JP7650168B2 - Composite structure, manufacturing method for composite structure, and design method for reinforcing member - Google Patents

Description

The present invention relates to a composite structure, a manufacturing method for a composite structure, and a design method for a reinforcing member.

In the body structure of an automobile, there is a structure in which a reinforcing structure is arranged at the joint between multiple components to improve rigidity (see, for example, Patent Document 1). In Patent Document 1, a vertical plate that functions as a reinforcing structure is arranged at the joint between the lower part of the center pillar and the side sill. This vertical plate suppresses deformation of the vehicle body due to loads in the front-rear, up-down, and diagonal directions, and the vehicle body structure described in Patent Document 1 achieves a joint structure with high joint rigidity.

JP 2017-039338 A

However, in the body structure described in Patent Document 1, because the vertical plate has a flat plate shape, the effect of increasing the moment of area in terms of improving rigidity against moment input is limited. Therefore, reinforcing the vertical plate near the center of gravity is disadvantageous. Furthermore, because the vertical plate needs to be embedded inside the joint, structural design is not easy and the manufacturing costs of the body structure increase. Also, there is insufficient reinforcement against cross-sectional collapse in the vehicle width direction in areas without bulkheads. Note that these issues are common to all composite structures that combine multiple structures, regardless of the body structure of the vehicle.

The present invention has been made to solve the above-mentioned problems, and aims to reduce the weight and increase the rigidity of composite structures while facilitating structural design.

The present invention has been made to solve at least one of the above problems, and can be realized in the following form: A composite structure comprising a reinforced structure having a plurality of frames connected to each other, and a reinforcing member selectively attached to an outer wall surface of the reinforced structure, the reinforcing member being made of one or more rod-shaped members extending along an axis parallel to any of three mutually perpendicular axes, at least a portion of the one or more rod-shaped members being connected from a joint portion of the plurality of frames to at least a portion of the ends of each of the frames extending to the joint portion, at least a portion of the plurality of frames being provided with a groove portion formed to be recessed inwardly with respect to the outer wall surface , the groove portion extending along an axis parallel to any of the three axes and having a semicircular cross section, the rod-shaped members being arranged to fill at least a portion of the groove portion, and the cross section of at least a portion of the rod-shaped members being a circle or semicircle having the same diameter as the cross section of the groove portion. The present invention can also be realized in the following form.

(1) According to one aspect of the present invention, a composite structure is provided. The composite structure includes a reinforced structure having a plurality of frames connected to one another, and one or more reinforcing members selectively attached to the outside of a wall surface of the reinforced structure, and at least a portion of the one or more reinforcing members is connected from a joint between the plurality of frames to at least a portion of the ends of each of the frames that extend to the joint.

According to this configuration, at least some of the reinforcing members continuously reinforce the area from the end of the frame away from the joint to the joint. Therefore, compared to a reinforcing member that locally reinforces only the joint, it is possible to suppress a decrease in rigidity at discontinuous areas, and therefore it is possible to increase the rigidity of the composite structure. In addition, since the reinforcing members have a simple shape that simply extends from the joint to the end, it is possible to suppress an increase in mass of the reinforcing members, and it is possible to achieve both high rigidity and light weight of the composite structure. Furthermore, since the reinforcing members are selectively attached to the outside of the wall surface of the reinforced structure, it is possible to easily obtain multiple variations of composite structures with different rigidities, and structural design can be simplified and shortened. As a result, it is possible to achieve lighter weight and higher rigidity in the composite structure, and to facilitate structural design.

(2) In the composite structure of the above aspect, at least a portion of the multiple frames may have a groove portion formed so as to be recessed inward relative to the wall surface, and the reinforcing member may be arranged so as to fill at least a portion of the groove portion.
In the composite structure of this configuration, the reinforcing member is filled in the groove formed in the frame, so that it is easier to attach the reinforcing member to the reinforced structure than to a reinforced structure that does not have a groove formed therein.

(3) According to another aspect of the present invention, there is provided a method for manufacturing a composite structure, the method including: arranging a reinforced structure having a plurality of frames joined to each other; and selectively attaching one or more reinforcing members to an outer side of a wall surface of the reinforced structure;
Equipped with.
According to this configuration, in the attachment step, one or more reinforcing members are selectively attached to the outer side of the wall surface of the reinforced structure. Therefore, by changing the number and shape of the reinforcing members according to the force components applied to the reinforced structure, it is possible to easily obtain a plurality of composite structures with different rigidities, and the structural design can be simplified and shortened in time.

