounced due to the drastic reduction of vehicle weights and body size, and inertial parameter has seldom been tackled and systematically estimated. This paper presents a dual central difference Kalman filter (DCDKF) where two Kalman filters run in parallel to simultaneously estimate vehicle different dynamic states and inertial parameters, such as vehicle sideslip angle, vehicle mass, vehicle yaw moment of inertia, the distance from the front axle to centre of gravity. The proposed estimation method only integrates and utilizes real-time measurements of hub torque information and other in-vehicle sensors from standard DDEVs. The four-wheel nonlinear vehicle dynamics estimation model considering payload variations, Pacejka tire model, wheel and motor dynamics model is developed, the observability of the DCDKF observer is analysed and derived via Lie derivative and differential geometry theory. To address system nonlinearities in vehicle dynamics estimation, the DCDKF and dual extended Kalman filter (DEKF) are also investigated and compared. Simulation with various maneuvers are carried out to verify the effectiveness of the proposed method using Matlab/Simulink-Carsim®. The results show that the proposed DCDKF method can effectively estimate vehicle dynamic states and inertial parameters despite the existence of payload variations and variable driving conditions. This research provides a boot-strapping procedure which can performs optimal estimation to estimate simultaneously vehicle system state and inertial parameter with high accuracy and real-time ability.

Effects of Advanced Driver Assistance Systems on Impact Velocity and Injury Severity: An Exploration of Data from the Crash Investigation Sampling System

This paper presents an exploratory analysis of advanced driver assistance systems (ADAS) features and safety outcomes using National Highway Transportation Safety Administration’s Crash Investigation Sampling System (CISS) database. In this database, we found improved safety outcomes associated with the presence of three ADAS features: lane departure warning, forward collision warning, and blind spot detection. In particular, vehicles with ADAS features were less likely to be involved in fatal and severe crashes than vehicles of a similar age and body style. Additionally, vehicles with ADAS features had a lower rate of change in velocity pre- and postcrash, a key proxy for injury severity. Vehicles with ADAS were also less likely to be involved in head-on and rear-end crashes than similar vehicles without ADAS and were less likely to experience a severe outcome than vehicles without ADAS when involved in sideswipe collisions. Despite these promising findings, however, small sample sizes precluded robust within-category and multivariate analysis. More robust data are urgently needed to disentangle the safety effects of ADAS features from those related to confounding variables such as vehicle age and body type for vehicle occupants, pedestrians, and bicyclists. We conclude the paper with recommendations for improvements to the CISS database that could support future investigations. We hope this work provides a baseline for scholars and practitioners to deepen our understanding of the effects of ADAS features on transportation safety.

Coupling dynamic model of vehicle-wheel-ground for all-terrain distributed driving unmanned ground vehicle

The establishment of a dynamic model of distributed driving unmanned ground vehicle (DDUGV) is the premise of vehicle state identification and high-quality control. However, due to the strong nonlinearity of the DDUGV system itself, the various external influence and the difficulties of real-time calculating, the simulation results based on existing conditions are far from the actual vehicle test results, resulting in the huge gap between the simulation test and the actual engineering practice. Regarding the problem mentioned above, this paper takes the 3-axles DDUGV with variable structure as the research object, and proposes a universal dynamic modeling method for DDUGV, which considers the uncertainty of terrain and variable structural parameters. Firstly, based on Newtonian mechanics, mathematical models of the vehicle's variable structure, body posture, static/dynamic suspension, hydraulic transmission, wheel and in-wheel motors are established. Secondly, taking the wheel as the coupling node between vehicle dynamics and ground mechanics, 3 tire models in typical driving environments are established, which are the magic tire model used in paved road, and the Bekker-Wong-Janosi theoretical model used in sandy and clay soil, respectively. Thirdly, based on the established mathematical model, a universal DDUGV modeling method is proposed. Then, based on the co-calibration of geotechnics and discrete element method (DEM), the particle parameters of sandy soil are obtained and the theoretical mathematical model of wheel-soil interaction is verified and optimized. Finally, based on the established vehicle-wheel-ground coupling model of the 3-axles DDUGV with variable structures, simulation tests are carried out under typical working conditions, which are compared with the results of existing vehicle dynamics software to verify the accuracy, computation efficiency and real-time property. The vehicle-wheel-ground coupling dynamic model established in this paper can provide a reference for the construction of the vehicle dynamic models, the analysis of driving characteristics, and the research of control strategies in complex environment.

