Analysis system, analysis method, and analysis program

Abstract

To provide an analysis system, an analysis method, and an analysis program capable of modeling each member by using beam elements and modeling the joining of the members with each other by using connection beam elements.SOLUTION: An analysis system that models a plurality of members joined with each other by using beam elements, comprises: a shape data acquiring unit S1 for acquiring shape data of the member; a joining position setting unit S2 for setting a joining position at which the members are joined to each other to the shape data; a beam element modeling unit S3 for modeling the shape data as a beam element; a connection beam element setting unit S4 for setting a connection beam element that connects the joining position and the beam element; and a deformation calculation unit S5 for calculating deformation of the member by finite element analysis of a structure analysis model created based on the beam element, the joining position, and the connection beam element.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to an analysis system, an analysis method, and an analysis program.

Background Art

[0002] Generally, a frame structure such as an automobile body or chassis is formed by joining a plurality of members by spot welding or bolt fastening. Knowing how this structure as a whole deforms, particularly plastically deform, is important for improving the collision safety of automobiles, and attempts have been made to do this using a computer. As a method of knowing how a structure deforms using a computer, a method of modeling the structure by the finite element method and analyzing the deformation of the entire structure by finite element analysis is known. This is called a structure analysis model.

[0003] For example, in Patent Document 1, a member such as a frame is modeled as a shell element (plate element) of the finite element method arranged in the plane direction, and the molten solidified portion of the spot welding is modeled as a solid element (three-dimensional element) of the finite element method connected to the shell element, thereby performing finite element analysis of the entire structure.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

[0005] Finite element analysis based on structural analysis models of shell elements and solid elements is an excellent method with high computational accuracy. However, it is extremely complex and time-consuming to create because it requires detailed modeling of the shape data of all members included in the structure using shell elements. Furthermore, a significant amount of computation time is required to perform finite element analysis based on the obtained model. Moreover, if the shape of a member is changed based on the results of the finite element analysis, even more time is required to remodel the structure.

[0006] Another method for modeling structures is the use of beam elements in the finite element method. Beam elements are generally constructed as linear finite elements passing through the centroid or center of gravity of the member, calculated from the member's first moment of area and cross-sectional area. The shape data is defined by cross-sectional property values ​​(second moment of area, polar second moment of area) or a set of integration points used to calculate stress and strain. While beam elements have fewer degrees of freedom for deformation than shell or solid elements, resulting in lower calculation accuracy for large deformations, their advantages include ease of creating and modifying shape data and reduced computation time required for finite element analysis.

[0007] Many structures are composed of multiple members, and are fabricated by appropriately joining each member. When such structures are modeled using shell elements, a solid element joining model, as shown in Patent Document 1, can be used to join each member. However, when members are modeled using beam elements, a solid element joining model cannot be used. Therefore, to model complex structures composed of multiple members using beam elements, a new joining method must be introduced. [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] Therefore, the object of the present invention is to provide an analysis system, analysis method, and analysis program that can model each member with beam elements and model the joints between members with connecting beam elements. [Means for solving the problem]

[0009] To solve the aforementioned problems, the present invention is characterized by being configured as follows.

[0010] First, the invention described in claim 1 of this application is an analysis system that models a plurality of members joined together using beam elements, A shape data acquisition unit that acquires the shape data of the aforementioned member, A joining position setting unit sets the joining positions in which the members are joined to each other, based on the shape data, A beam element modeling unit that models the shape data as beam elements, A connecting beam element setting unit sets a connecting beam element that connects the joining position and the beam element, The system includes a deformation calculation unit that calculates the deformation of the member by performing a finite element analysis of a structural analysis model created based on the beam element, the joint position, and the connecting beam element. It is characterized by the following:

[0011] Furthermore, the invention described in claim 2 is characterized in that, in the invention of claim 1, the beam element is configured to pass through the centroid of the cross-section of the member.

[0012] Furthermore, the invention described in claim 3 is characterized in that, in the invention described in claim 1 or claim 2, the connecting beam element setting unit is configured to set a predetermined rigidity for the connecting beam element.

[0013] Furthermore, the invention described in claim 4 is characterized in that, in the invention described in claim 3, the stiffness of the connecting beam element is automatically adjusted so that the stiffness of the structural analysis model when the member is modeled using beam elements matches the stiffness of the structural analysis model when the member is modeled using shell elements, by convergence calculation based on an optimization method.

[0014] Furthermore, the invention described in claim 5 is characterized in that, in the invention described in any one of claims 1 to 4, the beam element modeling unit is configured to select whether to model the shape data as a beam element or a shell element.

[0015] Furthermore, the invention described in claim 6 is characterized in that, in the invention of claim 5, the beam element modeling unit is configured to automatically determine whether to model the shape data as the beam element or the shell element by using the aspect ratio of the shape of the member as an indicator.

