JP7417089B2 - Relative displacement calculation method and relative displacement calculation device - Google Patents

Description

The present invention relates to a relative displacement calculation method and a relative displacement calculation device.

Patent Document 1 describes how parts of a structural body such as an automobile body are bonded by evaluating the displacement of the parts between a state where no load is applied and a state where a maximum load is applied to the part where the parts are joined. A technique has been disclosed that allows reinforcement measures to be easily taken without relying on trial and error by designers.

In addition, progress is being made in achieving both collision safety and weight reduction by thinning the high tensile strength steel sheets used in automobile bodies; decreases.

In addition, it is known that when a load is applied to a joint where parts such as flanges are joined, and the relative displacement between the parts becomes large, the rigidity can be improved by reinforcing it with adhesive, etc. There is. Furthermore, excitation force is input to the car body from the engine and undercarriage, propagates through the car body frame, causes panel parts to vibrate, and radiates noise. Panel radiated sound can be suppressed.

Patent No. 6278122

However, simply expanding the scope of reinforcement would require reinforcing joints that do not originally require reinforcement, i.e., joints where the relative displacement between parts is small, resulting in decreased productivity and increased costs. . Therefore, it is necessary to specify the magnitude of relative displacement in order to specify the appropriate reinforcement application range.

The present invention has been made in view of the above circumstances, and provides a relative displacement calculation method and a relative displacement calculation device that can easily specify the magnitude of relative displacement of joints of parts constituting a structure. It is something.

The relative displacement calculation method according to the first aspect includes displacement information of nodes of the plurality of elements obtained by a computer performing structural analysis on a structure model in which a structure is represented by a plurality of elements; and, based on the displacement information and the joint position information, obtain joint position information regarding the joint positions of the joint parts of the plurality of parts constituting the structure, and determine the joint surface of the joint parts of the plurality of parts constituting the structure based on the displacement information and the joint position information. A process is executed to extract each element and output the relative displacement of the node of the element on the joint surface.

In the relative displacement calculation method according to a second aspect, the computer outputs, among the relative displacements, a relative displacement in a direction parallel to the joint surface.

In the relative displacement calculation method according to a third aspect, the computer outputs a relative displacement in a direction perpendicular to the joint surface among the relative displacements.

In the relative displacement calculation method according to a fourth aspect, the computer displays the relative displacement in different display modes depending on the magnitude of the relative displacement.

In the relative displacement calculation method according to a fifth aspect, the computer displays locations where the relative displacement is equal to or greater than a predetermined threshold value in a manner indicating that the locations require reinforcement.

A relative displacement calculation device according to a sixth aspect includes displacement information of nodes of the plurality of elements obtained by performing structural analysis on a structure model in which the structure is represented by a plurality of elements, and displacement information of the nodes of the plurality of elements. an acquisition unit that acquires joint position information regarding joint positions of joint parts of a plurality of parts constituting the structure; an extraction unit that extracts each element; and an extraction unit that extracts each element, and a corresponding point corresponding to each node of an element on the joint surface of the first part of the two parts joined at the joint surface, is extracted from the first part and the joint surface. a setting unit configured to set on an element of the joint surface of the second part to be joined; a calculation unit that calculates a relative displacement of the node with respect to the corresponding point; and a calculation unit that calculates the relative displacement of the node with respect to the corresponding point, and and an output section that outputs a relative displacement in a direction.

According to the present invention, it is possible to easily specify the magnitude of the relative displacement of the joints of the parts that constitute the structure.

FIG. 2 is a block diagram showing the hardware configuration of a relative displacement calculation device. FIG. 2 is a block diagram showing the functional configuration of a relative displacement calculation device. It is a figure which shows an example of the structure which has a flange. It is a figure which shows an example of the FEM model of a structure. FIG. 3 is a diagram showing an example of a case where a FEM model of a structure is subjected to bending deformation. FIG. 3 is a diagram for explaining a method for extracting elements of a joint surface. FIG. 3 is a diagram for explaining a method of calculating relative displacement. FIG. 3 is a diagram for explaining a method of calculating relative displacement. FIG. 3 is a diagram for explaining a method of calculating relative displacement. It is a flowchart of relative displacement calculation processing. FIG. 2 is a diagram showing an example of a vehicle body as a structure. It is a figure which shows the example of a display of the relative displacement of a joint surface and a parallel direction. It is a figure which shows the example of a display of the relative displacement of a joint surface and a perpendicular direction.