Analysis of the effect of passenger car design on floor panel wear

The aim of the study presented in the paper was to analyse and identify the magnitude of shifts of the floor panel basis points in vehicles with different design parameters. In contrast to other studies, the analysis did not directly address the effect of vehicle mileage on changes to the floor panel geometry. The study carried out a comparative analysis of changes to the vehicle body geometry depending on the body type, the vehicle segment, the type of engine, and the power transmission system type. Depending on individual design parameters, the intensity of changes in the floor panel geometry may vary. The changes to the floor panel geometry were primarily influenced by the body type and the drive system of the vehicles. There were differences between the particular body types in the value of changes to the floor panel geometry. These changes resulted, to a large extent, from the different axle bases and the complete kerb weight of the vehicles. In most cars, the areas with the greatest intensity of changes in geometry were the points associated with the mounting of the front and rear axle suspension system components.

Asymmetric BLOS constraint-involved intelligent integrated guidance and control approach for flight vehicle equipped with strapdown seeker

The paper investigates the integrated guidance and control (IGC) issue for flight vehicle equipped with strapdown seeker. Distinguished from the routine flight vehicle in literatures, the equipped strapdown seeker is fixedly connected with the vehicle body and thus asymmetric body line of sight (BLOS) constraint is imposed, which makes the IGC design more challenging. Focusing on the point, an intelligent integrated guidance and control approach is proposed by virtue of two specific mechanisms. The improved explicit reference governor technique is adopted to generate auxiliary reference command to ensure asymmetric BLOS limitation not to be violated. On the other hand, the reinforcement learning-based adaptive dynamic programming algorithm is further integrated to guarantee the fine tracking of the auxiliary reference command. Consequently, the satisfactory miss distance is achieved despite of the asymmetric BLOS constraint and unmatched uncertainties, and the stability of the closed-loop system is analyzed. The numerical simulation results demonstrate the effectiveness of the proposed method.

Research on Height Adjustment Characteristics of Heavy Vehicle Active Air Suspension Based on Fuzzy Control

The suspension system’s performance has a direct impact on the ride comfort, handling stability, and driving safety of heavy vehicles. The active air suspension of heavy vehicles can adjust the stiffness, damping parameters, and body height in real-time based on different road conditions. This adjustment ensures that the entire vehicle experiences a smooth ride while also making vehicle loading and unloading more labor efficient. Additionally, the active air suspension system enables the vehicle to achieve automation and intelligence. This study focused on a particular 6 × 4 heavy vehicle and designed an active air suspension system that aligns with the vehicle parameters of the heavy truck. Through the use of a fuzzy PID active control strategy, this study investigated and analyzed the height adjustment of the air spring. The results indicate that at a vehicle speed of 60 km/h on a class A road surface, the vehicle body’s vertical acceleration was reduced by 22.1%, and the dynamic travel of the suspension was reduced by 20.1%. This indicates that the fuzzy PID active air suspension system effectively reduces the vehicle’s vibrations and improves ride comfort.

Enhanced dynamic performance of a half-vehicle system using inerter-based nonlinear energy sink

An inerter is introduced in the traditional nonlinear energy sink (NES) to replace its mass and constitutes the novel inerter-based nonlinear energy sink (INES). The INES combines the mass amplification effect of the inerter and the vibration dissipation effect of the NES, which satisfies the lightweight design requirement and further mitigates the vibration of the main structure. Here, the INES is applied in the half-vehicle system to investigate its dynamic performance both in the vertical and pitching directions. The dynamic model of the half-vehicle system coupled with INES is established, the harmonic balance method (HBM) and pseudo arc length method (PALM) is used to obtain its dynamic response under road harmonic excitation. The corresponding dynamic performance under road harmonic and shock excitations is evaluated using six performance indices, which considers the vertical and pitching vibrations of the vehicle body, suspension deflection, and road holding; the vibration suppression effect of the INES and traditional NES is compared. The results show that the traditional NES can enhance the dynamic performance of the half-vehicle system slightly at the cost of a very large mass, which violates the vehicles’ lightweight design and cannot be realized in the practical engineering. For road harmonic excitation, using the INES can obtain a better dynamic performance for the front and rear suspension deflections, front and rear dynamic tire loads, vehicle body vertical acceleration in high vehicle velocity, while the vehicle body pitching acceleration is larger. For road shock excitation, applying the INES can improve the shock performance for the front and rear suspension deflections, front and rear dynamic tire loads, while the peak values of the vehicle body vertical and pitching accelerations are larger. Therefore, the INES integrates the benefits of the inerter and NES and provides a new vibration attenuation device design in the vehicle engineering.