JP2013044718A - Simulation method and simulation apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To highly accurately implement a tire behavior analysis using a numerical analysis approach such as a finite element method (FEM) in a short time, even if a tire skeleton member or a reinforcement member such as a ply and a belt has a number of layers.SOLUTION: A simulation method includes a step A of defining a skeleton member or a reinforcement member of a tire 1 as a film element or a shell element when generating a tire model. The step A includes: a step A1 of defining the at least two layers of skeleton members or reinforcement members as the one layer of film element or shell element in an area where the plurality of skeleton members or reinforcement members are overlapped with each other; and a step A2 of performing multiple definition for the one layer of film element or shell element.

Description

  The present invention relates to a simulation method and a simulation apparatus.

  Conventionally, tire behavior was analyzed by measuring tires that were actually designed and manufactured, and using performance test results obtained by mounting tires that were actually designed and manufactured on automobiles. It was.

  However, in recent years, with the development of the computer (computer device) environment, it has become possible to realize the analysis of the behavior of the tire by simulation on the computer.

  As a method for analyzing tire behavior by simulation, a numerical analysis method such as a finite element method (FEM) is mainly known.

  FEM is a technique for analyzing the behavior of a target structure using a model generated by dividing the target structure into a finite number of elements on a computer device. The target structure is divided into a finite number of elements. (That is, performing mesh division or element division on the target structure) is necessary.

  In order to simulate the tire behavior with high prediction accuracy, the tire model (consisting of numerical data) generated by dividing the tire into a finite number of elements can be used in the same way as the actual tire shape. It is important to generate.

  Here, when generating a tire model using a numerical analysis method such as the finite element method, the skeleton member and the reinforcing member of the tire such as a ply and a belt are set to the physical property values (rigidity and anisotropy) of the member. A method of defining as a membrane element or a shell element having is known (for example, Chapter 9 of Reference 1).

  The membrane element or the shell element is defined by a line in the two-dimensional model (2D model), and is defined by a plane in the three-dimensional model (3D model).

Composite material engineering, edited by Hayashi Hayashi, Nikka Giren Publisher, 1971, ISBN 4-8171-9008-6

Japanese Patent No. 4533056 JP 2006-282078 A JP 2002-82998 A

  However, as described above, when a skeleton member or a reinforcing member portion of a tire such as a ply or a belt is defined as a membrane element or a shell element, if the number of layers of the skeleton member or the reinforcing member is large, the number of elements increases. As a result, there is a problem that the calculation cost is high (calculation time is required).

  In particular, in the three-dimensional model, even when the elements for one layer are increased, the influence on the calculation time is significant.

  Therefore, the present invention has been made in view of the above-mentioned problems, and numerical values such as the finite element method (FEM) can be used even when there are many layers of a skeleton member or a reinforcing member portion of a tire such as a ply or a belt. It is an object of the present invention to provide a simulation method and a simulation apparatus that enable a tire behavior analysis using an analysis technique to be performed with high accuracy in a short time.

  A first feature of the present invention is a simulation method using a tire model generated by dividing a tire into a finite number of elements, and when generating the tire model, a skeleton member or a reinforcing member of the tire Is defined as a membrane element or a shell element, and the step A includes at least two layers of the skeletal member or the reinforcing member in a region where a plurality of the skeleton members or the reinforcing members overlap. The gist of the present invention is to include a process A1 defined as an element or a shell element and a process A2 of performing overloading on the one-layer film element or shell element.

  In the first feature of the present invention, in the step A, the inclined belt layer of the tire that is the reinforcing member may be defined as a membrane element or a shell element.

  In the first feature of the present invention, in the step A, a belt reinforcing layer of the tire that is the reinforcing member may be defined as a membrane element or a shell element.

  In the first feature of the present invention, in the step A, the carcass ply layer of the tire that is the frame member may be defined as a membrane element or a shell element.

  The gist of the second feature of the present invention is that it is a simulation device for executing the simulation method according to the first feature of the present invention described above.

  As described above, according to the present invention, a tire using a numerical analysis method such as a finite element method (FEM) even when there are many layers of a skeleton member or a reinforcing member portion of a tire such as a ply or a belt. Thus, it is possible to provide a simulation method and a simulation apparatus that can analyze the behavior of the above in a short time with high accuracy.

It is a flowchart shown about the simulation method which concerns on the 1st Embodiment of this invention. It is sectional drawing which shows an example of the tire of the analysis object used with the simulation method which concerns on the 1st Embodiment of this invention. It is a perspective view which shows an example of the tire of the analysis object used with the simulation method which concerns on the 1st Embodiment of this invention. It is the schematic of the computer apparatus for performing the simulation method which concerns on the 1st Embodiment of this invention. It is a figure for demonstrating the comparative evaluation test done using the prior art example and Examples 1-3. It is a figure for demonstrating the comparative evaluation test done using the prior art example and Examples 1-3.