(4) In the manufacturing method of the above aspect, in the installation process, a reinforcing member that is connected from a joint portion of a plurality of the frames to at least a portion of the ends of each of the frames extending from the joint portion may be used as at least a portion of the one or more reinforcing members.
According to this configuration, at least some of the reinforcing members continuously reinforce the frame from the end to the joint. Therefore, compared to a reinforcing member that locally reinforces only the joint, the decrease in rigidity at the discontinuous portion is suppressed. In addition, since the reinforcing member that continuously reinforces has a simple shape that simply extends from the joint to the end, it is possible to suppress the increase in mass of the reinforcing member, and it is possible to achieve both high rigidity and light weight of the composite structure.

(5) The manufacturing method of the above aspect may further include a design process for determining the shape of each of the one or more reinforcing members used in the installation process, and in the design process, a force component acting on the joint at which the reinforcing member is placed may be calculated, and the shape of the reinforcing member may be determined in accordance with the calculated force component.
In a reinforced structure in which multiple frames are joined together, the joint may form one end of the frame. In this case, when a force or moment is applied to the other end of the frame, the joint receives the largest force. In this configuration, the shape of the reinforcing member is determined according to the force component of the joint where the largest force is applied, so that the rigidity of the composite structure can be efficiently increased.

(6) In the manufacturing method of the above aspect, in the design process, the force components may be calculated using the load on the joint when a six-degree-of-freedom load is independently applied to the end of each of the frames extending to the joint.
In this configuration, the shape of the reinforcing member is determined taking into consideration the improvement of the second moment of area of each frame to improve the rigidity against moments around each axis at the end of the frame. The reinforcing member is composed of at least a part of the reinforcing member selectively attached to the outside of the wall surface of the reinforced structure. Therefore, the composite structure manufactured by the manufacturing method of this configuration is advantageous in terms of the second moment of area, and is lightweight and highly rigid. In addition, the analysis of applying a six-degree-of-freedom load to each end is performed automatically by utilizing a conventional analysis method. Therefore, the reinforcing member can be designed in a short period of time and then attached to the reinforced structure later.

(7) The manufacturing method of the above aspect may further include a groove forming process for forming grooves that are recessed inwardly relative to the wall surface for at least a portion of the plurality of frames, and in the mounting process, the reinforcing member may be positioned so as to fill at least a portion of the grooves formed by the groove forming process.
In this configuration, since the reinforcing member is filled in the groove formed in the frame, it is easier to attach the reinforcing member to the reinforced structure than to a reinforced structure in which no groove is formed.

(8) According to another aspect of the present invention, there is provided a method for designing a reinforcing member, the design method including an information processing device that executes an end extraction step of extracting end portions of a plurality of frames of a reinforced structure having a plurality of frames connected to each other, a load application step of independently applying a load with six degrees of freedom to the input plate portion while fixing end portions other than one input end portion among the plurality of ends extracted in the end extraction step, and a determination step of performing the load application step on each of the plurality of ends and determining a shape of the reinforcing member to be attached to the outside of a wall surface of the reinforced structure according to the results of all the load application steps.
According to this configuration, by changing the number and shape of the reinforcing members depending on the force components applied to the reinforced structure to which the reinforcing members are attached, it is possible to easily obtain multiple variations of composite structures with different rigidity, making structural design easier and shorter.

The present invention can be realized in various forms, for example, in the form of a composite structure, a structure, a method for manufacturing a composite structure, a method for designing a composite structure, and a computer program for executing these devices, a server device for distributing this computer program, a non-transitory storage medium on which a computer program is stored, etc.

1 is a schematic perspective view of a composite structure according to an embodiment of the present invention; FIG. FIG. 2 is a schematic perspective view of a reinforcing member. FIG. 13 is an explanatory diagram of analysis conditions for a shell. FIG. 11 is an explanatory diagram of a provisional shape of a reinforcing member. FIG. 11 is an explanatory diagram of a provisional shape of a reinforcing member. FIG. 11 is an explanatory diagram of a provisional shape of a reinforcing member. FIG. 11 is an explanatory diagram of a provisional shape of a reinforcing member. FIG. 11 is an explanatory diagram of a provisional shape of a reinforcing member. FIG. 11 is an explanatory diagram of a provisional shape of a reinforcing member. 11A to 11C are explanatory diagrams of a method of reinforcing the shell with a reinforcing member. 4 is a flowchart of a method for designing a reinforcing member according to the present embodiment. 4 is a flowchart of a method for manufacturing a composite structure in the present embodiment. FIG. 1 is an explanatory diagram for evaluating the strength of a composite structure. FIG. 1 is an explanatory diagram for evaluating the strength of a composite structure. 13 is an explanatory diagram of a composite structure according to a modified example. FIG. 13 is an explanatory diagram of a composite structure according to a modified example. FIG. 13 is an explanatory diagram of a composite structure according to a modified example. FIG. 13 is a flowchart of a modified method for manufacturing a composite structure. 13 is a flowchart of a modified example of a method for designing a reinforcing member.