[0016] Furthermore, the invention described in claim 7 is an analysis method for modeling a plurality of members joined together using beam elements, A shape data acquisition step for acquiring the shape data of the aforementioned member, A joining position setting step for the shape data, which sets the joining positions where the members are joined to each other, A beam element modeling step in which the shape data is modeled as a beam element, A connecting beam element setting step involves setting a connecting beam element that connects the joining position and the beam element, The method includes a deformation calculation step of calculating the deformation of the member by performing a finite element analysis of a structural analysis model created based on the beam element, the joint position, and the connecting beam element. It is characterized by the following:

[0017] Furthermore, the invention described in claim 8 is an analysis program that models a plurality of members joined together using beam elements, A shape data acquisition process for acquiring the shape data of the aforementioned member, A joining position setting process for the shape data, which sets the joining positions where the members are joined to each other, A beam element modeling process that models the aforementioned shape data as beam elements, A connecting beam element setting process for setting a connecting beam element that connects the joint position and the beam element, and a deformation calculation process for calculating the deformation of the member by finite element analysis of a structural analysis model created based on the beam element, the joint position, and the connecting beam element. It is characterized by the above.

Advantages of the Invention

[0018] With the above configuration, according to the invention of each claim of the present application, the following effects can be obtained.

[0019] First, according to the invention described in claim 1 of the present application, the analysis system has a connecting beam element setting unit that sets a connecting beam element that connects the joint position and the beam element. Finite element analysis of the structural analysis model created based on this connecting beam element and the beam element and the joint position is performed, and the deformation of the member is calculated. Therefore, an analysis system that can model the joint between a plurality of members by a beam element can be provided.

[0020] Also, according to the invention described in claim 2, the beam element is configured to pass through the centroid of the cross-section of the member. Therefore, by connecting the centroid and the joint position with a connecting beam element, a complex structure in which a plurality of members are joined to each other can be simply modeled.

[0021] Also, according to the invention described in claim 3, the connecting beam element setting unit is configured to set a predetermined rigidity for the connecting beam element. Therefore, the calculation accuracy of the deformation of the members connected by the connecting beam element is improved.

[0022] Furthermore, according to the invention described in claim 4, the stiffness of the connecting beam element is automatically adjusted so that the stiffness of the structural analysis model when the member is modeled using beam elements matches the stiffness of the structural analysis model when the member is modeled using shell elements, through convergence calculations based on an optimization method. Therefore, by implementing a function to perform convergence calculations based on an optimization method in the analysis system, the stiffness is automatically adjusted to match the calculation results. Alternatively, the analysis system can also use stiffness data registered based on past calculation results. In this case, although the accuracy of stiffness reproduction is slightly lower, it is efficient because there is no need to perform convergence calculations.

[0023] Furthermore, according to the invention described in claim 5, the beam element modeling unit is configured to select whether to model the shape data as a beam element or a shell element. Therefore, by selecting to model a flat plate component, such as a flat sheet metal having a predetermined thickness, as a shell element, and by selecting to model a beam-like component having a predetermined cross-sectional shape and extending along a predetermined neutral axis as a beam element, it is possible to model a complex structure in which flat plate components and beam-like components are combined with each other.

[0024] Furthermore, according to the invention described in claim 6, the beam element modeling unit is configured to automatically determine whether to model the shape data as a beam element or a shell element by using the aspect ratio of the shape of the member as an indicator. Therefore, complex structures in which flat plate parts and beam-shaped parts are combined with each other can be automatically modeled.

[0025] Furthermore, according to the invention described in claim 7, the analysis method includes a connecting beam element setting step in which a connecting beam element is set to connect the joint position and the beam element. A finite element analysis is performed on this connecting beam element and the structural analysis model created based on the beam element and the joint position to calculate the deformation of the member. Therefore, an analysis method is provided that can model the joint between multiple members using beam elements.

[0026] Similarly, according to the invention described in claim 8, the analysis program has a connecting beam element setting process for setting connecting beam elements that connect the joint location and the beam elements. Finite element analysis is performed on the structural analysis model created based on these connecting beam elements and the beam elements and the joint location to calculate the deformation of the members. Thus, an analysis program is provided that can model the joint between multiple members using beam elements. [Brief explanation of the drawing]

[0027] [Figure 1] This figure shows the overall configuration of the analysis system according to an embodiment of the present invention. [Figure 2] This diagram shows the configuration of the storage device shown in Figure 1. [Figure 3] Figure 2 is a flowchart of the analysis program. [Figure 4] This figure shows the input screen for the shape data acquisition process in Figure 3. [Figure 5] This figure shows the 3D data acquired during the shape data acquisition process shown in Figure 3. [Figure 6] This is a cross-sectional view of the shape data along the line VI-VI in Figure 5. [Figure 7] Figure 3 illustrates the process for setting the joint position. [Figure 8] This diagram illustrates the joint position setting process for a cross-sectional view of shape data along the VI-VI line in Figure 5. [Figure 9] Figure 3 illustrates the beam element modeling process. [Figure 10] This figure illustrates the beam element modeling process for a cross-sectional view of shape data along the line VI-VI in Figure 5. [Figure 11] Figure 10 shows the 3D data of the floor panel on which the beam element modeling process is performed. [Figure 12] Figure 10 shows the 3D data of the side sill outer where the beam element modeling process is performed. [Figure 13] Figure 3 illustrates the process for setting up the connecting beam elements. [Figure 14] This diagram illustrates the process of setting connecting beam elements for a cross-sectional view of shape data along the line VI-VI in Figure 5. [Figure 15] This figure compares the calculation results of the torsional moment of a structure calculated by the deformation calculation process shown in Figure 3 with the calculation results of finite element analysis using shell elements. [Modes for carrying out the invention]

[0028] Embodiments of the present invention will be described below with reference to the accompanying drawings.

