JP2023122308A - Structure design support device, structure design support method and structure design support program - Google Patents

Abstract

To provide a structure design support device capable of automatically and efficiently extracting one or a plurality of components to execute rigidity measure processing and executing the rigidity measure processing on the extracted components.SOLUTION: A structure design support device 1 has: a reference rigidity arithmetic unit which computes reference rigidity data based upon numeric analysis data on a structure; a first rigidity arithmetic unit which computes first rigidity data based upon thickness change data, generated by changing data representing a thickness, from the numeric analysis data; a second rigidity arithmetic unit which computes second based upon elasticity change data, generated by changing physical property data, from the numeric analysis data; a bending degree index arithmetic unit which computes a bending degree index indicative of a degree of bending deformation of a component based upon the reference rigidity data, first rigidity data and second rigidity data; a measure necessity determination unit which determines whether respective components are extracted as object components on which rigidity measures processing is performed based upon the at least bending degree index; and a rigidity measure processing unit which performs the rigidity measure processing on the object components.SELECTED DRAWING: Figure 1

Description

The present invention relates to a structural design support device, a structural design support method, and a structural design support program.

Various techniques are known for optimizing the shape of parts of a structure by topology optimization (see, for example, Patent Documents 1 to 3). Patent Literature 1 describes a technology for detecting a part that contributes highly to the rigidity of a part by performing topology optimization analysis while applying a load corresponding to a stress that assumes springback deformation to the part. It is In Patent Document 2, after setting optimization conditions including objective conditions such as minimizing displacement, the optimization block model arranged in the design space is subjected to topology optimization processing, so that it can be practically used. A technique for finding the optimal shape is described. In Patent Document 3, the optimization blocks placed in the space specified by the sensitivity analysis using the design variables of the optimization analysis as the parameters related to the material properties are subjected to the topology optimization analysis process, whereby the vibration is generated from the vibrating parts. Techniques for optimizing the geometry of the transmitting components are described.

JP 2014-46336 A JP 2014-149732 A JP 2020-46185 A

Patent Documents 1 to 3 describe techniques for optimizing the shape of a predetermined optimization block by performing topology optimization analysis processing. However, for example, in a structure having tens of thousands of parts, a technique for automatically and efficiently extracting one or a plurality of parts to be subjected to rigidity countermeasure processing and executing rigidity countermeasures on the extracted parts is Patent Documents 1 to 3 do not describe a technique for improving the rigidity of the .

Therefore, the present invention provides a structure design support apparatus, a structure design support method, and a structure design support device that automatically and efficiently extract one or a plurality of parts for which rigidity countermeasure processing is to be performed, and perform rigidity countermeasure processing on the extracted parts. The purpose is to provide a structural design support program.

The gist of the present invention for solving such problems is the structure design support device described below.
(1) Data indicating the rigidity of a structure under predetermined boundary conditions, based on numerical analysis data including at least shape data including the thickness of each part of a structure having a plurality of parts and physical property data indicating elasticity. a reference stiffness calculator that calculates reference stiffness data that is
a first stiffness calculation unit that calculates first stiffness data representing the stiffness of the structure under boundary conditions, based on the thickness change data obtained by changing the data representing the thickness from the numerical analysis data;
a second stiffness calculation unit that calculates second stiffness data, which is data indicating the stiffness of the structure under boundary conditions, based on the modified elasticity data obtained by changing the physical property data from the numerical analysis data;
a bending degree index calculation unit that calculates a bending degree index indicating the degree of bending deformation of the component based on the reference rigidity data, the first rigidity data, and the second rigidity data;
a countermeasure necessity determination unit that determines, based on at least the bending degree index, whether or not each of the parts is to be extracted as a target part for which rigidity countermeasure processing is to be performed;
a rigidity countermeasure processing unit that executes rigidity countermeasure processing on a target part;
A structural design support device characterized by comprising:
(2) The reference stiffness data, the first stiffness data, and the second stiffness data are data indicating the reference frequency, the first frequency, and the second frequency, which are vibration frequencies when dynamic stiffness analysis is performed on the structure, and
The structural body design support device according to (1), wherein the bending degree index calculation unit calculates the bending degree index based on the reference frequency, the first frequency, and the second frequency.
(3) The reference frequency, the first frequency and the second frequency are the reference natural frequency, the first natural frequency and the second natural frequency obtained by the natural vibration analysis, or the reference resonance frequency obtained by the excitation response analysis, The structural design support device according to (2), wherein the first resonance frequency and the second resonance frequency.
(4) The structural design assisting apparatus according to (2) or (3), wherein the bending index is a function including a difference between the reference frequency and the first frequency and a difference between the reference frequency and the second frequency.
(5) The reference stiffness data, the first stiffness data, and the second stiffness data are data indicating the reference stiffness, the first stiffness, and the second stiffness, which are the stiffnesses obtained when the structure is subjected to static stiffness analysis, and
The structural design support device according to (1), wherein the bending index is calculated based on the reference stiffness, the first stiffness, and the second stiffness.
(6) The structure design assisting apparatus according to (2), wherein the bend index is a function including a difference between the reference stiffness and the first stiffness and a difference between the reference stiffness and the second stiffness.
(7) further includes a contribution index calculation unit for calculating a contribution index indicating the contribution of the part to the rigidity of the structure based on the reference rigidity data and either the first rigidity data or the second rigidity data. death,
The structure design support device according to any one of (1) to (6), wherein the countermeasure necessity determination unit determines whether or not to extract the target part based on the bending index and the contribution index. .
(8) The measure necessity determination unit determines whether or not to extract a target part based on data indicating at least one of the surface area, volume, and weight of the part in addition to the bend index and the contribution index. (7) The structure design support device according to (7).
(9) The stiffness countermeasure processing unit
Rigidity analysis is performed for each target part individually, the stiffness data of the target part is calculated,
The structure design support device according to any one of (1) to (8), wherein shape optimization processing is executed for each target part based on the calculated stiffness data of the target part.
(10) The stiffness countermeasure processing unit
Analyzing the stiffness of each of the target parts and the parts joined to each of the target parts to calculate the stiffness data of the target parts,
The structure design support device according to any one of (1) to (8), wherein shape optimization processing is executed for each target part based on the calculated stiffness data of the target part.
(11) The stiffness countermeasure processing unit executes shape optimization processing for collectively optimizing the shape of all the target parts for the structure including all the target parts, as described in (1) to (8). The structure design support device according to any one of the above.
(12) The stiffness countermeasure processing unit executes shape optimization processing for optimizing the shape of each of the target parts for the structure including all of the target parts. Any one of (1) to (8) 2. The structure design support device according to .
(13) Data indicating the rigidity of the structure under predetermined boundary conditions, based on numerical analysis data including at least shape data including the thickness of each part of the structure having a plurality of parts and physical property data indicating elasticity. Calculate the reference stiffness data that is
calculating first stiffness data, which is data representing the stiffness of the structure under boundary conditions, based on the thickness change data obtained by changing the data representing the thickness from the numerical analysis data;
calculating second stiffness data, which is data indicating the stiffness of the structure under boundary conditions, based on the modified elasticity data obtained by changing the physical property data from the numerical analysis data;
calculating a bending index indicating the degree of bending deformation of the component based on the reference stiffness data, the first stiffness data, and the second stiffness data;
Determining whether or not to extract each part as a target part on which rigidity countermeasure processing is to be performed, based on at least the bending degree index;
Execute rigidity countermeasure processing for the target part,
A structure design support method characterized by comprising:
(14) Data indicating the rigidity of the structure under predetermined boundary conditions, based on numerical analysis data including at least shape data including the thickness of each part of the structure having a plurality of parts and physical property data indicating elasticity. Calculate the reference stiffness data that is
calculating a first stiffness, which is data indicating the stiffness of the structure under boundary conditions, based on the changed thickness data obtained by changing the data indicating the thickness from the numerical analysis data;
calculating second stiffness data, which is data indicating the stiffness of the structure under boundary conditions, based on the modified elasticity data obtained by changing the physical property data from the numerical analysis data;
calculating a bending index indicating the degree of bending deformation of the component based on the reference stiffness data, the first stiffness data, and the second stiffness data;
Determining whether or not to extract each part as a target part on which rigidity countermeasure processing is to be performed, based on at least the bending degree index;
Execute rigidity countermeasure processing for the target part,
A structure design support program characterized by causing a computer to execute processing.