<Embodiment>
1. Shape of the composite structure:
Fig. 1 is a schematic perspective view of a composite structure 100 according to an embodiment of the present invention. As shown in Fig. 1, the composite structure 100 includes a shell (reinforced structure) 10 formed by joining two substantially rectangular parallelepiped frames together, and a reinforcing member 20 attached to the outside of a wall surface of the shell 10. That is, the composite structure 100 is a structure combining the shell 10 and the reinforcing member 20 attached to improve the rigidity of the shell 10. In the composite structure 100 of this embodiment, the reinforcing member 20 is selectively attached to the wall surface of the shell 10 later, and thus the rigidity of the composite structure 100 is efficiently improved by changing the reinforcing member 20.

Figure 2 is a schematic perspective view of the shell 10. Figure 3 is a schematic perspective view of the reinforcing member 20. As shown in Figure 2, the shell 10 includes a first frame 11 having a substantially rectangular parallelepiped shape with a flange portion 11F, and a second frame 16 having a rectangular parallelepiped shape that is connected to the first frame 11 at a connection portion CN. That is, the shell 10 has two frames 11 and 16 connected to it. As shown in Figure 2, the first frame 11 has a shape in which a flange portion 11F is added to a main body portion 11B having a rectangular parallelepiped shape that extends along the longitudinal axis (the X-axis described later). The first frame 11 and the second frame 16 of this embodiment are formed of the same metal material.

In this embodiment, an orthogonal coordinate system CS is defined as shown in Figs. 1 to 3. As shown in Figs. 1 to 3, the orthogonal coordinate system CS defines the longitudinal axis of the first frame as the X-axis, and the Y-axis and Z-axis are set as axes parallel to each surface of the main body portion 11B. The orthogonal coordinate system CS corresponds to the orthogonal coordinate system CS shown in Figs. 4 and onwards. Using the orthogonal coordinate system CS, the flange portion 11F can be said to be a flat plate extending in the Z-axis positive direction and the Z-axis negative direction relative to the main body portion 11B.

The second frame 16 has a rectangular parallelepiped shape extending along a longitudinal axis parallel to the Z axis. The second frame 16 is joined to the XY plane on the positive Z-axis side of the main body 11B of the first frame 11 by welding at the joint CN.

The reinforcing member 20 shown in FIG. 3 is formed by combining multiple rod-shaped members against the outside of the wall surface of the shell 10. For example, as shown in FIG. 3, a rod-shaped member 21, which is one element included in the reinforcing member 20, extends from the joint CN to the end of the first frame 11 on the positive side of the X-axis. In other words, the rod-shaped member 21 is connected from the joint CN to the end of the frame 11. In this embodiment, the combination of multiple rod-shaped members is selectively determined based on the force components acting on the shell 10. The rod-shaped members are joined to the wall surface of the shell 10 by a mold separate from the molds for molding the first frame 11 and the second frame 16.

2. Reinforcement member design method:
The shape of the reinforcing member 20 is determined by a topology optimization design method that maximizes the rigidity of the composite structure 100 in response to an input. In this embodiment, a force component acting on the joint CN in the shell 10 is calculated by FEM analysis using an information processing device such as a PC (Personal Computer). A plurality of beam elements 20S shown in FIG. 4, which will be described later, are laid out as candidates for reinforcing members, and the beam elements 20S that contribute to the rigidity under the given load conditions become thicker according to their degree of contribution, and the beam elements 20S that do not contribute to the rigidity become thinner and disappear, by using a topology optimization method. When a plurality of load conditions are considered, a configuration of the reinforcing member 20 that simultaneously satisfies all the conditions is obtained by using a topology optimization method.

Figure 4 is an explanatory diagram of the analysis conditions for the shell 10. Figure 4 shows three end points P1 to P3 set for the shell 10, and multiple beam elements 20S that are candidates for one element of the reinforcing member 20. End points P1 to P3 can be rephrased as the end points of the frames 11 and 16 that extend to the joint CN. In the design method for the reinforcing member 20, first, end points P1 to P3 of the frames 11 and 16 are extracted.

