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Slip Angle
In vehicle dynamics, slip angle or sideslip angle is the angle between the direction in which a wheel is pointing and the direction in which it is actually traveling (i.e., the angle between the forward velocity vector v_x and the vector sum of wheel forward velocity v_x and lateral velocity v_y, as defined in the image to the right). This slip angle results in a force, the cornering force, which is in the plane of the contact patch and perpendicular to the intersection of the contact patch and the midplane of the wheel. This cornering force increases approximately linearly for the first few degrees of slip angle, then increases non-linearly to a maximum before beginning to decrease. The slip angle, \alpha is defined as \alpha \triangleq -\arctan\left(\frac\right) Causes A non-zero slip angle arises because of deformation in the tire carcass and tread. As the tire rotates, the friction between the contact patch and the road results in individual tread 'elements' (finite ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anti-roll Bar
An anti-roll bar (roll bar, anti-sway bar, sway bar, stabilizer bar) is a part of many automobile suspensions that helps reduce the body roll of a vehicle during fast cornering or over road irregularities. It connects opposite (left/right) wheels together through short lever arms linked by a torsion spring. A sway bar increases the suspension's roll stiffness—its resistance to roll in turns—independent of its spring rate in the vertical direction. The first stabilizer bar patent was awarded to Canadian inventor Stephen Coleman of Fredericton, New Brunswick on April 22, 1919. Anti-roll bars were unusual on pre-WW2 cars due to the generally much stiffer suspension and acceptance of body roll. From the 1950s on, however, production cars were more commonly fitted with anti-roll bars, especially those vehicles with softer coil spring suspension. Purpose and operation An anti-sway or anti-roll bar is intended to force each side of the vehicle to lower, or rise, to similar heig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Automotive Safety
Automotive safety is the study and practice of design, construction, equipment and regulation to minimize the occurrence and consequences of traffic collisions involving motor vehicles. Road traffic safety more broadly includes roadway design. One of the first formal academic studies into improving motor vehicle safety was by Cornell Aeronautical Laboratory of Buffalo, New York. The main conclusion of their extensive report is the crucial importance of seat belts and padded dashboards. However, the primary vector of traffic-related deaths and injuries is the disproportionate mass and velocity of an automobile compared to that of the predominant victim, the pedestrian. According to the World Health Organization (WHO), 80% of cars sold in the world are not compliant with main safety standards. Only 40 countries have adopted the full set of the seven most important regulations for car safety. In the United States, a pedestrian is injured by a motor vehicle every 8 minutes, and a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Traction Circle
Traction may refer to: Engineering *Forces: ** Traction (engineering), adhesive friction or force ** Traction vector, in mechanics, the force per unit area on a surface, including normal and shear components * Traction motor, an electric motor used for propulsion of a vehicle, for example a car or a locomotive * Railway electric traction, the use of electric motors to propel rail cars * Traction engine, a self-propelled steam engine Other uses * Traction (agency), San Francisco-based interactive advertising agency * Traction (orthopedics), a set of mechanisms for straightening broken bones or relieving pressure on the skeletal system * Traction (organization), a non-profit activism organization in North Carolina * ''Traction'' (album), by New Zealand band Supergroove * Traction TeamPage, a commercial blog/wiki software platform * Traction (The Batman), 2nd episode of ''The Batman'' * Traction (geology) Traction is the geologic process whereby a current transports larger, he ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Slip (vehicle Dynamics)
In (automotive) vehicle dynamics, slip is the relative motion between a tire and the road surface it is moving on. This slip can be generated either by the tire's rotational speed being greater or less than the free-rolling speed (usually described as ''percent'' slip), or by the tire's plane of rotation being at an angle to its direction of motion (referred to as slip angle). In rail vehicle dynamics, this overall slip of the wheel relative to the rail is called ''creepage''. It is distinguished from the local sliding velocity of surface particles of wheel and rail, which is called ''micro-slip''. Longitudinal slip The longitudinal slip is generally given as a percentage of the difference between the surface speed of the wheel compared to the speed between axle and road surface, as: : \text=-\frac where \Omega is the longitudinal component of the rotational speed of the wheel, r is wheel radius at the point of contact and v_x is vehicle speed in the plane of the tire. A positi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cornering Force