[0029] Figure 1 is a diagram showing the overall configuration of an analysis system according to an embodiment of the present invention. As shown in Figure 1, the analysis system in the embodiment of the present invention is configured around a computer 10, which includes a central processing unit 11, input devices 12 such as a keyboard or mouse for inputting data necessary for acquiring shape data and creating structural analysis models, a display device 13 such as a display for displaying shape data and structural analysis models, a storage device 14 such as a memory for storing shape data, structural analysis models, and analysis programs for finite element analysis, and an output device 15 such as a display or printer for outputting calculation results.

[0030] The central processing unit 11 controls the input device 12 and the display device 13, and is configured to access the storage device 14. For example, it receives shape data from an external system via the input device 12, stores the shape data in the storage device 14, and performs finite element analysis using the information input via the input device 12 and the programs and data recorded in the storage device 14.

[0031] Figure 2 shows the configuration of the storage device 14 in Figure 1. As shown in Figure 2, the storage device 14 has a program storage unit and a data storage unit. The program storage unit stores an analysis program for calculating the deformation of multiple members that are joined together by modeling them with beam elements and performing finite element analysis of the structural analysis model created based on these beam elements.

[0032] On the other hand, the data storage unit is provided with a structure shape data file in which shape data of a structure formed by joining multiple members is taken in, a joining information data file in which joining information data (data recording the joining position and the combination of members to be joined) is recorded, a deformation calculation result file in which the calculation results of the deformation of the structure analysis model obtained by finite element analysis are recorded, and a structure analysis model file in which the structure analysis model is recorded.

[0033] Next, we will specifically explain the process of calculating the deformation of a structural analysis model, which is made up of multiple joined members, using finite element analysis.

[0034] Figure 3 is a flowchart of the analysis program shown in Figure 2.

[0035] First, the analysis program operates the shape data acquisition process S1. This shape data acquisition process S1 is configured to acquire shape data of a structure from an external system via the input device 12 into the data storage unit of the storage device 14, specifically into a structure shape data file. As shape data of a structure, not only shell elements of the finite element method but also CAD data can be read. In this analysis system, beam elements can be created from the shape data (shell elements or CAD data) of a selected member and finite element analysis can be performed. Alternatively, it is possible to model a selected member using shell elements, and then perform finite element analysis on that member by creating shell elements from the read shell elements or CAD data. Note that for CAD data, functions such as analyzing it using numerical simulation methods other than the finite element method may be implemented.

[0036] Figure 4 shows the input screen for the shape data acquisition process S1 shown in Figure 3. This input screen is displayed on the display device 13.

[0037] The input screen W1 shown in Figure 4 displays a shape data drawing screen W11, which is configured to show the shape data of a structure imported into the data storage unit of the storage device 14. Below this shape data drawing screen W11, a read button W12 is displayed for selecting shape data of a structure from an external system and importing it into the storage device 14. If the shape data includes joining information data (data that records the joining position and the combination of members to be joined), that information is used for joining each member. If there is joining information data in the external system separately from the shape data, that data is selected and imported into the joining information data file in the data storage unit of the storage device 14 using the read button W12. If joining information data does not exist, it is also possible to create joining information data within this analysis system by selecting the joining position and the members to be joined.

[0038] In this embodiment, the shape data drawing screen W11 displays the three-dimensional data of the structure 100 that has been stored in the data storage unit of the storage device 14.

[0039] In the input screen W1 of Figure 4, an execute button W13 is displayed adjacent to the load button W12. By pressing this execute button W13, the following processing is performed on the 3D data of the structure 100 displayed on the shape data drawing screen W11.

[0040] In the shape data acquisition process S1, the material properties of the structure 100, such as the mechanical properties (mass density, Young's modulus, Poisson's ratio, yield stress, etc.), are input via the input device 12.

[0041] Figure 5 shows the 3D data acquired in the shape data acquisition process S1 shown in Figure 3. The 3D data of the structure 100 shown in Figure 5 is the body frame of an automobile. In the following explanation, the longitudinal direction of the vehicle body in Figure 1 is referred to as the X direction, the width direction as the Y direction, and the vertical direction as the Z direction.

[0042] The structure 100 includes a roof side rail 104 configured to support the roof 102 of the automobile, a floor panel 106 configured as the floor of the automobile, a pair of side sills 108 disposed at both left and right ends in the Y direction of the floor panel 106 and extending in the X direction, and a B-pillar 110 extending in the Z direction between the roof side rail 104 and the side sills 108.

