Method and apparatus for predicting belt separation failure in aging tires by computer simulation

• US 20040230412A1
• Filed: 05/14/2003
• Published: 11/18/2004
• Est. Priority Date: 05/14/2003
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Hsu, Sheng-Yuan, Morman, Kenneth Nero Jr., Rakowska, Joanna
• Granted Patent: US 7,469,200 B2
• Time in Patent Office: Days
• US Class Current: 703/8
• CPC Class Codes: B60C 11/00 Tyre tread bands; Tread patterns; Anti-skid inserts
• CPC Class Codes: B60C 19/00 Tyre parts or constructions not otherwise provided for
• CPC Class Codes: B60C 9/20 built-up from rubberised plies each having all cords arranged substantially parallel
• CPC Class Codes: B60C 99/006 Computer aided tyre design or simulation
• CPC Class Codes: G06F 30/15 Vehicle, aircraft or watercraft design
• CPC Class Codes: G06F 30/23 using finite element methods [FEM] or finite difference methods [FDM]

Abstract

A method has been invented for predicting the build-up of heat, material aging, and subsequent belt separation failure in rolling steel-belted pneumatic tires (20). The procedure employs finite element analysis and a new fatigue crack propagation model that takes output generated by the finite element model to predict distance and time to belt separation in the tire. The finite element model uses input information on tire load, speed and inflation pressure (12) to calculate the temperature and energy release rate at the corresponding tips of the fatigue crack to generate four-dimensional response surfaces of crack-tip energy release rate as a function of crack length, crack-tip circumferential angular position, and crack-tip temperature. The fatigue crack propagation model samples the response surface and is numerically integrated to predict distance and/or time to belt separation failure (30).

Claims

1. A method of determining belt separation in a tire comprising:

entering a plurality of tire characteristics into a model;

entering a plurality of operating characteristics into the model;

predicting crack growth within the tire in response to the tire characteristics and operating characteristics; and

generating a distance to separation in response to said crack growth rate and said operating characteristics.

2. A method as recited in claim 1 further comprising generating a time to separation in response to said crack growth rate and said operating characteristics.

3. A method as recited in claim 1 wherein predicting crack growth comprises determining an energy release rate.

4. A method as recited in claim 1 wherein the operating characteristics include load.

5. A method as recited in claim 1 wherein the operating characteristics include speed.

6. A method as recited in claim 1 wherein the operating characteristics include tire pressure.

7. A method as recited in claim 1 wherein the tire construction features include mold shape.

8. A method as recited in claim 1 wherein the tire construction features include tread properties.

9. A method as recited in claim 1 wherein the tire construction features include tire materials

10. A method of determining belt separation in a tire comprising:

forming a finite element tire model in response to a tire construction features;

applying pressure loading to the model;

applying radial loading to the model;

applying a rotational speed to the model;

determining an energy release rate at a fatigue crack tip;

determining a path of fatigue propagation in response to the energy release; and

determining a time or distance until tread failure in response to the fatigue propagation.

11. A method as recited in claim 10 wherein the tire construction features include mold shape.

12. A method as recited in claim 10 wherein the tire construction features include tread properties.

13. A method as recited in claim 10 wherein the tire construction features include tire materials.

14. A method as recited in claim 10 wherein the operating characteristics include load.

15. A method as recited in claim 10 wherein the operating characteristics include speed.

16. A method as recited in claim 10 wherein the operating characteristics include tire pressure.

17. A system for determining belt separation comprising:

an input device for entering a plurality of tire characteristics into a model and entering a plurality of operating characteristics;

a display; and

a controller programmed to predict crack growth within the tire in response to the tire characteristics and operating characteristics and generate a distance to separation on said display in response to said crack growth rate and said operating characteristics.

18. A system as recited in claim 17 wherein the tire characteristics include mold shape.

19. A system as recited in claim 17 wherein the tire characteristics tread properties.

20. A system as recited in claim 17 wherein the tire characteristics tire materials.