In one embodiment, the structural design support device can automatically and efficiently extract one or more parts for which stiffness countermeasure processing is to be performed, and perform stiffness countermeasures on the extracted parts.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure for demonstrating the outline|summary of the structure-design assistance apparatus which concerns on embodiment. 1 is a block diagram of a structural design support device according to a first embodiment; FIG. 3 is a flowchart showing structural design support processing by the structural design support apparatus shown in FIG. 2; It is a figure which shows the deformation|transformation of a flat plate, (a) shows extension deformation and compression deformation, (b) shows shear deformation, (c) shows bending deformation. FIG. 4 is a flowchart showing more detailed processing of the processing shown in S112 shown in FIG. 3; FIG. It is a block diagram of the structure design assistance apparatus which concerns on 2nd Embodiment. FIG. 7 is a flow chart showing structural design support processing by the structural design support device shown in FIG. 6 ; FIG. FIG. 11 is a flow chart of rigidity countermeasure processing according to a first modified example; FIG. FIG. 11 is a flowchart of rigidity countermeasure processing according to a second modified example; FIG. (a) is a diagram showing the b value and Young's modulus sensitivity conditions for each of Examples and Comparative Examples, and (b) is a diagram showing the improvement margin of natural frequency per 1 kg of mass for each of Examples and Comparative Examples. is.

A structure design support device according to the present invention will be described below with reference to the drawings. However, the technical scope of the present invention is not limited to those embodiments.

(Overview of Structural Design Support Device According to Embodiment)
FIG. 1 is a diagram for explaining an outline of a structural body design support device. In the example shown in FIG. 1, rigidity countermeasure processing is executed for a part arranged at the end of the rear waist extracted by dynamic rigidity analysis of the vehicle body, which is a structural body.

As indicated by the dashed line in FIG. 1(a), the structural design support device uses numerical analysis data, which is the initial design data of the vehicle body, to perform a finite element method (FEM) to determine a predetermined boundary. The natural vibration analysis of the rear part of the car body under the conditions is performed. The structure design support device performs a natural vibration analysis on the rear portion of the vehicle body to calculate reference stiffness data, which is data indicating the stiffness of the rear portion of the vehicle body based on the numerical analysis data. The numerical analysis data includes at least shape data including the thickness of each of a plurality of parts forming the vehicle body, and physical property data indicating elasticity. Next, the structural body design support device generates modified thickness data obtained by modifying the data indicating the thickness from the numerical analysis data, and indicates the rigidity of the rear portion of the vehicle body under boundary conditions based on the generated modified thickness data. First stiffness data, which is data, is calculated. Next, the structural body design support device generates modified elasticity data obtained by modifying the physical property data from the numerical analysis data, and based on the modified elasticity data generated, the second data representing the rigidity of the rear portion of the vehicle body under boundary conditions. Calculate stiffness data.

Next, based on the reference stiffness data, the first stiffness data, and the second stiffness data, the structure design support device calculates a bending value, also called a b-value, which indicates the degree of bending deformation of each part forming the rear portion of the vehicle body. Calculate the degree index.

Next, based on the calculated bend index, the structural body design support device determines whether or not to extract each part as a target part on which rigidity countermeasure processing is to be performed. The structural body design support device extracts, for example, one or a plurality of parts whose b-value is higher than a predetermined b-value threshold as symmetric parts for which rigidity countermeasure processing is to be executed. In the example shown in FIG. 1, as indicated by an arrow A in FIG. 1B, parts arranged at the end of the rear waist are extracted as target parts.

