JP2024074218A - Structure and method for manufacturing the same - Google Patents

Abstract

To provide a structure which can bring strain energy which can be stored in a structure closer to strain energy of a maximum potential.SOLUTION: One embodiment of the present disclosure is a structure comprising: a first elastic member extending in a prescribed direction, and having first both end sections in the prescribed direction and a first middle section that is a section between the first both end sections; and a second elastic member which is disposed on one surface side of the first elastic member and in which second both end sections in the prescribed direction are connected to the first both end sections, and at least part of a second middle section, which is a section between the second both end sections, has a shape protruding to the side away from the first middle section.SELECTED DRAWING: Figure 1

Description

This disclosure relates to a structure and a method for manufacturing the same.

Patent Document 1 discloses a structure arranged between a first pressed body and a second pressed body facing each other, the structure being made of a band-shaped member and having a base with a curved main surface, two extension parts extending from both ends of the base and curved in a manner opposite to the curved manner of the base, and two bent parts extending from the ends of the two extension parts opposite the side connected to the base and curved in a manner opposite to the curved manner of the extension parts.

Patent No. 6866396

In the structure of Patent Document 1, the energy applied by the pressing force in the direction in which the first pressed body and the second pressed body approach each other is stored as strain energy associated with strain generated inside the base due to bending deformation of the base caused by the pressing force, thereby generating a reaction force due to the pressing force.

In general, when bending deformation is induced in a plate-shaped member, inside the plate-shaped member, compressive strain increases from the neutral axis of bending deformation toward the inner circumference of the bending deformation, and tensile strain increases from the neutral axis of bending deformation toward the outer circumference, with the strain being small near the neutral axis of bending deformation. For this reason, when viewed as a whole plate-shaped member, the strain energy that can be stored during bending deformation is relatively small compared to the maximum potential strain energy that the plate-shaped member can inherently store.

Therefore, the strain energy that can be stored in the base of the structure disclosed in Patent Document 1 is relatively small compared to the maximum potential strain energy. For this reason, there is a need to provide a structure that can bring the strain energy that can be stored in the structure closer to the maximum potential strain energy.

According to one aspect of the present disclosure, a structure includes a first elastic member extending in a predetermined direction and having first end portions and a first intermediate portion between the first end portions in the predetermined direction, and a second elastic member disposed on one side of the first elastic member, and having second end portions in the predetermined direction connected to the first end portions, respectively, and at least a part of the second intermediate portion between the second end portions having a convex shape on the side away from the first intermediate portion. When a pressing force is applied to the structure such that the second intermediate portion approaches the first intermediate portion, the second elastic member is bent, and a compressive stress is generated in the second elastic member and a tensile stress is generated in the first elastic member.

Other features and advantages of the present disclosure can be seen from the following description and the accompanying drawings, which are given by way of example and are non-exhaustive.

FIG. 1 is a perspective view illustrating a structure according to an embodiment of the present disclosure. FIG. 2 is a front view of the structure shown in FIG. 1 . 2 is a diagram conceptually showing a tensile force applied to a first elastic member and a compressive force applied to second and third elastic members of the structure shown in FIG. 1 . 1A to 1C are process diagrams showing a manufacturing process of a structure. 1A to 1C are process diagrams showing a manufacturing process of a structure. 2 is a schematic diagram showing the relationship between stress and reaction force R generated in a first elastic member, a second elastic member, and a third elastic member when a pressing force is applied to the structure shown in FIG. 1 so as to sandwich the structure from above and below in the figure. FIG. 11 is a diagram showing the relationship between displacement and reaction force when a pressing force is applied so as to sandwich a structure. FIG. 11 is a diagram showing the relationship between displacement and reaction force when a pressing force is applied so as to sandwich a structure. FIG. 13 is a diagram showing the relationship between the displacement and the maximum strain of the second and third elastic members when a pressing force is applied so as to sandwich the structure. FIG. 11 is a diagram showing the relationship between the displacement and the energy stored in the structure when a pressing force is applied so as to sandwich the structure. FIG. FIG. 13 is a perspective view showing a structure of a modified example. FIG. 12 is a front view of the structure shown in FIG. FIG. 13 is a perspective view showing a structure of a modified example. FIG. 14 is a front view of the structure shown in FIG. 13.

The following describes an embodiment of the present disclosure with reference to the drawings.

First, the overall configuration of the structure 10 according to one embodiment of the present disclosure will be described. FIG. 1 is a perspective view showing the structure according to one embodiment of the present disclosure, and FIG. 2 is a front view of the structure shown in FIG. 1.

As shown in Figures 1 and 2, the structure 10 of this embodiment includes a first elastic member 12 in the form of a rectangular flat plate extending in the front-rear and left-right directions, a second elastic member 14 having both end portions 14a, 14b in the left-right direction connected (fixed) to the upper surface sides of both end portions 12a, 12b of the first elastic member 12 in a state where at least a portion of the second elastic member 14 is bent to have a convex shape upward in the figure, and a third elastic member 16 having both end portions 16a, 16b in the left-right direction connected (fixed) to the lower surface sides of both end portions 12a, 12b of the first elastic member 12 in a state where at least a portion of the third elastic member 16 is bent to have a convex shape downward in the figure.

