JP2015203921A - Structure stiffness evaluating method, device and program, and computer-readable storage medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To precisely evaluate stiffness of a structure that is made of a metal plate having in-plane anisotropy of Young's modulus.SOLUTION: A material characteristic value input part 102 inputs a material characteristic value from a database 101, with respect to a metal plate that is a material of a target structure. A first calculation part 103 obtains a material parameter in a reference direction, which is necessary for stiffness analysis, from the material characteristic value input by the material characteristic value input part 102. A second calculation part 104 obtains a material parameter in a direction of an angle θ between the reference direction and a blank layout direction, from the material parameter in the reference direction obtained by the first calculation part 103. A stiffness analysis part 105 analyzes stiffness of the target structure by using the material parameter in the blank layout direction obtained by the second calculation part 104. By changing the blank layout direction θ at multiple stages and repeating the processing of the second calculation part and the processing of the stiffness analysis part 105, the blank layout direction θ making the stiffness maximum is determined.

Description

  The present invention relates to a structure rigidity evaluation method, apparatus, program, and computer-readable storage medium suitable for use in evaluating the rigidity of automobile parts, for example, when designing a vehicle body having excellent rigidity.

  In recent years, application of high-strength steel sheets to automobile bodies has been progressing in order to satisfy both collision safety and weight reduction of vehicle bodies at the same time. The reason why a high-strength steel sheet is applied to reduce the weight of the vehicle body is that a reduction in sheet thickness can be expected as the strength increases, but this leads to a decrease in rigidity. In particular, in vehicle body skeleton parts such as side members, sills, and center pillars, a reduction in rigidity becomes a bottleneck, and further weight reduction is difficult. Until now, in order to improve rigidity, the method of adhere | attaching resin between a steel plate or a steel plate or between structures is proposed (for example, refer patent documents 1-3). However, these conventional techniques have many problems in terms of production technology and manufacturing cost, such as the necessity of introducing new equipment, and the structures to be applied are limited.

  Since rigidity depends on the Young's modulus and thickness of the steel sheet, it is necessary to use a steel sheet having a high Young's modulus to reduce the thickness while maintaining rigidity. Normally, the Young's modulus of steel is about 205 GPa and is treated as isotropic in the plane of the plate, but the iron single crystal has cubic orthotropic anisotropy, and the maximum Young's modulus in the <111> direction is 284 GPa, < A minimum Young's modulus of 132 GPa is shown in the 100> direction. Therefore, when manufacturing a steel plate, the Young's modulus in a specific direction within the plate surface can be increased by controlling the crystal orientation. For example, Patent Document 4 discloses a method of manufacturing a steel sheet having a high Young's modulus of 230 GPa or more in a direction perpendicular to the rolling direction of the steel sheet. The Young's modulus described in the electromagnetic steel sheet and Patent Document 5 greatly exceeds 230 GPa between 45 and 70 ° from the rolling direction.

JP 58-177745 A JP-A-2-182448 JP-A-6-171001 JP 59-83721 A JP 58-9932 A JP 2014-26490 A

If the plate thickness of the vehicle body frame part is reduced in order to reduce the weight of the vehicle body, the rigidity is lowered. Therefore, the application of a steel plate having a high Young's modulus is being studied to compensate for this. However, since such a steel sheet has a strong elastic anisotropy in the plate surface and the Young's modulus in the other direction is remarkably lowered when the Young's modulus in a specific direction is increased, the method of applying to a structure In some cases, the effect of improving the rigidity cannot be obtained.
The rigidity of the automobile body at the design stage is evaluated by rigidity analysis. In the stiffness analysis, a simulation of elastic deformation such as bending, torsion and vibration acting on the structure is performed to evaluate whether or not the rigidity satisfying the required specifications can be obtained. If the required specifications are not satisfied, the plate thickness, welding method, reinforcing member, etc. are changed and the rigidity is evaluated again. Specifically, the amount of deformation such as a torsion angle and deflection at the longitudinal position of the body of the automobile is calculated, and it is examined whether the amount of deformation and the vibration mode with respect to the input load of each member are within an allowable range. The stiffness analysis at this time uses the Young's modulus based on the thickness of the material and isotropic in the plate surface, and the stiffness analysis when a steel plate exhibiting strong elastic anisotropy in the plate surface is applied. Not.
On the other hand, in Patent Document 6, although the importance of in-plane anisotropy of Young's modulus on member rigidity is pointed out, it relates to a method of inputting a rolling direction when a processed part is developed into a blank, and Young's modulus The stiffness analysis method considering the in-plane anisotropy and the identification method of the material parameters necessary for the analysis are not shown.
As described above, there is no conventional knowledge on how to rationally and efficiently design a high-rigidity vehicle body using a material with a high Young's modulus in a specific direction, and steel plates with a high Young's modulus in a specific direction have been put to practical use. Not.

