Simulering av friktion mellan däck och väg med borstmodellen
Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
The aim of this thesis is to investigate how the friction between a tire and the road can be simulated with a so called brush model, and how this simulation model can be used to improve friction measurements on roads.A tire has a complex structure that is not suitable for the same analytical treatment as used for isotropic and solid structures and materials. This thesis aims towards a way to simulate tire-road friction with a contact model often referred to as the brush model. The brush model is a contact-simulation model that is simplified by the assumption that the contact is thought of as an elastic foundation with a number of springs, or bristles, that deform independently. The influence from neighboring springs is neglected. This means that the contact calculations can be performed much faster than for more complex contact models.In order to calculate the friction forces from a tire, a friction coefficient is needed. The coefficient should be dependent on the rubber material and the road, and not on the tire geometry, contact pressure, etc. However, it is only the total forces (load, longitudinal, and lateral) that can be measured in the tire-road interface. To calculate the geometry-independent coefficient from the measured friction forces, a contact model is needed to describe the tire-road interface. The brush model presented in this thesis could be used for computing a friction coefficient from forces measured in a road-friction tester. This computed friction coefficient can be independent of tire size, inflation pressure and load, and thus be a better measure of the friction in the tire-road interface than a simple ratio between the tangential and normal force that is often referred to as the tire-road friction coefficient. A friction tester is a measurement device, usually equipped to a vehicle, that measures different parameters, for instance tangential forces (longitudinal or lateral), in order to get knowledge about the state of the friction between the tire and the road. A friction tester is used by, for example, transport administrations to get information about current road conditions, and by tire manufacturers to develop new tires.
Place, publisher, year, edition, pages
2014. , 66 p.
Teknik, Tires, hysteresis, grip, friction, limiting friction, traction, slip zone, stick zone, contact area, brush model, friction measurement method, winkler model, elastic foundation model
IdentifiersURN: urn:nbn:se:ltu:diva-51923Local ID: 918138a8-6360-41fb-b3bb-8d7db84c9dd8OAI: oai:DiVA.org:ltu-51923DiVA: diva2:1025287
Subject / course
Student thesis, at least 30 credits
Mechanical Engineering, master's level
Validerat; 20140219 (global_studentproject_submitter)2016-10-042016-10-04Bibliographically approved