(Simulation method according to the first embodiment of the present invention)
A simulation method according to the first embodiment of the present invention will be described with reference to FIGS. Specifically, the simulation method according to the present embodiment analyzes the behavior and performance of a tire (for example, a pneumatic tire) used in an automobile or the like using a finite element method.

  As shown in FIG. 1, in step S101, design information (for example, tire shape, structure, material, etc.) of the tire 1 to be analyzed is input. Here, the analysis target tire 1 may be a newly designed tire 1 or an existing tire 1.

  FIG. 2 shows a cross-sectional view of the tire 1 to be analyzed, and FIG. 3 shows a perspective view of the tire 1 to be analyzed.

  As shown in FIG. 2, the analysis target tire 1 includes two carcass ply layers 30A and 30B and two inclined belt layers (crossing layers) 20A provided on the outer layer side of the carcass ply layers 30A and 30B. And 20B, and two belt reinforcing layers (so-called spiral belt layers) 10A and 10B provided on the outer layer side of the inclined belt layers 20A and 20B.

  Here, the inclined belt layers 20A and 20B are two belt layers in which cords arranged at the same inclination angle with respect to the tire equatorial plane intersect each other, and the belt reinforcing layers 10A and 10B are tires. Two belt layers in the circumferential direction are arranged at an angle of approximately 0 degrees with respect to the equator plane.

  In step S102, a tire model including a finite number of elements is generated by performing element division corresponding to the finite element method (that is, mesh division) on the tire 1 to be analyzed.

  Such a tire model is digitized into a format that can be handled by a computer device.

  Here, when generating the tire model described above (that is, when dividing the mesh), the skeleton member or the reinforcing member of the tire 1 to be analyzed is defined as a membrane element or a shell element.

  For example, as shown in FIG. 2, belt reinforcing layers 10A and 10B and inclined belt layers 20A and 20B that are reinforcing members of the tire 1 to be analyzed are defined as membrane elements or shell elements, and the skeleton member of the tire 1 to be analyzed The carcass ply layers 30A and 30B are defined as membrane elements or shell elements.

  When generating the above tire model (that is, when dividing the mesh), in a region where a plurality of skeleton members or reinforcement members overlap, at least two skeleton members or reinforcement members are formed as one layer of membrane elements or shell elements. Define as

  For example, as shown in FIG. 2, in the region where the belt reinforcement layers 10A and 10B, which are the reinforcement members of the tire 1 to be analyzed, overlap, the two belt reinforcement layers 10A and 10B are used as a single layer membrane element or shell element 10C. It may be defined.

  Alternatively, in the region where the inclined belt layers 20A and 20B, which are the reinforcing members of the tire 1 to be analyzed, overlap, the two inclined belt layers 20A and 20B are defined as a single membrane element or shell element 20C (not shown). May be.

  Alternatively, in the region where the carcass ply layers 30A and 30B, which are the skeleton members of the tire 1 to be analyzed, overlap, the two carcass ply layers 30A and 30B are defined as one film element or shell element 30C (not shown). May be.

  When generating the above tire model (that is, when dividing the mesh), three or more belt reinforcing layers, inclined belt layers, and carcass ply layers may be defined as one layer of membrane elements or shell elements. .

  For each membrane element or shell element defined as one layer, each of physical property values (values indicating rigidity and anisotropy) of at least two layers of the skeleton member or the reinforcing member is input, that is, the membrane element. Alternatively, “overload” is performed on the shell element.

  For example, when two layers of the belt reinforcing layers 10A and 10B are defined as one layer of membrane element or shell element 10C, the physical property values and belt reinforcement of the belt reinforcing layer 10A with respect to the single layer of membrane element or shell element 10C. The physical property value of the layer 10B is input.

  Alternatively, when the two inclined belt layers 20A and 20B are defined as a single membrane element or shell element 20C, the physical property values of the inclined belt layer 20A and the inclined belt with respect to the single membrane element or shell element 20C. The physical property value of the layer 20B is input.

  Alternatively, when the two layers of the carcass ply layers 30A and 30B are defined as one layer of the membrane element or shell element 30C, the physical property values and the carcass ply of the carcass ply layer 30A with respect to the one layer of membrane element or shell element 30C. The physical property value of the layer 30B is input.

  Accordingly, such a one-layer membrane element or shell element is apparently a one-layer membrane element or shell element, but such a one-layer membrane element or shell element includes at least two skeleton members or reinforcing members. The physical property value of is defined.