[0043] Figure 6 is a cross-sectional view of the shape data along the line VI-VI in Figure 5. Figure 6 is a cross-sectional view of the side sill 108 in particular, viewed from the X direction.

[0044] In this embodiment, the side sill 108 includes a side outer panel 112 provided below the B pillar 110 in the Z direction and extending in the X direction, a side sill outer reinforcement 114 extending in the X direction on the Y-inside of the side outer panel 112 and spot-welded to the side outer panel 112, a side sill outer 116 extending in the X direction on the Y-inside of the side sill outer reinforcement 114 and spot-welded to the side sill outer reinforcement 114, a side sill inner 118 extending in the X direction on the Y-inside of the side sill outer 116 and spot-welded to the side sill outer 116, and a side sill inner reinforcement 120 extending in the X direction on the Y-outside of the side sill inner 118 and spot-welded to the side sill inner 118.

[0045] The side outer panel 112 has a side outer panel projection 122 that protrudes outward in the Y direction. The side sill outer reinforcement 114 has a side sill outer reinforcement projection 124 that protrudes outward in the Y direction, aligned with the side outer panel projection 122 that is aligned with the side outer panel projection 122 that is aligned with the side outer reinforcement projection 124 that is aligned with the side sill outer reinforcement projection 124 that is aligned with the side sill outer reinforcement projection 126 that protrudes outward in the Y direction. The side sill inner 118 has a side sill inner projection 128 that protrudes inward in the Y direction. The side sill inner reinforcement 120 has a side sill inner reinforcement projection 130 that protrudes inward in the Y direction, aligned with the side sill inner projection 128 that is aligned with the side sill inner projection 128 that is aligned with the side sill inner projection 128 that is aligned with the side sill inner reinforcement projection 130 that protrudes inward in the Y direction.

[0046] Returning to Figure 3, the analysis program operates the shape data acquisition process S1, and then the joint position setting process S2.

[0047] Figure 7 illustrates the joint position setting process S2 shown in Figure 3. In this joint position setting process S2, the joint position setting screen W14 is displayed on the input screen W1 shown on the display device 13, and the joint position is set for the 3D data of the structure 100 via the input device 12 shown in Figure 1. The joint position, especially the spot welding point, is automatically set from the data if the shape data includes joint information data, or if there is a joint information data file in the data storage unit of the storage device 14. If no joint information data exists, the joint point and the member to be joined are set by selecting them with an input device 12 such as a mouse on the shape data drawing screen W11 shown in Figure 7.

[0048] Figure 8 is a diagram illustrating the joint position setting process S2 with respect to a cross-sectional view of the shape data along the line VI-VI in Figure 5.

[0049] In this embodiment, a first spot welding point 132 is set as the first joining position above the side sill 108 in the Z direction, where the side outer panel 112, side sill outer reinforcement 114, side sill outer 116, and side sill inner 118 are overlapped and spot-welded along the Y direction. A second spot welding point 134 is set as the second joining position on the Y-outer side of the side sill 108, where the side outer panel projection 122 of the side outer panel 112, the side sill outer reinforcement projection 124 of the side sill outer reinforcement 114, and the side sill outer projection 126 of the side sill outer 116 are overlapped and spot-welded along the Y direction. A third spot welding point 136 is set as the third joining position below the side sill 108 in the Z direction, where the side sill outer 116 and side sill inner 118 are overlapped and spot-welded along the Y direction. A fourth spot welding point 138 is set as the fourth joining position, located below the inner side of the side sill 108 in the Y direction, where the side sill inner projection 128 of the side sill inner 118 and the floor panel 106 are overlapped and spot-welded along the Y direction. A fifth spot welding point 140 is set as the fifth joining position, located above the inner side of the side sill 108 in the Y direction, where the side sill inner projection 128 of the side sill inner 118 and the side sill inner reinforcement projection 130 of the side sill inner reinforcement 120 are overlapped and spot-welded along the Y direction.

[0050] In this embodiment, the joint position setting process S2 is configured to set the joint position for the 3D data of the structure 100 via the input device 12. However, if the joint position is already included in the 3D data, the process may be configured to extract the joint position from the 3D data.

[0051] Returning to Figure 3, the analysis program runs the joint position setting process S2, and then runs the beam element modeling process S3.

[0052] Figure 9 is a diagram illustrating the beam element modeling process S3 shown in Figure 3. In this beam element modeling process S3, the beam element modeling screen W15 is displayed on the input screen W1 shown on the display device 13, and the system is configured to model each member as a beam element for the 3D data of the structure 100.

[0053] Figure 10 is a diagram illustrating the beam element modeling process S3 for a cross-sectional view of the shape data along the line VI-VI in Figure 5.

[0054] In this embodiment, the side outer panel 112 has the centroid of the cross-section of the side outer panel 112 extending in the X direction on the Y-inside of the side outer panel 112, and is modeled as a side outer panel beam element 142 extending in the X direction so as to pass through the centroid. The side outer panel beam element 142 is composed of a plurality of connected linear finite elements of a predetermined length, and the cross-sectional shape of the side outer panel 112 is determined by integration points (not shown) arranged along the cross-section of the side outer panel 112.

