Method for generating tire model

Patent metadata

Field	Value
Publication number	US-9481217-B2
Application number	US-201313756608-A
Country	US
Kind code	B2
Filing date	Feb 1, 2013
Priority date	May 11, 2012
Publication date	Nov 1, 2016
Grant date	Nov 1, 2016

Abstract

In a computerized method for generating a finite element model of a pneumatic tire provided in the tread portion with a zero-degree band, a 2D tire model is firstly generated based on the finished tire shape in a tire vulcanization mold, where the 2D tire model includes a 2D model of a band ply. Secondary, a residual stress is computed and defined on each element of the band ply model. Then, a deformation calculation is made on the 2D tire model to obtain the deformed 2D tire model. Finally, a 3D tire model is generated by duplicating the 2D tire model around the tire rotational axis.

First claim

The invention claimed is:

1. A computerized method for generating a finite element model of a pneumatic tire manufactured through
a step of building a raw tire provided in a tread portion with a band ply composed of a band cord having a cord angle of not more than 5 degrees with respect to the tire circumferential direction, and
a step of vulcanizing the raw tire in a vulcanization mold,
the method comprising
a step in which, based on a cross-sectional shape of the tire in the vulcanization mold, a tire model which is a two-dimensional finite element model of the tire is generated, wherein the tire model includes a band ply model of the band ply made up of two-dimensional elements,
a step in which a deformation calculation is made on the two-dimensional tire model on which a condition of a tire pressure is defined,
a residual stress defining step in which a residual stress Si caused by the vulcanizing step is computed by the following manner (III) and defined on each of the two-dimensional elements of the band ply model of the two-dimensional tire model,
a step in which a deformation calculation is made on the two-dimensional tire model to obtain the deformed two-dimensional tire model, and
a step in which node points of the deformed two-dimensional tire model are circumferentially duplicated around the tire rotational axis at intervals of a small angle, and the node points are mutually linked to generate a three-dimensional tire model,

(III) the elements of the band ply model are grouped into a plurality of groups each consisting of axially abutting elements, and, for each of the groups, the residual stress Si is computed collectively by the following expression
Si=E ×{( Ra−ra )/ ra}×α

wherein
E: the Young's modulus of the band cord,
Ra: the mean value of the outside diameters of the elements belonging to the group,
ra: the mean value of the outside diameters of the elements belonging to the group before vulcanization,
α: a coefficient,
wherein said groups include a central group consisting of the elements existing in a central region of the tread portion, and two lateral groups consisting of the elements existing in shoulder regions of the tread portion, and
wherein the residual stress Si for the band ply elements belonging to the central group is more than the residual stress Si for the band ply elements belonging to the two lateral groups.

2. A computerized method for generating a finite element model of a pneumatic tire manufactured through a step of building a raw tire provided in a tread portion with a band ply composed of a band cord having a cord angle of not more than 5 degrees with respect to the tire circumferential direction, and a step of vulcanizing the raw tire in a vulcanization mold, the method comprising:
a step in which, based on a cross-sectional shape of the tire in the vulcanization mold, a tire model which is a two-dimensional finite element model of the tire is generated, wherein the tire model includes a band ply model of the band ply made up of two-dimensional elements,
a step in which a deformation calculation is made on the two-dimensional tire model on which a condition of a tire pressure is defined,
a residual stress defining step in which a residual stress Si caused by the vulcanizing step is computed by the following manner (III) and is defined on each of the two-dimensional elements of the band ply model of the two-dimensional tire model,
a step in which a deformation calculation is made on the two-dimensional tire model to obtain the deformed two-dimensional tire model, and
a step in which node points of the deformed two-dimensional tire model are circumferentially duplicated around the tire rotational axis at intervals of a small angle, and the node points are mutually linked to generate a three-dimensional tire model,
(III) the elements of the band ply model are grouped into a plurality of groups each consisting of axially abutting elements, and, for each of the groups, the residual stress Si is computed collectively by the following expression
Si=E ×{( Ra−ra )/ ra}×α

wherein
E: the Young's modulus of the band cord,
Ra: the mean value of the outside diameters of the elements belonging to the group,
ra: the mean value of the outside diameters of the elements belonging to the group before vulcanization,
α: a coefficient,
wherein said groups include a central group consisting of the elements existing in a central region of the tread portion, and two lateral groups consisting of the elements existing in shoulder regions of the tread portion,
wherein the residual stress Si for the band ply elements belonging to the central group is more than the residual stress Si for the band ply elements belonging to the two lateral groups, and,
wherein the axial width of the central group is in a range of from 30% to 60% of the axial width of the band ply model.

Assignees

• Sumitomo Rubber Ind

Inventors

• Iwasaki Naoaki

Classifications

• B60C99/006 Primary

  Computer aided tyre design or simulation · CPC title

• G06F30/15

  Vehicle, aircraft or watercraft design · CPC title

• G06F30/23 Primary

  using finite element methods [FEM] or finite difference methods [FDM] · CPC title

• G06F17/5095

  Physics · mapped topic

• G06F17/5018

  Physics · mapped topic