  The present invention has been made in view of the above points, and enables the rigidity of a structure made of a metal plate having Young's modulus in-plane anisotropy to be accurately evaluated, and further has a structure with excellent rigidity. The objective is to be able to determine the optimal planing direction for obtaining the body.

In order to solve the above-mentioned problems, the present inventor has conceived the present invention shown below as a result of intensive studies. The gist of the present invention is as follows.
(1) A structure rigidity evaluation method for evaluating the rigidity of a structure made of a metal plate having in-plane anisotropy of Young's modulus,
Computer
A first step of inputting material characteristic values from a database for a metal plate that is a material of a target structure;
A second step of obtaining a material parameter in a reference direction necessary for stiffness analysis from the material characteristic value input in the first step;
A third step of obtaining a material parameter in an angle θ direction (hereinafter, referred to as a material parameter in the cutting direction) formed from the reference direction material parameter obtained in the second step;
And a fourth step of performing a stiffness analysis of the target structure using the material parameters in the planing direction obtained in the third step.
(2) The angle θ formed by the reference direction and the planing direction is changed in a plurality of stages, the third step and the fourth step are repeated, and the planing direction that maximizes the rigidity is determined. The structure rigidity evaluation method according to (1).
(3) In the first step, at least three or more of the thickness t of the metal plate and the Young's modulus E (θ) in the angle θ direction from the rolling direction are input from the database,
In the second step, the two-dimensional orthogonal anisotropy parameters S ₁₁₁₁ , S ₁₁₂₂ , S ₂₂₂₂ , S ₁₂₁₂ in the rolling direction are used as material parameters in the reference direction, and the Young's modulus E _cal ( The structural rigidity evaluation method according to (1) or (2), wherein θ) is calculated and calculated by fitting that minimizes an error from Young's modulus E (θ).
(4) In the first step, from the database, the thickness t of the metal plate, the Young's modulus E (0) in the rolling direction, the Young's modulus E (90) in the 90 ° direction from the rolling direction, the Poisson's ratio ν, the shear elasticity Enter the rate G,
In the second step, the two-dimensional orthogonal anisotropy parameters S ₁₁₁₁ , S ₁₁₂₂ , S ₂₂₂₂ , S ₁₂₁₂ in the rolling direction are set as S ₁₁₁₁ = 1 / E (0), S ₁₁₂₂ = The method for evaluating rigidity of a structure according to (1) or (2), wherein -ν / E (0), S ₂₂₂₂ = 1 / E (90), and S ₁₂₁₂ = ¼G are calculated.
(5) In the third step, S _ijkl = r _mi r _nj r _ok r _pl S _mnop (where r ₁₁ = r ₂₂ = cos θ, r ₁₂ = −r ₂₁ = (sin θ) is obtained. The structure rigidity evaluation method according to any one of (1) to (4).
(6) A structure rigidity evaluation apparatus for evaluating the rigidity of a structure made of a metal plate having in-plane anisotropy of Young's modulus,
Material characteristic value input means for inputting material characteristic values from the database for the metal plate that is the material of the target structure,
First calculation means for obtaining a material parameter in a reference direction necessary for rigidity analysis from the material characteristic value input by the material characteristic value input means;
Second computing means for obtaining a material parameter in an angle θ direction (hereinafter referred to as a material parameter in the cutting direction) formed by the reference direction and the material parameter in the reference direction obtained by the first calculating means; ,
A structure rigidity evaluation apparatus comprising: a rigidity analysis means for performing a rigidity analysis of a target structure using the material parameters in the planing direction obtained by the second calculation means.
(7) A program for evaluating the rigidity of a structure made of a metal plate having in-plane anisotropy of Young's modulus,
For the metal plate that is the material of the target structure, the process of inputting the material characteristic value from the database,
A process for obtaining a material parameter in a reference direction necessary for rigidity analysis from the input material characteristic value;
A process for obtaining a material parameter in an angle θ direction (hereinafter, referred to as a material parameter in the cutting direction) from the obtained reference direction material parameter;
A program for causing a computer to execute a process of performing rigidity analysis of a target structure using the obtained material parameters in the cutting direction.
(8) A computer-readable storage medium storing the program according to (7).

