Finite element-based tire bead ring breaking force testing device and method

Abstract

The invention provides a tire bead ring breaking force testing device and method based on finite elements. The device comprises an annular mold and a steel wire ring section acting force extractor, a mold groove body is formed in the outer surface of the annular mold, and the mold groove body is used for assembling a steel wire ring; a loading surface is arranged on the inner surface of the annular mold and is used for enabling the annular mold to expand to apply breaking force to the steel wire ring; and the bead ring section acting force extractor is used for reading the acting force of the section of the bead ring and testing the breaking force of the bead ring. Acting force is applied to the steel wire ring through expansion of the annular mold, the use working condition of the steel wire ring is simulated, and the breaking force of the steel wire ring is judged more accurately; an annular expansion displacement field is applied to the bottom face of the annular mold, the displacement of the annular mold is restrained, and deviation of the annular mold is limited.

Description

Technical Field

[0001] The invention patent relates to the field of tire detection technology, and in particular to a tire wire ring breaking force testing device and method based on finite element. Background Art

[0002] The tire bead ring is the main load-bearing component of the tire. It is a circular ring with a cross section composed of multiple steel wires. The breaking force of the bead ring is an important indicator of product performance, but its testing is very difficult. Since the shape of the bead ring is a circular ring, the test must be done with the help of a mold. The breaking force test currently usually uses a combined fan-shaped mold to expand outward or two semicircular molds to stretch and break at both ends. However, both of these testing machines are limited by the size of the mold and cannot test bead rings of all sizes. Therefore, finite element simulation is a better way to solve this problem.

[0003] The difficulty of finite element simulation of wire rings lies in the application of loads. The structure of wire rings is complex, so it is impossible to directly apply surface forces such as force or pressure to the wire rings. The load can only be applied by applying body forces such as circumferential gravity.

[0004] However, the method of applying body force has the following defects: 1. In the tire, the inner layer of the steel wire of the wire ring is subjected to the pressure of the rim, while the remaining steel wires are subjected to the pressure of the inner layer of the steel wire, which is different from the form of action of body force; 2. Due to the complexity of the structure of the wire ring, the mass in the circumferential direction is not completely consistent, so applying body force will cause the position of the wire ring to shift, so the simulation of the breaking force of the wire ring must also rely on the mold. However, a new problem arises. If a combined fan-shaped mold is used, stress concentration will occur on both sides of a single mold, that is, at the two boundaries of the fan, which will affect the results of the analysis. If a ring-shaped closed mold is used, the modeling method of thermal expansion or rough expansion to break the wire ring can solve the problem of stress concentration, but it will cause the same problem as applying body force. The position of the entire model will shift due to uneven force. Summary of the invention

[0005] The purpose of the present invention is to overcome the deficiencies in the prior art and to provide a tire wire ring breaking force testing device and method based on finite element method.

[0006] To solve the problems of the prior art, in the first aspect, the present invention discloses a finite element-based tire wire ring breaking force testing device, comprising an annular mold and a wire ring cross-sectional force extractor, wherein the outer surface of the annular mold is provided with a mold groove body, and the mold groove body is used to assemble the wire ring; the inner surface of the annular mold is provided with a load surface, and the load surface is used to expand the annular mold to apply a breaking force to the wire ring; the wire ring cross-sectional force extractor is used to read the force of the wire ring cross-section and test the breaking force of the wire ring.

[0007] Furthermore, a restraining surface is provided on the side surface of the annular mold, and the restraining surface is used to limit the movement of the annular mold.

[0008] Furthermore, the wire ring cross-section force extractor is provided with a plurality of grid nodes, which include wire circumferential grid nodes and wire circular cross-section internal grid nodes; the wire circumferential grid nodes are evenly distributed on the circumference of the wire of the wire ring; the wire circular cross-section internal grid nodes are evenly distributed inside the cross-section of the wire.

[0009] Furthermore, the number of the grid nodes around the steel wire and the number of the grid nodes inside the circular cross-section of the steel wire are both 8.

[0010] Furthermore, it also includes cylindrical coordinate axes, wherein the Z axis is perpendicular to the plane where the annular mold is located, and the load surface applies a displacement load on the R axis to expand the annular mold.

[0011] Furthermore, a restraining line is provided on the outer side of the annular mold, and the restraining line is used to limit the movement of the annular mold.

[0012] Furthermore, it also includes a rectangular coordinate system, wherein the Z axis is perpendicular to the plane where the annular mold is located, and the load surface applies displacement fields in two perpendicular directions in the plane where the annular mold is located to expand the annular mold.