The end P1 is set at the center of gravity of the XY plane on the opposite side (Z-axis positive side) of the joint CN along the Z-axis direction of the longitudinal direction of the second frame 16. The end P2 is set at the center of gravity of the YZ plane on the X-axis positive side, which is one end of the first frame 11 along the X-axis in the longitudinal direction. The end P3 is set at the opposite position of the end P2 in the first frame 11, that is, at the center of gravity of the YZ plane on the X-axis negative side, which is the other end along the X-axis in the longitudinal direction. Each of the multiple beam elements 20S is set as a rod-shaped element parallel to one of the X-axis, Y-axis, and Z-axis. Note that the multiple beam elements 20S are not limited to the elements shown in FIG. 4 and can be modified.

As an example of a method for designing the reinforcing member 20, two of the three extracted ends P1 to P3 (e.g., ends P2 and P3) are fixed, and a six-degree-of-freedom load is applied to the remaining end (e.g., end P1).

5 to 10 are explanatory diagrams of the shape of the reinforcing member 20 under a single load. Each of Fig. 5 to 10 shows provisional shapes 20 FX , 20 FY , 20 FZ , 20 MX , 20 _MY , and 20 _MZ of the reinforcing member 20 determined from the analysis conditions and the shell 10 when a load with six degrees of freedom _is applied independently to the end ( _{input end} ) P1 with the ends _P2 and P3 fixed.

FIG. 5 shows a provisional shape 20 FX of the reinforcing member 20 optimized by analysis when a force FX acting on the end P1 in the positive direction of the X-axis is applied. As shown in FIG. 5, the provisional shape 20 _FX is formed by a collection of a plurality of beam elements 20S having different cross-sectional areas. For example _, as shown in an area AR1, a beam element parallel to the X-axis and a beam element parallel to the Y-axis intersect with each other, thereby improving the rigidity of the shell 10. FIG. 6 shows a provisional shape 20 _FY of the reinforcing member 20 optimized by analysis when a force FY acting on the end P1 in the positive direction of the Y-axis is applied. FIG. 7 shows a provisional shape 20 _FZ of the reinforcing member 20 optimized by analysis when a force _FZ acting on the end P1 in the positive direction of the Z-axis is applied.

FIG. 8 shows a provisional shape 20 MX of the reinforcing member 20 optimized by analysis when a moment MX acting on the _end P1 around the X-axis is applied. The provisional shape 20 _MX shown in FIG. 8 is formed by a collection of a plurality of beam elements 20S with different cross-sectional areas, similar to the provisional shapes 20 _FX , 20 _FY , and 20 _FZ shown in FIG. 5 to FIG. 7. FIG. 9 shows a provisional shape 20 _MY of the reinforcing member 20 optimized by analysis when a moment MY acting on the end P1 around the Y-axis is applied. FIG. 10 shows a provisional shape 20 _MZ of the reinforcing member 20 optimized by analysis when a moment MZ acting on the end P1 around the Z-axis is applied. The shape of the reinforcing member 20 (FIG. 3) is determined from the provisional shapes 20 _FX , 20 _FY , 20 _FZ , 20 _MX , 20 _MY , and 20 _MZ determined according to the force components of the six degrees of freedom.

Figure 11 is an explanatory diagram of a method for reinforcing the shell 10 with the reinforcing member 20. Figure 11 shows a schematic cross-sectional view of a part of the shell 10 and a beam element 20S, which is one element of the reinforcing member 20 attached to the shell 10. In this embodiment, a rod-shaped member with a semicircular cross section is joined to the flat outer wall surface of the shell 10 by the molding die DI. Therefore, in the composite structure 100 of this embodiment, the beam element 20S is selectively formed on the outer wall of the shell 10 using the same molding die DI.

Figure 12 is a flowchart of the design method of the reinforcing member 20 of this embodiment. As shown in Figure 12, the design flow of the reinforcing member 20 first involves an extraction process (end extraction process) in which ends P1 to P3 of the frames 11 and 16 that are joined to each other are extracted (step S21). Next, one end P1 is selected as an input end from among the extracted ends P1 to P3 (step S22). With the other ends P2 and P3 other than the input end, which is the one end P1, fixed, a load application process is carried out in which a six-degree-of-freedom load is applied independently to end P1 (step S23). In the load application process, the provisional shape of the resulting reinforcing member is determined.