The intermediate portion 14c between the two end portions 14a and 14b of the second elastic member 14 has a shape with the corners of an inverted V-shape smoothed (rounded) in a specified cross section, which is a cross section when cut on a specified plane extending in the up-down and left-right directions. Specifically, the intermediate portion 14c has a smooth curved shape (specifically, a curved shape combining multiple arcs) in the specified cross section, and has a convex shape upward in the figure that moves away from the intermediate portion 12c of the first elastic member 12 as it moves away from the two end portions 14a and 14b (towards the center in the left-right direction). The intermediate portion 16c between the two end portions 16a and 16b of the third elastic member 16 has a shape with the corners of an inverted V-shape smoothed (rounded) in a specified cross section. Specifically, in a given cross section, the middle portion 16c has a smooth curved shape (specifically, a curved shape combining multiple arcs) and is convex downward as shown in the figure, moving away from the middle portion 12a of the first elastic member 12 as it moves away from both end portions 16a, 16b (towards the center in the left-right direction).

Figure 3 is a conceptual diagram showing the tensile force applied to the first elastic member 12 of the structure 10 shown in Figure 1 and the compressive forces applied to the second and third elastic members 14 and 16, respectively.

3, in the structure 10 of this embodiment, a compressive force is applied in advance to both end portions 14a, 14b, 16a, 16b of the second and third elastic members 14, 16 in the direction toward each other along the left-right direction in the figure, and a tensile force is applied in advance to both end portions 12a, 12b of the first elastic member 12 in the direction away from each other along the left-right direction in the figure, and the both end portions 14a, 14b, 16a, 16b of the second and third elastic members 14, 16 are fixed to both end portions 12a, 12b of the first elastic member 12, respectively. The both end portions 14a, 14b, 16a, 16b of the second and third elastic members 14, 16 are fixed to both end portions 12a, 12b of the first elastic member 12 in a state in which the central portions are flexibly deformed by the compressive force so that they are convex upward or downward as shown in FIG. 1(b). The end portions 12a, 12b of the first elastic member 12 and the end portions 14a, 14b, 16a, 16b of the second and third elastic members 14, 16 can be fixed to each other by any suitable fixing method such as welding or riveting. Therefore, in the completed manufacturing state (the state shown in FIGS. 1 and 2), the end portions 14a, 14b, 16a, 16b of the second and third elastic members 14, 16 are subjected to compressive forces in the direction of approaching each other along the left-right direction in the figure, and tensile forces are applied to the end portions 12a, 12b of the first elastic member 12 in the direction of moving away from each other along the left-right direction in the figure. In other words, the structure 10 is prestressed.

The first elastic member 12 and the second and third elastic members 14, 16 may be made of metal materials, resin materials, rubber materials, composite materials such as carbon fiber reinforced plastic (CRFP), etc. The materials that make them up are appropriately selected depending on the various requirements required for the structure 10, such as the load resistance.

The structure 10 of this embodiment is manufactured, for example, by the first manufacturing method in FIG. 4 or the second manufacturing method in FIG. 5. The following describes each method in order. Note that the up-down direction, front-rear direction, and left-right direction are the same as in FIG. 1 and FIG. 2.

In the first manufacturing method of FIG. 4, first, the first, second, and third elastic members 12, 14, and 16 are arranged so that the third elastic member 16, the first elastic member 12, and the second elastic member 14 are arranged in this order from the bottom (step S100). Next, while pulling the first elastic member 12 in the left-right direction, both end portions 12a and 12b of the first elastic member 12, both end portions 14a and 14b of the second elastic member 14, and both end portions 16a and 16b of the third elastic member 16 are connected (fixed) (step S110). This completes the structure 10. In the structure 10, in the manufacturing completed state, a compressive force is applied to both end portions 14a, 14b, 16a, and 16b of the second and third elastic members 14 and 16 in a direction approaching each other along the left-right direction of FIG. 1 and FIG. 2, and a tensile force is applied to both end portions 12a and 12b of the first elastic member 12 in a direction moving away from each other along the left-right direction of FIG. 1 and FIG. 2. That is, the structure 10 is prestressed.

5, first, the first, second, and third elastic members 12, 14, and 16 are arranged in the order of the third elastic member 16, the first elastic member 12, and the second elastic member 14 from the bottom, as in step S100 (step S200). Next, the end portions 14a, 14b, 16a, and 16b of the second and third elastic members 14 and 16 are compressed in a direction approaching each other along the left-right direction in FIG. 1 and FIG. 2, while connecting (fixing) the end portions 12a and 12b of the first elastic member 12, the end portions 14a and 14b of the second elastic member 14, and the end portions 16a and 16b of the third elastic member 16 (step S210). This completes the structure 10. Even when the structure 10 is manufactured by the second manufacturing method, the structure 10 is prestressed in the same manner as when the structure 10 is manufactured by the first manufacturing method.

Figure 6 is a schematic diagram showing the relationship between the stresses σ1, σ2, and the reaction force R that occur in the first elastic member 12 and the second and third elastic members 14, 16 when a pressing force F is applied to the structure 10 shown in Figure 1 so as to sandwich the structure 10 from above and below as shown.

