Stiffening structure

Abstract

To provide a stiffening structure capable of improving out-of-plane rigidity of a plate-like body provided with an opening and suppressing a buckling waveform generated in the plate-like body.SOLUTION: A stiffening structure 1 includes an annular member 2 attached to an attachment surface of at least one surface side or the other surface side of a plate-shaped body having an opening T and provided to protrude from the attachment surface so as to surround a periphery of the opening, and one or more stiffening members 3 including a fixing portion 4 fixed to the annular member and a suppressing portion 5 that suppresses displacement based on a buckling waveform generated in the plate-shaped body.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a stiffening structure for improving the out-of-plane rigidity of a plate-like body having an opening. [Background technology]

[0002] An opening may be provided in the web of an H-shaped section member used as a beam or the like in a building to allow passage of ducts or cables. When an opening is provided in the web of the H-shaped section member, the strength of the H-shaped section member decreases compared to when no opening is provided, and there is a risk of buckling occurring. For example, Patent Documents 1 to 3 describe stiffening structures for stiffening openings provided in the web. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-162244 [Patent Document 2] Japanese Patent Application Publication No. 2020-133312 [Patent Document 3] Japanese Patent Application Publication No. 2018-131824 Summary of the Invention [Problem to be solved by the invention]

[0004] The conventional technology includes an annular member provided around the opening of the web portion. This annular member protrudes from at least one side of the web portion to improve the bending rigidity of the web portion where the opening is provided. However, the conventional technology does not propose reducing the buckling waveform that occurs in the web portion.

[0005] An object of the present invention is to provide a stiffening structure that can improve the out-of-plane rigidity of a plate-like body having an opening and can suppress buckling waves that occur in the plate-like body. [Means for solving the problem]

[0006] One aspect of the present invention is a stiffening structure comprising an annular member attached to a mounting surface on at least one side or the other side of a plate-like body having an opening and protruding from the mounting surface so as to surround the periphery of the opening, and one or more stiffening members each having a fixing portion fixed to the annular member and a suppression portion that suppresses displacement due to a buckling waveform that occurs in the plate-like body. [Effects of the Invention]

[0007] According to the present invention, it is possible to improve the out-of-plane rigidity of a plate-like body having an opening and to suppress buckling waves occurring in the plate-like body. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 2 is a front view showing the configuration of the stiffening structure according to the embodiment. [Figure 2] FIG. 10 is a perspective view showing the configuration of a stiffening structure including an annular member having the same diameter as the opening. [Figure 3] FIG. 10 is a front view showing the configuration of a stiffening structure including an annular member having a diameter larger than that of the opening. [Figure 4] FIG. 10 is a side view showing the configuration of a stiffening structure provided on one mounting surface side. [Figure 5] FIG. 10 is a side view showing the configuration of stiffening structures provided on the two mounting surface sides. [Figure 6] FIG. 10 is a perspective view showing an analytical model of a stiffening structure. [Figure 7] 10A to 10C are diagrams showing the calculation results of elastic buckling analysis of each analysis model for analyzing a stiffening structure. [Figure 8] FIG. 10 is a diagram showing displacements occurring in each analytical model. [Figure 9] FIG. 10 is a diagram showing the results of large deformation analysis of each analysis model when the diameter of the opening is 250 mm. [Figure 10] FIG. 10 is a diagram showing the relationship between the bending moment acting on both ends of each analysis model and the rotation angle when the diameter of the opening is 500 mm. [Figure 11]FIG. 10 illustrates an analytical model of a structural member having an annular member with an enlarged inner diameter relative to the diameter of the opening. [Figure 12] FIG. 10 is a diagram showing the comparison results of elastic buckling analysis of structural members. [Figure 13] This figure shows the results of a large deformation analysis when the diameter of the opening in the structural member is fixed at 250 mm. [Figure 14] The results of large deformation analysis are shown for the case where the diameter of the opening in the structural member is fixed at 500 mm. [Figure 15] 10A and 10B are diagrams illustrating examples of arrangement of stiffening members arranged around an annular member. [Figure 16] FIG. 10 is a diagram showing parameters corresponding to the dimensions of each part of an H-shaped cross-section member and parameters corresponding to the dimensions of each part of a stiffening structure. DETAILED DESCRIPTION OF THE INVENTION

[0009] As shown in FIGS. 1 to 3 , the stiffening structure 1 is provided in a structural member such as an H-shaped section member S. The H-shaped section member S according to the embodiment is used, for example, as a beam member. The H-shaped section member S includes a web portion S1 formed on a band-shaped plate. A pair of flange portions S2 formed on the band-shaped plate are provided at both longitudinal ends of the web portion S1. When viewed in the cross-sectional direction of the H-shaped section member S, the pair of flange portions S2 are arranged perpendicular to the web portion S1. The flange portions S2 provided at both longitudinal ends of the web portion S1 may be formed symmetrically with respect to each other or asymmetrically with respect to each other. With the above configuration, the H-shaped section member S is formed into an H-section shape. The web portion S1 of the H-shaped section member S has a plurality of openings T formed along the longitudinal direction. The openings T are formed, for example, as circular through-holes. The openings T may be formed not only in a circular shape but also in a polygonal shape.