[0055] The side sill outer reinforcement 114 has the centroid of the cross-section of the side sill outer reinforcement 114 extending in the X direction on the Y-inside of the side sill outer reinforcement 114, and is modeled as a side sill outer reinforcement beam element 144 that extends in the X direction so as to pass through the centroid. The side sill outer reinforcement beam element 144 is composed of a plurality of connected linear finite elements of a predetermined length, and the cross-sectional shape of the side sill outer reinforcement 114 is determined by integration points (not shown) arranged along the cross-section of the side sill outer reinforcement 114.

[0056] The side sill outer 116 has the centroid of the cross-section of the side sill outer 116 extending in the X direction on the Y-direction side of the side sill outer 116, and is modeled as a side sill outer beam element 146 that extends in the X direction so as to pass through the centroid. The side sill outer beam element 146 is composed of a plurality of connected linear finite elements of a predetermined length, and the cross-sectional shape of the side sill outer 116 is determined by integration points (not shown) arranged along the cross-section of the side sill outer 116.

[0057] The side sill inner 118 has the centroid of the cross-section of the side sill inner 118 extending in the X direction on the Y-outward side of the side sill inner 118, and is modeled as a side sill inner beam element 148 extending in the X direction so as to pass through this centroid. The side sill inner beam element 148 is composed of a plurality of connected linear finite elements of a predetermined length, and the cross-sectional shape of the side sill inner 118 is determined by integration points (not shown) arranged along the cross-section of the side sill inner 118.

[0058] The side sill inner reinforcement 120 has the centroid of the cross-section of the side sill inner reinforcement 120 extending in the X direction on the Y-outward side of the side sill inner reinforcement 120, and is modeled as a side sill inner reinforcement beam element 150 extending in the X direction so as to pass through the centroid. The side sill inner reinforcement beam element 150 is composed of a plurality of connected linear finite elements of a predetermined length, and the cross-sectional shape of the side sill inner reinforcement 120 is determined by integration points (not shown) arranged along the cross-section of the side sill inner reinforcement 120.

[0059] Returning to Figure 9, the beam element modeling process S3 is configured to model the side outer panel 112, side sill outer reinforcement 114, side sill outer 116, side sill inner 118, and side sill inner reinforcement 120 as beam elements, while flat plate components such as the roof 102 and floor panel 106 are modeled as shell elements.

[0060] In this embodiment, the beam element modeling process S3 is configured to set whether to model a member as a beam element or a shell element by selecting each member with an input device 12 such as a mouse. Alternatively, the beam element modeling process S3 may be configured to automatically determine whether to model each member as a beam element or a shell element using the ratio of the vertical length to the horizontal length of the shape of each member, i.e., the aspect ratio, as an indicator.

[0061] Figure 11 shows the three-dimensional data of the floor panel 106 on which the beam element modeling process S3 of Figure 10 is performed. Figure 12 shows the three-dimensional data of the side sill outer 116 on which the beam element modeling process S3 of Figure 10 is performed. In this embodiment, the floor panel 106 is a flat plate component because it is formed from a flat sheet metal having a predetermined thickness. On the other hand, the side sill outer 116 is a beam-shaped component because it has a predetermined cross-sectional shape and extends along the X direction.

[0062] As described above, in a modified example in which the beam element modeling process S3 is configured to automatically determine whether to model a beam element or a shell element based on the aspect ratio, the beam element modeling process S3 is configured to measure the dimensions of members such as the floor panel 106 and the side sill outer 116 along the X, Y, and Z directions. The dimensions measured along the X, Y, and Z directions of the members are identified as dimension values ​​L1, L2, and L3 in descending order.

[0063] Subsequently, in the beam element modeling process S3, the aspect ratio of the member is calculated based on the following equation 1.

[0064]

number

[0065] Subsequently, in the beam element modeling process S3, the shape of each member is classified as either a beam element or a shell element based on the aspect ratio of the member described above. When the aspect ratio of a member is 1 or greater and below a predetermined threshold, for example, 2 or less, it is automatically determined that the shape of the member will be modeled as a shell element. On the other hand, when the aspect ratio of a member is greater than 2, it is automatically determined that the shape of the member will be modeled as a beam element. The shape of a member determined to be modeled as a beam element is modeled as a beam element extending along the direction of the dimension identified as the dimension value L1.

[0066] In this embodiment, the floor panel 106 is determined to be modeled as a shell element because the aspect ratio calculated based on the length dimension L1 in the Y direction and the length dimension L2 in the X direction is 1 or greater and 2 or less. On the other hand, the side sill outer 116 is determined to be modeled as a beam element because the aspect ratio calculated based on the length dimension L1 in the X direction and the length dimension L2 in the Z direction is greater than 2.

[0067] In the above modified example, the threshold is set to 2, but a different value may be set. Also, the shape of the member that is determined to be modeled as a beam element may be modeled as a beam element extending along a direction selected by an input device 12 such as a mouse.

