Structural design support device, structural design support method, program, and recording medium

Abstract

This invention provides a structural design support device, a structural design support method, a program, and a recording medium that are also applicable to nonlinear analysis. [Solution] The structural design support device comprises an element information acquisition unit that acquires element information when a load is applied to a structure containing multiple elements, and a parameter calculation unit that calculates information regarding the deformation mode of the elements using the element information.

Description

[Technical Field]

[0001] This disclosure relates to a structural design support device, a structural design support method, a program, and a recording medium. [Background technology]

[0002] Conventionally, various structural design support devices have been proposed for evaluating and analyzing structures during the design phase. Generally, computers are used as structural design support devices, and programs for having the computer evaluate and analyze structures, as well as systems that implement these programs, have been proposed. In such structural design support devices, a model is constructed that represents the entire structure to be designed or each component of the structure divided into small regions (elements), and this model is used to simulate the response to external force inputs, and the obtained results are used to carry out the design.

[0003] Patent Document 1 discloses a structural design support device having a storage unit that stores numerical analysis data for each part constituting at least a part of a structure composed of one or more parts, a calculation unit that calculates the stiffness of the structure under specific boundary conditions based on the numerical analysis data stored in the storage unit, and calculates the sensitivity of the parts to the stiffness of the structure based on the calculated stiffness, and an output unit that outputs information regarding the deformation mode of the parts under boundary conditions based on the sensitivity calculated by the calculation unit. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2012-8787 [Overview of the project] [Problems that the invention aims to solve]

[0005] However, the structural design support device described in Patent Document 1 was difficult to apply to nonlinear analyses such as collision analysis.

[0006] This invention was made in view of the above circumstances, and aims to provide a structural design support device, a structural design support method, a program, and a recording medium that can also be applied to nonlinear analysis. [Means for solving the problem]

[0007] To solve the aforementioned problems, the present invention proposes the following means. (1) A structural design support device according to aspect 1 of the present invention, When a load is applied to a structure containing multiple elements, The coordinates of the nodes of the aforementioned element, A first stress parameter which is a first stress tensor or a part of the components of the first stress tensor that occurs on the first surface, which is one of the surfaces of the element, A second stress parameter which is a second stress tensor or a part of the components of the second stress tensor occurring on the second surface, which is the surface opposite to the first surface of the element, An element information acquisition unit that acquires element information including; A parameter calculation unit that uses the element information to calculate information regarding the deformation mode of the element from the first stress parameter and the second stress parameter; It is equipped with. (2) Embodiment 2 of the present invention is a structural design support device of Embodiment 1, The first stress parameter is the maximum principal stress vector occurring on the first surface, The second stress parameter is the minimum principal stress vector occurring on the second surface. (3) Aspect 3 of the present invention is a structural design support device according to aspect 1 or 2, The parameter calculation unit calculates transfer parameters from information regarding the deformation mode and parameters calculated from the stresses occurring on the first and second surfaces. (4) Aspect 4 of the present invention is a structural design support device of Aspect 3, The parameter calculated from the aforementioned stress is the average of the von Mises stress occurring on the first surface and the von Mises stress occurring on the second surface. (5) Embodiment 5 of the present invention is a structural design support device according to any one of Embodiments 1 to 4, The aforementioned element is a shell element. (6) The structural design support method according to aspect 6 of the present invention is In a structure consisting of multiple elements, when a load is applied, The coordinates of the nodes and integration points of the aforementioned element, A first stress parameter which is a first stress tensor or a part of the components of the first stress tensor that occurs on the first surface, which is one of the surfaces of the element, A second stress parameter which is a second stress tensor or a part of the components of the second stress tensor occurring on the second surface, which is the surface opposite to the first surface of the element, The first process involves obtaining element information including; A second process of calculating information regarding the deformation mode of the element from the first stress parameter and the second stress parameter using the element information; Includes. (7) Aspect 7 of the present invention is a structural design support method of Aspect 6, In the second process described above, transfer parameters are calculated from information regarding the deformation mode and parameters calculated from the stresses occurring on the first and second surfaces. (8) Aspect 8 of the present invention is the structural design support method of Aspect 7, The parameter calculated from the aforementioned stress is the average of the von Mises stress occurring on the first surface and the von Mises stress occurring on the second surface. (9) The program of aspect 9 of the present invention is Computer When a load is applied to a structure consisting of multiple elements, The coordinates of the nodes of the aforementioned element, A first stress parameter which is a first stress tensor or a part of the components of the first stress tensor that occurs on the first surface, which is one of the surfaces of the element, A second stress parameter which is a second stress tensor or a part of the components of the second stress tensor occurring on the second surface, which is the surface opposite to the first surface of the element, An element information acquisition unit that acquires element information including; A parameter calculation unit that uses the element information to calculate information regarding the deformation mode of the element from the first stress parameter and the second stress parameter; To make it function as such. (10) A computer-readable recording medium according to aspect 10 of the present invention records the program according to aspect 9. [Effects of the Invention]