Next, the structural body design support device executes rigidity countermeasure processing on the end of the rear waist, which is the target part. First, as shown in FIG. 1(c), the structural body design support device performs the natural vibration analysis for the end of the rear waist alone. The structural design support device compares the deformation of the end of the rear waist that was analyzed by natural vibration alone with the deformation of the end of the rear waist that was analyzed by natural vibration when it is assembled in the vehicle body, and compares the deformation. Extract vibration frequencies that match the motion. For example, the structural design support device can be used to analyze the stress distribution in the deformation of the end of the rear waist, which is analyzed by natural vibration alone, and the stress distribution in the deformation of the end of the rear waist, which is analyzed by the natural vibration when it is incorporated in the vehicle body. Extract the vibration frequency based on the matching degree of . The structural body design support device generates vectors indicating stress distributions at the ends of the rear waists of the single body and the vehicle body, and calculates the inner product of the generated vectors as the degree of matching of the stress distributions. The structural design support device extracts the vibration frequency with the highest degree of matching of the calculated stress distribution, and deforms the shape of the end of the rear waist so that the natural frequency is maximized at the extracted vibration frequency. This optimizes the shape of the rear waist edge. As shown in FIG. 1(d), the structural body design support device forms, for example, a circular protrusion at the end of the rear waist. Note that the structural body design support device may give a beat to the target part instead of forming the protrusion on the target part.

The structural body design support device automatically and efficiently extracts the parts to be subjected to the rigidity countermeasure process by extracting them as target parts to be subjected to the rigidity countermeasure process based on the bending index. stiffness measures can be implemented.

(Structure and function of structural design support device according to the first embodiment)
FIG. 2 is a block diagram of the structural design support device according to the first embodiment.

The structural design support device 1 has a communication unit 11 , a storage unit 12 , an input unit 13 , an output unit 14 and a processing unit 20 . The communication unit 11 , storage unit 12 , input unit 13 , output unit 14 and processing unit 20 are connected to each other via bus 15 .

The communication unit 11 has a wired communication interface circuit such as Ethernet (registered trademark). The communication unit 11 communicates with an electric computer such as a server via a communication network such as the Internet and a local area network (LAN).

The storage unit 12 includes, for example, at least one of a semiconductor storage device, a magnetic tape device, a magnetic disk device, or an optical disk device. The storage unit 12 stores an operating system program, a driver program, an application program, data, etc. used for processing in the processing unit 20 . For example, the storage unit 12 stores a structure design support program or the like for causing the processing unit 20 to execute structure design support processing for supporting structure design by the operator. The structural design support program may be installed in the storage unit 12 from a computer-readable portable storage medium such as a CD-ROM, DVD-ROM, etc. using a known setup program or the like.

The storage unit 12 stores numerical analysis data including at least data indicating the thickness, elasticity, and size of each part of a structure having a plurality of parts. Physical property data indicative of elasticity include longitudinal elastic modulus, also called Young's modulus, transverse elastic modulus, and Poisson's ratio. The storage unit 12 also stores CAD model data and generation condition data used when generating numerical analysis data, which is finite element model data. The storage unit 12 also stores material property data and vibration condition data used when calculating stiffness data. The material property data is data indicating elasticity, data indicating material properties such as density, coefficient of thermal expansion and yield stress, and the vibration condition data is data indicating the vibration frequency applied to the structure.

The input unit 13 may be any device as long as it can input data, such as a touch panel and a keyboard. An operator using the structural design support device 1 can use the input unit 13 to input characters, numbers, symbols, and the like. The input unit 13, when operated by an operator, generates a signal corresponding to the operation. The generated signal is then supplied to the processing unit 20 as an operator's instruction.

The output unit 14 may be any device as long as it can display video, images, and the like, such as a liquid crystal display or an organic EL display. The output unit 14 displays video corresponding to the video data supplied from the processing unit 20, images corresponding to the image data, and the like. Also, the output unit 14 may be an output device that prints video, images, characters, or the like on a display medium such as paper.

The processing unit 20 has one or more processors and their peripheral circuits. The processing unit 20 controls overall operations of the structural design support apparatus 1, and is, for example, a CPU. The processing unit 20 executes processing based on programs (a driver program, an operating system program, an application program, etc.) stored in the storage unit 12 . Also, the processing unit 20 can execute a plurality of programs (application programs, etc.) in parallel.

The processing unit 20 includes a numerical analysis data generation unit 21, a reference stiffness calculation unit 22, a first stiffness calculation unit 23, a second stiffness calculation unit 24, a bend index calculation unit 25, and a countermeasure necessity determination unit 26. , and a rigidity countermeasure processing unit 27 . Each of these units is a functional module implemented by a program executed by a processor included in processing unit 20 . Alternatively, each of these units may be implemented in the processing unit 20 as firmware.

(Structure design support processing by structure design support device 1)
FIG. 3 is a flow chart showing structural design support processing by the structural design support device 1 . The structural design support processing shown in FIG. 3 is executed mainly by the processing unit 20 in cooperation with each element of the structural design support apparatus 1 based on a control program stored in the storage unit 12 in advance. . The structure design support processing explained with reference to FIG. 3 is the structure design support processing in the analysis of the natural vibration of the vehicle body. It may be used for analyzes other than dynamic stiffness analysis, such as stiffness analysis, static stiffness analysis, and analysis of springback deformation.

First, the numerical analysis data generation unit 21 generates numerical analysis data, which is finite element model data, based on the CAD model data and generation condition data stored in the storage unit 12 (S101). is stored in the storage unit 12 . The numerical analysis data generation unit 21 generates numerical analysis data by dividing the shape of each of the plurality of parts forming the vehicle body into a plurality of elements with specific shapes and sizes. The numerical analysis data generator 21 generates numerical analysis data using application programs for generating finite element model data such as HyperMesh manufactured by ALTAIR and ANSA manufactured by BETA CAE Systems.

