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

Abstract

To provide a structural design support device that can easily evaluate structural parts that are important in terms of rigidity and where out-of-plane deformation is dominant. [Solution] The structural design support device 100 includes a storage unit 10 that stores numerical analysis data including an analysis model of a target part that constitutes at least a part of the structure; a stiffness calculation unit 20 that calculates the stiffness of the target part based on the stored numerical analysis data; a sensitivity calculation unit 30 that calculates the plate thickness sensitivity of the target part, which is the change in stiffness when the plate thickness of the target part is changed, and the Young's modulus sensitivity of the target part, which is the change in stiffness when the Young's modulus of the target part is changed; a sensitivity difference calculation unit 40 that calculates the sensitivity difference, which is the difference between the plate thickness sensitivity and the Young's modulus sensitivity of the target part; and a display unit 50 that displays the magnitude of the sensitivity difference in the target part in an identifiable manner.

Description

[Technical Field]

[0001] The present invention relates to a structural design support device, a structural design support method, and a structural design support program for supporting the design of structural components such as automobile bodies. In particular, the present invention relates to a structural design support device, a structural design support method, and a structural design support program that can easily evaluate structural components that are important in terms of rigidity and have a high degree of out-of-plane deformation. [Background technology]

[0002] In recent years, there has been an increasing demand for weight reduction in various structural components from the perspective of energy conservation and efficiency improvement. For example, in the automotive sector, there is a demand for lighter vehicle bodies. A common measure to achieve this is to reduce the thickness of the vehicle body panels. However, reducing panel thickness leads to a deterioration of vibration and noise characteristics due to a reduction in the rigidity and natural frequency of the vehicle body. Therefore, it is necessary to suppress this deterioration of characteristics by changing the structure of the vehicle body, and various techniques have been proposed to extract parts that require structural modification through numerical analysis.

[0003] For example, as described in Patent Document 1, a technique has been proposed to calculate the plate thickness sensitivity, which is the change in stiffness when the plate thickness of a part constituting a structure is changed, and the Young's modulus sensitivity, which is the change in stiffness when the Young's modulus of a part constituting a structure is changed, and to extract parts with high sensitivity (parts that are important in terms of stiffness) as parts that require structural modification.

[0004] Furthermore, as described in Patent Document 2, for example, a technique has been proposed to calculate the ratio of plate thickness sensitivity to Young's modulus sensitivity (degree of out-of-plane deformation), which represents the deformation mode of the parts constituting the structure, and to extract parts where this ratio is large (parts where out-of-plane deformation is dominant and load transmission efficiency is poor) as parts that require structural modification.

[0005] As described above, according to the techniques described in Patent Document 1 and the like, the sensitivity to rigidity is high, and the portions of the structure that are important for rigidity can be extracted. Further, according to the techniques described in Patent Document 2 and the like, the out-of-plane deformation degree is high and the out-of-plane deformation is dominant, so that the portions of the structure with poor load transfer efficiency can be extracted. However, in order to efficiently reduce the weight of the structure, it can be said that the portions that truly require structural changes are the portions that satisfy both the condition of being important for rigidity and the condition of having dominant out-of-plane deformation. In the techniques described in Patent Document 1, 2, etc., there is a problem that it is not possible to easily extract the portions that satisfy both conditions, so that it is not possible to efficiently reduce the weight of the structure.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0007] The present invention has been made in view of the problems of the above prior art, and an object thereof is to provide a structure design support device, a structure design support method, and a structure design support program that can easily evaluate portions of a structure that are important for rigidity and have dominant out-of-plane deformation.

Means for Solving the Problems

[0008] It should be noted that there seems to be an error in the original text where the tag

[0007] is repeated with a question mark in the middle in the translated text. Please check the original text for accuracy.In order to solve the above problems, the present invention provides a structural design support device including: a storage unit that stores numerical analysis data including an analysis model of a target part constituting at least a part of a structure; a rigidity calculation unit that calculates the rigidity of the target part based on the stored numerical analysis data; a sensitivity calculation unit that calculates a plate thickness sensitivity of the target part, which is a change in the rigidity when the plate thickness of the target part is changed, and a Young's modulus sensitivity of the target part, which is a change in the rigidity when the Young's modulus of the target part is changed; and a sensitivity difference calculation unit that calculates a sensitivity difference, which is a difference between the plate thickness sensitivity and the Young's modulus sensitivity of the target part.