[0008] According to each of the above aspects of the present invention, it is possible to provide a structural design support device, a structural design support method, a program, and a recording medium that can also be applied to nonlinear analysis. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic block diagram showing the configuration of a structural design support device 10 according to the first embodiment of the present invention. [Figure 2] This is a flowchart illustrating the operation of the parameter calculation unit 13. [Figure 3] This diagram shows the positional relationship between shell elements, nodes, and integration points. [Figure 4] This diagram illustrates the relationship between the maximum principal stress vector σ1 and the minimum principal stress vector σ2 on the same plane. [Figure 5] This figure shows the relationship between the maximum principal stress vector σ1top generated on the first face Ptop of an element during in-plane deformation and the minimum principal stress vector σ2bottom generated on the second face Pbottom. [Figure 6] This figure shows the relationship between the maximum principal stress vector σ1top generated on the first face Ptop of an element when it undergoes out-of-plane deformation and the minimum principal stress vector σ2bottom generated on the second face Pbottom. [Figure 7] This diagram shows the positional relationship between shell elements, nodes, and integration points. [Figure 8] This is a schematic block diagram showing the configuration of the structural design support device 10A according to the second embodiment. [Figure 9] This is a flowchart illustrating the operation of the parameter calculation unit 13A. [Figure 10] This is a diagram illustrating the structural model used in the analysis. [Figure 11] This is the result of analysis using the method described in Patent Document 1. [Figure 12] This is a distribution diagram of bending deformation. [Figure 13] This is a distribution diagram of transfer parameters. [Modes for carrying out the invention]

[0010] <First Embodiment> The structural design support device, structural design support method, program, and recording medium of this disclosure will be described below with reference to the drawings. Figure 1 is a schematic block diagram showing the configuration of the structural design support device 10 according to the first embodiment. The structural design support device 10 comprises an element information acquisition unit 11, an element information storage unit 12, a parameter calculation unit 13, an image creation unit 14, and a display unit 15. The structural design support device 10 evaluates a structure consisting of multiple parts using a virtual model (hereinafter referred to as "structure"). The structure is assembled from multiple parts joined together, for example, by welding, riveting, bolting, etc. The structure includes multiple elements. In addition to elements, the structure may also include nodes, material properties, element properties, boundary conditions, contact definitions, etc. The elements constituting the structure are not particularly limited as long as it is possible to calculate a first stress parameter occurring on a first face, which is one face of the element, and a second stress parameter occurring on a second face, which is the opposite face of the element. The first stress parameter is a first stress tensor or a part of the components of the first stress tensor. The second stress parameter is a second stress tensor or a part of the components of the second stress tensor. Examples of elements constituting the structure include shell elements and solid elements. It is preferable that the elements constituting the structure include at least one of shell elements and solid elements. Shell elements are preferred for the elements constituting the structure. A shell element is an element that appears to be just a surface with zero thickness, but has a rigidity equal to the plate thickness in calculations. A solid element is an element that has a three-dimensional, three-dimensional shape.

[0011] "Element Information Acquisition Unit 11" The element information acquisition unit 11 acquires element information including the coordinates of the nodes of the elements constituting the structure to be evaluated, the first stress parameter occurring on the first face, which is one face of the element, and the second stress parameter occurring on the second face, which is the opposite face of the element. Here, the coordinates of the integration point are derived from the shape function of the element and the node coordinates. An integration point is a point where a quadratic solution (such as stress or strain) is calculated using a degree-of-freedom solution. A node is a point located on the boundary of an element that connects elements as a result of dividing the structure into multiple elements. The element information acquisition unit 11 acquires element information in the state where a load is input to the structure (input state). The element information acquisition unit 11 may further acquire element information in the state where no external load is applied to the structure (static state). Element information (such as the maximum principal stress on the first face and the minimum principal stress on the second face) is, for example, information about the elements (e.g., shell elements) in the finite element method when the structure in each state is analyzed using the finite element method. Elemental information is calculated by performing static analysis, eigenvalue analysis, collision analysis, frequency response analysis, etc. on the structure. Elemental information may also be calculated using numerical simulations other than the finite element method. Elemental information may also be calculated using experimentally obtained stress tensors. For example, stress tensors may be calculated from strains obtained using methods such as the strain gauge method or digital image correlation (DIC), and elemental information may be calculated using the obtained stress tensors.

[0012] "Element Information Storage Unit 12" The element information storage unit 12 stores the element information acquired by the element information acquisition unit 11. That is, the element information storage unit 12 stores element information in the input state of multiple elements provided in a structural model composed of multiple parts. The element information storage unit 12 may also store element information in a stationary state (initial state). The element information storage unit 12 may also store information as element information indicating which of the multiple parts the element belongs to. The element information storage unit 12 may also store information related to deformation modes, which will be described later.