Next, based on the numerical analysis data stored in the storage unit 12, the reference stiffness calculation unit 22 calculates reference stiffness data representing the stiffness of each part forming the vehicle body under predetermined boundary conditions (S102). ). The reference stiffness calculation unit 22 stores reference stiffness information indicating the calculated reference stiffness data in the storage unit 12 . Boundary conditions used when calculating the reference stiffness data are conditions corresponding to the material physical property data and the vibration condition data stored in the storage unit 12 . The reference stiffness calculation unit 22 is an application program for finite element analysis such as HyperForm manufactured by ALTAIR, Ansys LS-DYNA manufactured by JSOL, Inc., PAM-MEDYSA manufactured by ESI Japan Co., Ltd., and Abaqus manufactured by CAE Solutions. to generate the reference stiffness information. The reference stiffness data corresponding to the reference stiffness information generated in the process of S102 includes the reference natural frequency _f0 , which is the natural vibration frequency when the vehicle body parts are subjected to the natural vibration analysis.

Next, the first stiffness calculation unit 23 generates modified thickness data by modifying the data indicating the thickness and density of one of the parts forming the vehicle body from the numerical analysis data generated in the process of S101 (S103), The generated thickness change data is stored in the storage unit 12 . The first stiffness calculation unit 23 changes the density of the target part so that the mass before changing the thickness of the target part matches the mass after changing the thickness of the target part. do.

Next, the first stiffness calculator 23 calculates the stiffness of the vehicle body under boundary conditions corresponding to the material property data and the vibration condition data stored in the storage unit 12, based on the thickness change data generated in the process of S103. The first stiffness data, which is the data shown, is calculated (S104). The first stiffness calculation unit 23 stores first stiffness information indicating the calculated first stiffness data in the storage unit 12 . The first stiffness calculator 23, like the reference stiffness calculator 22, uses an application program for finite element analysis to generate first stiffness information. The first stiffness data corresponding to the first stiffness information generated in the process of S104 includes the first natural frequency _f1 , which is the natural vibration frequency when the vehicle body parts are subjected to the natural vibration analysis.

Next, the first stiffness calculator 23 determines whether or not the process of S104 has been executed for all parts (S105). The first stiffness calculator 23 repeats the processing of S103 to S105 until it determines that the processing of S104 has been performed for all parts (S105-YES).

When it is determined that the process of S104 has been performed for all parts (S105-YES), the second stiffness calculator 24 generates elastic change data from the numerical analysis data generated in the process of S101 (S106). The modified elasticity data generated in the process of S106 is data obtained by modifying the data indicating the elastic modulus of one of the parts forming the vehicle body. The second stiffness calculation unit 24 stores the generated elasticity change data in the storage unit 12 .

Next, the second stiffness calculator 24 indicates the stiffness of the vehicle body under boundary conditions corresponding to the material property data and the vibration condition data stored in the storage unit 12, based on the elasticity change data generated in the process of S106. The second stiffness data, which is data, is calculated (S107). The second stiffness calculation unit 24 stores second stiffness information indicating the calculated second stiffness data in the storage unit 12 . The second stiffness data corresponding to the second stiffness information generated in the process of S107 includes the second natural frequency _f2 , which is the natural vibration frequency when the vehicle body parts are subjected to the natural vibration analysis.

Next, the second stiffness calculation unit 24 determines whether or not the process of S107 has been executed for all parts (S108). The second stiffness calculation unit 24 repeats the processes of S106 to S108 until it is determined that the process of S107 has been performed for all parts (S108-YES).

When the second stiffness calculation unit 24 determines that the process of S107 has been executed for all parts (S108-YES), the bending index calculation unit 25 calculates the bending degree indicating the degree of bending deformation of each part of the vehicle body. An index is calculated (S109). The bending degree index calculator 25 calculates a bending degree index based on the reference stiffness data, the first stiffness data, and the second stiffness data calculated in the processes of S102, S104, and S107. The bendability index is indicated by "b" in equation (1) and is also referred to as the b-value. In equation (1), the reference natural frequency that is the reference stiffness data is indicated by f ₀ , the first stiffness data that is the first natural frequency is indicated by f ₁ , and the second stiffness data that is the second natural frequency is f ₂ , the difference between the first eigenfrequency f ₁ as the first stiffness data and the reference eigenfrequency f ₀ as the reference stiffness data is indicated by Δf _t , and the second eigenfrequency f ₂ as the second stiffness data and the reference natural frequency f ₀ , which is the reference stiffness data, is indicated by Δf _E . Equation (1) is a function for calculating the bend index, where Δf _t is the difference between the reference frequency and the first frequency, and Δf _E is the difference between the reference frequency and the second frequency. Details of the definition of the b value are described in detail in Japanese Patent Laid-Open No. 2021-152894, so a detailed description is omitted here.

FIG. 4 shows deformation of a flat plate, FIG. 4(a) showing extension deformation and compression deformation, FIG. 4(b) showing shear deformation, and FIG. 4(c) showing bending deformation.

The stiffness of extensional deformation and compression deformation is proportional to the product (E×t) of Young's modulus E and plate thickness t, and the stiffness of shear deformation is proportional to the product (G×t) of shear elastic modulus G and plate thickness t. The bending deformation stiffness is proportional to the product (E×t ³ ) of Young's modulus E and the plate thickness cubed t ³ . In formula (1), the b value indicates a value of 1 or more and 3 or less. The b value approaches 3 as the bending deformation area increases, and approaches 1 as the bending deformation area decreases. In general, it is known that the material strength of parts is not efficiently utilized in parts with a large amount of bending deformation. preferably.

Next, the countermeasure necessity determination unit 26 determines whether or not each part of the vehicle body is to be extracted as a target part for which the rigidity countermeasure process is executed, based on the b value, which is the index of bending degree calculated in the process of S109. is determined (S110). When the b-value of the component is equal to or greater than a predetermined b-value threshold value, the countermeasure necessity determining unit 26 determines that the component is to be extracted as a target component on which rigidity countermeasure processing is to be performed (S110-YES). Further, when the b-value of the part is less than the predetermined b-value threshold value, the countermeasure necessity determining unit 26 determines that the part is not to be extracted as a target part for which the stiffness countermeasure process is executed (S110-NO). .

Next, the countermeasure necessity determination unit 26 determines whether or not the processing of S110 has been executed for all the components (S111). The countermeasure necessity determination unit 26 repeats the processes of S109 to S111 until it determines that the process of S110 has been performed for all parts (S111-YES).

