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Chassis systems
Published in Tom Denton, Automobile Mechanical and Electrical Systems, 2018
An anti-roll bar usually forms part of a suspension system (Fig. 4.23). The main purpose of an anti-roll bar is to reduce body roll on corners. The anti-roll bar can be thought of as a torsion bar. The centre is pivoted on the body and each end bends to make connection with the suspension/wheel assembly. When the suspension is compressed on both sides, the anti-roll bar has no effect because it pivots on its mountings. As the suspension is compressed on just one side, a twisting force is exerted on the anti-roll bar. Part of this load is transmitted to the opposite wheel, pulling it upwards. This reduces the amount of body roll on corners.
Product Development of Sugar Palm Composites: From Concept to Fabrication
Published in S.M. Sapuan, J. Sahari, M.R. Ishak, M.L. Sanyang, Sugar Palm Biofibers, Biopolymers, and Biocomposites, 2018
The anti-roll bar is one of the elements in a car's suspension that reduces vibration and keeps the tires in contact with the road. The anti-roll bar, also known as the stabilizer bar, is installed in a vehicle to counteract the forces that provoke swaying of the vehicle during operation. Spring steel is one of the materials that are commonly used as a core material in the design of anti-roll bars. Topac et al. (2011) manufactured 50CrV4 (51CrV4) spring steel that is suitable for the design of highly stressed springs. Bharane et al. (2014) found a study from Hubert and Kumar (2005) that discussed anti-roll bars usually manufactured from SAE Class 550 (G5160–G6150) and Class 700 (G1065–G1090) steel. On the other hand, Schulz and Braun (2012) invented an anti-roll bar using rope made from wound or braided fibers bonded with resin as a core material. In addition, Doody's (2013) research stated that hybrid carbon fiber could be used as a substitute material in anti-roll bars. However, the shape and size of a composite-based anti-roll bar should be different from that of a metal-based anti-roll bar. Manikandan et al. (2014) performed an experiment on an anti-roll bar made from a round solid steel bar wound with E-glass/epoxy. Renner et al. (2014) invented an anti-roll bar made from fiber-reinforced polymer composite materials. Audi, a renowned automaker, has developed a hybrid carbon fiber/aluminum anti-roll bar to reduce vehicle weight (Scoltock, 2014). Other than carbon and glass fiber-reinforced composites used in the manufacture of anti-roll bars, Nadaf and Naniwadekar (2015) compared the maximum angular displacement of a nylon anti-roll bar against that of a mild steel anti-roll bar. With recent research into material substitution in the design of anti-roll bars, there is a great potential for fiber-reinforced composites to be recognized as suitable materials for automotive anti-roll bars.
Chassis systems
Published in Tom Denton, Advanced Automotive Fault Diagnosis, 2020
The main purpose of an anti-roll bar is to reduce body roll on corners. The anti-roll bar can be thought of as a torsion bar. The centre is pivoted on the body and each end bends to make connection with the suspension/wheel assembly. When the suspension is compressed on both sides, the anti-roll bar has no effect because it pivots on its mountings (Figure 7.34).
Achieving anti-roll bar effect through air management in commercial vehicle pneumatic suspensions
Published in Vehicle System Dynamics, 2019
Yang Chen, Andrew W. Peterson, Mehdi Ahmadian
As compared to a passenger car, a heavy vehicle carries considerably larger loads with a higher center of gravity (CG), while having a limited track width due to regulations for motor vehicle dimensions [1]. As a result, the heavy truck is subjected to a larger body roll during cornering, leading to poor handling and increased rollover propensity, as compared with passenger cars. In order to resist the body roll in curves, a passive anti-roll bar can be used to increase the roll stiffness by twisting a U-shaped steel bar. Although the passive anti-roll bar helps suppress the body roll, it deteriorates the ride comfort in response to road irregularities [2]. To seek a means of improving the handling without sacrificing ride comfort, a number of active anti-roll bar mechanisms have been designed and studied. Zulkarnain et al. [2] applied a PID controller to adjust the resistance torque of an active anti-roll bar system. Significant improvements in body roll response and ride quality are observed in their simulation results for the vehicle with that active anti-roll. In a similar study, Cronje and Pieter [3] designed and tested an active anti-roll bar. Their testing results indicate improvements in body roll during dynamic handling tests without any significant influence on ride comfort. Darling and Hickson [4] investigated the application of an active anti-roll bar that was actuated by hydraulic actuators and controlled by an electric valve. They measured and evaluated the vehicle roll angle to rate the handling performance. Compared with a passive mechanism, their active anti-roll bar design improves the peak roll angle by approximately 80% during dynamic and steady-state steering maneuvers. Moreover, Cimba et al. [5] and Vu et al. [6] have studied and tested the performance of different hydraulic anti-roll bar designs. The systems discussed above, however, are not suitable for heavy trucks due to cost, complexity, and packaging. The objective of this paper is to introduce an anti-roll bar concept for heavy truck application, primarily using a slight modification to commonly-used components in pneumatic suspensions.
