JP2006040144A - Structure analysis model and method and computer program for generating the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To regenerate the shape and the internal stress of a structure with high accuracy. <P>SOLUTION: A residual stress in the reinforcement cord of a tire is acquired (step S101), and an initial analysis model regenerating the tire shape is generated (step S102). Next, a modified physical quantity obtained by multiplying the above residual stress by an enlargement coefficient f1 is obtained. By fixing the above modified physical quantity value, a first equilibrium calculation is executed for the above initial analysis model (step S104). Next, a modified analysis model is generated by reflecting the information in regard to the deformation of the initial analysis model posterior to the first equilibrium calculation onto the initial analysis model prior to the first equilibrium calculation (step S105). Thereafter, by fixing the above residual stress, a second equilibrium calculation is executed for the above modified analysis model (step S106). The resultant modified analysis model obtained above becomes the analysis model for the above tire (step S107). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a structure simulation, and more specifically, a structure analysis model creation method, a structure analysis model creation computer program, and a structure analysis that can accurately reproduce the shape and internal stress of the structure. It is about the model.

  The structure is generally configured by combining two or more different materials, and in recent simulations, it is required that such a structure can be accurately reproduced. A tire, which is one of such structures, is a rubber material reinforced with various fiber materials (reinforcement cords). In recent years, an actual tire is modeled to simulate rolling and ground contact. Thus, it is often performed to predict actual tire performance. In tire simulation, for example, Patent Document 1 discloses a technique for making the elastic modulus in the tension direction of the reinforcing cord larger than the elastic modulus in the compression direction.

JP 2004-102424 A

  By the way, in a structure configured by combining two or more different materials, such as a tire, residual stress may be generated inside when the materials have different linear expansion coefficients. Further, even in a structure formed of the same kind of material, residual stress may be generated inside the structure depending on heat treatment of the material, variation in manufacturing the structure, and the like. In the simulation, it is preferable to consider such residual stress, but when an analysis model is created in consideration of the residual stress of the structure, it is difficult to accurately reproduce the stress state and shape inside the actual structure. Met.

  Therefore, the present invention has been made in view of the above, and a structure analysis model creation method, a computer program for creating a structure analysis model, and a structure capable of accurately reproducing the shape of the structure and internal stress The purpose is to provide an analysis model of the body.

  In order to solve the above-described problems and achieve the object, the structure analysis model creation method according to the present invention acquires a physical quantity of a part of the structure to be analyzed, and sets this as an initial physical quantity. In addition, a procedure for creating an initial analysis model that reproduces the shape of the structure, and a modified physical quantity obtained by multiplying the physical quantity by a predetermined coefficient having a negative sign are used for the initial analysis model. A procedure for creating a modified analysis model obtained by deforming the initial analysis model by executing a balance calculation of 1 and a second balance calculation for the modified analysis model under a condition equal to or greater than the value of the physical quantity A modified analysis model after the second balance calculation is used as the analysis model of the structure.

  This method of creating an analysis model for a structure is to create a modified analysis model in which the outer dimensions of the structure to be analyzed are set larger than the actual structure, and under conditions that exceed the physical quantity value of the actual structure. Then, a balance calculation for the modified analysis model is executed to create an analysis model. As a result, an analysis model of the structure that accurately reproduces the shape and stress state of the actual structure can be created. Here, the physical quantity is a residual quantity, a residual strain, a tensile or compressive force, or other physical quantity of the structure to be analyzed, and means a physical quantity corresponding to the residual stress. Further, the “part of the structure” refers to a portion that is in a state of a physical quantity (for example, stress) different from the periphery. For example, in a structure made of a composite material in which a base material such as a resin is reinforced with a reinforcing material such as a fiber, the portion of the reinforcing material corresponds to “a part of the structure”. Further, even in a structure made of the same type of material, for example, when it has a portion where an internal stress such as a thermal stress or a compressive stress exists, the portion where the residual stress exists is expressed as "structure Corresponds to "a part of".

  The following method for creating an analysis model of a structure according to the present invention is to obtain a physical quantity of a part of the structure to be analyzed, set this as an initial physical quantity, and reproduce the shape of the structure. A procedure for creating a model; a procedure for obtaining a corrected physical quantity obtained by multiplying the initial physical quantity by a predetermined coefficient having a negative sign; and a value of the corrected physical quantity is fixed. A procedure for executing a balance calculation; a procedure for creating a modified analysis model by reflecting information on deformation of the initial analysis model after the first balance calculation in the initial analysis model before the first balance calculation; A step of performing a second balance calculation on the modified analysis model while fixing the initial physical quantity during the calculation, and the modified analysis after the second balance calculation Dell, characterized by an analysis model of the structure.

  This method for creating an analysis model for a structure is a condition in which a modified analysis model in which the outer dimensions of the structure to be analyzed is set larger than the actual structure is created and fixed to a physical quantity value or more in the actual structure. Below, a balance calculation is performed on the modified analysis model to create an analysis model. As a result, an analysis model of the structure that accurately reproduces the shape and stress state of the actual structure can be created.

  The structure analysis model creation method according to the present invention includes a procedure for acquiring a physical quantity of a part of a structure to be analyzed, creating an initial analysis model that reproduces the shape of the structure, A procedure for setting an initial value of a physical quantity of the same type and a predetermined size and executing an initial balance calculation of the initial analysis model under the initial value of the physical quantity, the physical quantity, and the physical quantity after the initial balance calculation The initial balance calculation is repeated while changing the physical quantity initial value until the difference from the initial value is within a predetermined range, and the difference between the physical quantity and the physical quantity initial value after the initial balance calculation is within a predetermined range. A procedure for setting the initial value of the physical quantity when it is within the initial physical quantity, and a corrected physical quantity is obtained by multiplying the initial physical quantity by a predetermined coefficient having a negative sign. Then, by executing a first balance calculation on the initial analysis model, a procedure for creating a corrected analysis model in which the shape of the initial analysis model is deformed, and using the initial physical quantity, the corrected analysis model is used. And a procedure for executing a second balance calculation for the structure, and the modified analysis model after the second balance calculation is an analysis model of the structure.

  The analysis model creation method for this structure sets the initial physical quantity so that it becomes the physical quantity of the acquired analysis target, and uses this initial physical quantity to make the outer dimension of the structure to be analyzed larger than the actual structure. Create the modified analysis model that has been set. Then, a balance calculation is performed on the modified analysis model under a condition equal to or greater than the physical quantity value in the actual structure to create an analysis model. As a result, an analysis model of the structure that accurately reproduces the shape and stress state of the actual structure can be created.

  The structure analysis model creation method according to the present invention is the structure analysis model creation method, wherein the difference between the physical quantity and the initial value of the physical quantity after the initial balance calculation is within a predetermined range. If not, the value of the physical quantity initial value is corrected using a ratio or difference between the physical quantity and the initial physical quantity value after the initial balance calculation.

