China
Africa
Explore chapters and articles related to this topic
Tribology in the Automotive Sector
Published in Jitendra Kumar Katiyar, Alessandro Ruggiero, T.V.V.L.N. Rao, J. Paulo Davim, Industrial Tribology, 2023
Sudheer Reddy Beyanagari, P. Kumaravelu, Dhiraj Kumar Reddy Gongati, Yashwanth Maddini, S. Arulvel, Jayakrishna Kandasamy
Different forces are applied on the vehicle during braking operation; for example, an overall force is applied on the moving vehicle that causes it to slowdown is referred to as the braking force. When the pressure applied on the brakes, the friction between the breaks and tyres produces work to retardation of vehicle’s kinetic energy thereby slowing it down. While the vehicle runs on the wet roads, high braking effect at the front would lead to the skidding of the front wheels, due to a decrease in weight transfer. Manual, servo, or power brakes are used in general in automobiles. When the brake pedal is pressed, cam turns through linkages. The cam turns the shoes outwards, causing them to come into contact with the retarding drums, which eventually stops the wheel and the vehicle. On the release of the brake pedal, the retracting spring helps the brake shoes return to their original position and release the brakes, allowing the vehicle to move after a halt. Hence, many forces act on the components of the braking system, causing wear, tear, and increased friction, resulting in heat and sometimes developing vibrations and noise, resulting in tribological issues [12, 32]. Therefore, proper lubrication is needed as per the SAE standards. Further, it is suggested to produce the parts with 2-D solid lubricants reinforced metal matrix composites so as to reduce tribological issues and enhance the mechanical efficiency of the vehicle.
Tire Models
Published in Donald E. Struble, John D. Struble, Automotive Accident Reconstruction, 2020
Donald E. Struble, John D. Struble
When a vehicle is sitting stationary on a flat, level surface, the normal force Nj is simply due to the tire carrying its portion of the vehicle weight. In turning or braking maneuvers, there is “weight transfer” due to additional normal forces being required to resist the pitch and roll moments emanating from the fact that the vehicle center of mass is above the ground (i.e., not in the same plane as the tire/roadway friction forces). For two-dimensional (coplanar) analysis of vehicle motions, such weight transfer effects are necessarily ignored, and will not be discussed further here.
Nonlinear state-feedback design for vehicle lateral control using sum-of-squares programming
Published in Vehicle System Dynamics, 2022
A. M. Ribeiro, A. R. Fioravanti, A. Moutinho, E. C. de Paiva
The peak factor is written in terms of the available friction coefficient and normal load , such that . To match the purpose of the present paper, the coefficients are chosen as and . Moreover, since we are considering constant longitudinal speed, weight transfer due to longitudinal acceleration can be neglected. Therefore, the nominal wheel loads can be expressed as and , where g is the gravity acceleration. The remaining lateral tyre parameters used throughout this paper are , , C = 1.4 and E = −0.2.
Mechanism design and simulation analysis of a new high-speed PET preform removal machine
Published in Mechanics Based Design of Structures and Machines, 2022
Zeng Huang, Chenxue Wang, Yujie Du
After the cooling of PET preform is completed, in order to correspond the preform to the slope groove in the shortest time, the vertical module needs to be linked with the crosswise module. In this case, the resultant acceleration of the Jig can be calculated according to Formula 1. According to the principle of moment translation, the tension load converted from the weight transfer of the Jig to the rotating axis can be calculated according to Formula 2, and the vertical distance between the center of mass and the rotating end of the Jig is about 600 mm, so the additional bearing moment load can be calculated according to Formula 3. The vertical distance between the center of mass of Jig and the end of rotating axis is about 100 mm, so the torque load (T1) generated by the Jig can be calculated according to Formula 4 (Pan et al. 2003). where a1 is the resultant acceleration of the Jig, a2 is the acceleration of vertical module, a3 is the acceleration of crosswise module, F1 is tension load, and MJig is the weight of Jig. The calculation results are shown in Table 2.
Unified dynamic and geometrical vehicle guidance strategy to cope with the discontinuous reference trajectory
Published in Vehicle System Dynamics, 2020
Mohamed Boudali, Rodolfo Orjuela, Michel Basset
This part is devoted to the modelling of the lateral vehicle dynamics. The lateral vehicle dynamics can be approximated by the bicycle model, a simplified model with two degrees of freedom widely used in the automotive field (see Figure 1). The simplified model is obtained by assuming that the vehicle motion is planar, the steering angle is small and neglecting the weight transfer and the rolling. The equations describing the vehicle lateral behaviour are given by Rajamani [14]: where and denote the lateral acceleration and the yaw acceleration, respectively. m and are the vehicle mass and the yaw inertia. and denote the distance between the CoG and the front and the rear axles. and are the front and the rear lateral axle force as shown in Figure 1.