[0010] A stiffening structure 1 is provided around each opening T to increase the rigidity of the web portion S1. The stiffening structure 1 may be applied not only to the web portion S1 of the H-section member S, but also to any structural member that is a plate-like body to which a load is applied. The stiffening structure 1 is provided on an attachment surface on at least one of the side SA or the other side SB of the plate-like body having an opening. The stiffening structure 1 is provided on the attachment surface on the side SA of the plate-like body having an opening T. The stiffening structure 1 is provided on the attachment surface on the other side SB of the plate-like body having an opening T. The stiffening structure 1 is provided on the attachment surface on the side SA of the plate-like body having an opening T, and also on the attachment surface on the other side SB. The stiffening structure 1 includes, for example, an annular member 2 provided around the opening T.

[0011] The annular member 2 is provided to protrude from the mounting surface so as to surround the periphery of the opening T. In the illustrated example, the annular member 2 is formed, for example, in a circular ring shape. The annular member 2 is provided on at least one of the mounting surfaces, either the one surface SA side or the other surface SB side, of the plate-like body having the opening T. The annular member 2 is provided on the mounting surface on the one surface SA side of the plate-like body having the opening T, and may also be provided on the mounting surface on the other surface SB side. In this case, the annular member 2 is provided around the opening T on the mounting surface on the one surface SA side of the plate-like body, and is also provided around the opening T on the mounting surface on the other surface SB side of the plate-like body. The annular member 2 may be formed with an outer diameter slightly smaller than the inner diameter of the opening T, and may be attached through the opening T, so that it protrudes from the mounting surface on the one surface SA side of the plate-like body and protrudes from the mounting surface on the other surface SB side of the plate-like body.

[0012] The annular member 2 may be formed not only in a circular ring shape but also in a polygonal shape. The shape of the annular member 2 does not necessarily have to match the shape of the opening T. That is, the stiffening structure 1 may be formed not only by a combination of a circular opening T and an annular member 2, but also by a combination of a circular opening T and an annular member 2 having a polygonal shape. The stiffening structure 1 may be formed by a combination of a polygonal opening T and an annular member 2 having a polygonal shape. The stiffening structure 1 may be formed by a combination of a polygonal opening T and an annular member 2 having a polygonal shape. When the annular members 2 are provided on the mounting surfaces of the one surface SA and the other surface SB of a plate-like body having an opening T, the shapes of the annular member 2 on the one surface SA of the plate-like body and the annular member 2 on the other surface SB of the plate-like body may not only be the same but also different. The inner diameter of the annular member 2 is formed to be the same as the diameter of the opening T. The inner diameter of the annular member 2 may be formed to be larger than the diameter of the opening T (see FIG. 3). The annular member 2 is attached to the attachment surface so that the center of the inner diameter and the center of the opening T are concentric, for example.

[0013] The center of the inner diameter of the annular member 2 and the center of the opening T do not necessarily have to be positioned strictly concentrically as long as it is within an allowable range. The annular member 2 is fixed to the web portion S1, for example, by welding. In addition to welding, the annular member 2 may be provided with a flange portion or the like and fixed to the web portion S1 by bolts or the like. The annular member 2 increases the out-of-plane rigidity of the web portion S1 that is reduced by the formation of the opening T.

[0014] The stiffening structure 1 includes one or more stiffening members 3 formed in a plate shape. The stiffening member 3 is formed, for example, in a rectangular plate shape. In the illustrated example, the stiffening structure 1 includes a pair of stiffening members. The stiffening members 3 are provided upright relative to the mounting surface. The stiffening members 3 include a fixing portion 4 fixed to the annular member. The fixing portion 4 is one side of the rectangular stiffening member 3. The fixing portion 4 is, for example, welded to the outer circumferential surface of the annular member 2. The fixing portion 4 may be fixed not only by welding but also by providing a flange portion or the like and fixing it to the outer circumferential surface of the annular member 2 with bolts or the like.

[0015] The stiffening member 3 is provided with a suppression portion 5 that contacts the mounting surface. The suppression portion 5 is one side of the rectangular stiffening member 3. The suppression portion 5 is disposed in a position in the web portion S1 where it breaks the buckling waveform that occurs around the annular member 2 when a load is applied. The suppression portion 5 is formed to suppress displacement due to the buckling waveform that occurs in the web portion S1 when a load is applied.