[0068] Returning to Figure 3, the analysis program runs the beam element modeling process S3, and then the connection beam element setting process S4.

[0069] Figure 13 is a diagram illustrating the connection beam element setting process S4 shown in Figure 3. In this connection beam element setting process S4, the connection beam element setting screen W16 is displayed on the input screen W1 shown on the display device 13, and the process is configured to set connection beam elements that connect the junction position and the beam elements of the modeled structure 100.

[0070] Figure 14 illustrates the process of setting connecting beam elements for a cross-sectional view of shape data along the VI-VI line in Figure 5.

[0071] In this embodiment, the side outer panel 112 is spot-welded at a first spot welding point 132 and a second spot welding point 134. Therefore, a first side outer panel connecting beam element 152 is provided between the side outer panel beam element 142 and the first spot welding point 132, connecting the side outer panel beam element 142 and the first spot welding point 132. Similarly, a second side outer panel connecting beam element 154 is provided between the side outer panel beam element 142 and the second spot welding point 134, connecting the side outer panel beam element 142 and the second spot welding point 134. The nodes of the first side outer panel connecting beam element 152 and the second side outer panel connecting beam element 154 are each connected to the nodes of the side outer panel beam element 142.

[0072] The side sill outer reinforcement 114 is spot-welded at a first spot welding point 132 and a second spot welding point 134. Therefore, a first side sill outer reinforcement connecting beam element 156 is provided between the side sill outer reinforcement beam element 144 and the first spot welding point 132, connecting the side sill outer reinforcement beam element 144 and the first spot welding point 132. Also, a second side sill outer reinforcement connecting beam element 158 ​​is provided between the side sill outer reinforcement beam element 144 and the second spot welding point 134, connecting the side sill outer reinforcement beam element 144 and the second spot welding point 134. The nodes of the first side sill outer reinforcement connecting beam element 156 and the second side sill outer reinforcement connecting beam element 158 ​​are each connected to the nodes of the side sill outer reinforcement beam element 144.

[0073] The side sill outer 116 is spot-welded at the first spot welding point 132, the second spot welding point 134, and the third spot welding point 136. Therefore, a first side sill outer connecting beam element 160 is provided between the side sill outer beam element 146 and the first spot welding point 132, connecting the side sill outer beam element 146 and the first spot welding point 132. Furthermore, a second side sill outer connecting beam element 162 is provided between the side sill outer beam element 146 and the second spot welding point 134, connecting the side sill outer beam element 146 and the second spot welding point 134. In addition, a third side sill outer connecting beam element 164 is provided between the side sill outer beam element 146 and the third spot welding point 136, connecting the side sill outer beam element 146 and the third spot welding point 136. The nodes of the first side sill outer connecting beam element 160, the second side sill outer connecting beam element 162, and the third side sill outer connecting beam element 164 are each connected to the nodes of the side sill outer beam element 146.

[0074] The side sill inner 118 is spot-welded at the first spot welding point 132, the third spot welding point 136, the fourth spot welding point 138, and the fifth spot welding point 140. Therefore, a first side sill inner connecting beam element 166 is provided between the side sill inner beam element 148 and the first spot welding point 132, connecting the side sill inner beam element 148 and the first spot welding point 132. Furthermore, a second side sill inner connecting beam element 168 is provided between the side sill inner beam element 148 and the third spot welding point 136, connecting the side sill inner beam element 148 and the third spot welding point 136. In addition, a third side sill inner connecting beam element 170 is provided between the side sill inner beam element 148 and the fourth spot welding point 138, connecting the side sill inner beam element 148 and the fourth spot welding point 138. Similarly, a fourth side sill inner connecting beam element 172 is provided between the side sill inner beam element 148 and the fifth spot welding point 140, connecting the side sill inner beam element 148 and the fifth spot welding point 140. The nodes of the first side sill inner connecting beam element 166, the second side sill inner connecting beam element 168, the third side sill inner connecting beam element 170, and the fourth side sill inner connecting beam element 172 are each connected to the nodes of the side sill inner beam element 148.

[0075] The side sill inner reinforcement 120 is spot-welded at the fifth spot welding point 140. Therefore, a side sill inner reinforcement connecting beam element 174 is set between the side sill inner reinforcement beam element 150 and the fifth spot welding point 140. The nodes of the side sill inner reinforcement connecting beam element 174 are connected to the nodes of the side sill inner reinforcement beam element 150. The connecting beam element is a spring element with 6 degrees of freedom (3 translational components, 3 rotational components) of rigidity. When the member is made of a metal material such as steel plate, it has high rigidity.

[0076] Returning to Figure 3, the analysis program runs the connection beam element setting process S4, and then runs the deformation calculation process S5. This deformation calculation process S5 calculates the deformation of the structure 100 by finite element analysis based on the beam elements, the joint position, and the connection beam elements.

