Theoretical And Experimental Research On Controllable Design For Ground Performance Of Radial Tire

Tire is one of the most important components of vehicle,which supports the full weight of vehicle and plays a significant role in transferring forces and moments.Footprints and contact pressure distributions of tire can directly affect the maneuverability,safety,comfort and other characteristics of vehicles,and it has been a hot area of researches in vehicle engineering industry.Ground performances of tire are closely related to the designs of inner profile,outward contour and layout of the materials.OEMs generally specify the tire footprint and contact pressure distribution for a vehicle.In order to obtain the optimal footprint and contact pressure distribution,engineers often have to make many trial tires and do lots of experiments,and repeatedly modify tire structures.This is attributed to the restriction that there is not design theory and method for active controlling tire ground performances.Therefore,the research on design theory and method for active controlling tire ground performances has theoretical and practical significances.In this work,tire carcass profiles are studied firstly.Structural parameters of tread are set as driving variables,and the characteristics of belt and bead are considered.The integral design method of tire structure is established by combining inner and outer profiles.The design theories of controlling ground performances for static loaded and steady rolling tires are proposed,and the effects of ground performances on tire forces and moments are revealed.The main contents of this paper are as follows.Firstly,the inflated and loaded carcass profiles of radial tires are studied.Based on the inextensible membrane model of tire carcass,as well as the minimum energy principle and variational method,we establish three equilibrium carcass contour theories for tire without belt,tire with flat belt and tire with curved belt.Restriction width of tire carcass by the belt is defined.According to the limitation standards,the design method of inflated carcass profile is established.Based on the single carcass model,the theory and calculation method of loaded carcass profile are built.The se theories are verified by experiments and numerical simulation,and the effects of structural parameters on carcass contour are also analyzed.Secondly,the design theory of controlling ground performances of static loaded tire is studied.Based on the inflated carcass profile,the tread contour is introduced,and the design theory of tire whole structure is proposed by combining inn er and outer tire profiles.Two parameters,extra shoulder thickness and shoulder compression factor,are defined,and the effects of shoulder deformation on tire footprint are quantized.A theory of controlling ground performances of static loaded tire is established by coupling with inflated and loaded tire carcass profiles,considering the rigid displacement of belt.This theory is verified by using experiment and FEM.Moreover,the effects of inflation pressure and tread rubber modulus on contact characteristics of tire are examined.Thirdly,the design theory of controlling ground performances of steady rolling tire is studied.By introducing density function and angular velocity,the steady equilibrium carcass profile theory and method are proposed.Th e equivalent inflation pressure method are used to investigate the effects of centrifugal force on the deformations of tread and belt.Based on the design theory for controlling ground performances of static loaded tire,the theory for controlling ground performances of steady rolling tire is built considering the tire deformations caused by rolling,and the numerical results has verified the accuracy of th is theory.Finally,the forces and moments of tires with typical ground performances are studied.Lots of experimental tests are carried out to measure the tire contact characteristics,from which the relationship between the footprint and normal pressure distribution are revealed.The friction characteristic of rubber material is reasonably introduced into FEA model.The forces and moments of tires designed according to the theory introduced before are analyzed,and the effects of typical ground performances on tire dynamics performances are also examined.