  Here, even if the physical property values of at least two layers of the skeleton member or the reinforcing member are defined in such one layer of membrane element or shell element, the number of elements is one layer, so the calculation time is 1 The cost for the layer will be sufficient.

  It is assumed that the decrease in calculation accuracy that is a concern with this method is very small. This is because the distance between the layers of a plurality of skeleton members or reinforcing members that are arranged in an overlapping manner in the tire 1 to be analyzed is generally very small, about 0.5 to 1.0 mm. This is because the deformation of the entire tire can be expressed generally. Even in the comparative evaluation test described later, it can be seen that the decrease in calculation accuracy is small.

  At locations where the number of layers of the skeleton member or reinforcing member of the tire decreases from the middle (location where the number of layers decreases from two layers to one layer), the physical property values for the reduced number of layers (one layer) can be defined. That's fine.

  By generating such a tire model, it becomes possible to analyze the skeleton member or the reinforcing member of the tire 1 with high accuracy in a short time without increasing the calculation time.

  On the other hand, in the simulation methods described in Patent Documents 1 to 3, when two belt layers are defined as one film element or shell element, the one layer film element or shell element is used. One physical property value is input.

  Here, as in the above-mentioned Patent Documents 1 to 3, two belt layers are defined as one film element or shell element, and one physical property value is assigned to the one film element or shell element. When inputting, the tensile rigidity and the compression rigidity of the two belt layers are defined as the uniaxial rigidity.

  In this simulation method, for example, “deformation contracting in the width direction when extending in the circumferential direction (pantograph deformation)”, which is a deformation peculiar to two layers inclined and intersecting like a belt layer of a tire, cannot be expressed.

  On the other hand, the simulation method according to the present invention expresses the above-described deformation because the physical property value and rigidity itself as the anisotropy in the inclined two belt layers are overloaded. It is possible to obtain a result with high calculation accuracy.

  As shown in FIG. 2, the tire model generated as a two-dimensional model is developed 360 degrees in a ring shape to obtain a three-dimensional model tire model as shown in FIG.

  In step S103, a road surface is set, that is, a road surface model is generated and a road surface state is input.

  For example, as a road surface state, for example, a friction coefficient corresponding to dry (DRY), wet (WET), ice, snow, non-paving, or the like is input.

  In step S104, boundary conditions are set. Such boundary conditions are necessary when analyzing a tire model, and are various conditions given to the tire model.

  For example, the internal pressure, vertical load, rotational displacement (speed, force, etc.), straight displacement (speed, force, etc.), etc. to be applied to the tire model are set as boundary conditions.

  In step S105, a predetermined calculation is performed using the numerical model set in steps S101 to S104 described above, and the behavior and performance of the tire 1 to be analyzed are analyzed.

  As shown in FIG. 4, the simulation device that executes the simulation method according to the present embodiment may be realized by a computer device or may be implemented by a software module executed by a processor of the computer device. However, it may be implemented by a combination of both.

  The software module includes a RAM (Random Access Memory), a flash memory, a ROM (Read Only Memory), an EPROM (Erasable Programmable ROM), an EEPROM (Electronically Erasable and Programmable ROM, a Hard Disk, a Registered ROM, a Hard Disk Alternatively, it may be provided in a storage medium of an arbitrary format such as a CD-ROM.

  According to the simulation method according to the first embodiment of the present invention, modeling is performed with a smaller number of layers for the skeleton member and the reinforcing member of the tire 1 to be analyzed without affecting the calculation accuracy. The calculation time can be shortened.

(Comparative evaluation test)
Next, in order to further clarify the effects of the present invention, a comparative evaluation test performed using the simulation method according to the conventional example and the simulation methods according to Examples 1 to 3 will be described. In addition, this invention is not limited at all by these examples.

  In this test, an internal pressure of 210 kPa is applied to a tire for a passenger car having a tire size of “195 / 65R15”, a vertical load of 4 kPa is applied at a camber angle of 0 ° and a slip angle of 0 °, and the coefficient of friction with the road surface is set to “1”. 0.0 ”, and the contact pressure distribution on the tire contact surface in the state of performing the pseudo rolling rotation analysis at a speed of 50 km / h, the measurement result in the actual tire, and the simulation according to the conventional example and Examples 1 to 3 The calculation results using the method were compared.

As shown in FIG. 5 and FIG. 6, the calculation results are obtained by comparing each contact position between the contact pressure measured in an actual tire and the contact pressure calculated using the simulation method according to the conventional example and Examples 1 to 3. The divergence allowance (displacement) at is defined as “ΔPi”, and “ΔPi ² ” integrated over the entire ground contact area is defined as “ΣΔPi ² ”.