When the countermeasure necessity determination unit 26 determines that the processing of S107 has been performed for all parts (S111-YES), the stiffness countermeasure processing unit 27 executes the stiffness countermeasure processing (S112).

FIG. 5 is a flowchart showing more detailed processing of the processing shown in S112.

First, the stiffness countermeasure processing unit 27 analyzes the stiffness of the target component alone, calculates stiffness data of the target component (S201), and stores stiffness information indicating the calculated stiffness data in the storage unit 12. FIG. The stiffness countermeasure processing unit 27 executes the natural vibration analysis of the target part at a plurality of frequencies sampled at a predetermined frequency pitch in a predetermined frequency band, and stores the result of the natural vibration analysis as the stiffness data of the target part.

Next, the stiffness countermeasure processing unit 27 determines the vibration frequency used when executing the shape optimization process for optimizing the shape of the target part (S202). The stiffness countermeasure processing unit 27 is used, for example, when executing a shape optimization process for a target part whose stiffness has been analyzed singly using a distribution vector in which the maximum principal strain of each element of the part is arranged in a predetermined order. determine the vibration frequency to be The stiffness countermeasure processing unit 27 obtains the degree of coincidence obtained by normalizing the absolute value of the inner product of the distribution vector of the target part whose stiffness is analyzed by itself and the distribution vector of the target part incorporated in the vehicle body by the size of each distribution vector. to determine the vibration frequency. The stiffness countermeasure processing unit 27 determines the frequency with the highest degree of matching as the vibration frequency that matches the vibration frequency of the target part incorporated in the vehicle body, and determines the vibration frequency to be used when executing the shape optimization process. do. Note that the stiffness countermeasure processing unit 27 may determine the vibration frequency used when executing the shape optimization processing based on an operator's instruction.

Next, the stiffness countermeasure processing unit 27 uses the vibration frequency determined in the process of S202 to execute the shape optimization process on the target part (S203). shape optimization data indicating the shape of is stored in the storage unit 12 . The stiffness countermeasure processing unit 27 uses, for example, ALTAIR's OptiStruct to optimize the shape of the target part so that the natural frequency at the vibration frequency determined in S202 is maximized. A target part is defined as an area whose shape is not changed in the shape optimization process in a joint area where the target part is joined to another part. The target part may also be changed in shape by adding a cylindrical protrusion, which in one example has a bottom diameter of 20 mm and a height of 10 mm. Note that the bonding area to be bonded with another component may be defined as an area whose shape is changed in the shape optimization process.

Next, the rigidity countermeasure processing unit 27 determines whether or not the shape optimization process has been executed for all the target parts extracted in the process of S110 (S204). The stiffness countermeasure processing unit 27 repeats the processing of S201 to S204 until it is determined that the shape optimization processing has been performed for all the target parts (S204-YES). When the rigidity countermeasure processing unit 27 determines that the shape optimization processing has been executed for all the target parts (S204-YES), the rigidity countermeasure processing ends.

After completing the rigidity countermeasure processing, the rigidity countermeasure processing unit 27 replaces the shape optimization data of the target part for which the shape optimization processing was executed in the processing of S204 with the corresponding data of the target part in the numerical analysis data to obtain the shape. Change analysis data is generated (S113). The rigidity countermeasure processing unit 27 stores the generated shape change analysis data in the storage unit 12 .

Next, based on the shape change analysis data stored in the storage unit 12, the stiffness countermeasure processing unit 27 calculates the stiffness data of the vehicle body under the boundary conditions corresponding to the material physical property data and the vibration condition data stored in the storage unit 12, respectively. is calculated (S114). The stiffness countermeasure processing unit 27 stores changed stiffness information indicating the calculated changed stiffness data in the storage unit 12 .

Next, the stiffness countermeasure processing unit 27 compares the reference stiffness data calculated in the process of S102 and the changed stiffness data calculated in the process of S114, and generates effect information indicating the effect of the stiffness countermeasure process ( S115). The effect information generated in the process of S115 is the improvement margin of the vibration frequency per 1 kg of the mass of the vehicle body in the analysis of the natural vibration of the vehicle body.

Then, the stiffness countermeasure processing unit 27 outputs the effect information generated in the processing of S115 to the output unit 14 (S116), thereby terminating the structural design support processing. The output unit 14 displays the input effect information, and the operator verifies the effect of the stiffness measures based on the effect information displayed on the output unit 14 .

(Action and effect of the structural body design support device according to the first embodiment)
The structural body design support device 1 automatically and efficiently extracts the parts for which the rigidity countermeasure process is to be executed by extracting them as target parts for which the rigidity countermeasure process is to be executed based on the bending index. Stiffness measures can be implemented on the part. Specifically, by using the b-value as the bending degree index, the structural design support device 1 can efficiently extract parts with many bending deformation regions as target parts.

(Structure and function of structural design support device according to the second embodiment)
FIG. 6 is a block diagram of a structural design support device according to the second embodiment.

The structure design support device 2 differs from the structure design support device 1 in that it has a processing unit 30 instead of the processing unit 20 . The processing unit 30 differs from the processing unit 20 in that it has a contribution index calculation unit 31 . The configuration and function of the components of the structural design support device 2 other than the storage unit 16 and the contribution degree index calculation unit 31 are the same as the configurations and functions of the components of the structural design support device 1 to which the same reference numerals are attached. Detailed description is omitted here.

(Structure design support processing by structure design support device 2)
FIG. 7 is a flow chart showing structural design support processing by the structural design support device 2 . The structural design support processing shown in FIG. 7 is executed mainly by the processing unit 30 in cooperation with each element of the structural design support device 2 based on a control program stored in advance in the storage unit 12. .

Since the processing of S301 to S309 is the same as the processing of S101 to S109, detailed description is omitted here.

After the process of S309 is completed, the countermeasure necessity determination unit 26 determines whether one of the vehicle body parts has undergone the rigidity countermeasure process based on the bending degree index calculated in the process of S309, as in the process of S110. It is determined whether or not to extract the part as a target part (S310). When it is determined by the countermeasure necessity determining unit 26 that the parts of the vehicle body are not to be extracted as the target parts (S310-NO), the process proceeds to S313.