According to the structure 10 of the present embodiment configured as described above, when a pressing force F is applied so as to sandwich the structure 10 from the vertical direction shown in the figure, the second and third elastic members 14, 16 are deformed so as to be expanded in a planar shape, and the pressing force F is converted into an axial force acting in the left-right direction of the second and third elastic members 14, 16. At this time, a compressive stress σ1 is generated inside the second and third elastic members 14, 16. Then, the axial force of the second and third elastic members 14, 16 is transmitted as a tensile force to the first elastic member 12 fixed to both end portions 14a, 14b, 16a, 16b of the second and third elastic members 14, 16 in the left-right direction shown in the figure. At this time, a tensile stress σ2 is generated inside the first elastic member 12. In this way, the pressing force F applied so as to sandwich the structure 10 in the vertical direction shown in the figure is converted into a tensile force P that pulls the first elastic member 12 in the left-right direction shown in the figure. The structure 10 generates a reaction force R against the pressing force F due to the internal stress of the first elastic member 12 and the second and third elastic members 14 and 16.

Furthermore, in the structure 10 of this embodiment, a compressive force is applied in advance (prestress is applied) to both end portions 14a, 14b, 16a, 16b of the second and third elastic members 14, 16 in the direction approaching each other along the left-right direction in the figure. This makes it possible to increase the curvature of the second and third elastic members 14, 16 while ensuring that the rigidity of the structure 10 (or the reaction force from the structure 10) falls within a desired range when a pressing force F is applied so as to sandwich the structure 10 and the structure 10 is deformed so as to be compressed in the up-down direction in the figure, thereby making it possible to increase the height of the second and third elastic members 14, 16. As a result, the effects described below can be obtained.
(1) The second and third elastic members 14, 16, which have been prestressed as described above to have a larger curvature and a larger height, can have a higher rigidity against the pressing force than a case in which no prestress is applied (a case in which the curvature is smaller and the height is lower) (in other words, the reaction force generated in the second and third elastic members 14, 16 against the pressing force can be made larger).
(2) By applying the above-mentioned prestress to the second and third elastic members 14, 16, it is possible to provide the structure 10 with a characteristic of softening the rigidity (flat load-displacement characteristic) as the displacement increases when the second and third elastic members 14, 16 are deformed so as to unfold into a planar shape due to the above-mentioned pressing force.
(3) When the second and third elastic members 14, 16 are deformed so as to expand into a planar shape, the total amount of strain energy absorbed by the second and third elastic members 14, 16 and the first elastic member 12 can be increased.
(4) Even if the curvature of the second and third elastic members 14, 16 is increased to increase the displacement stroke of the second and third elastic members 14, 16, the maximum value of the compressive stress in the second and third elastic members 14, 16 can be reduced.
(5) In the absence of prestress, when the second and third elastic members 14, 16 are deformed by the pressing force F, a mixture of bending stress and compressive stress is generated in the second and third elastic members 14, 16, so that the compressive stress available for pulling the first elastic member 12 is relatively small. However, when prestress is applied, the bending stress generated in the second and third elastic members 14, 16 when the second and third elastic members 14, 16 are deformed by the pressing force F becomes minute, so that a larger compressive stress can be used for pulling the first elastic member 12.

Figure 7 is a diagram showing the relationship between the displacement and the reaction force when a pressing force is applied to the structure 10 shown in Figure 1 so as to sandwich the structure 10 from above and below in Figures 1 and 2. In this embodiment, an analysis was performed on a structure 10 constructed according to the following conditions such as materials. In Figure 7, the displacement refers to the amount of change in the height (length in the vertical direction in the figure) H (see Figure 2) of the structure 10 from the completed manufacturing state. In addition, the displacement when the structure 10 is in the completed manufacturing state is set to 0, and the displacement when the second and third elastic members 14, 16 are flat, i.e., when the structure 10 is completely crushed, is set to the maximum value (7.8 mm).

(material)
First, second, and third elastic members 12, 14, and 16: structural steel (Young's modulus 200 GPa, Poisson's ratio 0.3)
(size)
Overall structure 10: width (left-right direction in the figure) 210 mm, depth (direction on the paper surface in the figure) 100 mm, height (up-down direction in the figure) 21.3 mm
Second and third elastic members 14 and 16: thickness 2.0 mm
First elastic member 12: Thickness 1.5 mm
(Prestress)
Compressive stress of the second and third elastic members 14, 16 due to prestress: 288 MPa
Tensile stress of the first elastic member 12 due to prestress: 60 MPa

7, when the above-mentioned pressing force is applied to the structure 10, the reaction force changes in the order of increasing, approximately constant, decreasing, approximately constant, and increasing as the second and third elastic members 14 and 16 are deformed so as to expand in a plane. Specifically, in the region where the displacement is around 0 mm to 4.0 mm, the reaction force of the structure 10 increases with a gradient that gradually decreases within a positive range as the displacement increases (softening with positive stiffness), and in the region where the displacement is around 4.0 mm to 5.0 mm, it becomes approximately constant (approximately zero stiffness). In addition, in the region where the displacement is around 5.0 mm to 7.2 mm, the reaction force of the structure 10 decreases with a gradient that gradually decreases (the absolute value increases) within a negative range as the displacement increases (negative stiffness), and in the region where the displacement is around 7.2 mm to 7.4 mm, it becomes approximately constant (approximately zero stiffness). Furthermore, in the region where the displacement is around 7.4 mm to the maximum value, the reaction force of the structure 10 increases with a gradient that gradually increases within a positive range (hardening with positive stiffness). These characteristics of the structure 10 are believed to be due to the effect of prestressing, in which the rigidity of the structure 10 is increased by the prestressed second and third elastic members 14, 16, and the rigidity is softened as the displacement increases when the second and third elastic members 14, 16 deform so as to unfold in a plane.