Here, “ΣΔPi ² ” is an index indicating a difference from the contact pressure measured in the actual tire (an index indicating a deviation from the contact pressure measured in the actual tire), and the smaller the value, the higher the calculation accuracy. Is a good one. In (Table 1) described later, “ΣΔPi ² ” in the simulation method according to the conventional example was set to “100” and compared.

  In all the simulation methods, the tire 1 to be analyzed has two layers of carcass ply layers 30A and 30B and two layers provided on the outer layer side of the carcass ply layers 30A and 30B as shown in FIG. The inclined belt layers 20A and 20B and two belt reinforcing layers (so-called spiral belt layers) 10A and 10B provided on the outer layer side of the inclined belt layers 20A and 20B are provided.

  In all simulation methods, a three-dimensional model is used as a tire model.

  Here, in the simulation method according to the conventional example, the two carcass ply layers 30A and 30B are defined as two membrane elements (shell elements), and the two inclined belt layers 20A and 20B are defined as two membrane elements ( The two belt reinforcing layers 10A and 10B are defined as two layers of membrane elements (shell elements).

  In contrast, in the simulation method according to the first embodiment, the two carcass ply layers 30A and 30B are defined as two film elements (shell elements), and the two inclined belt layers 20A and 20B are formed as two layers. It is defined as a membrane element (shell element), and the two belt reinforcing layers 10A and 10B are defined as one layer of membrane element (shell element).

  In the simulation method according to the second embodiment, the two carcass ply layers 30A and 30B are defined as two film elements (shell elements), and the two inclined belt layers 20A and 20B are formed as one film element ( The two belt reinforcing layers 10A and 10B are defined as a single membrane element (shell element).

  Furthermore, in the simulation method according to the third embodiment, the two carcass ply layers 30A and 30B are defined as one film element (shell element), and the two inclined belt layers 20A and 20B are formed as one film element (shell element). The two belt reinforcing layers 10A and 10B are defined as a single membrane element (shell element).

  However, in the simulation method according to Example 3, in the folded portion of the carcass ply layer on the side portion of the tire, the physical property value of the carcass ply layer for one layer is input at the portion where the carcass ply layer becomes one layer. .

Table 1 below shows “ΣΔPi ² ” (index) and calculation time (index) indicating calculation accuracy in the simulation method according to the conventional example and Examples 1 to 3.

  In the simulation method according to the conventional example, since all the skeleton members or reinforcing members of the tire are defined as membrane elements (shell elements), a large calculation time is required.

  On the other hand, in the simulation methods according to Examples 1 to 3 corresponding to the simulation method of the present invention, although the calculation accuracy is slightly lowered, a result that the calculation time can be greatly shortened is obtained.

  Such a decrease in the calculation accuracy is, for example, that the influence of the mesh roughness of the circumferential division on the analysis accuracy when the two-dimensional cross-sectional FEM model is developed into a three-dimensional model by expanding 360 degrees in an annular shape is generally 10%. %, It can be determined that the accuracy deterioration of about 1 to 2% is a very small influence.

  That is, by using the simulation method according to the present invention, it can be said that the calculation time can be shortened without substantially affecting the calculation accuracy.

  Although the present invention has been described in detail using the above-described embodiments, it is obvious to those skilled in the art that the present invention is not limited to the embodiments described in this specification. The present invention can be implemented as modified and changed modes without departing from the spirit and scope of the present invention defined by the description of the scope of claims. Therefore, the description of the present specification is for illustrative purposes and does not have any limiting meaning to the present invention.

DESCRIPTION OF SYMBOLS 1 ... Tire, 10A, 10B, 10C ... Inclined belt layer, 20A, 20B ... Belt reinforcement layer, 30A, 30B ... Carcass ply layer

Claims (5)

A simulation method using a tire model generated by dividing a tire into a finite number of elements,
In generating the tire model, the process A includes defining a tire skeleton member or a reinforcing member as a membrane element or a shell element,
Step A includes
A step A1 of defining at least two layers of the skeleton member or the reinforcing member as one layer of membrane elements or shell elements in a region where a plurality of the skeleton members or the reinforcing members overlap;
And a step A2 of performing overloading on the one-layer film element or shell element.   The simulation method according to claim 1, wherein in the step A, the inclined belt layer of the tire that is the reinforcing member is defined as a membrane element or a shell element.   The simulation method according to claim 1 or 2, wherein in the step A, a belt reinforcing layer of the tire that is the reinforcing member is defined as a membrane element or a shell element.   4. The simulation method according to claim 1, wherein, in the step A, a carcass ply layer of the tire that is the frame member is defined as a membrane element or a shell element. 5.   A simulation apparatus that executes the simulation method according to claim 1.