Cornering force or side force is the lateral (i.e., parallel to wheel axis) force produced by a vehicle tire during cornering. Cornering force is generated by tire slip and is proportional to slip angle at low slip angles. The rate at which cornering force builds up is described by relaxation length. Slip angle describes the deformation of the tire contact patch, and this deflection of the contact patch deforms the tire in a fashion akin to a spring. As with deformation of a spring, deformation of the tire contact patch generates a reaction force in the tire; the cornering force. Integrating the force generated by every tread element along the contact patch length gives the total cornering force. Although the term, "tread element" is used, the compliance in the tire that leads to this effect is actually a combination of sidewall deflection and deflection of the rubber within the contact patch. The exact ratio of sidewall compliance to tread compliance is a factor in tire c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Camber Thrust
Camber thrust and camber force are terms used to describe the force generated perpendicular to the direction of travel of a rolling tire due to its camber angle and finite contact patch. Camber thrust is generated when a point on the outer surface of a leaned and rotating tire, that would normally follow a path that is elliptical when projected onto the ground, is forced to follow a straight path while coming in contact with the ground, due to friction. This deviation towards the direction of the lean causes a deformation in the tire tread and carcass that is transmitted to the vehicle as a force in the direction of the lean. Camber thrust is approximately linearly proportional to camber angle for small angles, reaches its steady-state value nearly instantaneously after a change in camber angle, and so does not have an associated relaxation length. Bias-ply tires have been found to generate more camber thrust than radial tires. Camber stiffness is a parameter used to describe the c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
University Of Padua
The University of Padua ( it, Università degli Studi di Padova, UNIPD) is an Italian university located in the city of Padua, region of Veneto, northern Italy. The University of Padua was founded in 1222 by a group of students and teachers from Bologna. Padua is the second-oldest university in Italy and the world's fifth-oldest surviving university. In 2010, the university had approximately 65,000 students. In 2021, it was ranked second "best university" among Italian institutions of higher education with more than 40,000 students according to Censis institute, and among the best 200 universities in the world according to ARWU. History The university is conventionally said to have been founded in 1222 when a large group of students and professors left the University of Bologna in search of more academic freedom ('Libertas scholastica'). The first subjects to be taught were law and theology. The curriculum expanded rapidly, and by 1399 the institution had divided in two: a ''Univ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Motorcycle Tire
A motorcycle tyre (motorcycle tire in American English) is the outer part of motorcycle wheel, attached to the rim, providing traction, resisting wear, absorbing surface irregularities, and allowing the motorcycle to turn via countersteering. The two tyres' contact patches are the motorcycle's connection to the ground, and so are fundamental to the motorcycle's suspension behaviour, and critically affect safety, braking, fuel economy, noise, and rider comfort. History The history of motorcycle tyres is a clear progression of steady improvement in grip, allowing better acceleration, braking, and turning, along with improved comfort, safety, durability, and reliability. This progression has generally meant a steady increase in tyre width, so much so that Kevin Cameron noted the assumption among riders that "bigger must be better in every way", leading to, "the temptation to overwhelm motorcycles with the biggest tyres the owner can find." While many advances in tyre materials and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Self Aligning Torque
Self aligning torque, also known as aligning torque, aligning moment, SAT, or Mz, is the torque that a tire creates as it rolls along, which tends to steer it, i.e. rotate it around its vertical axis. In the presence of a non-zero slip angle, this torque tends to steer the tire toward the direction in which it is traveling, hence its name. The magnitude of this torque can be calculated as the product of the lateral force generated at the contact patch and the distance behind the wheel centre at which that force acts. This distance is known as the pneumatic trail. The steering torque around a non-vertical steer axis with non-zero mechanical trail is given by : (trail + pneumatic trail) · cos( caster angle) · ''F''''y''. Even if the slip angle and camber angle are zero, and the road is flat, this torque will still be generated due to asymmetries in the tire's construction and the asymmetrical shape and pressure distribution o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
