Study On The Mechanism Of Tire Abnormal Wear And Life Prediction

In recent years, as expressways are spread, driving at high and constant speed for a long time may be in usual way. Many new phenomenon and characters appear in the car tire wear and uneven wear. Tire wear is a systematic and complex dynamic behavior, so it shows academic and practical importance for suspension research and tire structure improvement. Based on PASSAT B5 by Volkswagen, dynamic wear characteristics of compound suspension—tire system are studied experimentally and theoretically.Main contents of the dissertation are given in the following:Tire of type 195/65R15 is tested for getting basic parameters. The parameters related to tire wear are all tested and studied. Processed experiment data were fitted and regressed in a least squares sense, which provide supports for building the tire model and simulating dynamic wear behavior.By using linearization and simplification method, a suspension-tire-ground system is built in the dynamic software ADAMS, which is a 5 freedom equivalent model due to twist beam axle character and FEM analysis. Then the kinematic and dynamic data related to tire wear is got through the simulation. Then system modes and their shapes are also analyzed. The model is verified through test. The dynamic model is required by the later simulation of tire wear.From classic tire brush model, an improved tire model with camber and combined slip is built. Based on it, a tire model that can calculate local forces in the lateral direction is set up by defining middle-plane and considering the changes of vertical pressure distribution, contact areas and effective radius etc. in tire cross section. The main factors that effect tire wear in the parameter analysis are found through calculating local force in the transverse direction.Based on experiment and tire model, a combined slip semi-empirical tire model is established. After referring to interacting surfaces tribology and confining the wear is only from the effects between tire tread and ground, the wear dissipation energy on the tire tread are calculated numerically. Then parameter analysis was processed. Combined with dynamic model in ADAMS, the transient data of mode frequency is coupled to tire model and numerical wear is compared. What the plots present through calculating are coincident with qualitative and theoretical results. Discussions are set to the effects of regionally characteristics to tire wear. Then criterion is given for diagnosing suspension problems by tire tread wear character graphics.With stability theory of dynamic system, integrated by randomicity of tire tread vibration and location on circle direction, the quantitative analysis of tire wear isstudied due to tread unstable vibration. Parameters of depressing tire wear are found theoretically.Through defining a base road sample and the proportion of composed sub-roads in the base sample, tire life is forecasted using tire wear linearly additive method. Then the method on forecasting tire life is built compressively and detailedly.The theoretical research provides design engineers with an efficient analysis tool in the development of new types of suspension systems and tire. The achievements obtained enrich the study of tire wear and uneven wear and give references for similar vehicles.