After the load application process is performed, a determination process is performed to determine the shape of the reinforcing member 20 (step S24), and the design flow ends. In the determination process, the shape of the reinforcing member 20 is determined using the provisional shapes of the six reinforcing members obtained as a result of the load application process for the end P1.

3. Manufacturing method of the composite structure:
FIG. 13 is a flowchart of a design method for the composite structure 100 in this embodiment. In the manufacturing flow shown in FIG. 13, first, a placement process in which the shell 10 is placed is performed (step S1). Next, a design process in which an analysis is performed to determine the shape of the reinforcing member 20 is performed (step S2). In the design process, the design flow of the reinforcing member 20 shown in FIG. 12 is performed. Specifically, in the design process, a force component acting on the joint CN is calculated by FEM analysis using an information processing device such as a PC. The shape of the reinforcing member 20 in which the beam element 20S is selectively formed is determined according to the calculated force component. In the design process of this embodiment, the force component is calculated using the load on the joint CN when a six-degree-of-freedom load is applied to the end P1 of the second frame 16 extending to the joint CN.

An attachment process is performed to attach the reinforcing member 20 to the outside of the wall surface of the shell 10 according to the determined shape (step S3). In the attachment process, as shown in FIG. 11, multiple beam elements 20S that make up the reinforcing member 20 are selectively attached to the outside of the wall surface of the shell 10 using a molding die DI. Once the attachment process is performed, the manufacturing flow ends.

4. Strength evaluation of composite structures:
14 and 15 are explanatory diagrams for the strength evaluation of the composite structure 100. FIG. 14 shows the displacement (mm) of the composite structure 100 when a load with six degrees of freedom is applied to the end P1 with the ends P2 and P3 of the composite structure 100 fixed. Also, FIG. 14 shows the displacement of a comparative shell 10z having the same mass as the composite structure 100 for comparison. Specifically, the mass of the composite structure 100 is the sum of the mass of the shell 10 of 4.2290 kg and the mass of the reinforcing member 20 of 6.6692 kg. The mass of the comparative shell 10z is 10.8980 kg, which is 2.577 times the plate thickness of the shell 10. That is, FIG. 14 shows the strength evaluation of the displacement of the composite structure 100 having almost the same mass and the comparative shell 10z. Fig. 14 also shows the displacement ratio obtained by dividing the displacement amount of the composite structure 100 by the displacement amount of the shell 10z of the comparative example. Fig. 15 shows the displacement ratio corresponding to the application of six-degree-of-freedom loads in Fig. 14 using a bar graph. Each displacement amount corresponding to the six-degree-of-freedom load represents the maximum displacement amount of the most changed portion of the composite structure 100.

As shown in FIG. 14, when a force component of 1 N (Newton) is applied to the end P1 in the positive direction of the X-axis with the ends P2 and P3 fixed, the displacement of the composite structure 100 is 8.65×10 ⁻⁵ mm. On the other hand, the displacement of the shell 10z of the comparative example is 1.17×10 ⁻⁴ mm, which is larger than the displacement of the composite structure 100. The displacement ratio in this case is 0.739 (73.9%), as shown in FIG. 14 and FIG. 15. Similarly, when FY=1 N, FZ=1 N and moments MX=1 N·mm, MY=1 N·mm, and MZ=1 N·mm are applied to the end P1, the displacement of the composite structure 100 is smaller than the displacement of the shell 10z of the comparative example. In particular, when FY=1 N, FZ=1 N are applied to the end P1, the displacement of the composite structure 100 is approximately half of the displacement of the shell 10z of the comparative example. In other words, even if the masses are the same, the rigidity of the composite structure 100 is higher than the rigidity of the shell 10z of the comparative example.

5. Effects:
As described above, in the composite structure 100 of this embodiment, the reinforcing member 20 is selectively attached to the outside of the wall surface of the shell 10. As shown in FIG. 3, the rod-shaped member 21, which is one element included in the reinforcing member 20, is connected from the joint CN to the end of the frame 11. That is, the rod-shaped member 21 continuously reinforces the area from the end of the frame 11 away from the joint CN to the joint CN. Therefore, compared with a reinforcing member in which only the joint CN is locally reinforced, in the composite structure 100 of this embodiment, the decrease in rigidity at the discontinuous portion of the rod-shaped member is suppressed. In addition, since the rod-shaped member 21 has a simple shape that simply extends from the joint CN to the end, the increase in mass of the reinforcing member 20 can be suppressed, and the composite structure 100 can be made both highly rigid and lightweight. Furthermore, since the reinforcing member 20 is selectively attached to the outside of the wall surface of the shell 10, it is possible to easily obtain a plurality of variations of the composite structure 100 having different rigidities, and the structural design of the composite structure 100 can be made easier and in a shorter time. As a result, the composite structure 100 can be made lighter and more rigid, and the structural design can be made easier.