  ADVANTAGE OF THE INVENTION According to this invention, the rigidity of the structure which consists of a metal plate which has in-plane anisotropy of Young's modulus can be evaluated exactly. Furthermore, it is possible to determine an optimum planing direction for obtaining a structure having excellent rigidity. As a result, it is possible to rationally and efficiently design a high-rigidity vehicle body using a material having a high Young's modulus in a specific direction.

It is a figure which shows the function structure of the rigidity evaluation apparatus of the structure which concerns on embodiment. It is a flowchart which shows the flow of the process which evaluates rigidity for vehicle body design. It is a characteristic view which shows the relationship between the boarding direction and torsional rigidity in an Example. It is a figure which shows the structural example of the computer apparatus which can function as a rigidity evaluation apparatus of a structure.

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.
FIG. 1 shows a functional configuration of a structure rigidity evaluation apparatus 100 according to the embodiment. The structure rigidity evaluation apparatus 100 evaluates the rigidity of a structure made of a metal plate having in-plane anisotropy of Young's modulus.
Reference numeral 101 denotes a database in which material characteristic values are registered.
Reference numeral 102 denotes a material characteristic value input unit that inputs material characteristic values from the database 101 for the metal plate that is the material of the target structure.
Reference numeral 103 denotes a first calculation unit, which obtains a material parameter in a reference direction necessary for stiffness analysis from the material property value input by the material property value input unit 102.
Reference numeral 104 denotes a second calculation unit, which is based on the material parameter in the direction θ (hereinafter referred to as the plate cutting direction θ) formed by the reference direction and the plate cutting direction based on the material parameter in the reference direction obtained by the first calculation unit 103. Hereinafter, it is referred to as a material parameter in the direction of cutting.
Reference numeral 105 denotes a stiffness analysis unit, which performs the stiffness analysis of the target structure using the material parameters in the planing direction obtained by the second calculation unit 104.
106 is a planing direction determination unit, which changes the planing direction θ by a plurality of stages, repeats the processing of the second calculation unit 104 and the processing of the stiffness analysis unit 105, and determines the planing direction θ that maximizes the rigidity. To do.

Referring to FIG. 2, the flow of processing for evaluating the rigidity of automobile parts for vehicle body design is shown.
In designing the vehicle body, first, the structure of the automobile is set (step S1), then the shape of the automobile part that is the target structure is set using CAD (step S2), and the three-dimensional automobile part is recorded. It should be noted that the processing in steps S1 and S2 may be performed by the structure rigidity evaluation apparatus 100, or a result obtained by another computer apparatus may be input to the structure rigidity evaluation apparatus 100. May be.

The material characteristic value input unit 102 takes in the material characteristic values of the steel sheet that is the material of the target structure from the database 101 (step 3). As material property value,
(1) At least three or more of sheet thickness t, density ρ, Poisson's ratio ν, Young's modulus E (θ) in the direction of angle θ from the rolling direction,
Or
(2) Sheet thickness t, density ρ, Poisson's ratio ν, shear modulus G, Young's modulus E (0) in the rolling direction, Young's modulus E (90) in the 90 ° direction from the rolling direction
By incorporating, elastic anisotropy in the plate surface can be reflected in the stiffness analysis.