[0009] According to the structural design support device of the present invention, numerical analysis data including an analysis model of a target part constituting at least a part of a structure is stored in a storage unit, and the rigidity calculation unit calculates the rigidity of the target part based on the stored numerical analysis data. Then, the sensitivity calculation unit calculates a plate thickness sensitivity of the target part, which is a change in the rigidity when the plate thickness of the target part is changed, and a Young's modulus sensitivity of the target part, which is a change in the rigidity when the Young's modulus of the target part is changed. Further, taking the plate thickness sensitivity calculated by the sensitivity calculation unit as s t and the Young's modulus sensitivity as s E , the sensitivity difference calculation unit calculates a sensitivity difference s t = s E - s b = s t - s E , which is the difference between the plate thickness sensitivity s of the target part and the Young's modulus sensitivity s b The sensitivity difference s t is a sensitivity to the out-of-plane deformation mode obtained by subtracting the Young's modulus sensitivity s E , which is a parameter acting on the in-plane deformation mode only, from the plate thickness sensitivity s b , which is a parameter acting on both the in-plane and out-of-plane deformation modes. Therefore, it can be determined that a part with a large sensitivity difference s EThe value of makes it easy to evaluate whether the target area is rigidly important and where out-of-plane deformation is dominant, and consequently the sensitivity difference s E Large target areas can be easily identified as areas that truly require structural modification. The plate thickness sensitivity calculated by the sensitivity calculation unit is the aforementioned plate thickness sensitivity s t s is the value obtained by dividing by the mass, volume, or surface area of ​​the target part. t It is also possible to make it '. Similarly, the Young's modulus sensitivity calculated by the sensitivity calculation unit is the Young's modulus sensitivity s mentioned above. E s is the value obtained by dividing by the mass, volume, or surface area of ​​the target part. E It is also possible to set it to '. In this case, the sensitivity difference is s b If we assume that, then s b '=s t '-s E ' and the sensitivity difference s b Areas with a large ' value can be determined to be areas that are important in terms of rigidity and where out-of-plane deformation is dominant (resulting in poor load transmission efficiency). Therefore, the sensitivity difference s calculated by the sensitivity difference calculation unit E The value of ' makes it easy to evaluate whether the target area is rigidly important and where out-of-plane deformation is dominant, and consequently the sensitivity difference s E Large target areas can be easily identified as areas that truly require structural modification.

[0010] Preferably, the structural design support device according to the present invention further comprises a display unit that displays the magnitude of the sensitivity difference in the target area in an identifiable manner.

[0011] According to the preferred configuration described above, the display unit clearly shows the magnitude of the sensitivity difference in the target area. Therefore, by visually inspecting this display, it is possible to easily extract target areas with large sensitivity differences.

[0012] Furthermore, in order to solve the above problems, the present invention is also provided as a structural design support method comprising: a storage step of storing numerical analysis data including an analysis model of a target part constituting at least a part of a structure; a stiffness calculation step of calculating the stiffness of the target part based on the stored numerical analysis data; a sensitivity calculation step of calculating the plate thickness sensitivity of the target part, which is the change in stiffness when the plate thickness of the target part is changed, and the Young's modulus sensitivity of the target part, which is the change in stiffness when the Young's modulus of the target part is changed; and a sensitivity difference calculation step of calculating the sensitivity difference, which is the difference between the plate thickness sensitivity and the Young's modulus sensitivity of the target part.

[0013] Preferably, the structural design support method according to the present invention further includes a display step that displays the magnitude of the sensitivity difference in the target area in an identifiable manner.

[0014] Furthermore, in order to solve the above problems, the present invention is also provided as a structural design support program that causes a computer to perform the following steps: a storage step of storing numerical analysis data including an analysis model of a target part constituting at least a part of a structure; a stiffness calculation step of calculating the stiffness of the target part based on the stored numerical analysis data; a sensitivity calculation step of calculating the plate thickness sensitivity of the target part, which is the change in stiffness when the plate thickness of the target part is changed, and the Young's modulus sensitivity of the target part, which is the change in stiffness when the Young's modulus of the target part is changed; and a sensitivity difference calculation step of calculating the sensitivity difference, which is the difference between the plate thickness sensitivity and the Young's modulus sensitivity of the target part.