  The structure analysis model creation method according to the present invention is characterized in that, in the structure analysis model creation method, the predetermined coefficient is changed according to the physical quantity.

  The structure analysis model creation method according to the present invention is characterized in that, in the structure analysis model creation method, the structure is made of a composite material.

  The structure analysis model creation method according to the present invention is characterized in that, in the structure analysis model creation method, the base material of the composite material is rubber.

  The structure analysis model creation method according to the present invention is the structure analysis model creation method according to the present invention, wherein the structure is a tire, and the physical quantity is a residual stress, a residual strain of a reinforcing cord inside the tire, or It is at least one of the residual tension.

  The structural analysis model creation method according to the present invention is the structural analysis model creation method according to the present invention, wherein at least one of residual stress, residual strain or residual tension of the reinforcing cord is measured, and the measurement result is the It is a physical quantity.

  The structural analysis model creation method according to the present invention is the structural analysis model creation method according to the present invention, in which the residual stress and residual strain of the reinforcing cord constituting at least one of the belt, the carcass or the belt reinforcing layer of the tire are used. Alternatively, at least one of the residual tension is set based on elongation of the cord in the tire manufacturing process.

  A computer program for creating an analysis model for a structure according to the present invention is characterized by causing a computer to execute the method for creating an analysis model for a structure. As a result, the above-described analysis model creation method for a structure can be realized using a computer.

  The following structure analysis model creation method according to the present invention is characterized by being produced by the structure analysis model creation method. As a result, the analysis model of the structure can accurately reproduce the shape and stress state of the actual structure.

  As described above, the structure analysis model creation method, the structure analysis model creation computer program, and the structure analysis model according to the present invention can accurately reproduce the shape and internal stress of the structure.

  Hereinafter, the present invention will be described in detail with reference to the drawings. The present invention is not limited to the best mode for carrying out the invention. In addition, constituent elements in the following embodiments include those that can be easily assumed by those skilled in the art or those that are substantially the same. The present invention can be preferably applied particularly to a composite structure, but the application target of the present invention is not limited to this. For example, although the structure is not a composite material structure, the present invention can be similarly applied to a case where the structure has an internal stress such as a thermal stress or a compressive stress. In the following examples, the case where the present invention is applied to a composite material will be described. An example of the composite material structure is a tire, but the application target of the present invention is not limited thereto.

  In the first embodiment, the residual stress, residual strain, and other physical quantities of the analysis model to be created are set larger than the actual physical quantities in consideration of stress relaxation by balance calculation, and the dimensions of the analysis model to be created are set. Considering the deformation of the structure due to the stress relaxation, the balance calculation is performed by setting it larger than the actual structure size, and an analysis model for performance evaluation is created.

  The method for creating an analysis model of a structure according to the first embodiment of the present invention can be applied to a structure made of a single material, but can be suitably applied particularly to a structure made of a composite material. A composite material refers to a material that combines dissimilar materials and embodies qualities that each material does not originally have. Among composite materials, for example, a combination of two or more kinds of materials, ie, a base material and a reinforcing material, and strengthening the base material with a reinforcing material is well known.

  Examples of the composite material include what is called a polymer matrix composite (PMC) using a polymer such as an epoxy resin or a polyester resin as a base material. PMC includes, for example, so-called fiber reinforced plastics in which a base material of a resin material is reinforced with a reinforcing material such as glass fiber or carbon fiber.

  There is also a composite material called a metal matrix composite (MMC) in which the base material is a metal such as aluminum, titanium, or copper. For example, MMC includes what is called fiber reinforced metal (FRM), and aluminum reinforced with boron fibers, titanium reinforced with silicon carbide fibers, and the like are known.

  There is also a composite material called a ceramic matrix composite (CNC). CMC is a composite material in which ceramics, which is a high-temperature material, is combined with a ceramic as a reinforcing phase, and is a composite material that aims to bring out excellent properties that are not found in single ceramics. The reinforcing phase includes ceramic particles, whiskers, short fibers, and continuous long fibers. The present invention can be applied to the composite materials as described above and other composite materials.

  The tire handled in Example 1 is a composite material structure in which rubber as a base material is reinforced by a reinforcing cord as a reinforcing material. In addition, the application object of Example 1 is not restricted to a tire, For example, to structures, such as a conveyor belt comprised of the composite material which strengthened the base material of rubber material with the fiber, a fender, or the structure of reinforced concrete It can also be applied to. First, before describing a method for creating a structural analysis model and a structural analysis model according to the first embodiment, a structure of a tire, which is an example of a composite material structure, will be briefly described. FIG. 1 is a partial cross-sectional view showing a cross section of a tire when cut along a meridian plane including a rotation axis of the tire.

  The cap tread 11 is a rubber layer that is disposed on the road surface grounding portion of the tire 10 and covers the outside of the carcass 15, the belt 14, or the breaker. The cap tread 11 is a rubber layer of the cap tread rubber 19C, and has a role of protecting the carcass 15 and the belt 14 against a cut impact. The undertread 12 is a rubber layer of undertread rubber 19U disposed between the cap tread 11 and the belt 14, and is used for the purpose of improving heat generation, adhesion and the like. Hereinafter, the cap tread rubber 19C and the under tread rubber 19U are referred to as rubber LT. The side tread 13 is disposed on the outermost side of the sidewall portion to prevent external scratches from reaching the carcass 15 and, in the case of a radial tire, has an auxiliary role of transmitting driving force from the axle to the road surface. I'm in charge.

  The belt 14 is a layer of reinforcing cords in which rubberized cords arranged between the cap tread 11 and the carcass 15 are bundled. In the case of a bias tire, it is called a breaker. In the radial tire, the belt 14 plays an important role as a shape maintaining and strength member. A belt cover material (hereinafter referred to as a cover material) 18 is disposed on the grounding surface side of the belt 14. For example, the cover material 18 is formed by arranging organic fiber materials in a layered manner, and has a role as a protective layer of the belt 14 and a role as a reinforcing layer of the belt 14. The carcass 15 is a reinforcing cord layer in which rubberized cords forming the skeleton of the tire 10 are bundled. The carcass 15 is a strength member that serves as a pressure vessel when the tire 10 is filled with air, and has a structure that supports a load by its internal pressure and withstands a dynamic load during traveling.

  The bead 16 is a ring in which a bundle of steel wires supporting the cord tension of the carcass 15 generated by internal pressure is hardened with hard rubber. The bead 16 serves as a strength member of the tire 10 together with the carcass 15, the belt 14, and the tread (cap tread 11, undertread 12) in addition to fixing the tire 10 to the wheel rim. The bead filler 17 is a rubber that fills a space generated when the carcass 15 is wound around the bead wire. While fixing the carcass 15 to the bead 16, the shape of the part is adjusted and the rigidity of the whole bead part is improved. As described above, the tire 10 is a composite material structure in which rubber as a base material is reinforced by a reinforcing cord such as a belt 14, a carcass 15, or a cover material 18 as a reinforcing material.