Next, the 1st calculating part 103 calculates | requires the material parameter of the rolling direction which is a reference direction from the material characteristic value input at step S3 (step 4). In the material coordinate system in which the rolling direction and the width direction are x ₁ and x ₂ respectively, the relationship between the in-plane strain ε _ij and stress σ _kl is ε _ij = s _ijkl σ _kl (i, j, k, l = 1, 2) and the material parameter is s _ijkl .
Here, when stress and strain are displayed in matrix notation according to γ ₁ = ε ₁₁ , γ ₂ = ε ₂₂ , γ ₃ = 2ε ₁₂ , and τ ₁ = σ ₁₁ , τ ₂ = σ ₂₂ , τ ₃ = σ ₁₂ , Rewritten as γ _m = S _mn τ _n (m, n = 1, 2, 3), and the two-dimensional orthotropic elastic matrix S ₁₁ = s ₁₁₁₁ , S ₁₂ = s ₁₁₂₂ , S ₁₃ = 2s ₁₁₁₂ in the rolling direction. S ₂₂ = s ₂₂₂₂ , S ₂₃ = 2s ₂₂₁₂ , S ₃₃ = 4s ₁₂₁₂ . Furthermore, assuming that a uniaxial stress is applied in the direction of angle θ from the rolling direction, and setting an experimental coordinate system in which the axial direction is X ₁ and the orthogonal direction is X ₂ , the coordinate transformation rule is X _i = r _ij x _j (r ₁₁ = r ₂₂ = cos θ, r ₁₂ = −r ₂₁ = sin θ). Each E _ij components of the strain and stress in the experimental coordinate system, when _{Σ ij, Ε ij = r ik} ε kl r jl, a _{σ kl = r ik Σ ij r} jl, strain gamma _m in experimental coordinate system stress T relationship _{m Γ m = p mu S uv} q vn Τ n is obtained and.
In the rolled steel sheet, the material coordinate system (x ₁ , x ₂ ) is the main axis of orthotropic anisotropy, but the fact that the stress-strain relational expression is invariant with respect to coordinate transformation with these as symmetry lines is used. S ₁₃ = S ₂₃ = 0 can be derived, and the number of material parameters to be identified is S ₁₁ , S ₁₂ , S ₂₂ , S ₃₃ .
In order to express the in-plane anisotropy of Young's modulus, it is preferable to determine material parameters by fitting by least square approximation to three or more measured values. Specifically, since p _mu S _uv q _vn is determined for a certain direction θ, the reciprocal 1/1 of Γ ₁ obtained for (Τ ₁ , Τ ₂ , Τ ₃ ) = (1, 0, 0) the first approximation E _cal of gamma ₁ is the Young's modulus in that direction (theta) is calculated, material parameters s ₁₁₁₁ = S ₁₁ by the least squares method so that the error obtained by the following formula (1) is minimized, s _{1122 = S 12 = -νS 11,} s 2222 = can determine _{S 22, s 1212 = S 33} /4.

Further, when sheet thickness t, density ρ, Poisson's ratio ν, shear modulus G, Young's modulus E (0) in the rolling direction, and Young's modulus E (90) in the 90 ° direction from the rolling direction are given, S ₁₁₁₁ = 1 / E (0), S ₁₁₂₂ = −ν / E (0), S ₂₂₂₂ = 1 / E (90), S ₁₂₁₂ = 1 / 4G.

Next, the 2nd calculating part 104 calculates | requires the material parameter of a boarding direction from the material parameter calculated | required by step S4 (step S5). In the material coordinate system in which the rolling direction and the width direction are respectively x ₁ and x ₂ , when the orthogonal coordinate system when the plate is cut in the angle θ direction from the rolling direction is X ₁ and X ₂ , the material parameters in the plate direction are , Elastic matrix S _ijkl = r _mi r _nj r _ok r _pl S _mnop (where r ₁₁ = r ₂₂ = cos θ, r ₁₂ = −r ₂₁ = sin θ).

Next, the stiffness analysis unit 105 simulates elastic deformation such as bending, torsion, and vibration acting on the structure using the material parameters in the planing direction obtained by the second calculation unit 104, and performs stiffness analysis. Do. For analysis of torsional rigidity when stripping from the rolling direction to the θ direction, the two-dimensional orthogonal anisotropy parameters S ₁₁₁₁ , S ₁₁₂₂ , S ₂₂₂₂ , S _{1212 in} the rolling direction and the material parameters in the stripping direction from the coordinate transformation law are used. (Step 6).

  Next, it is determined whether or not to end the rigidity analysis (step S7). In a material that exhibits strong elastic anisotropy in the plate surface, the member rigidity changes greatly depending on the plate taking direction θ, so the angle θ is changed by a plurality of steps (step S8), and steps S5 and S6 are repeated. For example, the cutting direction θ is changed every 15 ° from 0 ° to 90 ° in the rolling direction, and step S5 and step S6 are repeated.

  When the stiffness analysis is completed, the planing direction determination unit 106 determines the planing direction θ that maximizes the rigidity while changing the planing direction θ by a plurality of stages (step S9).

  Next, it is evaluated whether or not the rigidity satisfying the required specifications can be obtained (step 10). If satisfied, the process is terminated. If not satisfied, change material (change of plate thickness, etc.), change fastening method (change of welding method, etc.), change structure (addition of reinforcing material, etc.) (step S11), return to step S2 or step S3, The rigidity is evaluated again. If it is a material change, it will return to step S3 and newly take in a material characteristic value, and if it is a fastening direction change or a structure change, it will return to step S2 and will newly set the shape of a motor vehicle part using CAD.