[0015] Preferably, the structural design support program according to the present invention further causes the computer to perform a display step that displays the magnitude of the sensitivity difference in the target area in an identifiable manner. [Effects of the Invention]

[0016] According to the present invention, by calculating the sensitivity difference, which is the difference between the plate thickness sensitivity and the Young's modulus sensitivity of a target area constituting at least a part of the structure, it is possible to easily evaluate whether the target area is important in terms of rigidity and where out-of-plane deformation is dominant. Consequently, target areas with a large sensitivity difference can be easily identified as areas that truly require structural modification. [Brief explanation of the drawing]

[0017] [Figure 1] This is a block diagram showing the schematic configuration of a structural design support device according to one embodiment of the present invention. [Figure 2] This is a flowchart showing the general steps involved in a structural design support method performed using the structural design support device 100 shown in Figure 1. [Figure 3] This diagram conceptually illustrates the parts of a structure that require structural modification. [Figure 4] This figure shows an example of a display by the display unit 50 shown in Figure 1. [Modes for carrying out the invention]

[0018] Hereinafter, with reference to the attached drawings as appropriate, an embodiment of the present invention will be described using the case where the structure is an automobile body as an example. Figure 1 is a block diagram showing the schematic configuration of a structural design support device according to one embodiment of the present invention. As shown in Figure 1, the structural design support device 100 according to this embodiment comprises a storage unit 10, a stiffness calculation unit 20, a sensitivity calculation unit 30, and a sensitivity difference calculation unit 40. Furthermore, in a preferred embodiment, the structural design support device 100 further comprises a display unit 50. The structural design support device 100 is composed of a computer comprising, for example, a hardware processor such as a CPU (Central Processing Unit), memory such as RAM (Random Access Memory), ROM (Read Only Memory), or a hard disk, and a display such as a monitor or printer. The storage unit 10 is composed of, for example, memory. Furthermore, for example, a program stored in memory is executed by the hardware processor to perform various calculations, thereby enabling the stiffness calculation unit 20, the sensitivity calculation unit 30, and the sensitivity difference calculation unit 40 to function. Furthermore, the display unit 50 is composed of, for example, a display. Note that the structural design support device 100 may be implemented using a WWW system or by dedicated hardware such as an ASIC (Application Specific Integrated Circuit).

[0019] Figure 2 is a flowchart showing the schematic steps of a structural design support method performed using the structural design support device 100 shown in Figure 1. As shown in Figure 2, the structural design support method according to this embodiment includes a storage step ST1, a stiffness calculation step ST2, a sensitivity calculation step ST3, and a sensitivity difference calculation step ST4. Furthermore, in a preferred embodiment, the structural design support method according to this embodiment further includes a display step ST5. Each of the steps ST1 to ST5 will be described in order below.

[0020] <Memory Step ST1> In memory step ST1, the memory unit 10 stores numerical analysis data, including an analysis model of the target part that constitutes at least a portion of the structure. The stored numerical analysis data includes, for example, the analysis model of the target part (finite element analysis model) and load data applied to the target part (boundary conditions of the analysis model). If there are multiple target parts, the numbers assigned to each target part are also included in the numerical analysis data.

[0021] <Stiffness Calculation Step ST2> In the stiffness calculation step ST2, the stiffness calculation unit 20 calculates the stiffness K of the target part based on the stored numerical analysis data. Specifically, the stiffness calculation unit 20 calculates the stiffness K of the target part by applying the stored boundary conditions to the stored analysis model and performing structural analysis such as eigenvalue analysis using the finite element method.

[0022] Specifically, the stiffness K to be calculated can be a function of load (such as external forces or reaction forces at constraint points) and displacement, as shown in equation (1) below. However, the function may include parameters determined from the shape of the analysis model, etc.

number

[0023] A specific example of the stiffness K expressed by equation (1) above is the stiffness K expressed by the following equation (1-1) when a load F=(F1,F2,F3) is applied to a point in the analysis model and the displacement at the same point is d=(d1,d2,d3).

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[0024] Furthermore, the stiffness K calculated in the stiffness calculation step ST2 can also be the generalized stiffness in eigenvalue analysis, as shown in equation (2) below.

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[0025] Furthermore, the stiffness K calculated in the stiffness calculation step ST2 can also be the product of the eigenvalue and the generalized mass, for example, as shown in equation (3) below.