  In the tire 10 which is a composite material structure, a reinforcing cord which is a reinforcing material has a residual stress after manufacturing. For this reason, when simulating transient events such as the rolling state and cornering of the tire 10 or analyzing the contact state between the tire 10 and the road surface by simulation, the residual stress is considered from the viewpoint of improving accuracy. It is desirable. Therefore, it is necessary to reflect the residual stress of the reinforcing cord (reinforcing material) in the data for analysis.

  FIGS. 2-1 and 2-2 are conceptual views of a cross section of a tire. First, in the numerical simulation, a case will be described in which an analysis model (tire model) TM of the tire 10 to be analyzed is created using the residual stress value of the reinforcement cord as it is. The tire model TM includes a reinforcement cord model CM that models an internal reinforcement cord. In the tire model TM and the reinforcement cord model CM, a balance calculation is performed according to the input residual stress value, the shape is deformed, and the balance of internal stress changes. As a result, the tire model TM becomes a deformed tire model TM ′, and the reinforcing cord model becomes a deformed reinforcing cord model CM ′ (FIG. 2-2).

  As shown in FIG. 2-2, the outer diameter of the modified tire model TM ′ is smaller than the outer diameter of the tire model TM, and the residual stress of the deformed reinforcing cord model CM ′ is relaxed more than the reinforcing cord model CM. The That is, the shape and stress state of the tire model TM are different from those of the tire 10 to be analyzed. As described above, it is very difficult to create an analysis model that retains the geometric shape of the tire 10 to be analyzed and reproduces the actual residual stress of the reinforcing cord included in the tire 10.

The inventors of the present application have made extensive studies to solve the above problems. As a result, the external dimensions of the analysis model in which the structure to be analyzed is modeled for analysis, and the residual stress of the portion where the structure to be analyzed has residual stress (for example, a reinforcing material such as a reinforcement cord in composite materials) It has been found that an analysis model that accurately reproduces the actual shape and stress distribution can be created by setting the size to a value greater than the actual value. FIGS. 3A and 3B are cross-sectional views illustrating an example in which an analysis model is created by the structure analysis model creation method according to the first embodiment. As shown in FIG. 3A, the residual stress of the reinforcing cord such as the cover material 18 and the carcass 15 and the outer diameter of the analysis model are equal to or greater than the residual stress value of the reinforcing cord of the tire 10 to be analyzed and the outer diameter of the tire 10. The tire model TM ₁ and the reinforcement cord model CM ₁ are created.

Running the equilibrium calculations in this state, as shown in Figure 3-2, the modified tire model TM ₂ by reducing the outer diameter of the tire model TM _1. At this time, the modified tire model TM ₂ is substantially equal to the outer diameter of the tire 10. Similarly, the reinforcement cord model CM ₁ becomes a deformation reinforcement cord model CM ₂ by balance calculation. As a result of the balance calculation, the residual stress of the deformation reinforcing cord model CM ₂ is less than that of the reinforcing cord model CM _1, and becomes substantially equal to the residual stress of the reinforcing cord of the tire 10. As a result, it is possible to create an analysis model that retains the geometric shape of the tire 10 to be analyzed and reproduces the actual residual stress state of the reinforcing cord included in the tire 10. Here, the solid lines in FIGS. 3A and 3B represent the tire model TM ₁ , the reinforcement cord model CM _{1, and the} like, and the dotted lines represent the actual tire 10.

  Next, a specific processing procedure of the structure analysis model creation method according to the first embodiment will be described. FIG. 4 is a flowchart illustrating an example of a processing procedure of the structure analysis model creation method according to the first embodiment. FIG. 5 is a configuration diagram illustrating an example of a structure analysis model creation apparatus that can realize the structure analysis model creation method according to the first embodiment. 6A to 6C are schematic diagrams illustrating an initial analysis model and an analysis model of the structure according to the first embodiment. FIG. 7 is a schematic view showing the stress distribution of the reinforcing cord inside the tire. First, the structure of the structure analysis model creation apparatus according to the first embodiment will be described with reference to FIG.

  The structure analysis model creation apparatus 50 includes a calculation unit 51 and a storage unit 52. Further, an input / output device 55 is connected to the structure analysis model creation device 50 via an input port (I / P) 53 and an output port (O / P) 54. The input / output device 55 includes input means 55i, display means 55d, and processing means 55p. The input means 55 i provided in the input / output device 55 inputs various instructions, data necessary for creating an analysis model, and the like to the arithmetic unit 51 and the storage unit 52. Here, an input device such as a keyboard and a mouse can be used as the input means 55i.

  The computing unit 51 and the storage unit 52 are connected to an input port (I / P) 53 and an output port (O / P) 54, respectively. Thereby, the calculating part 51 can store data in the memory | storage part 52, or can read the data and computer program which are stored in the memory | storage part 52. FIG. The structure analysis model creation apparatus 50 is connected to a communication network 65 via an input port (I / P) 53 and an output port (O / P) 54. As a result, the computing unit 51 can use various data stored in the data servers 61 and 62 connected to the communication network 65 and the functions of the computer connected to the communication network 65.

  The storage unit 52 stores a computer program that realizes the structure analysis model creation method according to the first embodiment, an FEM computer program used for rolling analysis, grounding analysis, and other performance analysis. Here, the storage unit 52 is a hard disk device, a magneto-optical disk device, a non-volatile memory such as a flash memory (a storage medium that can be read only such as a CD-ROM), or a RAM (Random Access Memory). Such a volatile memory or a combination thereof can be used.

  Further, the computer program may be one that can realize the physical property prediction method for a structure according to the present invention in combination with a computer program already recorded in a computer system. 5 is recorded on a computer-readable recording medium, and the computer program recorded on the recording medium is read into a computer system and executed. The prediction method according to the present invention may be executed. The “computer system” here includes an OS and hardware such as peripheral devices.

  The calculation unit 51 includes a memory and a CPU (Central Processing Unit). At the time of performance prediction, based on the set initial analysis model and input data, the calculation unit 51 reads the computer program into the memory, and the CPU executes the computer program. At that time, the calculation unit 51 appropriately stores a numerical value in the middle of the calculation in the storage unit 52, takes out the stored numerical value, and uses it for the execution of the computer program. Note that instead of the calculation unit 51 executing the computer program, the calculation unit 51 may be configured by dedicated hardware to realize the function of the computer program.