[0013] "Parameter calculation unit 13" The parameter calculation unit 13 uses the element information acquired by the element information acquisition unit 11 to calculate information regarding the deformation mode of the element from the first stress parameter and the second stress parameter. Information regarding the deformation mode includes bending deformation degree and transmission parameters. Details of the method by which the parameter calculation unit 13 calculates the bending deformation degree will be described later. The parameter calculation unit 13 sends the calculated information regarding the deformation mode to the image creation unit 14. The information regarding the deformation mode calculated by the parameter calculation unit 13 may be stored in the element information storage unit 12 or displayed by the display unit 15.

[0014] "Image Creation Section 14" The image creation unit 14 creates an image in which information about the deformation mode is visible at the position of the element in the structure (structure model). For example, the image creation unit 14 generates a three-dimensional image of the structure model in which the deformation mode information of each element calculated by the parameter calculation unit 13 is represented by shades of gray. Alternatively, the deformation mode information of each element may be represented in color instead of shades of gray. The image creation unit 14 sends the created image to the display unit 15.

[0015] "Display section 15" The display unit 15 may display information about the deformation mode calculated by the parameter calculation unit 13, or it may display a three-dimensional image of the structural model generated by the image creation unit 14.

[0016] <Structure design support method> The structural design support method of this disclosure includes a first step of acquiring element information, which includes the coordinates of the nodes of an element (e.g., a shell element), a first stress parameter occurring on a first face, which is one face of the element, and a second stress parameter occurring on a second face, which is the opposite face of the element, in a state in which a load is applied to a structure consisting of multiple elements (input state). The structural design support method of this disclosure further includes a second step of using the element information acquired in the first step to calculate information regarding the deformation mode of the element from the first stress parameter and the second stress parameter. In the second step, for example, the degree of bending deformation is calculated as information regarding the deformation mode from a function of the angular difference between the maximum principal stress vector and the minimum principal stress vector.

[0017] "The first process" In the first process, element information is obtained, including the coordinates of the nodes of the elements constituting the structure to be evaluated, a first stress parameter occurring on one face of the element (the first face), and a second stress parameter occurring on the second face opposite the first face of the element. In the first process, element information is obtained in the state where a load is applied to the structure (input state). In the first process, element information may be further obtained in the state where no external load is applied to the structure (initial state). Element information is, for example, information about the elements in the finite element method (e.g., shell elements) when the structure is analyzed using the finite element method in each state. Element information is calculated by performing static analysis, eigenvalue analysis, collision analysis, frequency response analysis, etc. on the structure. Element information may also be calculated by numerical simulation other than the finite element method, for example.

[0018] "The second process" In the second process, using the element information obtained in the first process, information regarding the deformation mode of the element is calculated from the first stress parameter and the second stress parameter. In the following description, an example is given in which the first stress parameter is the maximum principal stress vector, the second stress parameter is the minimum principal stress vector, and the deformation mode information is the degree of bending deformation, but the present invention is not limited to the maximum principal stress vector, the minimum principal stress vector, and the degree of bending deformation. Furthermore, a method for calculating the degree of bending deformation using the parameter calculation unit 13 of the structural design support device 10 is described, but the present invention is not limited to the following method.

[0019] (Operation of the parameter calculation unit 13) Figure 2 is a flowchart illustrating the operation of the parameter calculation unit 13. The parameter calculation unit 13 performs steps S1 to S3 for each element included in the element information stored in the element information storage unit 12 (steps S1 to S3). In step S1, one of the unprocessed elements is selected and designated as element i (for example, initial value i=0). Next, the parameter calculation unit 13 reads element information from the element information storage unit 12, including the coordinates of the element's nodes in the input state, the maximum principal stress vector occurring on the first face (one of the elements' faces), and the minimum principal stress vector occurring on the second face (the opposite face of the element's face).

[0020] In step S2, the parameter calculation unit 13 uses the element information read from the element information storage unit 12 to calculate the degree of bending deformation of the element from the maximum principal stress vector of the first face and the minimum principal stress vector of the second face. As will be described later, the parameter calculation unit 13 calculates the degree of bending deformation from a function of the angular difference between the maximum principal stress vector and the minimum principal stress vector.

[0021] In step S3, if there are any elements for which the degree of bending deformation has not been determined (unprocessed elements) (YES in step S3), return to step S1 and select one of the unprocessed elements to process. If there are no unprocessed elements among the elements (NO in step S3), terminate the process.