Embodiments of the present invention will be described below.

FIG. 1 is a configuration diagram of a relative displacement calculation device 10 according to the present embodiment. The relative displacement calculation device 10 is a device including a general computer, and is configured with, for example, a personal computer.

As shown in FIG. 1, the relative displacement calculation device 10 includes a controller 12. The controller 12 includes a CPU (Central Processing Unit) 12A, a ROM (Read Only Memory) 12B, a RAM (Random Access Memory) 12C, a nonvolatile memory 12D, and an input/output interface (I/O) 12E. A CPU 12A, a ROM 12B, a RAM 12C, a nonvolatile memory 12D, and an I/O 12E are connected to each other via a bus 12F.

Further, an operation section 14, a display section 16, a communication section 18, and a storage section 20 are connected to the I/O 12E.

The operation unit 14 includes, for example, a mouse and a keyboard.

The display unit 16 is composed of, for example, a liquid crystal display.

The communication unit 18 is an interface for performing data communication with an external device.

The storage unit 20 is composed of a nonvolatile storage device such as a hard disk, and stores a relative displacement calculation program 20A, displacement information 20B, bonding position information 20C, etc., which will be described later. The CPU 12A reads and executes the relative displacement calculation program 20A stored in the storage unit 20.

Next, the functional configuration of the CPU 12A when the relative displacement calculation device 10 executes the relative displacement calculation program 20A will be described.

As shown in FIG. 2, the CPU 12A functionally includes an acquisition section 30, an extraction section 32, a setting section 34, a calculation section 36, and an output section 38.

The acquisition unit 30 acquires displacement information 20B of nodes of a plurality of elements obtained by performing structural analysis on a structure model in which a structure is represented by a plurality of elements. Further, the acquisition unit 30 acquires joint position information 20C regarding the joint positions of the joints of the plurality of components that constitute the structure. The joining position information 20C includes the coordinate values of the joining position of a joint where a plurality of parts are joined, and a part number (Part ID, hereinafter referred to as PID) uniquely assigned to each of the plurality of parts to be joined. This is the associated information. Note that the joining method includes, but is not limited to, resistance spot welding, arc welding, laser welding, and the like.

As the structure model, for example, an FEM model used in a numerical analysis method represented by the finite element method (hereinafter referred to as FEM) is used. Examples of the plurality of elements representing the structure include, but are not limited to, shell elements, solid elements, and the like.

FIG. 3 shows, as an example of a structure, a structure 40 that is assembled by welding two parts PID1 and PID2 formed from thin steel plates and each having a flange. The flange FL1 of the component PID1 and the flange FL2 of the component PID2 are joined at a predetermined interval by spot welding, for example.

FIG. 4 shows a structural model 40A representing the structure 40 as an FEM model. In the structure model 40A, the parts PID1 and PID2 are represented by rectangular shell elements, and the spot welded joint SPW of flanges FL1 and FL2 is represented by a rectangular solid element.

By performing a structural analysis using FEM on such a structure model 40A, for example, as shown in FIG. Displacement information 20B of the node is obtained. The obtained displacement information 20B is stored in the storage unit 20 in advance.

The acquisition unit 30 acquires the displacement information 20B of each node obtained as a result of the structural analysis in this way by reading it from the storage unit 20. The displacement information 20B includes information on the three-dimensional coordinates of each node after displacement.

Further, the acquisition unit 30 acquires joining position information 20C regarding the joining position of the joining parts SPW of the parts PID1 and PID2 that constitute the structure 40 by reading from the storage unit 20. The joining position information 20C can be obtained from the design information of the structure 40, for example, and is stored in the storage unit 20 in advance.