In this way, according to the structure 10 of this embodiment, the pressing force applied to the structure 10 is converted into a tensile force acting on the first elastic member 12, so that more strain energy can be stored. Moreover, by applying prestress to the second and third elastic members 14 and 16 in advance, the initial rigidity of the structure 10 (rigidity when the displacement is small) is increased, while the rigidity is given the property of softening as the displacement increases, so that it is possible to provide a structure 10 that produces a relatively high stroke ratio within a limited design space.

Here, a comparison will be made between the structure 10 of this embodiment, the structure 10B of the first modified example, and the structure 10C of the comparative example. The structure 10 of this embodiment has the shape shown in Figures 1 and 2, and as described above, in the completed manufacturing state, a compressive force is applied to both end portions 14a, 14b, 16a, 16b of the second and third elastic members 14, 16 in a direction approaching each other along the left-right direction of Figures 1 and 2, and a tensile force is applied to both end portions 12a, 12b of the first elastic member 12 in a direction moving away from each other along the left-right direction of Figures 1 and 2. In other words, the structure 10 is prestressed. The structure 10B of the first modification has the same shape as the structure 10, and in the completed manufacturing state, no compressive force is applied to the end portions 14a, 14b, 16a, 16b of the second and third elastic members 14, 16 in the direction of approaching each other along the left-right direction in Figures 1 and 2, and no tensile force is applied to the end portions 12a, 12b of the first elastic member 12 in the direction of moving away from each other along the left-right direction in Figures 1 and 2. That is, the structure 10B is not prestressed. The structure 10B is formed, for example, by integral molding of a metal material, a resin material, a rubber material, a composite material such as carbon fiber reinforced plastic (CRFP), or the first, second, and third elastic members 12, 14, 16 are formed separately and connected to each other. In the comparative structure 10C, the first elastic member 12 is removed from the structure 10B, and both end portions 14a, 14b of the second elastic member 14 and both end portions 16a, 16b of the third elastic member 16 are connected (fixed) to each other. The structure 10C is formed, for example, by integral molding of a metal material, a resin material, a rubber material, a composite material such as carbon fiber reinforced plastic (CRFP), or the second and third elastic members 14, 16 are formed separately and connected to each other.

Figure 8 is a diagram showing the relationship between the displacement and the reaction force when a pressing force is applied to the structures 10, 10B, and 10C of this embodiment, the first modified example, and the comparative example from the top and bottom directions of Figures 1 and 2 so as to sandwich the structures 10, 10B, and 10C. Figure 9 is a diagram showing the relationship between the displacement when such a pressing force is applied to the structures 10, 10B, and 10C and the maximum strain of the structures 10, 10B, and 10C. Figure 10 is a diagram showing the relationship between the displacement when such a pressing force is applied to the structures 10, 10B, and 10C and the energy stored in the structures 10, 10B, and 10C. In Figures 8 to 10, the solid line shows the relationship of the structure 10 of this embodiment, the dotted line shows the relationship of the structure 10B of the first modified example, and the dashed line shows the relationship of the structure 10C of the comparative example. The conditions such as the material of the structure 10 are the same as the above-mentioned conditions used in the analysis to obtain the analysis results of Figure 7. Therefore, the relationship (solid line) of the structure 10 in Figure 8 is the same as that in Figure 7. The material conditions of the structure 10B are the same as those of the structure 10, except that the compressive stress of the second and third elastic members 14, 16 due to prestress and the tensile stress of the first elastic member 12 due to prestress are both set to zero. The material conditions of the structure 10C are the same as those of the structure 10B, except that the height of the entire structure 10 is lowered by the amount that the first elastic member 12 is not used. Since the structure 10 is prestressed, the curvature of the second and third elastic members 14, 16 in the completed manufacturing state is larger than the initial curvature, which is the curvature of the second and third elastic members 14, 16 before prestressing. On the other hand, since the structures 10B and 10C are not prestressed, the curvature of the second and third elastic members 14, 16 in the completed manufacturing state is the same as the initial curvature of the second and third elastic members 14, 16. That is, the initial curvature of the second and third elastic members 14, 16 of the structure 10 is smaller than the initial curvature of the second and third elastic members 14, 16 of the structures 10B, 10C. In Figures 8 to 10, the definition of displacement and the state of the structures 10, 10B, and 10C when the displacement is 0 or at its maximum value are the same as those in Figure 7.