[0022] "Method for calculating bending deformation" The bending deformation degree will be explained below using the case where the element is a shell element as an example. First, the target shell element will be described. Figure 3 is a diagram showing the positional relationship between the shell element and the nodes and integration points. In the example in Figure 3, the shell element SE1 has nodes n1, n2, n3, n4 and integration points I1, I2, I3. Nodes n1, n2, n3, n4 are set at the center of the shell element SE1 in the thickness direction and at the edges of the shell element (the four corners of the square if the shell element is a square in plan view). Integration point I2 is set at the center of the shell element SE1 (here, the center in the thickness direction and the center in the plane). Integration point I1 is on the first plane P top Set on the side, the integration point I3 is on the second plane P. bottom It is set on the side. For example, integration points I11, I2, and I3 are set based on the Gaussian integration point arrangement. When the thickness of the element is t, for example, the distance from the top surface of the element to integration point I1 (distance in the thickness direction) is 0.8872983·t, the distance from the top surface of the element to integration point I2 is 0.50000·t, and the distance from the top surface of the element to integration point I3 is 0.1127017·t. It is preferable that the distance between integration point I1 and integration point I2 is equal to the distance between integration point I2 and integration point I3.

[0023] Next, we will explain the relationship between the maximum principal stress vector σ1 and the minimum principal stress vector σ2 on the same plane. Note that the maximum principal stress σ1 and minimum principal stress σ2 may be obtained from either the element coordinate system or the global coordinate system.

[0024] The stress tensor is represented by equation (1) below. The principal stresses are calculated as solutions to the eigenvalue equations in equation (2) below. Here, if the maximum principal stress is σ1, the minimum principal stress is σ2, and the intermediate principal stress is σ3, then σ1≧σ3≧σ2. In equation (2), I is the identity matrix represented by equation (3) below, and λ is the eigenvalue. The principal stresses (maximum, intermediate, and minimum) are obtained as eigenvalues ​​of the stress tensor. In the case of a two-dimensional stress state, the principal stresses can be obtained from equation (4) below.

[0025]

number

[0026] Figure 4 is a diagram for explaining the relationship between the maximum principal stress vector σ1 and the minimum principal stress vector σ2 on the same plane. The solid line in Figure 4 indicates the maximum principal stress, and the dashed line in Figure 4 indicates the minimum principal stress. As shown in Figure 4, the maximum principal stress vector σ1 and the minimum principal stress vector σ2 on the same plane of the element are orthogonal. Here, if the angle of the maximum principal stress vector σ1 is θ, the angle of the minimum principal stress vector σ2 can be expressed as θ + 0.5π.

[0027] Next, the relationship between the maximum principal stress vector σ 1top on the first surface and the minimum principal stress vector σ 2bottom on the second surface when in-plane deformation and out-of-plane deformation occur is explained. Here, in the following explanation, the maximum principal stress vector σ top generated on the first surface P 1top is obtained by calculating the principal stress generated at the integration point I1 on the first surface P top side, and the minimum principal stress vector σ bottom [[ID=2"]] 2bottom generated on the second surface P bottom is obtained by finding the principal stress vector generated at the integration point I3 on the second surface P

[0028] Figure 5 is a diagram showing the relationship between the maximum principal stress vector σ top generated on the first surface P 1top of the element when in-plane deformed and the minimum principal stress vector σ bottom generated on the second surface P 2bottom The solid line in Figure 5 indicates the maximum principal stress vector σ top generated on the first surface P 1top , and the dashed line in Figure 5 indicates the minimum principal stress vector σ bottom generated on the second surface P 2bottom As shown in Figure 5, when in-plane loads such as tension, compression, and shear are input to the element, the stress states of the first surface (here, the upper surface) and the second surface (here, the lower surface) of the element are the same. Therefore, the angle θ top formed by the maximum principal stress vector σ 1top generated on the first surface P top and the minimum principal stress vector σ bottom ​The maximum principal stress vector σ that occurs in this location 1bottom angle θ bottom Between, θ top =θ bottom Therefore, the first plane P in in-plane deformation holds true. top The maximum principal stress vector σ that occurs in this location 1top and the second side P bottom The minimum principal stress vector σ that occurs in this case 2bottom The angle difference is -0.5π.

[0029] Next, when plate bending (out-of-plane load) is input to shell element SE1, the maximum principal stress vector σ of the first face is considered. 1top and the minimum principal stress vector σ of the second surface 2bottom This explains the relationship. Figure 6 shows the first face P of the element when it undergoes out-of-plane deformation. top The maximum principal stress vector σ that occurs in this location 1top and the second side P bottom The minimum principal stress vector σ that occurs in this case 2bottom This figure shows the relationship. The solid line in Figure 6 represents the first plane P. top The maximum principal stress vector σ that occurs in this location 1top The dashed line in Figure 6 represents the second plane P. bottom The minimum principal stress vector σ that occurs in this case 2bottom This indicates.