The extraction unit 32 extracts each element of a joint surface of a plurality of parts constituting a structure, for example, an element of a flange surface, based on the displacement information and joint position information 20C acquired by the acquisition unit 30. Note that the joint surface is not limited to a flange surface as long as it is a joint surface where a plurality of parts are joined.

An example of a method for extracting the bonding surface of the structure 40 shown in FIG. 4 will be described below.

First, based on the joint position information 20C of the structure 40, the extraction unit 32 selects an element EL1 that includes the node ND1 closest to the joint position of the joint part SPW among the elements of the component PID1, as shown in FIG. 6, for example. Extract.

Next, an element adjacent to the extracted element EL1, that is, an element EL2 that shares two nodes ND3 and ND4 with the element EL1 is extracted. If the angle θ1 formed by the surface EL1A, which is the extension of the element EL1 toward the element EL2, and the element EL2 is less than a predetermined threshold TH, the element EL2 is selected as a candidate for the joint surface (flange surface), and the angle θ1 is set to the threshold. If it is larger than TH, it is determined that the element EL2 is not an element candidate for the joint surface. In the example of FIG. 6, since the angle θ1 is less than or equal to the threshold TH, the element EL2 is determined to be an element candidate for the joint surface.

Further, similar processing is performed for element EL2. That is, if the element EL3 adjacent to the element EL2 is extracted and the angle θ2 formed by the element EL3 and the surface EL2A obtained by extending the element EL2 toward the element EL3 side is less than or equal to the predetermined threshold TH, the element EL3 is replaced with the element of the joining surface. Candidate. On the other hand, if the angle θ2 is larger than the threshold TH, it is determined that the element EL3 is not an element candidate for the joint surface. In the example of FIG. 6, since the angle θ2 is larger than the threshold TH, it is determined that the element EL3 is not an element candidate for the joint surface.

By repeating such processing, all element candidates constituting the joint surface are extracted for the joint SPW. By performing this for all joints, all element candidates for the joint surface of component PID1 and component PID2 are extracted.

Then, among the element candidates of component PID1, element candidates for which no node of component PID2 does not exist within a predetermined distance D from the node of the element candidate are determined not to be elements of the joint surface. On the other hand, among the element candidates of component PID1, element candidates for which the node of component PID2 exists within a predetermined distance D from the node of the element candidate are determined to be elements of the joint surface.

Then, by executing the same process for the component PID2, all elements of the joint surface of the components PID1 and PID2 are extracted for the joint SPW.

Further, by performing similar processing for other joints, all elements of the joint surfaces of parts PID1 and PID2 are extracted.

The setting unit 34 sets the corresponding points corresponding to each node of the element of the joint surface of component PID1 among the two parts to be joined at the joint surface to the joint between the first component and the second component to be joined at the joint surface. Set on surface elements.

The calculation unit 36 calculates the relative displacement of the node with respect to the corresponding point set by the setting unit 34.

An example of a method for setting corresponding points and calculating relative displacement will be described below.

For each node included in the element of the joint surface extracted by the extraction unit 32, the relative displacement with the corresponding element is calculated using the displacement information of the node obtained from the analysis result of the numerical analysis by FEM.

First, as shown in FIG. 7, the normal vector at a certain node _N0 of the element constituting the flange FL1 of part number PID1 is determined. In the element (there is a plurality of elements) including the node N ₀ , planes defined by the node N ₀ and two adjacent nodes can be defined as many as the number of elements including the node N ₀ . A vector n N0 parallel to the average (here, a simple additive average) of unit length normal vectors n _i (i = 1, 2, 3, 4) of these planes and having a unit length is defined as a node ^N ₀ is defined as the normal vector at . In the example of FIG. 7, the vector n ^N0 is defined by the following equation using the unit normal vector n _i .

...(1)

As shown in FIGS. 7 and 8, the intersection of the straight line passing through the node _N0 in the direction determined by the vector ^nN0 and the element surface constituting the flange of the part PID2 is defined as the corresponding point P (pair-point P) of the node _N0 . , the corresponding point P exists within the triangle formed by the three nodes N1, N2, and N3 in the above element. At this time,

s ₁ and s ₂ are defined in advance as shown in the following equation.