[0013] Furthermore, the displacement fields in two perpendicular directions are expressed as u x and u y ; ; ; In the formula u is the displacement of the wire ring expansion, X and Y are the displacement field parameters respectively.

[0014] In a second aspect, accordingly, the present invention further provides a tire bead ring breaking force testing method based on finite element method, comprising: Establish the corresponding closed annular mold according to the wire ring; The wire ring is placed in the groove of the annular die, and a displacement constraint perpendicular to the annular surface is applied to one side surface or the bottom edge of the side surface of the annular die; Applying a displacement load or displacement field of annular expansion to the annular die, so that the annular die expands outward until the wire ring is broken; The force acting on any cross section of the wire ring is extracted to obtain the breaking force of the wire ring.

[0015] The present invention has the beneficial effects: (1) Apply force to the wire ring through the expansion of the annular die to simulate the working conditions of the wire ring and more accurately judge the breaking force of the wire ring; (2) By applying a displacement field of annular expansion to the bottom surface of the annular mold, constraints are imposed on the displacement of the annular mold to limit the deviation of the annular mold. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the wire ring breaking force testing device based on finite element of the present invention under the cylindrical coordinate axis; Figure 2 It is a schematic diagram of the wire ring breaking force testing device based on finite element of the present invention under the rectangular coordinate axis; Figure 3 This is a schematic diagram of the annular mold groove structure of the present invention; Figure 4 It is a schematic diagram of the steel wire circular cross-section grid node of the present invention.

[0017] Reference numerals: 1. Wire ring; 2. Ring mold; 3. Mold slot; 4. Load surface; 5. Constraint surface; 6. Cylindrical coordinate axis; 7. Wire ring cross-section force extractor; 8. Displacement load; 9. Constraint line; 10. Cartesian coordinate system; 11. Displacement field; 21. Steel wire; 22. Grid nodes on the circumference of the steel wire; 23. Grid nodes inside the circular cross-section of the steel wire. DETAILED DESCRIPTION

[0018] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and cannot be used to limit the protection scope of the present invention.

[0019] Embodiment 1, as Figure 1 As shown, this embodiment introduces a tire wire ring breaking force testing device based on finite element, including: Traveler 1, the object of analysis; Steel wire 21, used to form the steel wire ring 1; The annular die 2 is a closed circular ring, which applies a load that causes the wire ring 1 to break. The mold groove body 3 is arranged on the outer surface of the annular mold 2, and is used to assemble the wire ring 1, and its shape matches the wire ring; A load surface 4 is provided on the inner surface of the annular mold 2; The restraining surface 5 is provided on one side of the annular mold 2 and is used to restrict the movement of the annular mold 2; Cylindrical coordinate axis 6, the coordinate axis of the model, the Z axis is perpendicular to the plane where the annular mold 2 is located; The wire ring cross-sectional force extractor 7 is used to extract the cross-sectional force of the wire ring.

[0020] In this embodiment, the contact between the steel wires 21 is impenetrable, the friction coefficient is an actual parameter, the contact between the steel wire ring 1 and the annular mold 2 is impenetrable, and the friction coefficient is zero. For the accuracy of the analysis, the grid nodes on the circular section of the steel wire 21 are: the radius of the steel wire is r, the center of the circle is (0,0), the node (0, r) on the circumference of the steel wire is used as the starting point, and 8 steel wire circular grid nodes 22 are evenly spaced; 8 steel wire circular cross-section internal grid nodes 23 are arranged inside the circular section, which are (-0.5r, 0.5r), (0.5r, 0.5r), (0.5r, -0.5r), (-0.5r, -0.5r), (-0.6r, 0), (0.6r, 0), (0, 0.6r) and (0, -0.6r). The grid length in the length direction of the steel wire 21 is 0.5r~5r, and the total number of grids of the steel wire ring 1 does not exceed 2 million and is not less than 500,000.

[0021] In this embodiment, the annular mold 2 is made of elastic material, and the elastic modulus is greater than the elastic modulus of the wire ring 1. A displacement load 8 on the R axis is applied to the load surface 4 to expand the annular mold 2, and the wire ring cross-section force extractor 7 reads the force on the wire ring cross-section to test the breaking force of the wire ring 2.

[0022] Embodiment 2 is based on the same inventive concept as embodiment 1. In this embodiment, the operation constraint on the annular mold 2 is achieved by applying a constraint line 9; the constraint line (9) is arranged on the outer side of the annular mold 2.