Hereinafter, the present invention will be described based on examples. The test material is a steel plate for automobiles with a thickness of 1.2 mm having strong elastic anisotropy in the plate surface, and Young's moduli in the rolling direction of 0 °, 45 °, and 90 ° are 205, 195, and 230 GPa, respectively. . Evaluation of the effect of in-plane anisotropy of Young's modulus on torsional rigidity when this is applied to a rectangular tube member having a closed cross section of 80 × 80 mm and a length of 300 mm. It was investigated.
After fixing the node displacement and rotation at the end of the member, the deformation when a torsional moment of 1.5 kNm was applied to the other end was analyzed. The analysis model was discretized with a 4-node quadratic bilinear thick shell element of 2 mm × 2 mm, and a two-dimensional orthotropic material was used as the material model. In the material coordinate system in which the rolling direction and the width direction are x ₁ and x ₂ , the material parameters are obtained by the method described above, and S ₁₁₁₁ = 4.88 [TPa ⁻¹ ] and S ₂₂₂₂ = 4.36 [TPa ^{−. 1} ], S ₁₂₁₂ = 3.47 [TPa ^-1 ], and S ₁₁₂₂ = -1.43 [TPa ^-1 ]. Here, the case where the sheet is cut in the direction of the angle θ = 0 °, 22.5 °, 45 °, 67.5 °, 90 ° from the rolling direction on the basis of the rolling direction of the material is set, and the torsional rigidity is analyzed. It was.
FIG. 3 shows the relationship between the planing direction and torsional rigidity. As shown in FIG. 3, it can be seen that the plate can be cut in a 45 ° direction from the rolling direction in order to maximize the torsional rigidity of the member.

As described above, the rigidity of a structure made of a metal plate having in-plane anisotropy of Young's modulus can be accurately evaluated. Furthermore, it is possible to determine an optimum planing direction for obtaining a part having excellent rigidity. As a result, it is possible to rationally and efficiently design a high-rigidity vehicle body using a material having a high Young's modulus in a specific direction.
As a result, the steel plate with strong elastic anisotropy in the plate surface is cut in the optimum direction on the premise of assembly by conventional cold press and spot welding without introducing new resin bonding equipment etc. As a result, the rigidity of the automobile frame parts such as the side member, the sill, and the center pillar can be increased, and the thickness can be reduced without impairing the rigidity.
As described above, the present invention has been described in detail using an example of an automobile part. However, the present invention can be applied to any structure made of a metal plate having in-plane anisotropy of Young's modulus.

Each step of the structure rigidity evaluation method according to the present invention can be realized, for example, by the CPU operating a program stored in a RAM, a ROM, or the like. This program and a computer-readable storage medium storing the program are included in the present invention.
Specifically, this program is recorded on a storage medium such as a CD-ROM, or provided to a computer via various transmission media. As a storage medium for recording the program, a flexible disk, a hard disk, a magnetic tape, a magneto-optical tape, a nonvolatile memory card, and the like can be used in addition to the CD-ROM. On the other hand, as a transmission medium for this program, a communication medium in a computer network system for propagating and supplying program information as a carrier wave can be used. Here, the computer network is a WAN such as a LAN or the Internet, a wireless communication network, or the like, and the communication medium is a wired line or a wireless line such as an optical fiber.
Further, the program included in the present invention is not limited to the one in which the functions of the above-described embodiments are realized by the computer executing the supplied program. For example, such a program is also included in the present invention when the function of the present invention is realized in cooperation with an OS (operating system) running on a computer or other application software. In addition, when all or part of the processing of the supplied program is performed by a function expansion board or a function expansion unit of a computer and the functions of the present invention are realized, such a program is also included in the present invention.

The structure rigidity evaluation apparatus according to the present invention can be realized by, for example, a computer apparatus as shown in FIG. A personal computer (PC) 400 includes a CPU 401 and executes device control software stored in a ROM 402 or a hard disk (HD) 411 or supplied from a flexible disk drive (FD) 412. The RAM 403 functions as a main memory, work area, and the like for the CPU 401.
The PC 400 generally controls each device connected to the system bus 404. Reference numeral 405 denotes a keyboard controller (KBC) that controls input of instructions from a keyboard (KB) 409, a device (not shown), and the like. A CRT controller (CRTC) 406 controls display on a CRT display (CRT) 410. Reference numeral 407 denotes a disk controller (DKC). The DKC 407 controls access to the HD 411 and the FD 412 that store a boot program, a plurality of applications, an edit file, a user file, a network management program, and the like. Here, the boot program is a startup program: a program for starting execution of hardware and software of a personal computer. 408 exchanges data bidirectionally with a network printer, another network device, or another PC.