In addition, in the manufacturing method of the composite structure 100 of this embodiment, the reinforcing member 20 is selectively attached to the outside of the wall surface of the arranged shell 10. Therefore, by changing the number of beam elements 20S of the reinforcing member 20 and the shape of the reinforcing member 20 according to the force components applied to the shell 10, it is possible to easily obtain multiple variations of the composite structure 100 with different rigidities, and the structural design of the composite structure 100 can be easily completed in a short time.

In addition, in the manufacturing method of the composite structure 100 of this embodiment, a design process is carried out in which an analysis is performed to determine the shape of the reinforcing member 20 (step S2 in FIG. 13). In the design process, the force components acting on the joint CN are calculated, and the shape of the reinforcing member 20 is determined according to the calculated force components. In a shell 10 in which multiple frames 11, 16 are joined, the joint CN may form one end of the frame. In this case, when a force or moment is applied to the other end of the frame, the largest force is applied to the joint CN. In the manufacturing method of this embodiment, the shape of the reinforcing member 20 is determined according to the force components of the joint CN where the largest force is applied, so that the rigidity of the composite structure 100 can be efficiently increased.

<Modifications of the above embodiment>
The present invention is not limited to the above-described embodiment, and can be embodied in various forms without departing from the spirit and scope of the invention. For example, the following modifications are also possible.

<Modification 1>
In the above embodiment, the composite structure 100 including the shell 10 having a plurality of frames 11, 16 joined to each other and the reinforcing member 20 selectively attached to the outside of the wall surface of the shell 10 has been described, but each configuration of the composite structure 100 can be modified in various ways. For example, the frame does not have to have a substantially rectangular parallelepiped shape along the longitudinal axis like the frames 11, 16 in the above embodiment, and may simply be a spherical member or a flat plate-shaped member. The frame refers to a member that is joined to another frame (member) at the joint CN, and the shape and material of the frame can be modified. The shape of the reinforcing member 20 in the above embodiment is an example, and the reinforcing member 20 may be composed of a plurality of divided reinforcing members rather than being composed as a single joined member. The material of the reinforcing member 20 may be the same as that of the frames 11, 16, or may be a different material such as a resin.

The Cartesian coordinate system CS set in the above embodiment is just an example, and may be set freely depending on the number and shape of the frames to be joined by the joining part CN. The positional relationship between the frames 11 and 16 changes depending on each axis of the set Cartesian coordinate system CS.

<Modification 2>
16 to 18 are explanatory diagrams of a composite structure of a modified example. FIG. 16 shows a part of a second frame 16a included in the composite structure of the modified example. As shown in the schematic perspective view of FIG. 16, the second frame 16a of the shell 10a of the modified example has a groove CH formed so as to be recessed inward from the wall surface. As shown in FIG. 16, the cross section of the groove CH is semicircular, and the groove CH extends along the X-axis or Z-axis.

Figure 17 shows a schematic cross-sectional view of a state in which a beam element 20Sa, which is one element of the reinforcing member 20a, is attached to a groove CH formed in the second frame 16a. In the modified example, a rod-shaped member having a circular cross section is joined to the groove CH of the second frame 16a by a molding die. On the other hand, Figure 18 shows a schematic cross-sectional view of a state in which a filler 16in is filled into the groove CH formed in the second frame 16a. As shown in Figure 18, in the modified example, the filler 16in having a semicircular cross section is filled so as to fill the groove CH of the second frame 16a, thereby forming the second frame 16a that constitutes a part of the shell 10a. Depending on the force components calculated in the design process, there may be a portion of the second frame 16a in which neither the beam element 20Sa nor the filler 16in is attached, and the groove CH remains as it is.

As described above, in the modified composite structure, the beam element 20Sa of the reinforcing member 20 is selectively attached to the groove CH formed in the wall surface of the second frame 16a. Therefore, in the modified composite structure, it is easier to attach the beam element 20Sa to the second frame 16a in which the groove CH is formed than to a second frame 16 in which the groove CH is not formed.