[0030] When plate bending (out-of-plane load) is applied to shell element SE1, the first face P of shell element SE1 top and the second face P of shell element SE1 bottom The stress states that occur are different. The first face P of shell element SE1. top From the second page P bottom Assuming that a load is applied in the direction, the first surface P top The second surface P is bent outwards. bottom The curve is inside, and the first surface P top Tensile stress is present on the lower surface P bottom Compressive stress is applied to it. In the case of out-of-plane deformation, as shown in Figure 6, the first plane P top The maximum principal stress vector σ that occurs in this location 1top and the second side P bottom The minimum principal stress vector σ that occurs in this case 2bottom They become parallel. Therefore, in the case of out-of-plane deformation, the first plane Ptop The maximum principal stress vector σ that occurs in this location 1top and the second side P bottom The minimum principal stress vector σ that occurs in this case 2bottom The angle difference is 0.

[0031] As described above, in the case of in-plane deformation, the first plane P top The maximum principal stress vector σ that occurs in this location 1top and the second side P bottom The minimum principal stress vector σ that occurs in this case 2bottom The angle difference is -π / 2, and in the case of out-of-plane deformation, the first plane P top The maximum principal stress vector σ that occurs in this location 1top and the second side P bottom The minimum principal stress vector σ that occurs in this case 2bottom The angle difference is 0. In other words, the degree of in-plane deformation and out-of-plane deformation (bending deformation) is the first plane P top The maximum principal stress vector σ that occurs in this location 1top and the second side P bottom The minimum principal stress vector σ that occurs in this case 2bottom This can be calculated using a function of the angle difference.

[0032] The parameter calculation unit 13 may calculate the degree of bending deformation b as a function of the angle difference using the following equation (5). In the following equation (5), θ top This is the first face P top The maximum principal stress vector σ that occurs in this location 1top The angle is shown as θ bottom This is the second side P bottom The maximum principal stress vector σ that occurs in this location 2top This indicates the angle of the second face P. bottom The minimum principal stress vector σ that occurs in this case 2bottom The angle is θ bottom This results in +0.5π. In this case, the closer the deformation is to in-plane deformation, the closer the bending deformation b approaches 0, and the closer the deformation is to out-of-plane deformation, the closer the bending deformation b approaches 1. b = cos{θ top -(θ bottom +0.5π)}···(5)

[0033] The structural design support apparatus 10 and the structural design support method of the present disclosure have been described above. The structural design support apparatus 10 of the present disclosure is the maximum principal stress vector σ top generated on the first surface P 1top and the minimum principal stress vector σ bottom generated on the second surface P 2bottom to calculate the bending deformation degree as a function of the angular difference. Therefore, the bending deformation degree can be quantified even in a non-linear analysis such as a collision analysis.

[0034] In the first embodiment, the shell element SE1 had three integration points in the thickness direction, but in the present invention, the number of integration points is not particularly limited. For example, the number of integration points may be 1 or more. When the number of integration points is an odd number of 3 or more (for example, the number of integration points is 3, 5, 7, 9, 11), the maximum principal stress vector σ top generated on the first surface P 1top may be obtained from the principal stress vector generated at any one of the integration points on the first surface P top side selected from the integration points located at the center in the thickness direction (thickness center integration point). Similarly, the minimum principal stress vector σ bottom generated on the second surface P 2bottom may be obtained from the principal stress vector generated at any one of the integration points on the second surface P bottom side selected from the integration points located at the center in the thickness direction.

[0035] FIG. 7 is a diagram showing the positional relationship between the nodes and the integration points in the shell element SE2 having only one integration point Ic. The method of obtaining the angular difference between the maximum principal stress vector σ top generated on the first surface P 1top and the minimum principal stress vector σ bottom generated on the second surface P 2bottom will be described. In this case, the stress tensors of the first surface Ptop and the second surface Pbottom can be obtained from the stress at the integration point on the central plane and the bending moment about each axis, and the principal stress vector can be obtained.

[0036] In the first embodiment, the degree of bending deformation was determined for each element, but the parameter calculation unit 13 may calculate the degree of bending deformation for each part by calculating the average of the degrees of bending deformation of each element included in the part.

[0037] (Second Embodiment) Next, a structural design support device 10A according to a second embodiment of the present invention will be described with reference to Figure 8. Figure 8 is a schematic block diagram showing the configuration of the structural design support device 10A according to the second embodiment. In this second embodiment, the same reference numerals are used for parts that are the same as those in the first embodiment, and their descriptions may be omitted. The structural design support device 10A includes an element information acquisition unit 11A, an element information storage unit 12A, a parameter calculation unit 13A, an image creation unit 14A, and a display unit 15A. The structural design support device 10A evaluates a structure consisting of multiple parts using a virtual model. The structure to be evaluated is the same as in the first embodiment.