  DESCRIPTION OF SYMBOLS 100: Structure rigidity evaluation apparatus, 101: Database, 102: Material characteristic value input part, 103: 1st calculating part, 104: 2nd calculating part, 105: Stiffness analysis part, 106: Planing direction determination part

Claims (8)

A structure rigidity evaluation method for evaluating the rigidity of a structure made of a metal plate having in-plane anisotropy of Young's modulus,
Computer
A first step of inputting material characteristic values from a database for a metal plate that is a material of a target structure;
A second step of obtaining a material parameter in a reference direction necessary for stiffness analysis from the material characteristic value input in the first step;
A third step of obtaining a material parameter in an angle θ direction (hereinafter, referred to as a material parameter in the cutting direction) formed from the reference direction material parameter obtained in the second step;
And a fourth step of performing a stiffness analysis of the target structure using the material parameters in the planing direction obtained in the third step.   The angle θ formed by the reference direction and the planing direction is changed by a plurality of stages, and the third step and the fourth step are repeated to determine the planing direction that maximizes the rigidity. 2. The method for evaluating rigidity of a structure according to 1. In the first step, at least three or more of the thickness t of the metal plate and the Young's modulus E (θ) in the angle θ direction from the rolling direction are input from the database,
In the second step, the two-dimensional orthogonal anisotropy parameters S ₁₁₁₁ , S ₁₁₂₂ , S ₂₂₂₂ , S ₁₂₁₂ in the rolling direction are used as material parameters in the reference direction, and the Young's modulus E _cal ( 3. The structure rigidity evaluation method according to claim 1 or 2, wherein [theta] is calculated and calculated by fitting that minimizes an error from Young's modulus E ([theta]). In the first step, the metal sheet thickness t, the Young's modulus E (0) in the rolling direction, the Young's modulus E (90) in the 90 ° direction from the rolling direction, the Poisson's ratio ν, and the shear modulus G are obtained from the database. type in,
In the second step, the two-dimensional orthogonal anisotropy parameters S ₁₁₁₁ , S ₁₁₂₂ , S ₂₂₂₂ , S ₁₂₁₂ in the rolling direction are set as S ₁₁₁₁ = 1 / E (0), S ₁₁₂₂ = The structural rigidity evaluation method according to claim 1, wherein calculation is performed as −ν / E (0), S ₂₂₂₂ = 1 / E (90), and S ₁₂₁₂ = 1 / 4G. In the third step, S _ijkl = r _mi r _nj r _ok r _pl S _mnop (where r ₁₁ = r ₂₂ = cos θ, r ₁₂ = −r ₂₁ = sin θ) is used as a material parameter in the _planing direction. The structure rigidity evaluation method according to claim 1, wherein the structure rigidity evaluation method is obtained. A structure rigidity evaluation apparatus for evaluating the rigidity of a structure made of a metal plate having in-plane anisotropy of Young's modulus,
Material characteristic value input means for inputting material characteristic values from the database for the metal plate that is the material of the target structure,
First calculation means for obtaining a material parameter in a reference direction necessary for rigidity analysis from the material characteristic value input by the material characteristic value input means;
Second computing means for obtaining a material parameter in an angle θ direction (hereinafter referred to as a material parameter in the cutting direction) formed by the reference direction and the material parameter in the reference direction obtained by the first calculating means; ,
A structure rigidity evaluation apparatus comprising: a rigidity analysis means for performing a rigidity analysis of a target structure using the material parameters in the planing direction obtained by the second calculation means. A program for evaluating the rigidity of a structure made of a metal plate having in-plane anisotropy of Young's modulus,
For the metal plate that is the material of the target structure, the process of inputting the material characteristic value from the database,
A process for obtaining a material parameter in a reference direction necessary for rigidity analysis from the input material characteristic value;
A process for obtaining a material parameter in an angle θ direction (hereinafter, referred to as a material parameter in the cutting direction) from the obtained reference direction material parameter;
A program for causing a computer to execute a process of performing rigidity analysis of a target structure using the obtained material parameters in the cutting direction.   A computer-readable storage medium storing the program according to claim 7.

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