The shape and the position where the groove CH is formed can be changed. For example, the shape of the groove CH may be rectangular. The position where the groove CH is formed may be, for example, only near the joint CN, and not near the ends P1 to P3. The cross-sectional shape and cross-sectional size of the groove CH may differ depending on the position where it is formed. Furthermore, the filler 16in filled in the groove CH may differ depending on the position, and may be a different material (for example, a resin material) from that of the second frame 16a. The filler 16in shown in FIG. 17 may be treated as part of the reinforcing member 20a, rather than as part of the second frame 16a.

<Modification 3>
19 is a flow chart of a manufacturing method of a composite structure of the modified example. In the manufacturing flow of the modified example, first, a frame manufacturing process (groove forming process) is performed to manufacture a first frame 11 and a second frame 16a (FIG. 16) having a substantially rectangular parallelepiped shape (step S11). The frames 11 and 16a are manufactured by molding using a molding die. A predetermined groove CH is formed in the second frame 16a during molding. A joining process is performed to join the joints CN of the manufactured first frame 11 and second frame 16a by welding (step S12). A placement process is performed to place the shell 10a in which the first frame 11 and the second frame 16a are joined (step S13).

Next, a design process is carried out to determine the shape of the reinforcing member 20a (step S14). In the design process, the force components acting on the joint CN are calculated by FEM analysis, taking into account the shape of the groove CH, and the shape of the reinforcing member 20a in which the beam element 20Sa is formed is determined. In accordance with the determined shape, an attachment process is carried out to attach the reinforcing member 20a to the outside of the wall surface of the shell 10a (step S15).

The manufacturing flow of the above embodiment and modified example can be modified to the extent that it includes a process of arranging the shells 10, 10a and a mounting process of attaching the reinforcing members 20, 20a to the wall surfaces of the shells 10, 10a. For example, the manufacturing flow of the above embodiment (FIG. 13) does not need to include a design process. In the design process, a known analysis method may be used instead of an analysis in which a six-degree-of-freedom load is applied to the ends P1 to P3. In addition, in the manufacturing flow of the modified example, the groove forming process for forming the groove CH may be performed before the reinforcing member 20a is attached. Therefore, the groove CH may be formed by cutting at a predetermined position of the frame 11, 16a after the arrangement process. In addition, the groove forming process and the mounting process may be performed after the design process.

<Modification 4>
FIG. 20 is a flowchart of a design method of a reinforcing member of a modified example. The design flow of the reinforcing member 20 shown in FIG. 20 is different from the design flow of the above embodiment (FIG. 12) in that each of the ends P1 to P3 is selected as an input end to determine the shape of the reinforcing member. As shown in FIG. 20, in the design flow of the reinforcing member of the modified example, an extraction step is performed to extract the ends P1 to P3 (step S21). Next, one end P1 is selected as an input end from among the extracted multiple ends P1 to P3 (step S22), and a load application step is performed on the end P1 with the ends P2 and P3 fixed (step S23). In the load application step, a provisional shape of the reinforcing member when the end P1 is the input end is determined.

When the process of step S23 is performed, it is determined whether there are any ends that have not been selected as input ends (step S231). If it is determined that there are unselected ends P2 and P3 (step S231: YES), a new input end P2 is selected from the unselected ends P2 and P3 (step S232), and the process from step S23 onwards is repeated. If all ends P1 to P3 have been selected as input ends (step S231: NO), a determination process is performed to determine the shape of the reinforcing member (step S24), and the design flow ends. In the determination process, the shape of the reinforcing member 20 is determined using the provisional shapes of the three reinforcing members obtained as a result of the load application process for each of the ends P1 to P3.

In addition, in the manufacturing method of the composite structure 100 of the modified example, the force components calculated to determine the shape of the reinforcing member are calculated using the load on the joint CN when a six-degree-of-freedom load is applied to the end P1 of each frame 11, 16 extending to the joint CN. That is, in this manufacturing method of the modified example, the shape of the reinforcing member is determined taking into account the improvement of the second moment of area of each frame 11, 16 to improve the rigidity against the moment around each axis at the end P1. Since the reinforcing member is composed of multiple rod-shaped members 21 selectively attached to the outside of the wall surface of the shell 10, it is advantageous in terms of the second moment of area, and the composite structure 100 can be made lightweight and highly rigid. In addition, the FEM analysis to apply a six-degree-of-freedom load to each end P1 to P3 is performed automatically by reusing the conventional analysis method. Therefore, the reinforcing member can be designed in a short period of time and then attached to the shell 10 later.

