Study On Tire High Frequency Dynamic Properties Based On Brush Model To Road Unevenness

The pneumatic tire is of great importance to vehicle dynamic simulation as thetire forms a vital component of a road vehicle since it interacts with the road inorder to produce the forces necessary for support and movement of the vehicle. Athorough understanding of the behavior of pneumatic tire is an essential aspect ofanalyzing the dynamics of vehicles.As we consider the tire in Vehicle–Tire–Road system, the tire takes contactswith axle, road and air. When neglecting the effects of aerodynamics, the tirecontact only with axel and road. For the purpose of this study is in-plane dynamics,all lateral tire movement is not considered. The inputs of axle to the tire are forwardvelocity, traction and braking torque and vertical load. The road provides the tiretwo main effects: friction and unevenness.The objective of the study is to establish a tire model that could calculate tiredynamic properties when rolling over road obstacles. Two methods are used tostudy tire dynamic properties: rigid ring model and flexible ring model. Flexiblemodel which can effectively deal with tire dynamics however, cost a lot of time inprocessing and unable to be blocked in on-time Vehicle dynamic simulation. Bycontrast, the tire rigid ring model has rather simple model system and the precisioncan still be able to meet the requirement.Typical structure of the radial tire is improvement of the belt stiffness. Thestiff belt is attached to relatively soft tread. The tire rigid ring model developed inthis article is based on the assumption that the tire belt remains circular as tirevibrates. Therefore, the tire belt is assumed to be a rotating rigid ring and connectedto the rim with spring-damper system which stands for tire sidewall andcompressed air. Carcass model is to describe the relationship between the ring andrim. The forces generated in the contact patch is still calculated by contact model.The rigid ring model is the sum of the carcass model and contact model. Thedynamic parameters of compact tire rigid ring model should have a goodextrapolation and distinct tire are differentiated by varying parameter spaces.Chapter 2 introduced tire contact model and enveloping model. As a basis oftire rigid ring model, tire steady state, transient and enveloping properties aredescribed and modeled. Tire steady state characteristics are analyzed withtheoretical brush model UniTire semi-empirical model. Tire transient characteristicis analyzed theoretically by brush model assumption and frequency responsefunction of the longitudinal force due to the slip variation and vertical loadvariation is calculated. Based on the theoretical result, a transient empirical modelis developed. Tire itself is elastic and filter road input when rolling over roadobstacle. Tire rigid ring model cannot use directly to the road input as the rigid ringmodel is a single point contact model. Tire enveloping model is used to separate theentire process into two independent parts and provide a plug-in interface to therigid ring modelChapter 3 is the main part of this article as the rigid ring model is developed inthis chapter. Tire carcass model is developed and connected with contact model bya tread vertical spring.Experimental validation is conducted in chapter 4. Tire parameters areidentified first and the simulation results and the experiment data is compared.Chapter 5 is the final conclusions and recommendations.