[0077] As described above, the structure 100 includes a first side outer panel connecting beam element 152 and a second side outer panel connecting beam element 154 that connect the side outer panel beam element 142 to the first spot weld point 132 and the second spot weld point 134, respectively; a first side sill outer reinforcement connecting beam element 156 and a second side sill outer reinforcement connecting beam element 158 ​​that connect the side sill outer beam element 144 to the first spot weld point 132 and the second spot weld point 134, respectively; and a first side sill outer connecting beam element 146 that connects the first spot weld point 132, the second spot weld point 134 and the third spot weld point 136, respectively. The system is modeled by multiple beam elements, including a beam element 160, a beam element 162 for connecting the second outer side sill, and a beam element 164 for connecting the third outer side sill; a beam element 166 for connecting the first inner side sill, a beam element 168 for connecting the first spot weld point 132, a beam element 136, a beam element 138, a beam element 170, and a beam element 172 for connecting the fifth spot weld point 140, respectively, and a beam element 174 for connecting the inner side sill reinforcement beam element 150 and the fifth spot weld point 140.

[0078] Therefore, the deformation calculation process S5 calculates the deformation of the structure 100, in which the selected members are modeled by beam elements, using finite element analysis.

[0079] Thus, the analysis system according to this embodiment connects the joint position including the first spot welding point 132, the second spot welding point 134, the third spot welding point 136, the fourth spot welding point 138, and the fifth spot welding point 140 with beam elements including the side outer panel beam element 142, the side sill outer reinforcement beam element 144, the side sill outer beam element 146, the side sill inner beam element 148, and the side sill inner reinforcement beam element 150, respectively, using the first side outer panel connecting beam element 152, the second side outer panel connecting beam element 154, the first side sill outer reinforcement connecting beam element 156, the second side sill outer reinforcement connecting beam element 158, and the first side sill outer The analysis program has a connection beam element setting process S4 which is configured as a connection beam element setting unit that sets connection beam elements including a connecting beam element 160, a second side sill outer connecting beam element 162, a third side sill outer connecting beam element 164, a first side sill inner connecting beam element 166, a second side sill inner connecting beam element 168, a third side sill inner connecting beam element 170, a fourth side sill inner connecting beam element 172, and a side sill inner reinforcement connecting beam element 174, and a deformation calculation process S5 which is configured as a deformation calculation unit that calculates the deformation of the structure 100 by finite element analysis of a structural analysis model created based on the beam elements, joint positions and connection beam elements.

[0080] Based on these connecting beam elements and the beam elements and their joint positions, finite element analysis is performed to calculate the deformation of the structure 100. Therefore, an analysis system is provided that can model the joints between multiple members using beam elements.

[0081] Furthermore, the beam elements, including the side outer panel beam element 142, side sill outer reinforcement beam element 144, side sill outer beam element 146, side sill inner beam element 148, and side sill inner reinforcement beam element 150, are configured to pass through the centroid of the cross-section of the member, which includes the side outer panel 112, side sill outer reinforcement 114, side sill outer 116, side sill inner 118, and side sill inner reinforcement 120. Therefore, by connecting the centroid and the joint position with the connecting beam elements, a complex structure 100 in which multiple members are joined to each other can be easily modeled.

[0082] In this embodiment, the connecting beam elements, including the first side outer panel connecting beam element 152, the second side outer panel connecting beam element 154, the first side sill outer reinforcement connecting beam element 156, the second side sill outer reinforcement connecting beam element 158, the first side sill outer connecting beam element 160, the second side sill outer connecting beam element 162, the third side sill outer connecting beam element 164, the first side sill inner connecting beam element 166, the second side sill inner connecting beam element 168, the third side sill inner connecting beam element 170, the fourth side sill inner connecting beam element 172, and the side sill inner reinforcement connecting beam element 174, are each modeled as deformable elements and possess appropriate rigidity.

[0083] Figure 15 compares the calculation result of the torsional moment of structure 100 calculated by the deformation calculation process S5 in Figure 3 with the calculation result of finite element analysis using shell elements. The horizontal axis of the graph in Figure 15 shows the rotation angle when twisting to deform the member. The vertical axis of the graph in Figure 15 shows the torsional moment when twisting to deform the member. The solid curve 201 shows the calculation result of finite element analysis using shell elements. The dashed curve 202 shows the calculation result of finite element analysis using the analysis system of the present invention.

[0084] Generally, finite element analysis using shell elements yields calculation results that closely resemble the deformation characteristics of actual members.

[0085] The analysis system of the present invention has standard stiffness data registered based on similar calculation results. When this stiffness is set for the connecting beam elements, the calculation results of the bending moment generated when torsional deformation is applied to a structural analysis model of a complex structure 100, in which multiple members including side outer panels 112, side sill outer reinforcements 114, side sill outers 116, side sill inners 118, and side sill inner reinforcements 120 are joined to each other, are shown in curve 202. Comparing this with curve 201, which shows the calculation results of finite element analysis of a structural analysis model using shell elements, it can be seen that curve 202 is close to curve 201. Furthermore, if there are differences in the results, the stiffness can be automatically adjusted to match the calculation results by implementing a function in the analysis system to perform convergence calculations based on optimization methods.