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[0026] <Sensitivity calculation step ST3> In sensitivity calculation step ST3, the sensitivity calculation unit 30 calculates the plate thickness sensitivity s of the target area, which is the change in stiffness K when the plate thickness t of the target area is changed. t The Young's modulus sensitivity of the target area is the change in stiffness K when the Young's modulus E of the target area is changed. E And, it calculates. Specifically, the sensitivity calculation unit 30 calculates ∂K / ∂x| obtained by performing sensitivity analysis. x=x0 Using this, the sensitivity s is expressed by the following equation (4). x (If x=t, plate thickness sensitivity s)t When x=E, the Young's modulus sensitivity s E Calculate ).

number

[0027] Furthermore, the sensitivity calculation unit 30 calculates the sensitivity s, which is expressed by the following formula (5). x (If x=t, plate thickness sensitivity s) t When x=E, the Young's modulus sensitivity s E You may also calculate ).

number

[0028] Furthermore, the sensitivity calculation unit 30 calculates the sensitivity s represented by the above formula (4) or formula (5). x s is the value obtained by dividing the target part by the mass M, volume V, or surface area A, and is expressed by the following formulas (6-1), (6-2), or (6-3). x ' is the sensitivity (if x=t, then plate thickness sensitivity s t ', in the case of x=E, Young's modulus sensitivity s E You can also calculate it as ').

number

[0029] The sensitivity calculation unit 30 calculates the change in stiffness K ΔK / Δx in response to a change in the design variable x (x=t or E), thereby determining the sensitivity s expressed by the above equations (4), (5), (6-1), (6-2), or (6-3). x or s x ∂K / ∂x| x=x0 It is also possible to approximate this using any of the following equations (7-1), (7-2), or (7-3).

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[0030] Note that the plate thickness sensitivity s in the sensitivity calculation unit 30 t or st In the calculation of ', it is desirable to perform the calculation so that the product of the plate thickness t and density of the target part remains constant in order to exclude the effect of mass change.

[0031] <Sensitivity difference calculation step ST4> In sensitivity difference calculation step ST4, the sensitivity difference calculation unit 40 calculates the plate thickness sensitivity s of the target area. t and Young's modulus sensitivity s E The difference between this and the sensitivity difference s b , or the plate thickness sensitivity s of the target area t 'and Young's modulus sensitivity s E The difference between this and the sensitivity difference s b The value of ' is calculated. The value of the sensitivity difference sb or sb' calculated in this sensitivity difference calculation step ST4 makes it easy to evaluate whether the target area is a rigidly important area and where out-of-plane deformation is dominant. This point will be explained below with reference to the drawings.

[0032] Figure 3 is a diagram that conceptually illustrates the parts of a structure that require structural modification. As shown in Figure 3, the parts that truly require structural modification in order to efficiently reduce the weight of the structure are those that satisfy both the condition that they are important in terms of rigidity (large values ​​on the horizontal axis in Figure 3) and the condition that out-of-plane deformation is dominant (large values ​​on the vertical axis in Figure 3) (the parts that meet the conditions of the hatched area in Figure 3). Parts that are important in terms of rigidity are those with high sensitivity (for example, Young's modulus sensitivity s E Areas where ) is large and out-of-plane deformation is dominant have plate thickness sensitivity s t and Young's modulus sensitivity s E The out-of-plane deformation degree b(b=s) is the ratio of to t / s E ) is a large part of the body. The sensitivity difference s calculated in sensitivity difference calculation step ST4 b The plate thickness sensitivity s is a parameter that acts on both in-plane and out-of-plane deformation modes. t The Young's modulus sensitivity s is a parameter that acts only on deformation modes in the in-plane plane. E This is the sensitivity to deformation modes that involve only out-of-plane deformation, obtained by subtracting the difference. Therefore, the sensitivity difference s bAreas with a large value can be determined to be areas that are important in terms of rigidity and where out-of-plane deformation is dominant (resulting in poor load transmission efficiency). Therefore, the sensitivity difference s calculated in sensitivity difference calculation step ST4 is E Depending on the value, the target area is important for rigidity (Young's modulus sensitivity s E It is possible to easily evaluate whether the area is one in which (b is large) and out-of-plane deformation is dominant (out-of-plane deformation degree b is large) (whether the target area meets the conditions of the hatched area in Figure 3). Sensitivity difference calculation step ST4: Sensitivity difference s b The same applies when calculating '. Furthermore, if the target area is one of the areas that meet the conditions of the hatched region in Figure 3, the target area should be structurally modified so that the value of the out-of-plane deformation b decreases (so that it changes in the direction of the thick arrow shown in Figure 3).

[0033] The stiffness calculation step ST2, sensitivity calculation step ST3, and sensitivity difference calculation step ST4 described above can be performed using, for example, general-purpose finite element analysis software (e.g., "NASTRAN" or "Marc" from MSC). It is also possible to perform each of steps ST2 to ST4 in a single step using this software.