  Here, a CRT (Cathode Ray Tube), a liquid crystal display device, or the like can be used for the display means 55d. Further, the storage unit 52 may be built in the calculation unit 51 or may be in another device (such as the data servers 61 and 62 and the computer 63). Furthermore, the structure analysis model creation device 50 may be configured to access the calculation unit 51 and the storage unit 52 via the communication network 65 from the terminal device 64 including the input / output device 55. Next, the procedure of a method for creating an analysis model for a structure according to the first embodiment will be described with reference to FIG. In the following description, please refer to FIGS.

  First, the residual stress α of the reinforcement cord of the tire 10 to be analyzed or a physical quantity corresponding to the residual stress α is acquired (step S101). That is, a partial physical quantity of the structure to be analyzed is acquired. The tire reinforcement cord refers to the belt 14, the carcass 15, the cover material (belt reinforcement layer) 18 or the like (see FIG. 1). The present invention can be applied without limitation to the material of the reinforcing cord, the twisting method, and the like, but is particularly preferable for the reinforcing cord of organic fiber whose tension is likely to change during tire manufacture. Here, examples of the physical quantity corresponding to the residual stress α include tension and strain of the reinforcing cord. When acquiring the residual stress α of the reinforcing cord or a physical quantity corresponding to the residual stress α, it is preferable to acquire it from at least one location of the reinforcing cord in consideration of the distribution of the residual stress α and the like.

For example, as shown in FIG. 7, when the residual stress α or a physical quantity corresponding to the residual stress α has a distribution in the width W direction of the tire 10, W ₁ , W ₂ , W ₃ ,. Residual stress α and the like are acquired from each position of _n . This makes it possible to create an analysis model that reproduces the actual tire stress distribution and shape with higher accuracy.

  In the example shown in FIG. 7, the distribution in the width W direction of the tire 10 is considered, but the distribution of the residual stress α and the like in the circumferential direction of the tire 10 may be considered. In the example shown in FIG. 7, the residual stress α and the like are obtained from each of the n positions in the width W direction of the tire 10. May be obtained.

  The residual stress α or the physical quantity corresponding to the residual stress α can be obtained by actual measurement. If the residual stress α or the distribution of the physical quantity corresponding to the residual stress α can be estimated from past knowledge, the residual stress obtained from the past knowledge, etc., without actually measuring them. α or an estimated value of a physical quantity corresponding to the residual stress α may be used. For example, in the case of the tire 10, the residual tension distribution of the reinforcing cords constituting the belt 14 and the carcass 15 is estimated from the growth rate of the outer diameter of the tire 10 during manufacture, and the residual stress α and the like are based on the estimated value. Can be estimated. Further, the residual stress α may be set based on the elongation of the reinforcing cords constituting the cover member 18 and the carcass 15 in the manufacturing process of the tire 10.

  Next, the initial analysis model 1 of the tire 10 that is the structure to be analyzed is created (step S102). In the creation of the initial analysis model 1, the structure to be analyzed (the tire 10 in the first embodiment) is modeled with elements that allow numerical analysis. In the first embodiment, since the FEM (Finite Element Method) is used for analyzing the structure, the tire 10 is modeled with an element that can be analyzed by the finite element method. The analysis method applicable to the structure analysis model creation method according to the first embodiment is not limited to FEM, and BEM (Boundary Element Method), FDM (Finite Differences Method), and the like can also be used. . It is preferable to select the most appropriate analysis method according to the structure to be predicted, boundary conditions, or the like, or to use a combination of a plurality of analysis methods.

FIG. 8 is a perspective view showing an initial analysis model of a tire as a structure. As shown in FIG. 8, the tire 10 is a structure (see FIG. 1) is based on the finite element method, is divided into a finite number of small elements e _1, e _2, e _n, etc., an initial analysis model 1 Created. The microelements based on the finite element method are, for example, a quadrilateral element in a two-dimensional plane, a solid element such as a tetrahedral solid element, a pentahedral solid element, a hexahedral solid element as a three-dimensional body, a triangular shell element, and a rectangular shell. It is desirable that the element can be handled by a computer, such as a shell element. The microelements divided in this way are identified one by one using the three-dimensional coordinates in the process of analysis.

  Next, an example of reinforcing cord modeling will be described. FIG. 9A is an explanatory diagram of an example of a reinforcing cord. 9-2 and 9-3 are explanatory diagrams illustrating an example in which the reinforcing cord is modeled as a shape having no cross-sectional shape change. As the reinforcing cord 20 disposed in the rubber (base material) LT of the tire 10, a stranded wire (FIG. 9-1) or a monofilament with spiral or planar corrugation is used. Thus, the cross-sectional shape of the reinforcement cord 20 changes with respect to the length direction of the reinforcement cord 20, and the shape of the reinforcement cord 20 is complicated. For this reason, if the reinforcing cord 20 is divided into minute elements as it is, the amount of calculation becomes extremely large, which is not realistic.

Therefore, in the first embodiment, as shown in FIGS. 9-2 and 9-3, a simplified reinforcing cord model is assumed in which the cross-sectional shape of the reinforcing cord 20 does not change with respect to the length direction of the reinforcing cord 20. 2a and 2b are created. This can reduce the amount of calculation, which can reduce the load on the CPU, memory and other hardware resources, which is preferable. The rubber LT is converted into a rubber model LT _M based on the finite element method. The reinforcement cord modeling that can be applied to the structural body analysis model creation method according to the first embodiment is not limited to the above example, and may be modeled in consideration of a change in cross-sectional shape. The initial analysis model 1 of the tire 10 including the reinforcing cord 20 can be created by the above procedure. Note that the processing order for obtaining the residual stress α (step S101) and creating the initial analysis model (step S102) is not limited (the same applies hereinafter).

  Next, an enlargement coefficient f1, which is a predetermined coefficient, is set (step S103). FIG. 10A is a schematic diagram illustrating the residual stress of the reinforcing cord. FIG. 10-2 is a schematic diagram illustrating a state in which stress opposite to the residual stress of the reinforcing cord is applied to the reinforcing cord. As shown in FIG. 10A, tensile residual stress α acts on the reinforcing cord 20 in the manufactured tire 10. In the structure analysis model creation method according to the first embodiment, as shown in FIG. 10-2, the physical quantity (here, residual stress) of a part of the structure (here, the reinforcing cord 20 of the tire 10) is opposite to that of the structure. Perform balance calculations under physical quantities.

  Then, by reflecting the calculation result in the initial analysis model 1, the outer dimension of the initial analysis model 1 after the balance calculation is set in advance to be larger than the outer dimension of the actual structure (tire 10). In the first embodiment, the balance analysis of the initial analysis model 1 is executed under a stress condition obtained by multiplying the acquired residual stress α and the like by the set expansion coefficient f1. That is, the balance calculation is performed on the initial analysis model 1 so as to balance the physical quantity (residual stress) in the direction opposite to the physical quantity of a part (reinforcement cord) of the structure (tire 10). For this reason, the enlargement coefficient f1 is a negative value. In this way, by using the physical quantity of the structure and multiplying this by the expansion factor f1, the state of stress inside the structure can be reflected in the shape of the structure easily and accurately.

