Primary Study On Turn-Slip Properties Of Tire

The analysis, modeling and simulation of vehicle dynamics are all based on tire model. As a result of the complexity of tire material, structure and the complexity of the mutual action between tire and road, the study of tire mechanical property is always the difficulty and pivot of vehicle dynamics. The in-plane and out-plane mechanical property have important influence on vehicle handling, braking, driving stability , power and economic characteristic. When tire is rolling, it produces leaning and list, when steering it also produces cornering. The paper makes a study on tire cornering property, the main content and conclusion is as following:Firstly, the paper introduce the basic knowledge of tire modeling, among which the theory of tire translation, bending , twisting deflection ,coordinate of tire model and load distribution is the basic theory of former tire modeling, which is also the basic theory of building discrete simulation tire model in this paper.Secondly, make a study on the influence of the tire structure property change to the non-steady turn-slip frequency property of former non-steady cornering property tire model considering the complicate carcass deflection. According to the theory, when the velocity of vehicle is not high, tire non-steady cornering property is the function of path frequencyωsand rolling distance X which is not influenced by velocity, make a study of the response under pure turn-slip input using the non-steady cornering property linear semi-empirical tire model which ignoring the bending and twisting deformation of carcass established by simplification of E function. From the simulation result we can see the error conduced by ignoring the additional aligning torque produced by tread. By comparing different non-steady cornering property semi-empirical tire model, we can find out that there is some difference between the description of turn-slip motion mechanical property. The lateral force response produced by tire turn-slip is always zero in the"two-side"semi-empirical tire model which is can not be used to express the lateral force property when the tire is under turn-slip motion."First-order"and"high-order"semi-empirical tire model show the same lateral property response to tire turn-slip motion, while at the same time show different response of tire align torque property.Thirdly, the paper introduce the establishment of turn-slip discrete simulation tire model. The model considers the carcass deformation of twisting, bending, lateral and longitudinal translation. The paper developed the relationship between tire force and contact patch deformation by formula ratiocination for the purpose of precisely describing tire property under turn-slip motion.Simulating results shows that static lateral force increase first and then decrease with the increase of cornering. The lateral deformation of tread has two forms when static lateral force increases with the cornering by analyzing tire patch deformation. The lateral deformation direction of tread unit is same when cornering is small. When the cornering rate is positive, tread unit produce negative lateral deformation. The lateral deformation of tread unit becomes bigger with the increase of cornering rate, tire static lateral force increase. With the further increase of cornering rate ,deformation direction of the back end of patch tread unit changes , the negative deformation and positive deformation increase in which the negative deformation is bigger. Tire static lateral force keeps increasing, and a maximum value appears when the cornering rate increase to certain value. The positive deformation unit in the patch back end becomes more and more, the according tread unit deforms bigger, while the negative deformation of tread keeps the same and static lateral force decrease.The static aligning torque increases quickly with the increase of cornering rate, and then decrease. The deformation direction of patch inside and outside is just opposite, the aligning torque direction produced by longitudinal deformation is just the same. When the cornering rate is small, the lateral deformation direction is just the same , the aligning torque produced by patch back end lateral deformation is bigger than the aligning torque produced by the front end. When the cornering rate is positive, longitudinal deformation produces positive aligning torque and lateral deformation produces negative aligning torque, the total aligning torque is positive direction. With the increase of cornering rate, both aligning torque increase ,while the increased amount of aligning torque produced by longitudinal deformation is bigger. The total aligning torque increases. With the further increase of cornering rate, the negative aligning torque produced by lateral deformation decreases and the positive aligning torque produced by longitudinal deformation keeps increasing, the total aligning torque increases. With the increase of cornering rate, the lateral deformation produces positive aligning torque and increases, the positive aligning torque produced by longitudinal deformation decreases, the total aligning torque has a little decrease when it reaches a certain value.