[0038] "Element information acquisition unit 11A" The element information acquisition unit 11A acquires element information including the coordinates of the nodes of the elements constituting the structure to be evaluated, a first stress parameter occurring on one of the elements, which is a first face, and a second stress parameter occurring on the second face, which is the opposite face of the element. The element information acquisition unit 11A further acquires parameters calculated from the stresses occurring on the first and second faces as element information. The parameters calculated from the stresses occurring on the first and second faces are not particularly limited as long as they can indicate how much stress is being applied to the element (e.g., a shell element). Examples of parameters representing the stresses occurring on the first and second faces (parameters representing the magnitude of the stresses) include the average value of the von Mises stress occurring on the first face and the von Mises stress occurring on the second face, and the absolute value of the difference between the maximum principal stress on the first face and the minimum principal stress on the second face. Preferably, the parameter calculated from the stresses occurring on the first and second faces is the average of the von Mises stress occurring on the first face and the von Mises stress occurring on the second face. The element information acquisition unit 11A acquires element information in the state in which a load is input to the structure (input state). The element information acquisition unit 11A may further acquire element information for the structure in a state where no external load is applied (initial state). The element information (such as the maximum principal stress on the first surface and the minimum principal stress on the second surface) is, for example, information about the elements (e.g., shell elements) in the finite element method when the structure is analyzed by the finite element method in each state. The element information is calculated by performing static analysis, eigenvalue analysis, collision analysis, frequency response analysis, etc. on the structure. The element information may be calculated in the same way as in the first embodiment.

[0039] "Element information storage section 12A" The element information storage unit 12A stores element information (element information including parameters calculated from the stresses occurring on the first surface and the second surface) acquired by the element information acquisition unit 11A. The element information storage unit 12A may also store information as element information indicating which of a plurality of parts the element belongs to. The element information storage unit 12 may also store information regarding the deformation mode and transmission parameters.

[0040] "Parameter calculation unit 13A" The parameter calculation unit 13A uses the element information acquired by the element information acquisition unit 11A to calculate information regarding the deformation mode of the element from the first stress parameter and the second stress parameter. The parameter calculation unit 13A further calculates a transfer parameter from the information regarding the deformation mode and a parameter calculated from the stresses occurring on the first surface and the second surface. Details of how the parameter calculation unit 13A calculates the information regarding the deformation mode and the transfer parameter will be described later. The parameter calculation unit 13A sends at least one of the calculated information regarding the deformation mode and the transfer parameter to the image creation unit 14A. The information regarding the deformation mode and the transfer parameter calculated by the parameter calculation unit 13A may be stored in the element information storage unit 12 or displayed by the display unit 15A.

[0041] "Image creation unit 14A" The image creation unit 14A creates an image in which at least one of the information regarding the deformation mode of an element and the transmission parameters of that element are visible at the position of the element in the structure (structure model). The image creation unit 14 may, for example, generate a three-dimensional image of the structure model in which the information regarding the deformation mode of each element or the transmission parameters calculated by the parameter calculation unit 13A is represented by shades of gray. The information regarding the deformation mode of each element may be represented in color instead of shades of gray. Similarly, the transmission parameters of each element may be represented in color instead of shades of gray. The image creation unit 14A sends the created image to the display unit 15A.

[0042] "Display section 15A" The display unit 15A may display at least one of the deformation mode information and the transfer parameters calculated by the parameter calculation unit 13A, or it may display a three-dimensional image of the structural model generated by the image creation unit 14A.

[0043] <Structure design support method> The structural design support method of this disclosure includes a first step of acquiring element information, which includes the coordinates of the nodes of an element (e.g., a shell element), a first stress parameter occurring on a first face, which is one face of the element, and a second stress parameter occurring on a second face, which is the opposite face of the element, in a state in which a load is applied to a structure consisting of multiple elements (input state). The structural design support method of this disclosure further includes a second step of using the element information acquired in the first step to calculate information about the deformation mode of the element from the first stress parameter and the second stress parameter. In the second step, for example, the degree of bending deformation is calculated from a function of the angular difference between the maximum principal stress vector and the minimum principal stress vector. Furthermore, a transfer parameter is calculated from the calculated information about the deformation mode and the parameters calculated from the stresses occurring on the first and second faces.

[0044] "The first process" In the first process, element information is obtained, including the coordinates of the nodes of the elements constituting the structure to be evaluated, a first stress parameter occurring on the first face (one of the elements), and a second stress parameter occurring on the second face (the opposite face of the element). In the first process, element information is obtained in the state where a load is applied to the structure (input state). In the first process, parameters calculated from the stresses occurring on the first and second faces are further obtained as element information. Examples of parameters calculated from the stresses occurring on the first and second faces include the average of the von Mises stress occurring on the first face and the von Mises stress occurring on the second face, and the absolute value of the difference between the maximum principal stress on the first face and the minimum principal stress on the second face. Preferably, the parameter calculated from the stresses occurring on the first and second faces is the average of the von Mises stress occurring on the first face and the von Mises stress occurring on the second face. In the first process, element information may be further obtained in the state where no external load is applied to the structure (static state). Element information is, for example, information about the elements in the finite element method (e.g., shell elements) when the structure in each state is analyzed using the finite element method. Elemental information is calculated by performing static analysis, eigenvalue analysis, collision analysis, frequency response analysis, etc., on the structure. Elemental information may also be calculated using numerical simulations other than the finite element method.