  The range of the expansion coefficient f1 is preferably −1.5 or more and −0.5 or less, more preferably −1.1 or more and −0.9. Furthermore, the enlargement factor f1 is preferably -1. Further, as shown in FIG. 7, when the magnitude of the residual stress of the reinforcing cord 20 has a distribution, the expansion factor f1 may be changed for each location according to the magnitude of the residual stress. In this way, it is possible to create an analysis model that reproduces the actual shape and stress state of the tire 10 with higher accuracy.

  Next, a value obtained by multiplying the acquired residual stress α or the like by the set expansion coefficient f1 is set as a correction stress (correction physical quantity) σ of the reinforcement cord model 2a or the like. Then, the calculation unit 51 fixes the correction stress σ of the reinforcement cord model 2a and the like to f1 × α, and executes the first balance calculation of the initial analysis model 1 (step S104). Here, “fixed” means that the correction stress σ of the reinforcing cord model 2a and the like is maintained at f1 × α for a predetermined time (for example, until the end of the balance calculation) from the start of the balance calculation (the same applies hereinafter). . Thus, by executing the balance calculation while fixing the stress of the reinforcing cord model 2a and the like, the influence of stress relaxation of the reinforcing cord model 2a and the like can be eliminated during the execution of the first balance calculation.

  When the first balance calculation is completed, the calculation unit 51 reflects the deformation information of the initial analysis model 1 based on the first balance calculation on the initial analysis model 1 to create a modified analysis model 1c (step S105, FIG. 6). -2). As shown in FIG. 6B, the modified analysis model 1 c has a larger outer dimension than the initial analysis model 1. When the correction analysis model 1c is created, the calculation unit 51 fixes the stress of the reinforcement code model 2a or the like to the residual stress α, that is, the initial physical quantity, and executes the second balance calculation of the correction analysis model 1c (step S106). .

  Thus, by executing the balance calculation while fixing the stress of the reinforcement cord model 2a and the like, the influence of stress relaxation of the reinforcement cord model 2a and the like can be eliminated during the execution of the second balance calculation. Note that fixing the stress of the reinforcement cord model 2a and the like means that there is no stress relaxation during execution of the balance calculation. Therefore, during the balance calculation, the stress of the reinforcement cord model 2a and the like is the residual stress α (analysis target). The physical quantity of the structure is maintained at a value equal to or higher than the physical quantity.

  A model obtained as a result of the second balance calculation is an analysis model 1t (FIG. 6-3) to be obtained. Thus, the analysis model 1t according to the first embodiment is completed by the above procedure (step S107). Thereafter, using the completed analysis model 1t, the performance of the tire 10 is predicted, or a tire / wheel assembly in which the analysis model 1t is fitted to the wheel is created, and this performance is predicted (step S108). ).

(Modification)
FIG. 11 is a flowchart illustrating a procedure of a method for creating an analysis model for a structure according to a modification of the first embodiment. This modification has substantially the same configuration as that of the first embodiment, except that the expansion coefficient is corrected based on the physical quantity (residual stress) of the created modified analysis model, and the modified analysis model is recreated. Since other configurations are the same as those of the first embodiment, description thereof is omitted. In the following description, please refer to FIGS.

  In the structure analysis model creation method according to this modification, steps S201 to S206 are the same as steps S101 to S101 to step S106 of the structure analysis model creation method according to the first embodiment, and thus description thereof is omitted. To do. When the second balance calculation is performed on the correction analysis model 1c (step S206), the calculation unit 51 acquires the stress γ of the correction analysis model 1c after the second balance calculation (step S207).

  The computing unit 51 compares the difference between the acquired stress γ and the residual stress α acquired in step S201 (here, the absolute value of the difference between the two) and a predetermined threshold ε (step S208). The predetermined threshold ε is preferably in the range of 0 to 0.1 × α, more preferably in the range of 0 to 0.01 × α. Further, in the calculation unit 51, the shape of the correction analysis model 1c (second correction analysis model) obtained by the second balance calculation is substantially the same as the shape of the initial analysis model 1, that is, the shape of the tire 10. It is determined whether or not. The shape of the second correction analysis model and the shape of the initial analysis model 1 are the nodes (Xi, Yi, Zi) of each element constituting the second correction analysis model and the initial analysis model 1 corresponding to the nodes. The node (xi, yi, zi) is compared. When the displacement amount (ΔX, ΔY, ΔZ) of the node is smaller than a predetermined threshold, it is determined that the shape of the second modified analysis model and the shape of the initial analysis model 1 are substantially the same shape. . Here, ΔXi = | Xi−xi |, ΔYi = | Yi−yi |, and ΔZi = | Zi−zi |. “I” is a parameter indicating a node number.

  | Γ−α | ≧ ε, or when the shape of the second correction analysis model and the shape of the initial analysis model 1 are not substantially the same shape (step S208; No), the second correction analysis model is the actual tire 10 It can be judged that the shape and the stress state are not sufficiently reproduced. In this case, the enlargement factor f1 is reset (step S209), and a new correction stress σ (= f1 × α) is generated using the enlargement factor f1 (step S204 to step S206). ). Then, the correction coefficient f1 is reset until the correction analysis model 1c created again has | γ−α | <ε and the shape of the second correction analysis model and the shape of the initial analysis model 1 are substantially the same. Repeat the regeneration of the modified analysis model.

  When | γ−α | <ε and the shape of the second modified analysis model and the shape of the initial analysis model 1 are substantially the same shape (step S208; Yes), the result of the second balance calculation is obtained. The correction analysis model 1c (second correction analysis model) becomes the analysis model 1t to be obtained (FIG. 6-3), and the analysis model 1t according to the modification of the first embodiment is completed (step S210). Then, using the completed analysis model 1t, the performance of the tire 10 is predicted, or a tire / wheel assembly in which the analysis model 1t is fitted to the wheel is created, and this performance is predicted (step S211). ).

  Note that when all the nodes of the reinforcing cord model 2a or the like do not satisfy | γ−α | <ε, the enlargement factor f1 may be reset, or a predetermined ratio (for example, 10% of all nodes) or more. If the node does not satisfy the relationship, the enlargement factor f1 may be reset. In addition, in consideration of rolling analysis, grounding analysis, etc., about 100% of the nodes satisfying the condition of | γ−α | <ε in the region of the reinforcing cord that affects the evaluation of the created analysis model. Good. Further, | γ−α | at all nodes of the reinforcing cord model 2a and the like is statistically processed, and when the standard deviation exceeds a predetermined value, the expansion coefficient f1 may be reset. . The same applies to the shape determination of the correction analysis model 1c.