Prediction of rail profile evolution on metro curved tracks: wear model and validation
Published in International Journal of Rail Transportation, 2022
Bingguang Wen, Shenghua Wang, Gongquan Tao, Jiaxin Li, Dexiang Ren, Zefeng Wen
A trailer vehicle dynamics model of a type-A metro train was established using the multibody dynamics software, SIMPACK. The parameters of the vehicle system are presented in Table 1. The model comprised a car body, two bogie frames, four wheelsets, and eight axle boxes. Each structure of the vehicle was regarded as an ideal rigid body without deformation, and the elasticity of the track system was not considered. The model contained 15 rigid bodies, and the degrees of freedom of the vehicle system dynamics model are listed in Table 2. In the primary suspension, the rotary axle box positioning mode was adopted, where a steel spring and vertical damper were used to connect the wheelset and bogie frame. The secondary suspension comprised two air springs, two traction rods, two vertical dampers, a lateral damper, an anti-roll bar, and a lateral bump stop that connects the bogie frame to the car body. The structure and parameters of the front and rear bogies were symmetric about the centre of the car body, and the entire vehicle model can be easily established via the substructure modelling of SIMPACK. The steel spring, damper, and lateral bump stop were simplified into equal force elements. To render the vehicle system dynamics model more similar to the actual condition, piecewise linearization was performed to simulate the nonlinear characteristics of the lateral bump stop. To verify the accuracy of the vehicle system dynamics model established in this study, the comparison between the measured results and simulation results in terms of wheel‒rail force and derailment coefficient was performed, as shown in Figure 3. In the field test, the LM type wheel profile was employed in the vehicle. In the simulation, the LM type wheel profile was also employed in the vehicle system dynamics model. The simulated speed was 60 km/h, and the American 6-level track irregularity was used. It can be seen that the simulation results of vertical force (Figure 3(a)), lateral force (Figure 3(b)) and derailment coefficient (Figure 3(c)) are in good agreement with the measured results. The vehicle system dynamics model established in this study is regarded to be correct and reliable.
Sensitivity analysis and optimisation of suspension bushing using Taguchi method and grey relational analysis
Published in Vehicle System Dynamics, 2018
Sadegh Yarmohammadisatri, Mohammad Hasan Shojaeefard, Abolfazl Khalkhali, Soheil Goodarzian
The main goal of this study is to develop an optimisation method for designing suspension bushing in order to efficiently enhance the vehicle ride and handling performances simultaneously. In this case, the parameters of suspension geometry are optimised initially to present the optimum design Renault Logan suspension. The GRA method is stated as a method for exploring the optimum suspension parameters based on Taguchi method. Through these analyses, the most influencing parameters in the performance of suspension system have been investigated. Front and rear Camber angle, front and rear Toe angle, Caster and Kingpin angles, front and rear springs stiffness coefficient, front and rear damping coefficient, anti-roll bar stiffness, length of suspension geometry arm are chosen to be design variables. Design range of each parameter is defined in three levels. The roll angular of vehicle body, vehicle lateral slip (Handling), vertical acceleration of chassis, 4-poster roll angular acceleration, pitch angle acceleration (ride comfort) are selected as objective functions. Grey relational coefficient and grey relational grade are obtained for roll angle of vehicle body, vehicle lateral side slip angle (Handling), vertical acceleration of car body, torsional roll acceleration, pitch angle acceleration (ride comfort). In this paper, GRA and Taguchi approach is utilised simultaneously. The ADAMS/CAR simulation results revealed that the Anti-roll bar diameter, front damping coefficient and length of link have the most effective influence among the suspension parameters. The order of other suspension parameters which have the biggest influence on suspension performance are rear axle spring stiffness, front tyre camber, front axle spring stiffness, rear tyre camber, rear axle damping coefficient, rear axle toe, caster angle, front axle toe and kingpin angle. In next step, this algorithm is used for determining the optimum bushing parameters of vehicle suspension. The effective parameters of suspension bushing are investigated based on multi-body dynamics simulation ADAMS/CAR. Bushing parameters of suspension that include type of the bushing, mechanical properties of the bushing in different directions, spring stiffness of bushing and damping coefficient of bushing are optimised considering GRA. In this case, grey relational optimisation is utilised based on considering Taguchi approach for Renault Logan as an example. Six objective functions are considered to evaluate ride and handling qualities of the vehicle. As a result, increasing damping coefficient of bushing for front and rear suspension and changing the spring stiffness of bushing for both longitudinal and rotational directions develop the performance of the suspension. Finally, this paper presents that the GRA approach is a suitable method for optimising suspension and suspension bushing parameters.