[0034] <Display Step ST5> In display step ST5, the display unit 50 shows the sensitivity difference s in the target area. b or s b Display the magnitude of ' in a distinguishable way. For example, the sensitivity difference s b or s b Depending on the size of the ', you can consider changing the shade or color. Figure 4 shows an example of the display by the display unit 50. Figure 4(a) is an example in which the magnitude of the out-of-plane deformation b in the target area is displayed in shades for comparison, and Figure 4(b) shows the sensitivity difference s in the same target area as in Figure 4(a). bThis is an example of displaying the magnitude of the deformation using shades of gray. In the example shown in Figure 4(a), areas with a large out-of-plane deformation b are displayed darker (blacker), and areas with a small out-of-plane deformation b are displayed lighter (whiter). In the example shown in Figure 4(b), the sensitivity difference s b The larger the target area, the darker (blacker) it will be displayed, and the sensitivity difference s b The smaller the target area, the lighter (whiter) it is displayed. In the display shown in Figure 4(a), the out-of-plane deformation degree b is large, and out-of-plane deformation is dominant, so it is possible to extract target areas with poor load transmission efficiency (target areas shown in darker colors). However, the extracted target areas may not be important in terms of rigidity (Young's modulus sensitivity s E Because it includes elements with low sensitivity (such as those mentioned above), even if the structure of the extracted target area is modified, it cannot necessarily be said that the rigidity will improve. In contrast, the representation shown in Figure 4(b) is important in terms of rigidity (Young's modulus sensitivity s E Since it is possible to extract target areas (for example, the target areas enclosed by dashed lines in Figure 4(b)) where the (b) is large and out-of-plane deformation is dominant (out-of-plane deformation degree b is large), efficient structural modification becomes possible. [Explanation of Symbols]

[0035] 10...Storage section 20...Rigidity calculation section 30. Sensitivity Calculation Unit 40. Sensitivity Difference Calculation Unit 50...Display section 100...Structure design support equipment ST1...Memory Step ST2... Stiffness calculation step ST3...Sensitivity Calculation Step ST4...Sensitivity Difference Calculation Step ST5... Display Step

Claims

1. A storage unit that stores numerical analysis data including an analysis model of a target part that constitutes at least a part of the structure, A stiffness calculation unit calculates the stiffness of the target part based on the stored numerical analysis data, A sensitivity calculation unit that calculates the plate thickness sensitivity of the target part, which is the change in stiffness when the plate thickness of the target part is changed, and the Young's modulus sensitivity of the target part, which is the change in stiffness when the Young's modulus of the target part is changed. A sensitivity difference calculation unit calculates the sensitivity difference, which is the difference between the plate thickness sensitivity and the Young's modulus sensitivity of the target portion. A structural design support device equipped with the following features.

2. The system further includes a display unit that displays the magnitude of the sensitivity difference in the target area in a manner that allows for identification. A structural design support device according to claim 1.

3. A storage step of storing numerical analysis data including an analysis model of a target part that constitutes at least a part of the structure, A stiffness calculation step that calculates the stiffness of the target part based on the stored numerical analysis data, A sensitivity calculation step for calculating the plate thickness sensitivity of the target part, which is the change in stiffness when the plate thickness of the target part is changed, and the Young's modulus sensitivity of the target part, which is the change in stiffness when the Young's modulus of the target part is changed. A sensitivity difference calculation step for calculating the sensitivity difference, which is the difference between the plate thickness sensitivity and the Young's modulus sensitivity of the target part, A structural design support method having the following features.

4. The system further includes a display step that displays the magnitude of the sensitivity difference in the target area in a way that allows for identification. The structural design support method according to claim 3.

5. A storage step of storing numerical analysis data including an analysis model of a target part that constitutes at least a part of the structure, A stiffness calculation step that calculates the stiffness of the target part based on the stored numerical analysis data, A sensitivity calculation step for calculating the plate thickness sensitivity of the target part, which is the change in stiffness when the plate thickness of the target part is changed, and the Young's modulus sensitivity of the target part, which is the change in stiffness when the Young's modulus of the target part is changed. A sensitivity difference calculation step for calculating the sensitivity difference, which is the difference between the plate thickness sensitivity and the Young's modulus sensitivity of the target part, A structural design support program that has a computer execute the necessary steps.

6. The computer is further instructed to perform a display step that displays the magnitude of the sensitivity difference in the target area in a way that allows for identification. A structural design support program according to claim 5.

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