The relationship in FIG. 8 will be described. As shown by the dashed line in FIG. 8, the reaction force of the structure 10C increases linearly in the region where the displacement is around 0 mm to 5.0 mm (it is approximately constant with positive stiffness). In addition, in the region where the displacement is around 5.0 mm to the maximum value, the reaction force of the structure 10C increases with a gradually increasing slope as the displacement increases (it hardens with positive stiffness), and increases rapidly especially in the region where the displacement is around the maximum value. As shown by the dotted line in FIG. 8, the reaction force of the structure 10B increases with a gradually decreasing slope within the positive range as the displacement increases (it softens with positive stiffness) in the region where the displacement is around 0 mm to 5.0 mm, and becomes approximately constant (it becomes approximately zero stiffness) in the region where the displacement is around 5.0 mm to 7.0 mm. In addition, the reaction force of the structure 10B increases gradually with the displacement increases in the region where the displacement is around 7.0 mm to the maximum value (it hardens with positive stiffness), and increases rapidly especially in the region where the displacement is around the maximum value. The reaction force of the structure 10 shown by the solid line in FIG. 8 was described above using FIG. 7.

Comparing structures 10, 10B and structure 10C, structures 10, 10B have a greater increase in reaction force with a greater gradient in the region where the displacement is around 0 to 3.0 mm than structure 10C, i.e., they have higher rigidity. Also, in the region where the displacement is around 0 to 7.0 mm, structures 10, 10B have a greater reaction force than structure 10C. Furthermore, in the region where the displacement is around 2.0 to 5.0 mm, the relationship between the displacement and reaction force is roughly linear for structure 10C, while the relationship between the displacement and reaction force is roughly nonlinear for structures 10B and 10C. These differences depend on whether or not the first elastic member 12 is provided. That is, when a pressing force is applied to sandwich the structures 10, 10B, and 10C, the bending deformation of the central portions 14c and 16c of the second and third elastic members 14 and 16 causes compressive stress in the second and third elastic members 14 and 16, and tensile stress in the first elastic member 12.

Comparing structure 10 and structure 10B, the reaction forces are approximately equal in the region where the displacement is around 0 to 3.0 mm. Compared to structure 10B, structure 10 has a smaller reaction force gradient as the displacement increases in the region where the displacement is around 3.0 to 7.0 mm (the stiffness becomes softer). Compared to structure 10B, structure 10 has a smaller reaction force when the displacement is at its maximum value. This is due to the difference in the initial curvature between structures 10 and 10B.

The reason why the reaction force increases rapidly in the region where the displacement is near the maximum value in the structures 10, 10B, and 10C is as follows. When a pressure force is applied to the structures 10, 10B, and 10C by a flat body having a plane of a certain length in the left-right and front-back directions in FIG. 1 and FIG. 2 and having higher rigidity than the structures 10, 10B, and 10C, the contact area between the second and third elastic members 14, 16 and the flat body is sufficiently narrow when the displacement is small, whereas when the displacement reaches a certain value, the contact area between the second and third elastic members 14, 16 and the flat body increases rapidly, and the reaction force increases rapidly. The greater the initial curvature of the second and third elastic members 14, 16, the greater the degree of the sudden increase in the reaction force. For this reason, the reaction force of the structure 10 increases less rapidly than that of the structures 10B and 10C.

The relationship in FIG. 9 will be explained. As shown by the dashed line in FIG. 9, the maximum strain of the second and third elastic members 14, 16 of the structure 10C increases linearly in the region where the displacement is around 0 to 5.0 mm, and is approximately constant in the region where the displacement is around 5.0 mm to the maximum value. The displacement around 5.0 mm in the structure 10C has been described above. As shown by the dotted line in FIG. 9, the maximum strain of the second and third elastic members 14, 16 of the structure 10B increases with a gradually (gently) smaller slope as the displacement increases in the region where the displacement is around 0 to 3.0 mm, increases with a steeply smaller slope in the region where the displacement is around 3.0 to 3.2 mm, and increases with a gradually smaller slope in the region where the displacement is around 3.2 mm to the maximum value. In the structure 10B, the maximum strain gradually increases even in the region where the displacement is around 3.2 mm to the maximum value because a compressive stress occurs in the second and third elastic members 14, 16 via the first elastic member 12. As shown by the solid line in FIG. 9, the maximum strain of the second and third elastic members 14, 16 of the structure 10 is a positive value when the displacement is 0 mm (in the completed manufacturing state). This is because the structure 10 is prestressed. The maximum strain of the second and third elastic members 14, 16 of the structure 10 gradually decreases as the displacement increases in the region where the displacement is greater than 0 mm to approximately 1.5 mm. This is because deformation occurs that relieves the prestress applied to the structure 10. The maximum strain of the second and third elastic members 14, 16 of the structure 10 increases with a gradually (gently) smaller slope as the displacement increases in the region where the displacement is approximately 1.5 mm to approximately 3.7 mm, increases with a steeply smaller slope in the region where the displacement is approximately 3.7 to 3.9 mm, and increases with a gradually smaller slope in the region where the displacement is 3.9 mm to the maximum value. This is for the same reason as the structure 10B.

Comparing structure 10B and structure 10C, structure 10B has a larger maximum strain in the second and third elastic members 14, 16 than structure 10C. This is due to whether or not the first elastic member 12 is provided. That is, when a pressing force is applied to sandwich structures 10B and 10C, the bending deformation of the central portions 14c and 16c of the second and third elastic members 14, 16 causes compressive stress in the second and third elastic members 14, 16 and tensile stress in the first elastic member 12. Comparing structure 10 and structure 10B, structure 10 has a smaller maximum strain in the second and third elastic members 14, 16 than structure 10B in the region where the displacement is around 0.7 mm to the maximum value. This is due to whether or not prestress is applied to structures 10 and 10B.

