Traction is the force that allows a vehicle to move forward or backward on a surface. It is the result of friction between the tires and the ground. Traction is important for vehicle safety and performance, as it affects acceleration, braking, and cornering.
The theory predicts that failure occurs when the maximum tensile stress reaches a critical value. This critical value is determined by the same factors as in shear, namely the friction angle and the cohesion of the material.
The Mohr-Coulomb failure envelope in traction is a plot of the tensile stress versus the normal stress acting on the material. The slope of the envelope still represents the friction angle, while the intercept on the tensile stress axis represents the tensile strength of the material.
factors affecting
Tire type
Surface conditions
Vehicle weight
Driving style
Road grade and slope
Temperature
tire pressure
2. Traction is the force that allows a
vehicle to move forward or backward
on a surface. It is the result of friction
between the tires and the ground.
Traction is important for vehicle
safety and performance, as it affects
acceleration, braking, and cornering.
Introduction
3. Mohr-Coulomb Failure Theory
The theory predicts that failure occurs when the maximum tensile
stress reaches a critical value. This critical value is determined by
the same factors as in shear, namely the friction angle and the
cohesion of the material.
The Mohr-Coulomb failure envelope in traction is a plot of the tensile
stress versus the normal stress acting on the material. The slope of
the envelope still represents the friction angle, while the intercept on
the tensile stress axis represents the tensile strength of the material.
Angle of friction
Cohesion
6. Tractor Performance Parameters
Gross Traction Force(F): It is the main pull of traction device corresponding
to the particular of soil wheel combination.
F = AC +W. tanΦ
Rolling Resistance/Towed Force(TF): It is a resisting force on a traction
devices which is parallel and opposite to direction of travel.
Net Traction force (H) = F - TF
7. TRACTION PREDICTION FROM DIMENSIONAL ANALYSIS
Dimensional analysis is used to simplify the prediction equations for the
multivariable system.
Towed Force: The towed force or motion resistance of a pneumatic tire is
dependent on load, size, and inflation pressure, as well as soil strength. For soils
that are not very soft and tires that are operated at nominal tire inflation
pressures, the towed force can be predicted from
Cn = wheel numeric =
CI = cone index measured with a cone penetrometer
Gross Tractive Force: The variations of the gross tractive force with soil strength
and slip have been incorporated into a relation including the effect of wheel load
and tire size:
8. the net traction coefficient µ is given by
A practical restriction of b/d 0.30 is imposed on the final equation along with a tire
deflection/section height ratio (/h) limitation of 0.20. The restriction on d/h is
associated with an r/d 0.475.
Tractive Efficiency: The pull, torque and slip characteristics of a driving wheel define
both the magnitude and efficiency of tractive performance. The pull/weight ratio or net
tractive coefficient is an accepted term for defining performance level. Similarly, the
term tractive efficiency (TE) has been adopted to define efficiency. Tractive efficiency of
a wheel is defined as:
Which can be expressed as,
14. Factors Affecting Traction
1.Tire type
2.Surface conditions
3.Vehicle weight
4.Driving style
5.Road grade and slope
6.Temperature
7.tire pressure
15. Measuring Traction: Testing Methods and Techniques points
1.The Skidpad test
2.The Straight Line Acceleration test
3.The Brake Traction test
16. Case
Studies Case 1:
Use of studded winter tires on icy roads.
Studded tires have metal studs embedded in the tread
that provide additional grip on icy surfaces. Studies have
shown that studded tires can significantly improve traction
and reduce the risk of accidents in icy conditions.
Case 2:
Use of advanced driver assistance systems (ADAS) such as
traction control and electronic stability control.
These systems use sensors and algorithms to monitor
vehicle behaviour and adjust the engine and brakes to
maintain traction and stability in challenging conditions.
17. Advances in Traction Prediction: Machine Learning and AI
Applications
Advances in machine learning and artificial intelligence (AI) are transforming the
field of traction prediction, allowing researchers to develop more accurate and
efficient models for predicting traction on various surfaces.Machine learning and AI
algorithms use large datasets to learn patterns and make predictions, allowing them
to detect subtle changes in surface conditions and vehicle behavior that traditional
models may not be able to capture.
One application of machine learning and AI in traction prediction is the use of
sensor data from vehicles and the environment. By collecting data on factors such as
vehicle speed, tire pressure, and road conditions, researchers can train algorithms to
predict traction in real time
18. Traction in Motorsports: Strategies and Techniques
1. Traction is a crucial factor in motorsports, affecting acceleration,
cornering, and braking.
2. The type of motorsport and the track conditions play a significant role in
determining the ideal traction strategy.
3. In racing, the optimal level of traction depends on the track surface,
weather conditions, and the tire type and compound.
4. Motorsports teams use a range of techniques to maximize traction,
including tire pressure adjustments, camber settings, and suspension
tuning.
5. In some forms of racing, such as rally and off-road racing, drivers use
specialized techniques to maintain traction on loose surfaces, such as "left
foot braking" and "power sliding.“
6. Traction control systems have become increasingly common in
motorsports, allowing drivers to maintain optimal traction even in
challenging conditions.
7. In addition to these strategies, driver skill and experience play a critical
role in maintaining traction and optimizing vehicle performance