横滨的新轮胎设计方法学

Tire Design Methodology Based onSafety- Factor to Satisfy Tire Life轮 胎 设计 方法学 (主要以安全和使用寿命的因素考 虑 ),此方法同 样 适用与 载 重胎和 BUS胎Simulation Approach to Truck rubber part;The durability of rubber is evaluated by principal strain（ belt layer, carcass layer）The durability of FRR is evaluated by stress(Margin of safety)(Safety-Factor)Tire condition under operation:Tire profile growth & rubber aging due to heat build-up2. It is necessary to take tire profile growth & rubber aginginto consideration.The new design technology considering actual condition,for example,Tire Simulation Approach to Rubber Product (1)NEWGROWNSTRESS (Mpa)STRAIN (%)EbS - S CurveMILEAGE (km)O.D. GROWTH (mm)NEWGROWNThe Growth of Overall DiameterGrowth of tire ： Double Inflation Pressure Method 3. Introduction of the Safety Factor conceptTimeOLDNEWDangerous zone20Safety FactorMargin of Safety = Eb / (max)Eb = Breaking strain of rubber(max) = Maximum value of principal strain in tire parts4. Example: Tire size 11R22.5 Effect of tire profile on durabilityby Simulation Approach of FEMSimulation Approach to Rubber Product (2) Safety zone10Double Inflation Pressure Method Estimation ：Principal strain of belt edge fillerDeflectedDeflectedInflatedNew model Remodel InflatedDouble Inflation PressureTire size：11R22.5Room temperature：30Load ：21.4kNA.P. ：700kPa100km/h8h + 60km/h24h1set=29,120 km 6set = 174,720km(with shaving tread rubber)What happens to TB tires due to high heat and pressure ?Profile is changed.!NEWGROWN1SET 29,120km3SET 87,360km5SET 145,600km2SET 58,240km4SET 116,480km6SET 174,720kmGrowth of Overall Diameter !What happens to TB tires due to high heat and pressure ?O.D. growth begins in early stages of tire life.After that , it stabilizes.The growth of tire under operation TB tires have following change under operation.The Growth of Overall Diameter012345670 50000 100000 150000 200000mileage ( km )O.D. growth ( mm )TRANSITION STABILITYOverall Diameter ( mm )Mileage (km)Overall Diameter ： Growth O.D. (low pressure) New tire O.D. ( high pressure)The growth of tire under operation TIRE GROWTHOverall Diameter ( mm )Air Pressure ( kPa )Air Pressure vs. Overall Diameter (11R22.5) New (actual tire )Grown (actual tire)Outside Diameter ： Growth O.D.(Low Pressure) New Tire O.D. ( High Pressure)Section Width ： Almost non-changeAir Pressure vs. Section Width (11R22.5) Section Width ( mm )Air Pressure ( kPa )The growth of tire under operation New (actual tire )Grown (actual tire)NEWGROWN-aTire growth Rubber propertiesCalculation of principal strain in tire by FEMRubber propertiesMILEAGE (km)O.D. GROWTH (mm)GROWN-bGROWN-aNEWTB tires have following change under operationEstimation ： Margin of Safety The Growth Of Overall Diameter S - S Curve FEM Model ：NEW TIRE 1st inflatedProcedure of NEW TIRE simulationNEW TIRE MODEL INFLATED LOADED ANALYSISActual (NEW)SIZE：11R22.5 RIM：22.57.50A.P 700KPaInflated calculation： 1 timeSimulation of NEW TIRE ( FEM )Inflated calculation & Inflated calculation ( 2 times )Double Inflation Pressure Method !2nd-inflatedActual (GROWN)RIM：22.57.50A.P 700KPa1st-inflated profile=REMODELSimulation of GROWN TIRE ( FEM )Procedure of GROWN TIRE simulationNEW TIRE MODEL INFLATED INFLATED LOADED ANALYSISDouble Inflation Pressure MethodActual (GROWN)Calculated profile corresponds to actual profile.Air Pressure vs. Overall DiameterOverall Diameter ( mm )Air Pressure vs. Tire Overall DiameterNew (actual)Grown (actual)New(calculation)Grown(calculation)NEWGROWNAir Pressure (KPa)Example : Effect of tire profile on durability by FEMEstimation ：Principal strain of belt edge fillerLoadedLoadedInflatedNew model Remodel InflatedDouble Inflation PressureMODEL AMODEL BMODEL CExample : Effect of tire profile on durability by FEMOutside surfaceBody ply line SIZE : 11R22.5New (loaded) Grown (loaded)Contour of strainContact areaContact areaNEWGROWNStrainRotationAir pressure Principal strainTire growth Principal strainExample ： Principal strain of belt edge by FEMMargin of Safety = Eb / (max)Which is the best ? = “ MODEL B ”New design technology applying simulation approach.Example :Effect of tire profile on durability by FEMConclusions1. Double Inflation Pressure Method was developed as prediction of tire profile under operation.2. Safety Factor (Margin of Safety)was introduced,which means not only judging durability by principal strain amount itself,but also applying material property (Eb) of tire.3. New tir