When the countermeasure necessity determination unit 26 determines that the vehicle body parts are to be extracted as target parts (S310-YES), the contribution index calculation unit 31 performs the processing of S310 based on the reference stiffness information and the second stiffness information. A contribution index indicating the contribution of the extracted target part is calculated (S311). The contribution index calculation unit 31, also called Young's modulus sensitivity, divides the amount of change between the second stiffness data of each part forming the vehicle body and the reference stiffness data calculated in the process of S302 by the reference stiffness data. The rate of change of the stiffness data is calculated as a contribution index.

Next, based on the contribution index calculated in the process of S311, the countermeasure necessity determination unit 26 determines whether the target part extracted in the process of S310 is to be extracted as a target part on which the rigidity countermeasure process is executed. is determined (S312). When the contribution degree index extracted in the process of S311 is equal to or greater than a predetermined contribution degree threshold value, the countermeasure necessity determination unit 26 determines to extract the component as a target component (S312-YES). Further, when the contribution degree index extracted in the process of S311 is less than the contribution degree threshold value, the countermeasure necessity judgment unit 26 judges not to extract the part as a target part (S312-NO).

Next, the countermeasure necessity determination unit 26 determines whether or not the process of S310 has been executed for all the components (S313). The countermeasure necessity determination unit 26 repeats the processes of S309 to S313 until it determines that the process of S310 has been performed for all parts (S313-YES).

If the countermeasure necessity determining unit 26 determines that the processing of S310 has been executed for all parts (S313-YES), the rigidity countermeasure processing unit 27 executes the rigidity countermeasure processing (S314 ). Since the processing of S315 to S318 is the same as the processing of S110 to S113, detailed description is omitted here.

(Action and effect of the structural body design support device according to the second embodiment)
Since the structural body design support device 2 extracts target parts for which rigidity countermeasure processing is executed based on the contribution index in addition to the bending degree index, parts that contribute highly to improving the rigidity of the vehicle body are targeted. Can be extracted as parts.

(Modification of structural body design support device according to embodiment)
The structural design support apparatuses 1 and 2 extract a part as a target part when the b value of the part is equal to or greater than a predetermined b value threshold value. A mean value of the values may be used as the b-value threshold. Further, the structural body design support device according to the embodiment may extract a predetermined number of parts with large b-values as target parts.

Further, the structural design support apparatus 2 extracts a part as a target part when the contribution degree index of the part is equal to or greater than a predetermined contribution degree threshold value. The average value of the contribution index may be used as the contribution threshold. Further, the structural body design support device according to the embodiment may extract a predetermined number of parts with a large contribution index as target parts.

The structural design support device 2 uses Young's modulus sensitivity as a contribution index, but the structural design support device according to the embodiment may use indices other than Young's modulus sensitivity as a contribution index. For example, the structural body design support device according to the embodiment may use plate thickness sensitivity as a contribution index. The board thickness sensitivity is the rate of change in stiffness data obtained by dividing the amount of change between the first stiffness data calculated in the process of S304 and the reference stiffness data calculated in the process of S302 by the reference stiffness data.

Further, the structural design support device 2 extracts target parts based on the bending degree index and the contribution degree index. The target parts may be extracted based on the degree of accuracy. The size of the part used when extracting the target part is the volume of the part in one example, the weight in another example, and the surface area of the part in yet another example.

Further, the structural design support apparatuses 1 and 2 generate the thickness change data and the elasticity change data. You can remember.

Further, the structural body design support apparatus 2 executes stiffness countermeasure processing by analyzing the stiffness of the target part alone and calculating the stiffness data of the target part. The target part may be subjected to stiffness analysis along with the part to be joined to the .

FIG. 8 is a flowchart of rigidity countermeasure processing according to the first modification. The stiffness countermeasure processing shown in FIG. 8 is executed mainly by the processing unit 20 in cooperation with each element of the structural body design support apparatus 1 based on a control program stored in the storage unit 12 in advance.

First, the stiffness countermeasure processing unit 27 analyzes the stiffness of the target component together with the components joined to the target component, calculates the stiffness data of the target component (S401), and stores the stiffness information indicating the calculated stiffness data in the storage unit 12. Remember. Similar to the process of S201, the stiffness countermeasure processing unit 27 executes the natural vibration analysis of the target part at a plurality of frequencies sampled at a predetermined frequency pitch in a predetermined frequency band, and the result of the natural vibration analysis is applied to the target part. Store as stiffness data.

Next, the stiffness countermeasure processing unit 27 determines the vibration frequency used when executing the shape optimization processing (S402), as in the processing of S202. The stiffness countermeasure processing unit 27 determines the vibration frequency based on the degree of coincidence between the distribution vector of the target part subjected to stiffness analysis together with the part joined to the target part and the distribution vector of the target part incorporated in the vehicle body.

Next, the stiffness countermeasure processing unit 27 uses the vibration frequency determined in the process of S402 to perform the shape optimization process on the target part (S403), as in the process of S203. The rigidity countermeasure processing unit 27 stores in the storage unit 12 shape optimization data indicating the shape of the target part on which the shape optimization processing has been performed. Note that the part to be joined to the target part is defined as a region whose shape is not changed in the shape optimization process.

Next, the rigidity countermeasure processing unit 27 determines whether or not the shape optimization processing has been executed for all the target parts (S404). The stiffness countermeasure processing unit 27 repeats the processing of S401 to S404 until it is determined that the shape optimization processing has been performed for all the target parts (S404-YES). When the stiffness countermeasure processing unit 27 determines that the shape optimization processing has been executed for all the target parts (S404-YES), the stiffness countermeasure processing ends.

In addition, in the structural body design support device according to the embodiment, the stiffness countermeasure processing unit 27 executes shape optimization processing for collectively optimizing the shape of all target parts for the vehicle body including all target parts. You may

Further, in the structural body design support apparatus according to the embodiment, the rigidity countermeasure processing unit 27 performs shape optimization processing for optimizing the shape of each target part for each target part, with respect to the vehicle body including all of the target parts. may be executed.