[0045] "The second process" In the second process, information regarding the deformation mode of the element is calculated from the first stress parameter and the second stress parameter using the element information obtained in the first process. In the second process, a transfer parameter is further calculated from the calculated deformation mode information and the parameters calculated from the stresses occurring on the first and second surfaces. The following describes a method for calculating deformation mode information and transfer parameters using the parameter calculation unit 13A of the structural design support device 10A, but the present invention is not limited to the following method. The following description is based on an example in which the first stress parameter is the maximum principal stress vector, the second stress parameter is the minimum principal stress vector, and the deformation mode information is the degree of bending deformation.

[0046] (Operation of Parameter Calculation Unit 13A) FIG. 9 is a flowchart for explaining the operation of the parameter calculation unit 13A. The parameter calculation unit 13 performs the processes of steps S1A to S3A for each element included in the element information stored in the element information storage unit 12A (steps S1A to S3A). In step S1, one selected from the unprocessed elements is defined as element i (for example, the initial value i = 0). Next, the parameter calculation unit 13A reads from the element information storage unit 12A the element information including the coordinates of the nodes of the element, the maximum principal stress vector generated on the first surface, which is one surface of the element, the minimum principal stress vector generated on the second surface, which is the opposite surface of the first surface of the element, and the parameter calculated from the stresses generated on the first and second surfaces, in the input state.

[0047] In step S2A, the parameter calculation unit 13A calculates the bending deformation degree of the element from the maximum principal stress vector on the first surface and the minimum principal stress vector on the second surface, using the element information read from the element information storage unit 12A. For example, the parameter calculation unit 13 calculates the bending deformation degree from the above formula (5).

[0048] In step S2B, the parameter calculation unit 13A calculates the transmission parameter TR from the bending deformation degree and the parameter calculated from the stresses generated on the first and second surfaces, using the element information read from the element information storage unit 12A. As the parameter calculated from the stresses generated on the first and second surfaces, it is preferable to use the average of the von Mises stress generated on the first surface and the von Mises stress generated on the second surface. The parameter calculation unit 13 may calculate the transmission parameter TR from, for example, the following formula (6). In the following formula (6), θ top represents the angle of the maximum principal stress vector σ top generated on the first surface P 1top , and θ bottom represents the angle of the maximum principal stress vector σ bottom generated on the second surface P 2top . That is, the angle of the minimum principal stress vector σ bottom generated on the second surface P 2bottom is θ bottomIt becomes +0.5π. In equation (6) below, σ eq_top This is the first face P top This is the von Mises stress that occurs in σ eq_bottom This is the second side P bottom This shows the von Mises stress that occurs. That is, equation (6) below shows that the transfer parameter TR is calculated from the product of the degree of bending deformation b and the average of the von Mises stress that occurs on the first surface and the von Mises stress that occurs on the second surface. TR=cos{θ top -(θ bottom +0.5π)} × 0.5(σ eq_top +σ eq_bottom )···(6)

[0049] In step S3A, if there are any elements for which the degree of bending deformation b and the transfer parameter TR have not been determined (unprocessed elements) (YES in step S3A), the process returns to step S1A, and one of the unprocessed elements is selected and processed. If there are no unprocessed elements among the elements that make up the structure (NO in step S3A), the process ends.

[0050] The structural design support device 10A and structural design support method of this disclosure have been described above. The structural design support device 10 of this disclosure is shown on the first surface P top The maximum principal stress vector σ that occurs in this location 1top and the second side P bottom The minimum principal stress vector σ that occurs in this case 2bottom The degree of bending deformation is calculated as a function of the angle difference. Therefore, the degree of bending deformation can be quantified even in nonlinear analyses such as collision analysis. Furthermore, since the structural design support device 10A calculates the transmission parameters from the degree of bending deformation, it is possible to extract areas where the load transmission efficiency is poor. This allows for more efficient improvement of the structure.

[0051] Each step of this embodiment described above may be configured to be performed automatically by the structural design support devices 10 and 10A.

[0052] The structural design support devices 10 and 10A may be realized by recording a program for realizing the functions of the structural design support devices 10 and 10A on a computer-readable recording medium, loading the program recorded on this recording medium into a computer system, and executing it. The term "computer system" here includes hardware such as the operating system and peripheral devices.

[0053] Furthermore, "computer system" shall also include the homepage provisioning environment (or display environment) if a WWW system is being used. Furthermore, "computer-readable recording media" refers to portable media such as flexible disks, magneto-optical disks, ROMs, and CD-ROMs, as well as storage devices such as hard disks built into computer systems. Moreover, "computer-readable recording media" also includes those that dynamically hold programs for a short period of time, such as communication lines used when transmitting programs over networks such as the Internet or communication lines such as telephone lines, and those that hold programs for a certain period of time, such as volatile memory inside computer systems that act as servers or clients in such cases. In addition, the above-mentioned programs may be for the purpose of realizing some of the functions described above, and may also be able to realize the above-mentioned functions in combination with programs already recorded in the computer system.