  As described above, in the first embodiment and the modified example, the outer dimension of the structure to be analyzed is set larger than that of the actual structure, and the residual stress, the residual strain, and the like of a part of the structure to be analyzed are set. An analysis model of the structure is created by setting the physical quantity to be equal to or greater than the value of the physical quantity in the actual structure. As a result, an analysis model of the structure that accurately reproduces the shape and stress state of the actual structure can be created. Moreover, since the balance calculation is executed with the physical quantity fixed, a method for creating an analysis model of the structure can be realized with a simple algorithm. As a result, the load on the hardware resource can be reduced, and the calculation speed is also improved. Note that the configurations disclosed in the first embodiment and the modifications thereof can be applied as appropriate in the following embodiments. In addition, as long as the configuration similar to the configuration disclosed in the first embodiment and the modification thereof is provided, the same operations and effects as the first embodiment and the modification thereof are exhibited.

  The second embodiment has substantially the same configuration as that of the first embodiment or its modification, but an initial physical quantity is set so as to be a partial physical quantity of the acquired structure, and a modified analysis model is based on the initial physical quantity. In the balance calculation, the residual stress, residual strain and other physical quantities of the structure are not fixed. Since other configurations are the same as those of the first embodiment, the description thereof is omitted. In the following description, please refer to FIGS.

  FIG. 12 is a flowchart illustrating the procedure of the structure analysis model creation method according to the second embodiment. The acquisition of the residual stress (step S301) and the creation of the initial analysis model (step S302) are the same as those in the first embodiment and the description thereof is omitted. After obtaining the residual stress α and creating the initial analysis model, the initial stress value β, which is the physical quantity initial value, is set (step S303). The initial stress value β is, for example, the residual stress α acquired in step S301.

Next, the stress of the initial analysis model 1 created in step S302 is β, and under this condition, the calculation unit 51 performs a balance calculation on the initial analysis model 1 (step S304). This balance calculation corresponds to “initial balance calculation”. Next, the computing unit 51 acquires the stress α ₁ of the initial analysis model 1 after the balance calculation in Step S304 (Step S305). Thereby, the information regarding the stress change of the reinforcement cord model 2a etc. by the initial balance calculation can be obtained.

The calculation unit 51 compares the difference between the acquired stress α ₁ and the residual stress α acquired in step S301 (here, the absolute value of the difference between the two) and a predetermined threshold ε ₁ (step S306). . The predetermined threshold ε ₁ is preferably in the range of 0 to 0.05 × α, and more preferably in the range of 0 to 0.005 × α. If | α ₁ −α | ≧ ε ₁ (step S306; No), it can be determined that the initial stress value β is inappropriate as the initial physical quantity of the analysis model to be created. In this case, the stress initial value β is reset (step S307), and the balance calculation for the initial analysis model 1 is executed using the new stress initial value β (step S304, step S305). Then, until the stress α ₁ of the initial analysis model 1 after the balance calculation in step S304 becomes | α ₁ −α | <ε ₁ , the resetting of the stress initial value β and the balance calculation of the initial analysis model 1 are repeated. .

Here, the resetting of the stress initial value β will be described. The stress initial value β can be corrected by the equation (1) assuming, for example, linearity.
β _new = β _old × (α / α ₁ ) (1)
Further, using Equation (2), and residual stresses alpha, it may be corrected by the difference between the stress alpha ₁ in the initial analysis model 1 after balance calculation in step S304.
β _new = β _old × (α−α ₁ ) (2)
Here, β _new is an initial stress value to be reset, and β _old is an initial stress value when | α ₁ −α | ≧ ε ₁ is determined.

The stress initial value β may be reset when all the nodes of the reinforcing cord model 2a or the like do not satisfy | α ₁ −α | <ε ₁ , or a predetermined ratio (for example, 10% of all nodes) ) If the above nodes do not satisfy the above relationship, the stress initial value β may be reset. Also, in consideration of rolling analysis, grounding analysis, etc., for the area of the reinforcing cord that affects the evaluation of the created analysis model, approximately 100% of the nodes should satisfy | α ₁ −α | <ε _1. May be. Furthermore, statistical processing is performed on | α ₁ −α | at all nodes of the reinforcement cord model 2a and the like, and when the standard deviation exceeds a predetermined value, the stress initial value β is reset. Also good.

When | α ₁ −α | <ε ₁ (step S306; Yes), in order to obtain a state in which the entire structure to be analyzed (tire 10) is balanced by the actual residual stress α of the reinforcing cord 20, It can be determined that an initial stress value β satisfying | α ₁ −α | <ε ₁ may be set as the initial physical quantity of the reinforcement code model 2a or the like of the analysis model to be created. In this case, the initial stress (β initial value) β when | α ₁ −α | <ε ₁ is set as the initial physical quantity.

  Next, an enlargement coefficient f1 is set (step S308). The enlargement coefficient f1 is the same as that in the first embodiment. In setting the expansion coefficient f1, as shown in FIG. 7, when the residual stress of the reinforcing cord 20 has a distribution, the expansion coefficient f1 may be changed for each location in consideration of this distribution. In this way, it is possible to create an analysis model that reproduces the actual shape and stress state of the tire 10 with higher accuracy.

Next, a balance calculation of the initial analysis model 1 is executed under the stress condition obtained by multiplying the initial physical quantity (β in this case) set by the above procedure by the expansion coefficient f1 set in step S308. Here, a value obtained by multiplying the set initial physical quantity (here, β) by the set enlargement coefficient f1 is set as a correction stress (correction physical quantity) σ (= f1 × β) of the reinforcement cord model 2a and the like. The calculation unit 51 performs the first balance calculation on the initial analysis model 1 under the condition that the stress of the reinforcement cord model 2a and the like is the correction stress σ (= f1 × β) (step S309). When | α ₁ −α | <ε ₁ , the stress of the reinforcing cord model 2a or the like is equal to or greater than the residual stress α (physical quantity of the structure to be analyzed).

  When the first balance calculation is completed, the calculation unit 51 reflects the deformation information of the initial analysis model 1 based on the first balance calculation on the initial analysis model 1 to create a modified analysis model 1c (step S310, FIG. 6). -2). As shown in FIG. 6B, the modified analysis model 1 c has a larger outer dimension than the initial analysis model 1. When the correction analysis model 1c is created, the calculation unit 51 sets the stress of the reinforcement code model 2a or the like to the initial physical quantity (here, β), and executes the second balance calculation of the correction analysis model 1c (step S311). .