[0023] Embodiment 3 is based on the same inventive concept as Embodiment 1. In this embodiment, the displacement load applied to the load surface 4 is applied in a rectangular coordinate system 10. Specifically, a displacement field 11 in two perpendicular directions in the plane where the annular mold 2 is located is applied to the load surface 4. The formula is: (1) (2) In the formula u is the displacement of the wire ring expansion, u x and u y are the displacement fields in two perpendicular directions, X and Y are the displacement field parameters respectively.

[0024] Embodiment 4. This embodiment provides a method for testing the breaking force of a wire ring based on finite elements: for a specific wire ring, a corresponding closed annular mold is established, and the outer diameter of the mold groove is slightly smaller than the inner diameter of the wire ring. The wire ring is placed in the groove of the mold, and a displacement constraint perpendicular to the annular surface is applied to one side surface or the bottom edge of the side surface of the annular mold to constrain the movement of the model in a direction perpendicular to the displacement surface. A displacement field of annular expansion is applied to the bottom surface of the mold ring. The application of the displacement field has two functions: one is to make the annular mold expand outward, thereby breaking the wire ring to test the breaking force, and the other is to impose specific displacement constraints on the mold to limit the displacement of the mold. By extracting the force acting on any cross section of the wire ring, the force on the wire ring during the expansion of the mold can be obtained, thereby realizing the analysis of the breaking force of the wire ring by finite elements.

[0025] It should be noted that, in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. At the same time, in the description of the present invention, it should be understood that the orientation or position relationship indicated by the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like are based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the equipment or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention. And in the drawings of the present invention, the filling pattern is only to distinguish the layers, without any other limitation.

[0026] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A tire bead ring breaking force testing device based on finite element, characterized in that: The invention comprises an annular die (2) and a wire ring cross-sectional force extractor (7), wherein the outer surface of the annular die (2) is provided with a die groove body (3), and the die groove body (3) is used to assemble the wire ring (1); the inner surface of the annular die (2) is provided with a load surface (4), and the load surface (4) is used to expand the annular die (2) to exert a breaking force on the wire ring (1); the wire ring cross-sectional force extractor (7) is used to read the force on the cross section of the wire ring (1) and test the breaking force of the wire ring (1).

2. The finite element based tire bead ring breaking force testing device according to claim 1, characterized in that: A restraining surface (5) is provided on the side surface of the annular mold (2), and the restraining surface (5) is used to restrict the movement of the annular mold (2).

3. The finite element based tire bead ring breaking force testing device according to claim 1, characterized in that: The wire ring cross-sectional force extractor (7) is provided with a plurality of grid nodes, the grid nodes comprising wire circumferential grid nodes (22) and wire circular cross-sectional internal grid nodes (23); the wire circumferential grid nodes (22) are evenly distributed on the circumference of the wire (21) of the wire ring (1); the wire circular cross-sectional internal grid nodes (23) are evenly distributed inside the cross-section of the wire (21).

4. The finite element based tire bead ring breaking force testing device according to claim 3, characterized in that: The number of the steel wire circumferential grid nodes (22) and the number of the steel wire circular cross-section internal grid nodes (23) are both 8.

5. The finite element based tire bead ring breaking force testing device according to claim 1, characterized in that: It also includes cylindrical coordinate axes (6), wherein the Z axis is perpendicular to the plane where the annular mold (2) is located, and the load surface (4) applies a displacement load (8) on the R axis to expand the annular mold (2).

6. The finite element based tire bead ring breaking force testing device according to claim 1, characterized in that: A restraining line (9) is provided on the outer side of the annular mold (2), and the restraining line (9) is used to limit the movement of the annular mold (2).

7. The finite element based tire bead ring breaking force testing device according to claim 1, characterized in that: It also includes a rectangular coordinate system (10), wherein the Z axis is perpendicular to the plane where the annular mold (2) is located, and the load surface (4) applies displacement fields (11) in two perpendicular directions within the plane where the annular mold (2) is located, so that the annular mold 2 expands.

8. The finite element based tire bead ring breaking force testing device according to claim 7, characterized in that: The displacement fields in two perpendicular directions are expressed as u x and u y ; ； ； In the formula u is the displacement of the wire ring expansion, X and Y are the displacement field parameters respectively.

9. A finite element based tire bead ring breaking force test method, characterized in that: include: Establish the corresponding closed annular mold according to the wire ring; The wire ring is placed in the groove of the annular die, and a displacement constraint perpendicular to the annular surface is applied to one side surface or the bottom edge of the side surface of the annular die; Applying a displacement load or displacement field of annular expansion to the annular die, so that the annular die expands outward until the wire ring is broken; The force acting on any cross section of the wire ring is extracted to obtain the breaking force of the wire ring.

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