[0086] By using these rigidity-set connecting beam elements to join beam elements that model each member, it becomes possible to model many members in a structural analysis model with beam elements without significantly reducing calculation accuracy. The cross-sectional shape of the beam elements can be set by cross-sectional property values ​​or a set of integration points, making it easy to create and modify the cross-sectional shape, and it also has the advantage of requiring less computation time for finite element analysis than shell elements. However, beam elements are not as accurate as shell elements in large deformations. One application of this technology is the initial stage of product design (concept design). Concept design requires the examination of various shapes in a short time, which can greatly reduce problems that occur in subsequent detailed design. While the application of finite element analysis is required for concept design, the modeling work with shell elements is complicated and computationally intensive, limiting efficiency. Therefore, when the new technology of this invention, which models complex structures with beam elements while also considering joining, is applied, although the calculation accuracy is inferior to shell elements, the creation and modification of shape data can be easily performed, and the computation time is reduced, making it possible to dramatically improve the efficiency of concept design. [Explanation of symbols]

[0087] 112 Side outer panel (component) 114 Side sill outer reinforcement (component) 116 Side sill outer (part) 118 Side sill inner (part) 120 Side sill inner reinforcement (component) 132 First spot welding point (joining position) 134 Second spot welding point (joining position) 136 Third spot welding point (joining position) 138. Fourth spot welding point (joining position) 140 Fifth spot welding point (joining position) 142 Side outer panel beam element 144 Side sill outer reinforcement beam element 146 Side sill outer beam element 148 Side sill inner beam element 150 Side sill inner reinforcement beam element 152 Beam element for connecting the first side outer panel 154 Beam element for connecting the second side outer panel 156. Beam element for connecting the first side sill outer reinforcement. 158 Beam element for connecting the second side sill outer reinforcement 160 First side sill outer connection beam element 162 Beam element for connecting the second side sill outer 164 Third side sill outer connection beam element 166. Beam element for connecting the inner side sill of the first side sill. 168 Beam element for connecting the inner side sill of the second side sill 170 Third side sill inner connection beam element 172 Fourth side sill inner connection beam element 174 Beam element for connecting side sill inner reinforcement S1 Shape data acquisition process (shape data acquisition unit) S2 Joint position setting process (join position setting unit) S3 Beam element modeling process (Beam element modeling section) S4 Connection beam element setting process (connection beam element setting unit) S5 Deformation calculation process (deformation calculation unit)

Claims

1. An analysis system that models multiple members joined together using beam elements, A shape data acquisition unit that acquires the shape data of the aforementioned member, A joining position setting unit sets the joining positions in which the members are joined to each other, based on the shape data, A beam element modeling unit that models the shape data as beam elements, A connecting beam element setting unit sets a connecting beam element that connects the joining position and the beam element, The system includes a deformation calculation unit that calculates the deformation of the member by performing a finite element analysis of a structural analysis model created based on the beam element, the joint position, and the connecting beam element. The connecting beam element setting unit is configured to set a predetermined rigidity for the connecting beam element. Analysis system.

2. The analysis system according to claim 1, wherein the beam element is configured to pass through the centroid of the cross-section of the member.

3. The analysis system according to claim 1, wherein the stiffness of the connecting beam element is automatically adjusted so that the stiffness of the structural analysis model when the member is modeled using beam elements matches the stiffness of the structural analysis model when the member is modeled using shell elements, by convergence calculation based on an optimization method.

4. The analysis system according to any one of claims 1 to 3, wherein the beam element modeling unit is configured to select whether to model the shape data as a beam element or a shell element.

5. The analysis system according to claim 4, wherein the beam element modeling unit is configured to automatically determine whether to model the shape data as a beam element or a shell element by using the aspect ratio of the shape of the member as an indicator.

6. A computer analysis method for modeling a plurality of members joined together using beam elements, The computer performs a shape data acquisition step in which it acquires the shape data of the member, The computer performs a joining position setting step in which it sets joining positions in relation to the shape data where the members are joined to each other, The computer performs a beam element modeling step in which it models the shape data as a beam element, The computer performs a connecting beam element setting step in which it sets a connecting beam element that connects the joining position and the beam element, The computer has a deformation calculation step of calculating the deformation of the member by finite element analysis of a structural analysis model created based on the beam element, the joint position and the connecting beam element, The connecting beam element setting step involves the computer setting a predetermined stiffness for the connecting beam element. Analysis method.

7. An analysis program for a computer that models a plurality of members joined together using beam elements, To the aforementioned computer, A shape data acquisition process for acquiring the shape data of the aforementioned member, A joining position setting process for the shape data, which sets the joining positions where the members are joined to each other, A beam element modeling process that models the aforementioned shape data as beam elements, A connecting beam element setting process for setting a connecting beam element that connects the joining position and the beam element, A deformation calculation process that calculates the deformation of the member by finite element analysis of a structural analysis model created based on the beam element, the joint position, and the connecting beam element, Make it run, The aforementioned beam element setting process causes the computer to perform the task of setting a predetermined stiffness for the beam element. Analysis program.

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