...(2)

Then, the relative displacement of the node _N0 with respect to the corresponding point P is defined as the relative displacement of PID2 with respect to the flange FL2 at the node _N0 .

Further, as shown in FIG. 9, it is assumed that each point moves to a point with a dash "'" after the transformation. A translational displacement vector u ^P and a rotational displacement vector φ ^P at the corresponding point P are defined as follows.

...(3)
...(4)

Here, u _i and φ _i (where i=1, 2, 3) are the translational displacement vector and rotational displacement vector at the node N _i , respectively, and can be obtained from the FEM analysis results. Moreover, the weighting coefficient wi is defined as in the following equation.

...(5)

Here, matrix C ^P is defined by the following equation.

...(6)

Here, I ₃ is a 3 × 3 identity matrix, rotation axis vector λ ^P and outer product matrix

is defined by the following equation.

...(7)

Using the matrix C ^P obtained above, the relative displacement S is calculated using the following formula.

...(8)

Furthermore, as n'=C ^P n, the relative displacement (gap change) vector S _⊥ of the node N ₀ in the vertical direction with respect to the joint surface of component PID2, and the parallel direction (relative slip) with respect to the joint surface of component PID2. Slip) vector S _∥ is expressed by the following equation.

...(9)

Then, by performing the above processing for all nodes included in the elements of the joint surface, a relative displacement distribution is obtained.

The output unit 38 outputs the relative displacement in the direction parallel to the joint surface among the relative displacements calculated by the calculation unit 36. For example, the relative displacement may be displayed on the display unit 16 or stored in the storage unit 20. At this time, the display unit 16 may display different display modes depending on the magnitude of the relative displacement. Alternatively, locations where the relative displacement is greater than or equal to a predetermined threshold may be displayed in a manner that indicates that the locations require reinforcement. Further, among the relative displacements calculated by the calculation unit 36, the relative displacement in the direction perpendicular to the joint surface may be output.

The relative displacement calculation process executed by the CPU 12A will be described below with reference to the flowchart shown in FIG. Note that the relative displacement calculation process shown in FIG. 10 is executed by reading the relative displacement calculation program from the storage unit 20, for example, when execution of the relative displacement calculation program is instructed by a user's operation. Further, below, a case will be described in which the relative displacement of the joint surfaces of parts constituting the vehicle body 50 of an automobile as shown in FIG. 11 is calculated. The vehicle body 50 is, for example, a middle-class hatchback type (5 door) that is widely available on the market.

Note that before executing the relative displacement calculation program, a structural analysis is performed when, for example, bending deformation is applied to the FEM model of the vehicle body 50. As a result, displacement information 20B of each node of a plurality of elements constituting the FEM model of the vehicle body 50 is obtained. Then, the obtained displacement information 20B is stored in the storage unit 20. Further, joining position information 20C regarding joining positions of joint parts of a plurality of parts constituting the vehicle body 50 is acquired from, for example, design information of the vehicle body 50 and stored in the storage unit 20.

In step S100, the CPU 12A, as the acquisition unit 30, obtains displacement information 20B of each node of a plurality of elements constituting the FEM model of the vehicle body 50, and joint position information regarding the joint positions of the joints of the plurality of parts constituting the vehicle body 50. 20C is obtained by reading out from the storage unit 20.

In step S102, the CPU 12A, as the extracting unit 32, extracts each element of the joint surface of the plurality of parts constituting the vehicle body 50 based on the displacement information and joint position information acquired in step S100.

In step S104, the CPU 12A, as the setting unit 34, sets the corresponding points corresponding to each node of the element of the joint surface of the first component among the two components to be joined at the joint surface between the first component and the joint surface. Set on the element of the joint surface of the second part to be joined. This is performed on the joint surfaces of all parts of the vehicle body 50.

In step S106, the CPU 12A, as the calculation unit 36, calculates the relative displacement of the node with respect to the corresponding point. This is performed on the joint surfaces of all parts of the vehicle body 50.

In step S108, the CPU 12A outputs, as the output unit 38, the relative displacement S _∥ in the direction parallel to the joint surface among the relative displacements calculated in step S106. For example, as shown in FIG. 12, the relative displacement S _∥ of the vehicle body 50 is displayed on the display unit 16 or stored in the storage unit 20. In the example of FIG. 13, the display mode is changed by color-coding according to the magnitude of relative displacement.