[0054] Each aspect of the present invention can be broadly applied to structural design support devices, structural design support methods, programs, and recording media for evaluating and analyzing structures during the design phase of various structures. Each aspect of the present invention makes it possible to realize structural design support devices, structural design support methods, programs, and recording media that can quantify the degree of bending deformation even in nonlinear analyses such as collision analysis.

[0055] (Example 1) The following shows an example of analysis performed using the structural design support device 10 of this embodiment. Using MSC Nastran 2024.1 from Hexagon as the software, and the structural model in Figure 10, a stiffness analysis of the rear subframe damper mounting point was performed. A shell element with only one integration point on its central face was used, and the stress tensors, principal stresses, and von Mises stresses on the front and back surfaces were calculated by the software from the stress at the integration point and the bending moment. The degree of bending deformation of each shell element was determined from equation (5) above. The obtained results are shown in Figure 11. Furthermore, the transfer parameters of each shell element were determined from equation (6) above. The obtained results are shown in Figure 12. As a comparative example, the results of analysis using the method of Patent Document 1 are shown in Figure 13.

[0056] As shown in Figure 11, it was confirmed that when using the structural design support device 10 of this disclosure, locations with large bending deformations can be easily identified. As shown in Figure 12, it was confirmed that locations with poor load transmission efficiency can be easily identified by mapping with transmission parameters. On the other hand, as shown in Figure 13, when analyzing using the method of Patent Document 1, the analysis is performed on a part-by-part basis, making it difficult to identify areas that require countermeasures. Furthermore, the method of Patent Document 1 was difficult to use when the load applied to the shell element changes moment by moment. [Explanation of symbols]

[0057] 10. Structural design support device, 11. Element information acquisition unit, 12. Element information storage unit, 13. Parameter calculation unit, 14. Image creation unit

Claims

1. When a load is applied to a structure containing multiple elements, The coordinates of the nodes of the aforementioned element, A first stress parameter which is a first stress tensor or a part of the components of the first stress tensor that occurs on the first surface, which is one of the surfaces of the element, A second stress parameter which is a second stress tensor or a part of the components of the second stress tensor occurring on the second surface, which is the surface opposite to the first surface of the element, An element information acquisition unit that acquires element information including; A parameter calculation unit that uses the element information to calculate information regarding the degree of bending deformation of the element from the first stress parameter and the second stress parameter; A structural design support device equipped with the following features.

2. The first stress parameter is the maximum principal stress vector occurring on the first surface, The structural design support device according to claim 1, wherein the second stress parameter is the minimum principal stress vector occurring on the second surface.

3. The structural design support device according to claim 1, wherein the parameter calculation unit calculates a transmission parameter relating to the load transmission efficiency of the structure from information relating to the degree of bending deformation and parameters calculated from the stresses occurring on the first surface and the second surface.

4. The structural design support device according to claim 3, wherein the parameter calculated from the stress is the average of the von Mises stress occurring on the first surface and the von Mises stress occurring on the second surface.

5. The structural design support device according to claim 1 or 2, wherein the element is a shell element.

6. In a structure consisting of multiple elements, when a load is applied, The coordinates of the nodes and integration points of the aforementioned element, A first stress parameter which is a first stress tensor or a part of the components of the first stress tensor that occurs on the first surface, which is one of the surfaces of the element, A second stress parameter which is a second stress tensor or a part of the components of the second stress tensor occurring on the second surface, which is the surface opposite to the first surface of the element, The first process involves obtaining element information including; A second process of calculating information regarding the degree of bending deformation of the element from the first stress parameter and the second stress parameter using the element information; A structural design support method, including the above.

7. The structural design support method according to claim 6, wherein in the second process, a transfer parameter relating to the load transfer efficiency of the structure is calculated from information relating to the degree of bending deformation and parameters calculated from the stresses occurring on the first surface and the second surface.

8. The structural design support method according to claim 7, wherein the parameter calculated from the stress is the average of the von Mises stress occurring on the first surface and the von Mises stress occurring on the second surface.

9. Computers, When a load is applied to a structure consisting of multiple elements, The coordinates of the nodes of the aforementioned element, A first stress parameter which is a first stress tensor or a part of the components of the first stress tensor that occurs on the first surface, which is one of the surfaces of the element, A second stress parameter which is a second stress tensor or a part of the components of the second stress tensor occurring on the second surface, which is the surface opposite to the first surface of the element, An element information acquisition unit that acquires element information including; A parameter calculation unit that uses the element information to calculate information regarding the degree of bending deformation of the element from the first stress parameter and the second stress parameter; A program that makes something function as such.

10. A computer-readable recording medium on which the program described in claim 9 is recorded.

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