The relationship in FIG. 10 will be explained. As shown by the solid line, dotted line, and dashed line in FIG. 10, in all of the structures 10, 10B, and 10C, the energy stored in the structures 10, 10B, and 10C increases as the displacement increases. Comparing the structures 10, 10B and 10C, the structures 10, 10B store about four times as much energy as the structure 10C when the displacement is about 5 mm. This is because when a pressing force is applied to the structures 10, 10B, and 10C, the structure 10C stores the energy as strain energy caused by the bending deformation of the second and third elastic members 14, 16, while the structures 10, 10B store the energy as strain energy caused by the bending deformation and compressive stress of the second and third elastic members 14, 16 and the tensile stress of the first elastic member 12. Comparing the structures 10 and 10B, the structure 10 stores slightly less energy than the structure 10B. This depends on whether or not structures 10 and 10B are prestressed.

According to the structure 10, 10B of the present embodiment and the first modified example, by providing the first elastic member 12 in addition to the second and third elastic members 14, 16, when a pressing force is applied to sandwich the second and third elastic members 14, 16, the intermediate portions 14c, 16c of the second and third elastic members 14, 16 are bent, and a tensile stress is generated in the first elastic member 12. In contrast, since the structure 10C does not have the first elastic member 12, when a pressing force is applied to sandwich the second and third elastic members 14, 16, only the intermediate portions 14c, 16c of the second and third elastic members 14, 16 are bent. Therefore, the structure 10, 10B can store a larger amount of strain energy when a pressing force is applied to sandwich the second and third elastic members 14, 16 compared to the structure 10C (see FIG. 10). That is, the strain energy that the structure can store can be made closer to the maximum potential strain energy that the structure can originally store. Furthermore, compared to structure 10C, structures 10 and 10B can generate a relatively large reaction force from an area where the displacement is relatively small (see Figure 8).

In addition, the structure 10 of this embodiment is prestressed, which gives it a characteristic that when a squeezing pressure is applied, the rigidity becomes softer as the displacement increases, as compared to the structure 10B of the first modified example (see FIG. 8), and the maximum strain of the second and third elastic members 14, 16 can be prevented from increasing (see FIG. 9). On the other hand, the structure 10B of the first modified example can store a larger amount of strain energy when a squeezing pressure is applied, as compared to the structure 10B of the first modified example (see FIG. 10).

Furthermore, according to the structures 10 and 10B of this embodiment and the first modified example, the second and third elastic members 14 and 16 have a smooth curved shape (specifically, a curved shape combining multiple arcs) in a given cross section, so that it is possible to prevent the occurrence of any portion with a sufficiently large curvature. This makes it possible to suppress the occurrence of stress concentration at specific points of the second and third elastic members 14 and 16 when a pressing force is applied to the structure 10.

In addition, according to the structures 10, 10B of this embodiment and the first modified example, the second and third elastic members 14, 16 are formed in a symmetrical shape with respect to the first elastic member 12, so that when a pressing force is applied to the structure 10 from above and below, the intermediate portions 14c, 16c of the second and third elastic members 14, 16 are caused to deform in the same manner, and similar compressive stresses are generated in the second and third elastic members 14, 16.

In the above-mentioned embodiment and modified structure 10, 10B, as shown in Figs. 1 and 2, the intermediate portions 14c, 16c of the second and third elastic members 14, 16 are each shaped in a generally inverted V shape with smoothed (rounded) V corners in a given cross section, that is, with one protrusion on the side away from the first elastic member 12. However, the shape of the intermediate portions 14c, 16c is not limited to this. Fig. 11 is a perspective view showing the structure of the second modified structure, and Fig. 12 is a front view of the structure shown in Fig. 11. Fig. 13 is a perspective view showing the structure of the third modified structure, and Fig. 14 is a front view of the structure shown in Fig. 13.

11 and 12, the structure 110 of the second modified example differs from the structure 10 in that the shapes of the intermediate parts 114c, 116c of the second and third elastic members 14, 16 are changed from the shapes of the intermediate parts 14c, 16c of the second and third elastic members 14, 16 of the structure 10 of the embodiment. The intermediate parts 114c, 116c are inverted W-shaped, with the corners of the W-shaped parts smoothed (rounded), that is, have two convexities on the side away from the first elastic member 12 at a distance in the left-right direction in the figure. By having two convexities on the intermediate parts 114c, 116c, when a pressing force is applied by a plane body having a high rigidity and a plane of a certain length in the left-right direction and the front-back direction in Figures 1 and 2, the two convexities come into contact with the plane body, so that the structure 110 can be prevented from rotating in the clockwise or counterclockwise direction in Figure 12 compared to when one convexity comes into contact with the plane body.

As shown in Figures 13 and 14, the structure 210 of the third modified example differs from the structure 110 in that the shapes of the intermediate portions 214c, 216c of the second and third elastic members 14, 16 are changed from the shapes of the intermediate portions 114c, 116c of the second and third elastic members 14, 16 of the modified structure 110. The intermediate portions 214c, 216c have a shape that connects the two convex portions of the intermediate portions 114c, 116c in a straight line (flat shape).