Next, the computing unit 51 acquires the stress γ of the modified analysis model 1c after the second balance calculation (step S312). The computing unit 51 compares the absolute value of the difference between the acquired stress γ and the residual stress α acquired in step S301 with a predetermined threshold ε ₂ (step S313). The predetermined threshold ε ₂ is preferably in the range of 0 to 0.1 × α, and more preferably in the range of 0 to 0.01 × α. Further, in the calculation unit 51, the shape of the correction analysis model 1c (second correction analysis model) obtained by the second balance calculation is substantially the same as the shape of the initial analysis model 1, that is, the shape of the tire 10. It is determined whether or not. This determination is as described in the modification of the first embodiment.

| Γ−α | ≧ ε ₂ , or when the shape of the second correction analysis model and the shape of the initial analysis model 1 are not substantially the same shape (step S313; No), the second correction analysis model is the actual tire 10 It can be judged that the shape and the stress state of are not sufficiently reproduced. In this case, the process returns to step S302 to recreate the initial analysis model. Then, until the corrected analysis model 1c created again is | γ−α | <ε, and the shape of the second correction analysis model and the shape of the initial analysis model 1 are substantially the same, step S303 to step S303 Repeat S313.

When | γ−α | <ε ₂ and the shape of the second modified analysis model and the shape of the initial analysis model 1 are substantially the same shape (step S313; Yes), the result of the second balance calculation is obtained. The corrected analysis model 1c (second corrected analysis model) becomes the desired analysis model 1t (FIG. 6-3), and the analysis model 1t according to the modified example of the first embodiment is completed (step S314). Thereafter, using the completed analysis model 1t, the performance of the tire 10 is predicted, or a tire / wheel assembly in which the analysis model 1t is fitted to the wheel is created, and this performance is predicted (step S315). ).

When all the nodes of the reinforcing cord model 2a or the like do not satisfy | γ−α | <ε ₂ , the initial analysis model may be recreated, or a predetermined ratio (for example, 10% of all nodes) If the above nodes do not satisfy the relationship, the initial analysis model may be recreated. In addition, in consideration of rolling analysis, grounding analysis, etc., about 100% of the nodes satisfying the condition of | γ−α | <ε in the region of the reinforcing cord that affects the evaluation of the created analysis model. Good. Further, | γ−α | at all nodes of the reinforcing cord model 2a and the like is statistically processed, and when the standard deviation exceeds a predetermined value, the initial analysis model may be recreated. . The same applies to the shape determination of the correction analysis model 1c.

  As described above, in Example 2, the outer dimensions of the structure to be analyzed are set larger than the actual structure, and the residual stress, residual strain, and other physical quantities of the structure to be analyzed are actually measured. An analysis model of the structure is created so as to be equal to or greater than the physical quantity value in the structure. As a result, an analysis model of the structure that accurately reproduces the shape and stress state of the actual structure can be created. Further, in the first and second balance calculations, it is not necessary to fix the stress. Therefore, even when using an analysis tool having no such function, an analysis model of the structure can be created.

  Example 3 describes an example in which the present invention is applied to an analysis object other than a structure made of a composite material such as a tire. FIG. 13 is an explanatory diagram illustrating another structure according to the third embodiment. This structure 80 has a structure in which two first members 81 arranged in parallel are fastened by two second members 82 and one third member 83 which are orthogonal to them. Here, the first to third members 81 to 83 are all made of the same material.

  For example, it is assumed that the temperature of the third member 83 is lower than the temperature of the second member 82. In this case, the length of the third member 83 in the longitudinal direction is shortened, but the contraction is restricted by the second member 82. Therefore, when viewed from the whole structure 80, a tensile stress is generated in the third member 83, and a compressive stress is generated in the second member 82. At this time, if the third member 83 is the reinforcing cord 20 of the tire 10 in the first and second embodiments, the structure analysis model creation method according to the first and second embodiments is applied as it is. 3 can be created.

  Thus, the present invention can be applied not only to a structure made of two or more different materials but also to a structure made of a single material, such as a composite material. Further, the present invention can be applied to a structure made of a single material, such as residual stress generated in a heat-treated metal material, when internal stress is generated inside the material by a material processing step. Furthermore, even in the case of a structure made of a single material, the present invention can be applied when an internal stress is generated in the structure in the structure manufacturing process due to, for example, a dimensional error of the structure component.

(Evaluation example)
For passenger car tires (205 / 65R15), tire analysis models were created by three different analysis model creation methods. Then, the stress distribution of the reinforcing cord, the geometric shape of the analytical model, and the ground contact shape of the analytical model were evaluated. The first analysis model (hereinafter referred to as model 1) is created by setting the residual stress α of the reinforcing cord constituting the belt cover material to the initial analysis model obtained by modeling the initial shape of the tire. The second analysis model (hereinafter referred to as model 2) obtains the residual stress α of the reinforcement cord constituting the belt cover material, executes balance calculation on the initial analysis model under the condition of −α, and then executes the reinforcement cord. The residual stress α is set. The third analysis model (hereinafter referred to as model 3) is created by the structural analysis model creation method according to the first embodiment of the present invention.

  FIG. 14 is an explanatory diagram showing the stress distribution of the belt cover material in a meridional section passing through the rotation axis of the tire. In FIG. 14, the ■ mark is the measured value, the one-dot chain line is the model 1, the broken line is the model 2, and the solid line is the model 3. As can be seen from FIG. 14, compared with model 1 and model 2, model 3 created by the structural model analysis method creation method according to Example 1 of the present invention according to Example 1 has a correlation with the measured value. You can see that it is the highest.

  FIG. 15 is a partial cross-sectional view showing the shape of a tire cross section. The two-dot chain line in FIG. 15 is the actual tire shape, the one-dot chain line is the model 1, the broken line is the model 2, and the solid line is the model 3. As can be seen from FIG. 15, it can be seen that the model 3 created by the structural model analysis method creation method according to Example 1 of the present invention related to Example 1 well reproduces the actual tire shape.

  FIGS. 16A to 16C are plan views illustrating the ground contact shape and the ground pressure distribution. 16-1 shows the result of model 1, FIG. 16-2 shows the result of model 2, and FIG. 16-3 shows the result of model 3. Table 1 shows an evaluation result of the installation shape. The grounding shape is evaluated by the maximum grounding length, the maximum grounding width, and the grounding area. The results in Table 1 are relative values when the actual measurement result is 100. From Table 1, it can be seen that Model 3 reproduces the measured values best. Also, from the results of FIGS. 16-1 to 16-3, it can be seen that Model 3 well reproduces the actual contact shape and contact pressure distribution.

  Table 2 summarizes the evaluation results. In the evaluation results, x is impossible, Δ is practically minimum accuracy, and ○ is practically sufficient accuracy. As can be seen from Table 2, the model 3 created by the analytical model creation method for the structure according to Example 1 of the present invention is an actual tire in all of the stress distribution of the reinforcing cord, the geometric shape of the analytical model, and the ground contact shape. Is well reproduced, and it is understood that sufficient accuracy is practically secured.