Further, in the structural body design support device according to the embodiment, the rigidity countermeasure processing unit 27 may adopt the result of the shape optimization process with the most improved rigidity from among the results of a plurality of shape optimization processes with different modes. .

FIG. 9 is a flowchart of rigidity countermeasure processing according to the second modification. The stiffness countermeasure processing shown in FIG. 9 is executed mainly by the processing unit 20 in cooperation with each element of the structural body design support apparatus 1 based on a control program stored in the storage unit 12 in advance.

First, the stiffness countermeasure processing unit 27 executes a first stiffness countermeasure process for calculating the stiffness of the target part by analyzing the stiffness of the target part alone (S501). The converted data is stored in the storage unit 12 . The first rigidity countermeasure process is the same as the rigidity countermeasure process shown in S112 described with reference to FIG. 5, so detailed description thereof will be omitted here. Next, a second rigidity countermeasure process is executed to analyze the rigidity of the target part together with the parts joined to the target part (S502), and the second shape optimization data generated by the second rigidity countermeasure process is stored in the storage unit 12. . The second rigidity countermeasure process is the same as the rigidity countermeasure process according to the first modification described with reference to FIG. 8, so detailed description thereof will be omitted here.

Next, the stiffness countermeasure processing unit 27 executes a third stiffness countermeasure process for collectively optimizing the shape of all the target parts for the vehicle body including all the target parts (S503). ). The stiffness countermeasure processing unit 27 stores the third shape optimization data generated by the third stiffness countermeasure processing in the storage unit 12 . Next, the stiffness countermeasure processing unit 27 executes the third stiffness countermeasure processing for executing the shape optimization processing for collectively optimizing the shape of all the target parts for the vehicle body including all the target parts (S504). ). The stiffness countermeasure processing unit 27 stores the third state optimization data generated by the fourth stiffness countermeasure processing in the storage unit 12 .

Next, the rigidity countermeasure processing unit 27 generates first effect information indicating the effect of the first rigidity countermeasure processing (S505). Next, the stiffness countermeasure processing unit 27 generates second effect information indicating the effect of the second stiffness countermeasure processing (S506). Next, the stiffness countermeasure processing unit 27 generates third effect information indicating the effect of the third stiffness countermeasure processing (S507). Next, the stiffness countermeasure processing unit 27 generates fourth effect information indicating the effect of the fourth stiffness countermeasure processing (S508). Since each process of S505 to S508 is the same as the process of S113 to S115, detailed description is omitted here.

Next, the stiffness countermeasure processing unit 27 compares the first effect information to the fourth effect information generated in the respective processes of S505 to S508, and finds the most stiffness countermeasure process among the first stiffness countermeasure process to the second stiffness countermeasure process. A stiffness countermeasure process with improved data is determined (S509).

Further, the structural body design support devices 1 and 2 perform the natural vibration analysis of the vehicle body, but the structure design support device according to the embodiment performs the dynamic stiffness analysis other than the natural vibration analysis on the structure other than the vehicle body, and the reference A frequency, a first frequency and a second frequency may be calculated.

For example, the structural body design support device according to the embodiment may calculate the reference resonance frequency, the first resonance frequency and the second resonance frequency obtained by the excitation response analysis as the reference frequency, the first frequency and the second frequency. good. The reference resonance frequency is calculated based on the numerical analysis data, and the first resonance frequency is calculated based on the thickness change data obtained by changing the thickness data from the numerical analysis data. The second resonance frequency is calculated based on modified elasticity data obtained by modifying physical property data indicating elasticity such as Young's modulus from the numerical analysis data.

Further, the structural design support devices 1 and 2 analyze the natural vibration of the vehicle body, but the structure design support device according to the embodiment may perform the static rigidity analysis of the vehicle body and structures other than the vehicle body.

The structural body design support device according to the embodiment calculates the b value shown in Equation (2) as a bending degree index when static stiffness analysis is performed on the structure. In equation (2), the reference stiffness data is indicated by _K0 , the first stiffness data is indicated by _K1 , the second stiffness data is indicated by _K2 , and the first stiffness data _K1 and the reference stiffness data _K0 is indicated by ΔK _t , and the difference between the second stiffness data K ₂ and the reference stiffness data K ₀ is indicated by ΔK _E . The stiffness data K is, for example, a torsional stiffness represented by (M/θ) with a torsional moment M and a torsional angle θ. Equation (2) is a function for calculating the bend index, with ΔK _t representing the difference between the reference stiffness and the first stiffness and ΔK _E representing the difference between the reference stiffness and the second stiffness.

Using an automobile body as a structure, three parts were extracted from about 150 parts included in the body, and rigidity countermeasure processing was executed using, for example, ALTAIR's OptiStruct.

FIG. 10( a ) is a diagram showing conditions of b values and Young's modulus sensitivities in Examples and Comparative Examples.

In the example, three parts with high b-values were extracted from the parts with b-values higher than a predetermined b-value threshold and Young's modulus sensitivity higher than a predetermined Young's modulus sensitivity threshold. For the comparative example, three parts with low b-values were extracted from the parts whose b-value was lower than the predetermined b-value threshold and whose Young's modulus sensitivity was higher than the predetermined Young's modulus sensitivity threshold.

Rigidity countermeasure processing was executed for each of the three extracted examples and comparative examples, and the increase in natural frequency per 1 kg of mass was calculated from changes in the natural frequency of the vehicle body before and after the rigidity countermeasure processing was executed.

FIG. 10(b) is a diagram showing the improvement margin of the natural frequency per 1 kg of mass in each of the example and the comparative example.

The margin for improvement of the natural frequency per kg of mass in Example 1 is 0.038 Hz, and the margin for improvement in the natural frequency per kg of mass in the comparative example is 0.017 Hz. The improvement margin of the natural frequency per 1 kg of mass in the example is more than twice the improvement margin of the natural frequency per 1 kg of mass in the comparative example. It was confirmed that the effect produced by performing the treatment is improved.