For example, as shown in FIG. 13, among the relative displacements calculated in step S106, the relative displacement S _⊥ in the direction perpendicular to the joint surface may be displayed on the display unit 16 or stored in the storage unit 20. Good too.

Furthermore, locations where the relative displacement is greater than or equal to a predetermined threshold may be displayed in a manner that indicates that the locations require reinforcement. For example, by coloring and displaying only the locations where the relative displacement is greater than or equal to a predetermined threshold value, it may be possible to clearly distinguish between locations that require reinforcement and locations that do not require reinforcement.

In this way, in this embodiment, the displacement information of each node of a plurality of elements obtained by performing structural analysis on a structure model in which a structure is represented by a plurality of elements, and the displacement information of each node of a structure The elements of the joint surfaces of the plurality of parts constituting the structure are each extracted based on the joint position information regarding the joint positions of the joint parts of the plurality of parts. Then, the corresponding points corresponding to each node of the element of the joint surface of the first part of the two parts to be joined by the joint surface are set to the joint surface of the first part and the second part to be joined by the joint surface. is set on the element, and the relative displacement of the node with respect to the corresponding point is calculated and output. This makes it possible to easily specify the magnitude of the relative displacement of the joints of the parts that make up the structure.

Note that, in this embodiment, a mode has been described in which the relative displacement calculation program is stored (installed) in advance in the storage unit 20, but the present invention is not limited to this. The relative displacement calculation program can be used with CD-ROM (Compact Disc Read Only Memory), DVD-ROM (Digital Versatile Disc Read Only Memory), USB (Universal Serial Bus) memory, etc. Provided in the form recorded on a recording medium Good too. Further, the relative displacement calculation program may be downloaded from an external device via a network.

10 Relative displacement calculation device 12 Controller 14 Operation unit 16 Display unit 18 Communication unit 20 Storage unit 20A Relative displacement calculation program 20B Displacement information 20C Joining position information 30 Acquisition unit 32 Extraction unit 34 Setting unit 36 Calculation unit 38 Output unit 40 Structure

Claims (6)

The computer is
Displacement information of the nodes of the plurality of elements obtained by performing structural analysis on a structure model in which the structure is represented by a plurality of elements, and the joints of the joints of the plurality of parts constituting the structure. Obtain joint position information regarding the position, and
extracting each element of a joint surface of a plurality of parts constituting the structure based on the displacement information and the joint position information,
A relative displacement calculation method that executes a process of outputting a relative displacement of a node of an element of the joint surface. The computer includes:
The relative displacement calculation method according to claim 1, wherein, among the relative displacements, a relative displacement in a direction parallel to the joint surface is output. The computer includes:
The relative displacement calculation method according to claim 1 or 2, wherein a relative displacement in a direction perpendicular to the joint surface is outputted among the relative displacements. The computer includes:
The relative displacement calculation method according to any one of claims 1 to 3, wherein the relative displacement is displayed in different display modes depending on the magnitude of the relative displacement. The relative displacement calculation method according to any one of claims 1 to 4, wherein the computer displays locations where the relative displacement is equal to or greater than a predetermined threshold value in a manner indicating that the locations require reinforcement. Displacement information of the nodes of the plurality of elements obtained by performing structural analysis on a structure model in which the structure is represented by a plurality of elements, and the joints of the joints of the plurality of parts constituting the structure. an acquisition unit that acquires joint position information regarding the position;
an extraction unit that extracts elements of joint surfaces of a plurality of parts constituting the structure based on the displacement information and the joint position information;
The corresponding points corresponding to each node of the element of the joint surface of the first part of the two parts to be joined by the joint surface are set on the first part and the second part to be joined by the joint surface. a setting section set on the element of the joint surface;
a calculation unit that calculates a relative displacement of the node with respect to the corresponding point;
an output unit that outputs a relative displacement in a direction parallel to the joint surface among the relative displacements;
Relative displacement calculation device equipped with