The second and third modified structures 110 and 210 can achieve the same effect as the structure 10 of the embodiment compared to the comparative example structure 10C.

In the above-described embodiment and the first modified structure 10, 10B, as shown in Figs. 1 and 2, the intermediate portions 14c, 16c of the second and third elastic members 14, 16 have a curved, convex shape in a specified cross section that combines multiple arcs. However, the curved shape of the intermediate portions 14c, 16c may be a shape in which some or all of the multiple arcs are replaced by an elliptical arc or a part of a sine wave, or a shape in which all of the multiple arcs are replaced by one period of a sine wave. In addition, the intermediate portions 14c, 16c may have a shape that includes a straight line in a specified cross section.

In the above-described embodiment and the first modified structure 10, 10B, as shown in Figs. 1 and 2, the second and third elastic members 14, 16 are symmetrical with respect to the first elastic member 12. However, the second and third elastic members 14, 16 do not have to be symmetrical with respect to the first elastic member 12. For example, in the structures 10, 10B, the third elastic member 16 may be replaced with the third elastic member 116 or the third elastic member 216. The same applies to the structures 110, 210 of the second and third modified structures.

In the above-described embodiment and the first modified structure 10, 10B, as shown in Figs. 1 and 2, the first elastic member 12 is a flat plate-shaped member. However, the first elastic member 12 may be, for example, one or more rod-shaped members.

The structures 10 and 10B in the above-described embodiment and first modified example are provided with the first elastic member 12 and the second and third elastic members 14 and 16. However, it is also possible to provide only one of the first elastic member 12 and the second and third elastic members 14 and 16.

Although the present disclosure has been described above through the disclosed embodiments and examples, the above-mentioned embodiments and examples do not limit the invention according to the claims. In addition, forms that combine the features described in the embodiments and examples of the present disclosure may also be included in the technical scope of the present disclosure.

[Additional Notes]
[1] The structure disclosed herein comprises a first elastic member extending in a predetermined direction and having first end portions and a first intermediate portion that is a portion between the first end portions in the predetermined direction, and a second elastic member arranged on one side of the first elastic member and having second end portions in the predetermined direction connected to the first end portions, respectively, and at least a portion of the second intermediate portion that is a portion between the second end portions having a convex shape on a side away from the first intermediate portion, wherein when a pressing force is applied to bring the second intermediate portion closer to the first intermediate portion, the second elastic member is bent, and a compressive stress is generated in the second elastic member and a tensile stress is generated in the first elastic member.

When a pressing force is applied to the structure of the present disclosure such that the second intermediate portion approaches the first intermediate portion, the second elastic member is bent, causing compressive stress in the second elastic member and tensile stress in the first elastic member. This makes it possible to increase the strain energy that can be stored in the structure. In other words, the strain energy that can be stored in the structure can be brought closer to the maximum potential strain energy that can be inherently stored in the structure.

[2] In the structure of the present disclosure (the structure described in [1] above), a tensile force in the predetermined direction may be applied in advance to the first end portions, and a compressive force in the predetermined direction may be applied in advance to the second end portions. In this way, it is possible to prevent the maximum strain of the second elastic member from increasing when the second elastic member is deformed by a pressing force that moves the second intermediate portion closer to the first intermediate portion.

[3] In the structure of the present disclosure (the structure described in [1] or [2] above), the second intermediate portion may have a smoothly curved convex shape.

[4] In this case (the structure described in [3] above), the second intermediate portion may have a curved convex shape formed by combining multiple arcs.

[5] The structure of the present disclosure (the structure described in [1] above) may further include a third elastic member disposed on the other side of the first elastic member, and having third end portions in the predetermined direction connected to the first end portions, respectively, and at least a part of a third intermediate portion between the third end portions having a convex shape on the side away from the first intermediate portion, and the structure may be configured such that, when a pressing force is applied so as to bring the second and third intermediate portions closer to the first intermediate portion, bending deformation of the second and third elastic members is accompanied by compressive stress in the second and third elastic members and tensile stress in the first elastic member.

[6] In the structure of the present disclosure (the structure described in [5] above), a tensile force in the specified direction may be applied in advance to the first end portion, and a compressive force in the specified direction may be applied in advance to the second and third end portions.

[7] In the structure of the present disclosure (the structure described in [5] or [6] above), the second and third intermediate portions may be symmetrical in shape with respect to the first elastic member.

[8] The first method for manufacturing a structure of the present disclosure includes a first elastic member extending in a predetermined direction and having first end portions and a first intermediate portion between the first end portions in the predetermined direction, and a second elastic member disposed on one side of the first elastic member, and having second end portions in the predetermined direction connected to the first end portions, respectively, and at least a part of the second intermediate portion between the second end portions having a convex shape on the side away from the first intermediate portion, and when a pressing force is applied to bring the second intermediate portion closer to the first intermediate portion, the second elastic member is bent to generate a compressive stress in the second elastic member and a tensile stress in the first elastic member, and the method includes the steps of: (A) arranging the first and second elastic members so that the first and second elastic members are arranged in this order; and (B) connecting the first end portions and the second end portions while pulling the first elastic member in the predetermined direction.