Reference Signs List 1, 2 Structural body design support device 20, 30 Processing unit 21 Numerical analysis data generation unit 22 Reference stiffness calculation unit 23 First stiffness calculation unit 24 Second stiffness calculation unit 25 Bend index calculation unit 26 Countermeasure necessity determination unit 27 Rigidity Countermeasure processing unit 31 Contribution degree index calculation unit

Claims (14)

Data indicating the rigidity of a structure having a plurality of parts under predetermined boundary conditions based on numerical analysis data including at least shape data including the thickness of each part of the structure and physical property data indicating elasticity. a reference stiffness calculator for calculating reference stiffness data;
a first stiffness calculation unit that calculates first stiffness data representing the stiffness of the structure under the boundary condition based on the thickness change data obtained by changing the data representing the thickness from the numerical analysis data;
a second stiffness calculation unit that calculates second stiffness data, which is data indicating the stiffness of the structure under the boundary conditions, based on the modified elasticity data obtained by changing the physical property data from the numerical analysis data;
a bending degree index calculation unit that calculates a bending degree index indicating the degree of bending deformation of the component based on the reference rigidity data, the first rigidity data, and the second rigidity data;
a countermeasure necessity determination unit that determines, based on at least the bend index, whether or not each of the parts is to be extracted as a target part on which rigidity countermeasure processing is to be performed;
a rigidity countermeasure processing unit that executes rigidity countermeasure processing on the target part;
A structural design support device characterized by comprising: The reference stiffness data, the first stiffness data, and the second stiffness data are data indicating a reference frequency, a first frequency, and a second frequency, which are vibration frequencies when dynamic stiffness analysis is performed on the structure, and
2. The structure design support device according to claim 1, wherein said bending degree index calculation unit calculates said bending degree index based on said reference frequency, said first frequency, and said second frequency. The reference frequency, the first frequency, and the second frequency are the reference natural frequency, the first natural frequency, and the second natural frequency obtained by natural vibration analysis, or the reference resonance frequency obtained by excitation response analysis, 3. The structural design support device according to claim 2, wherein the first resonance frequency and the second resonance frequency. 4. The structure design assisting apparatus according to claim 2, wherein said bending degree index is a function including a difference between said reference frequency and said first frequency and a difference between said reference frequency and said second frequency. The reference stiffness data, the first stiffness data, and the second stiffness data are data indicating the reference stiffness, the first stiffness, and the second stiffness, which are stiffnesses obtained when the structure is subjected to static stiffness analysis,
2. The structural body design support device according to claim 1, wherein said bending degree index is calculated based on said reference stiffness, said first stiffness, and said second stiffness. 6. The structure design assisting apparatus according to claim 5, wherein said bend index is a function including a difference between said reference stiffness and said first stiffness and a difference between said reference stiffness and said second stiffness. a contribution index calculation unit that calculates a contribution index indicating a contribution of the part to the rigidity of the structure based on the reference rigidity data and either the first rigidity data or the second rigidity data; further have
The structure design according to any one of claims 1 to 6, wherein the countermeasure necessity determination unit determines whether or not to extract as the target part based on the bending index and the contribution index. support equipment. The countermeasure necessity determination unit determines whether or not to extract the target part based on data indicating at least one of the surface area, volume, and weight of the part in addition to the bend index and the contribution index. 8. The structural body design support device according to claim 7. The rigidity countermeasure processing unit
performing stiffness analysis on each of the target parts individually to calculate stiffness data of the target parts;
9. The structural body design support device according to claim 1, wherein shape optimization processing is executed for each of the target parts based on the computed stiffness data of the target part. The rigidity countermeasure processing unit
analyzing the stiffness of each of the target parts and the parts joined to each of the target parts to calculate stiffness data of the target parts;
9. The structural body design support device according to claim 1, wherein shape optimization processing is executed for each of the target parts based on the computed stiffness data of the target part. 9. The rigidity countermeasure processing unit according to any one of claims 1 to 8, wherein, with respect to the structure including all of the target parts, shape optimization processing is performed to collectively optimize shapes of all of the target parts. 1. The structure design support device according to claim 1. 9. The rigidity countermeasure processing unit executes, for each target part, a shape optimization process for optimizing the shape of each of the target parts, with respect to the structure including all of the target parts. The structure design support device according to any one of 1. Data indicating the rigidity of a structure having a plurality of parts under predetermined boundary conditions based on numerical analysis data including at least shape data including the thickness of each part of the structure and physical property data indicating elasticity. Calculate the reference stiffness data,
calculating first stiffness data, which is data representing the stiffness of the structure under the boundary conditions, based on thickness change data obtained by changing the data representing the thickness from the numerical analysis data;
calculating second stiffness data, which is data indicating the stiffness of the structure under the boundary conditions, based on the modified elasticity data obtained by changing the physical property data from the numerical analysis data;
calculating a bending degree index indicating the degree of bending deformation of the part based on the reference rigidity data, the first rigidity data and the second rigidity data;
determining whether or not to extract each of the parts as a target part on which rigidity countermeasure processing is to be performed, based on at least the bend index;
executing rigidity countermeasure processing on the target part;
A structure design support method characterized by comprising: Data indicating the rigidity of a structure having a plurality of parts under predetermined boundary conditions based on numerical analysis data including at least shape data including the thickness of each part of the structure and physical property data indicating elasticity. Calculate the reference stiffness data,
calculating first stiffness data, which is data representing the stiffness of the structure under the boundary conditions, based on thickness change data obtained by changing the data representing the thickness from the numerical analysis data;
calculating second stiffness data, which is data indicating the stiffness of the structure under the boundary conditions, based on the modified elasticity data obtained by changing the physical property data from the numerical analysis data;
calculating a bending degree index indicating the degree of bending deformation of the part based on the reference rigidity data, the first rigidity data and the second rigidity data;
determining whether or not to extract each of the parts as a target part on which rigidity countermeasure processing is to be performed, based on at least the bend index;
executing rigidity countermeasure processing on the target part;
A structure design support program characterized by causing a computer to execute processing.

Images