  As described above, the structure analysis model creation method, the structure analysis model creation computer program, and the structure analysis model according to the present invention are useful for structure simulation. Suitable for simulation of structures with internal stresses such as

It is a partial sectional view showing the section of a tire at the time of cutting with the meridian plane containing the rotation axis of a tire. It is a conceptual diagram of the cross section of a tire. It is a conceptual diagram of the cross section of a tire. 6 is a cross-sectional view illustrating an example in which an analysis model is created by a structure analysis model creation method according to Embodiment 1. FIG. 6 is a cross-sectional view illustrating an example in which an analysis model is created by a structure analysis model creation method according to Embodiment 1. FIG. 6 is a flowchart illustrating an example of a processing procedure of a structure analysis model creation method according to the first embodiment; BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a configuration diagram illustrating an example of a structure analysis model creation apparatus that can realize a structure analysis model creation method according to a first embodiment; 2 is a schematic diagram illustrating an initial analysis model and an analysis model of a structure according to Embodiment 1. FIG. 2 is a schematic diagram illustrating an initial analysis model and an analysis model of a structure according to Embodiment 1. FIG. 2 is a schematic diagram illustrating an initial analysis model and an analysis model of a structure according to Embodiment 1. FIG. It is the schematic which shows the stress distribution of the reinforcement cord inside a tire. It is a perspective view which shows the initial analysis model of the tire which is a structure. It is explanatory drawing which shows an example of a reinforcement cord. It is explanatory drawing which shows an example which modeled the reinforcement cord as a shape without a cross-sectional shape change. It is explanatory drawing which shows an example which modeled the reinforcement cord as a shape without a cross-sectional shape change. It is a schematic diagram which shows the residual stress of a reinforcement cord. It is a schematic diagram which shows the state where the stress opposite to the residual stress of the reinforcement cord acted on the reinforcement cord. 10 is a flowchart illustrating a procedure of a method for creating an analysis model of a structure according to a modification of Example 1; 12 is a flowchart illustrating a procedure of a structure analysis model creation method according to the second embodiment. 10 is an explanatory view showing another structure according to Embodiment 3. FIG. It is explanatory drawing which shows the stress distribution of the belt cover material in the meridional section which passes along the rotating shaft of a tire. It is a partial sectional view showing the shape of a tire cross section. It is a top view which shows a contact shape and contact pressure distribution. It is a top view which shows a contact shape and contact pressure distribution. It is a top view which shows a contact shape and contact pressure distribution.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Initial analysis model 1c Correction | amendment analysis model 1t Analysis model 2a, 2b Reinforcement cord model 10 Tire 11 Cap tread 12 Under tread 13 Side tread 14 Belt 15 Carcass 16 Bead 17 Bead filler 18 Cover material 20 Reinforcement cord 50 Analysis model creation apparatus 51 Calculation part 52 Memory unit

Claims (12)

A procedure for acquiring a physical quantity of a part of a structure to be analyzed, setting it as an initial physical quantity, and creating an initial analysis model that reproduces the shape of the structure;
A modification in which the initial analysis model is deformed by executing a first balance calculation on the initial analysis model using a corrected physical quantity obtained by multiplying the physical quantity by a predetermined coefficient having a negative sign. The steps to create an analysis model,
Performing a second balance calculation on the modified analysis model under a condition equal to or greater than the value of the physical quantity,
A structure analysis model creation method, wherein the modified analysis model after the second balance calculation is the analysis model of the structure. A procedure for acquiring a physical quantity of a part of a structure to be analyzed, setting it as an initial physical quantity, and creating an initial analysis model that reproduces the shape of the structure;
A procedure for obtaining a corrected physical quantity obtained by multiplying the initial physical quantity by a predetermined coefficient having a negative sign;
A procedure of performing a first balance calculation on the initial analysis model with the value of the corrected physical quantity fixed;
A procedure for creating a modified analysis model by reflecting information on deformation of the initial analysis model after the first balance calculation in the initial analysis model before the first balance calculation;
A step of fixing the initial physical quantity during the calculation and executing a second balance calculation on the modified analysis model,
A structure analysis model creation method, wherein the modified analysis model after the second balance calculation is the analysis model of the structure. A procedure for acquiring a physical quantity of a part of a structure to be analyzed and creating an initial analysis model that reproduces the shape of the structure;
A procedure of setting a physical quantity initial value of the same kind as the physical quantity and having a predetermined size, and executing an initial balance calculation of the initial analysis model under the physical quantity initial value;
The initial balance calculation is repeated while changing the physical quantity initial value until the difference between the physical quantity and the initial value of the physical quantity after the initial balance calculation is within a predetermined range, and the physical quantity and the initial balance calculation are calculated. A procedure for setting the initial value of the physical quantity when the difference from the initial value of the physical quantity in a predetermined range is an initial physical quantity;
The initial analysis model is obtained by multiplying the initial physical quantity by a predetermined coefficient having a negative sign to obtain a corrected physical quantity, and using the corrected physical quantity, a first balance calculation is performed on the initial analysis model. To create a modified analysis model with the shape of
Performing a second balance calculation on the modified analysis model using the initial physical quantity, and
A structure analysis model creation method, wherein the modified analysis model after the second balance calculation is the analysis model of the structure.   When the difference between the physical quantity and the initial physical quantity after the initial balance calculation is not within a predetermined range, the ratio or difference between the physical quantity and the initial physical quantity after the initial initial balance calculation is used. 4. The structure analysis model creation method according to claim 3, wherein the initial value of the physical quantity is corrected.   5. The structure analysis model creation method according to claim 1, wherein the predetermined coefficient is changed in accordance with a magnitude of the physical quantity.   6. The structure analysis model creation method according to claim 1, wherein the structure is made of a composite material.   The method of creating an analysis model for a structure according to claim 6, wherein the base material of the composite material is rubber.   8. The structure analysis model creation according to claim 7, wherein the structure is a tire, and the physical quantity is at least one of residual stress, residual strain, or residual tension of a reinforcing cord inside the tire. Method.   9. The method for creating an analysis model for a structure according to claim 8, wherein at least one of residual stress, residual strain, or residual tension of the reinforcing cord is measured, and the measurement result is used as the physical quantity.   Setting at least one of residual stress, residual strain or residual tension of a reinforcing cord constituting at least one of the belt, carcass or belt reinforcing layer of the tire based on elongation of the cord in the tire manufacturing process; The method for creating an analysis model of a structure according to claim 8.   A computer program for creating a structure analysis model, which causes a computer to execute the structure analysis model creation method according to any one of claims 1 to 10.   A structure analysis model produced by the structure analysis model creation method according to any one of claims 1 to 10.

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