In addition, in the design method of the reinforcing member of the modified example, an extraction step is performed to extract the ends P1 to P3 of the frames 11, 16 connected by the joint CN (step S21 in FIG. 20). With two ends (e.g. ends P2, P3) of the extracted three ends P1 to P3 fixed, a load application step is performed to apply a six-degree-of-freedom load to the remaining end (e.g. end P1) (step S23). Therefore, by changing the number of beam elements 20S of the reinforcing member and the shape of the reinforcing member according to the force components applied to the shell 10 to which the reinforcing member is attached, it is possible to easily obtain multiple variations of the composite structure 100 with different rigidities. In addition, the structural design of the composite structure 100 manufactured using the design method of this modified example can be easily and quickly completed.

Although this aspect has been described above based on the embodiment and modified examples, the embodiment of the above-mentioned aspect is intended to facilitate understanding of this aspect and does not limit this aspect. This aspect may be modified or improved without departing from the spirit and scope of the claims, and equivalents are included in this aspect. Furthermore, if a technical feature is not described as essential in this specification, it may be deleted as appropriate.

10, 10a, 10z...Shell 11...First frame 11B...Main body 11F...Flange 16, 16a...Second frame 16in...Filler 20, 20a...Reinforcing member 20 _FX , 20 _FY , 20 _FZ , 20 _MX , 20 _MY , 20 _MZ ...Temporary shape of reinforcing member 20S, 20Sa...Beam element 21...Rod-shaped member 100...Composite structure AR1...Area CH...Groove CN...Connection CS...Cartesian coordinate system DI...Mold FX, FY, FZ...Force MX, MY, MZ...Moment P1 to P3...End (input end)

Claims (8)

1. A composite structure comprising:
a reinforced structure having a plurality of frames joined together;
A reinforcing member selectively attached to the outer wall surface of the reinforced structure, the reinforcing member being made of one or more rod-shaped members extending along an axis parallel to any one of three mutually orthogonal axes;
Equipped with
At least a portion of the one or more rod-shaped members is connected from a joint portion of the plurality of frames to at least a portion of ends of each of the frames that extend to the joint portion,
At least a portion of the plurality of frames includes a groove portion formed to be recessed inward with respect to the outer wall surface , the groove portion extending along an axis parallel to any one of the three axes and having a semicircular cross section,
The rod-shaped member is disposed so as to fill at least a portion of the groove,
A composite structure, wherein a cross section of at least a portion of the bar-shaped member is a circle or semicircle having the same diameter as the cross section of the groove. 2. The composite structure of claim 1,
The reinforcing member is composed of two or more rod-shaped members extending along axes parallel to two axes perpendicular to each other,
A composite structure, wherein the grooves extend parallel along each of at least two of the three axes. 3. The composite structure according to claim 1 or 2 ,
A composite structure, wherein the one or more rod-shaped members have the same shape. A method for manufacturing a composite structure, comprising the steps of:
a placement step of placing a reinforced structure having a plurality of frames joined together;
a groove forming step of forming grooves in at least some of the frames, the grooves being recessed inwardly with respect to an outer wall surface of the reinforced structure, the grooves extending along an axis parallel to any one of three mutually orthogonal axes and having a semicircular cross section;
a mounting step of selectively mounting a reinforcing member, which is made of one or more rod-shaped members extending along an axis parallel to any one of the three axes, to the groove portion formed on the outer wall surface ;
Equipped with
In the mounting step,
At least a portion of the one or more rod-shaped members is connected from a joint portion of the plurality of frames to at least a portion of ends of each of the frames that extend to the joint portion;
The rod-shaped member is disposed so as to fill at least a portion of the groove;
A manufacturing method in which a cross section of at least a portion of the rod-shaped member is a circle or semicircle having the same diameter as the cross section of the groove portion. The method according to claim 4, further comprising the steps of:
The groove portion extends along an axis parallel to each of two axes perpendicular to each other,
A manufacturing method in which the reinforcing member is made of two or more rod-shaped members extending parallel along at least two of the three axes. The method according to claim 4 or 5 ,
The method of manufacturing, wherein the one or more rod-shaped members have the same shape. The method according to any one of claims 4 to 6, further comprising:
a design step of determining a shape of each of the one or more rod-shaped members used in the mounting step,
In the design step, a force component acting on the joint where the rod-shaped member is disposed is calculated,
The manufacturing method includes forming the rod-shaped member into a shape corresponding to the calculated force component. The method according to claim 7 , further comprising the steps of:
A manufacturing method in which, in the design process, the force components are calculated using the load on the joint when loads with a total of six degrees of freedom, including three degrees of freedom in directions along the three axes and three degrees of freedom around the three axes, are applied independently to the ends of each of the frames extending to the joint.

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