By manufacturing a structure using the first method for manufacturing a structure of the present disclosure, a tensile force in a predetermined direction is applied in advance to the first elastic member, and a compressive force in a predetermined direction is applied in advance to the second end portions of the second elastic member. This can provide the same effect as the structure described in [2] above.

[9] The second method of manufacturing a structure of the present disclosure includes a first elastic member extending in a predetermined direction and having first end portions and a first intermediate portion between the first end portions in the predetermined direction, and a second elastic member disposed on one side of the first elastic member, and having second end portions connected to the first end portions in the predetermined direction, with at least a portion of the second intermediate portion between the second end portions being convex on the side away from the first intermediate portion, and when a pressing force is applied to bring the second intermediate portion closer to the first intermediate portion, the second elastic member is bent to generate a compressive stress in the second elastic member and a tensile stress in the first elastic member, and the method includes the steps of: (A) arranging the first and second elastic members in the order of the first and second elastic members; and (B) connecting the first and second end portions while compressing the second end portions in a direction approaching each other along the predetermined direction.

By manufacturing a structure using the second method for manufacturing a structure of the present disclosure, a tensile force in a predetermined direction is applied in advance to the first elastic member, and a compressive force in a predetermined direction is applied in advance to the second end portions of the second elastic member. This can provide the same effect as the structure described in [2] above.

10, 10B, 10C, 110, 210 Structure, 12 First elastic member, 12a, 12b, 14a, 14b, 16a, 16b End portion, 12c, 14c, 16c, 114c, 116c, 214c, 216c Middle portion, 14 Second elastic member, 16 Third elastic member.

Claims (9)

A structure comprising:
a first elastic member extending in a predetermined direction and having first end portions and a first intermediate portion between the first end portions in the predetermined direction;
a second elastic member disposed on one side of the first elastic member, and having second end portions in the predetermined direction connected to the first end portions, and at least a part of a second intermediate portion between the second end portions having a convex shape on a side away from the first intermediate portion;
Equipped with
When a pressing force is applied to the structure so as to move the second intermediate portion closer to the first intermediate portion, a compressive stress is generated in the second elastic member and a tensile stress is generated in the first elastic member, accompanied by bending deformation of the second elastic member.
Structure. 2. The structure of claim 1,
A tensile force is applied to the first end portions in the predetermined direction in advance,
A compressive force in the predetermined direction is applied to the second end portions in advance.
Structure. 3. The structure according to claim 1 or 2,
The second intermediate portion has a smoothly curved convex shape.
Structure. 4. The structure of claim 3,
The second intermediate portion has a curved convex shape formed by combining a plurality of circular arcs.
Structure. 2. The structure of claim 1,
a third elastic member disposed on the other surface side of the first elastic member, and having third end portions in the predetermined direction connected to the first end portions, and at least a part of a third intermediate portion between the third end portions having a convex shape on a side away from the first intermediate portion,
When a pressing force is applied to the structure so as to move the second and third intermediate portions closer to the first intermediate portion, the second and third elastic members are bent, whereby a compressive stress is generated in the second and third elastic members and a tensile stress is generated in the first elastic member.
Structure. 6. The structure of claim 5,
A tensile force is applied to the first end portions in the predetermined direction in advance,
A compressive force in the predetermined direction is applied to the second and third end portions in advance.
Structure. 7. The structure according to claim 5 or 6,
The second and third intermediate portions are symmetrical with respect to the first elastic member.
Structure. a first elastic member extending in a predetermined direction and having first end portions and a first intermediate portion between the first end portions in the predetermined direction;
a second elastic member disposed on one side of the first elastic member, and having second end portions in the predetermined direction connected to the first end portions, and at least a part of a second intermediate portion between the second end portions having a convex shape on a side away from the first intermediate portion;
Equipped with
When a pressing force is applied to the structure so as to move the second intermediate portion closer to the first intermediate portion, a compressive stress is generated in the second elastic member and a tensile stress is generated in the first elastic member, accompanied by bending deformation of the second elastic member.
A method for manufacturing a structure, comprising the steps of:
(A) arranging the first and second elastic members so that the first and second elastic members are aligned in this order;
(B) connecting the first end portions and the second end portions while pulling the first elastic member in the predetermined direction;
A method for producing a structure comprising the steps of: a first elastic member extending in a predetermined direction and having first end portions and a first intermediate portion between the first end portions in the predetermined direction;
a second elastic member disposed on one side of the first elastic member, and having second end portions in the predetermined direction connected to the first end portions, and at least a part of a second intermediate portion between the second end portions having a convex shape on a side away from the first intermediate portion;
Equipped with
When a pressing force is applied to the structure so as to move the second intermediate portion closer to the first intermediate portion, a compressive stress is generated in the second elastic member and a tensile stress is generated in the first elastic member, accompanied by bending deformation of the second elastic member.
A method for manufacturing a structure, comprising the steps of:
(A) arranging the first and second elastic members so that the first and second elastic members are aligned in this order;
(B) connecting the first end portions and the second end portions while compressing the second end portions in a direction toward each other along the predetermined direction;
A method for producing a structure comprising the steps of:

Images