1、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 & Bus Tire DesignKazuyuki Kabe The Yokohama Rubber CO.,LTD,14th China Tire Technology Conference,2006.9.20,Contents目录,1. Introduction 简介 2. Radial Tire Constructi
2、on , Function & Characteristics特征 3. FRR (Characteristics of Cord & Rubber) 4. Introduction of Safety-Factors for rubber products 5. Simulation Approach to Durability of Rubber Product 6. Numerical Example: Truck and Bus Tire 7. Conclusions,Introduction,Purpose of This Paper : Proposal for the new d
3、esign method considering actual condition of rubber products, for example a tire, 12R22.5,Radial Tire Construction,Bead Core,Basic function required of a tire 1) Load - carrying capacity 2) Transmission of driving and breaking torque 3) Cushioning ability 4) Road - holding abilityOther requirement A
4、nd also Information center of a vehicle,Characteristics of Tire,rubber,cord,large deformation &,large strain,incompressibility,material nonlinearity,composite structure,viscoelasitcity,rolling contact,Characteristics of Tire,Rubber model in tire part Heterogeneous异型 structure model for carbon black
5、filed rubber,Quasi-glassy state (C phase),Liquid state (A phase),Cross linked rubber molecules(B phase),Carbon black,Interaction betweenC phases,Reinforcemant of Elastomers:(edited by Gerard Kraus, Interscience Publishers, N.Y., 1965) Section 6:Microscopy in the Study of Elastomer Reinforcement by P
6、igment Fillers(by William M. Hess),Rubber in tire part by MicroscopyHeterogeneous structure for carbon black filed rubber,Mechanical properties of cord & rubber,From the above table Modulus of cord Modulus of rubberBreaking strain of cord Breaking strain of rubber,Introduction of Safety-Factors for
7、rubber products,FRR(cord);,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-up 2. It i
8、s necessary to take tire profile growth & rubber aging into consideration.,The new design technology considering actual condition,for example,Tire,Simulation Approach to Rubber Product (1),3. Introduction of the Safety Factor concept,Time,OLD,NEW,Dangerous zone,20,Safety Factor,Margin of Safety = Eb
9、 / (max)Eb = Breaking strain of rubber (max) = Maximum value of principal strain in tire parts,Simulation Approach to Rubber Product (2),Safety zone,10,Double Inflation Pressure Method,Estimation ：Principal strain of belt edge filler,Deflected,Deflected,Inflated,New model,Remodel,Inflated,Double Inf
10、lation Pressure,Tire size：11R22.5Room temperature：30 Load ：21.4kN A.P. ：700kPa 100km/h8h + 60km/h24h 1set=29,120 km 6set = 174,720km (with shaving tread rubber),What happens to TB tires due to high heat and pressure ?,Profile is changed.!,Growth of Overall Diameter !,What happens to TB tires due to
11、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 Diameter,0,1,2,3,4,5,6,7,0,50000,100000,150000,200000,mileage ( km ),O.D. growth ( mm ),TRANS
12、ITION,STABILITY,Overall Diameter ( mm ),Mileage (km), Overall Diameter ： Growth O.D. (low pressure) New tire O.D. ( high pressure),The growth of tire under operation, Outside Diameter ： Growth O.D.(Low Pressure) New Tire O.D. ( High Pressure) Section Width ： Almost non-change,The growth of tire unde
13、r operation,NEW GROWN-a,Tire growth,Rubber properties,Calculation of principal strain in tire by FEM,Rubber properties,MILEAGE (km),O.D. GROWTH (mm),GROWN-b,GROWN-a,NEW,TB tires have following change under operation,Estimation ： Margin of Safety,The Growth Of Overall Diameter,S - S Curve,FEM Model ：
14、NEW TIRE,1st inflated,Procedure of NEW TIRE simulation NEW TIRE MODEL INFLATED LOADED ANALYSIS,SIZE：11R22.5,RIM：22.57.50 A.P 700KPa,Inflated calculation： 1 time,Simulation of NEW TIRE ( FEM ),Inflated calculation & Inflated calculation ( 2 times ) Double Inflation Pressure Method !,2nd-inflated,RIM：
15、22.57.50 A.P 700KPa,1st-inflated profile =REMODEL,Simulation of GROWN TIRE ( FEM ),Procedure of GROWN TIRE simulation NEW TIRE MODEL INFLATED INFLATED LOADED ANALYSIS,Double Inflation Pressure Method,Calculated profile corresponds to actual profile.,Air Pressure vs. Overall Diameter,Example : Effect
16、 of tire profile on durability by FEM,Estimation ：Principal strain of belt edge filler,Loaded,Loaded,Inflated,New model,Remodel,Inflated,Double Inflation Pressure,Example : Effect of tire profile on durability by FEM,Outside surface,Body ply line,SIZE : 11R22.5,New (loaded),Grown (loaded), Contour o
17、f strain,Contact area,Example ： Principal strain of belt edge by FEM,Margin of Safety = Eb / (max),Which is the best ? = “ MODEL B ” New design technology applying simulation approach.,Example :Effect of tire profile on durability by FEM,Conclusions,1. Double Inflation Pressure Method was developed
18、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 tire design technology was developed applying the above concept through whole tire life.4. This simulation approachcan be applied to other rubber products.,Thank you for your attentions !,