[0016] FIG. 4 shows the stiffening structure 1 attached to one of the mounting surfaces, either the one surface SA side or the other surface SB side, of the web portion S1. In the illustrated example, the stiffening structure 1 is provided with the one surface SA side of the web portion S1 as the mounting surface. The suppression unit 5 is fixed to the one surface SA side, which is the mounting surface, of the web portion S1. When a buckling waveform occurs due to the stress state of the web portion S1, the suppression unit 5 fixed to the mounting surface side presses against the buckling waveform that displaces so as to bulge toward the one surface SA side of the web portion S1 where the suppression unit 5 is present, thereby suppressing the buckling waveform that displaces so as to bulge toward the other surface SB side of the web portion S1 where the suppression unit 5 is present, thereby pulling against the buckling waveform that displaces so as to bulge toward the other surface SB side of the web portion S1 where the suppression unit 5 is not present, when a buckling waveform occurs due to the stress state of the web portion S1.

[0017] 5 shows a stiffening structure including an annular member 2 and one or more stiffening members 3 on one surface SA of the web portion S1, and an annular member 2 and one or more stiffening members 3 on the other surface SB of the web portion S1. According to this stiffening structure, the web portion S1 is sandwiched between the stiffening member 3 on the one surface SA and the stiffening member 3 on the other surface SB. In this state, the suppression unit 5 on the one surface SA does not need to be fixed to the mounting surface, and the suppression unit 5 on the other surface SB does not need to be fixed to the mounting surface. That is, the pair of suppression units 5, which are provided at symmetrical positions with respect to the web portion S1, are not fixed to the mounting surface. When a buckling waveform occurs due to the stress state of the web portion S1, they press against the buckling waveform, which displaces so as to bulge toward the mounting surface where the annular member 2 is provided.

[0018] The pair of suppression units 5 provided at symmetrical positions with respect to the web portion S1 may be fixed to the mounting surface. In this case, when a buckling waveform occurs due to the stress state of the web portion S1, the pair of suppression units 5 provided at symmetrical positions with respect to the web portion S1 press and suppress the buckling waveform that displaces so as to bulge toward one surface SA of the web portion S1 on which they are located. When a buckling waveform occurs due to the stress state of the web portion S1, the pair of suppression units 5 provided at symmetrical positions with respect to the web portion S1 pull and suppress the buckling waveform that displaces so as to bulge toward the other surface SB of the web portion S1 opposite the mounting surface on which they are attached.

[0019] Figure 6 shows an analytical model for verifying the stiffening structure 1. The analytical model compares six types of structural members. The analytical model is set up with a structural member without an opening (see Figure 6(A)). The analytical model is set up with a structural member with an opening (see Figure 6(B)). The analytical model is set up with a structural member with a ring-shaped member 2 provided around the opening (see Figure 6(C)).

[0020] The analytical model is set up as a structural member with a stiffening structure 1 provided around the opening (see Figure 6(D)). The analytical model is set up as a structural member with a ring-shaped member 2 whose diameter is larger than the diameter of the opening (see Figure 6(E)). The analytical model is set up as a structural member with a stiffening structure 1 provided with a ring-shaped member 2 whose inner diameter is enlarged compared to the diameter of the opening (see Figure 6(F)). The dimensions of each part are set up to the following values. Diameter of circular opening: d = 500 mm Enlarged inner diameter of annular member: dr = 600 mm Annular member thickness: tr = 12 mm Thickness of stiffening member: th = 12 mm Length of suppression part: lh=200mm

[0021] Figure 7 shows the calculation results of the first-order buckling eigenvalues ​​of each analytical model. Figure 8 shows the displacements occurring in each analytical model. An antisymmetric moment was applied to both ends of the analytical model, and analytical results were calculated for each structural member. Using structural member (A) without an opening as a reference, analytical results for each structural member (B) to (F) were calculated. The analytical results confirmed that structural member (D), which is provided with a stiffening structure 1 comprising an annular member 2 and a stiffening member 3, has improved buckling resistance compared to structural member (A) without an opening and structural member (B) with only an opening (see Figure 7).

[0022] The analysis results confirmed that the out-of-plane rigidity of the web portion S1 (plate-like body) is improved by providing the annular member 2 and stiffening member 3 in the area where buckling occurs. The suppression portion 5 is positioned in the web portion S1 when a load is applied, at a position that breaks the buckling waveform that occurs around the annular member 2, thereby improving the out-of-plane rigidity (see Figure 8).

[0023] Figures 9 and 10 show the relationship between the bending moment acting on both ends of each analytical model and the rotation angle. Figure 9 shows the large deformation analysis results for each analytical model set with an opening diameter of d = 250 mm. Figure 10 shows the calculation results for each analytical model set with an opening diameter of d = 500 mm. It can be seen that the structural member (C) equipped with the ring member 2 has higher strength and deformation capacity than the structural member (B) with only an opening. It can be seen that the structural member (D) equipped with the stiffening structure 1 equipped with the ring member 2 and stiffening member 3 has even higher strength and deformation capacity than the structural member (C). It can be seen that the structural member (F) has the highest strength and deformation capacity. The calculation results show that the structural member with the added stiffening member 3 has even higher strength and deformation capacity than the structural member with only the ring member 2.

[0024] FIG. 11 shows an analytical model of a structural member 100 having an annular member 2 with an inside diameter that is enlarged compared to the diameter of the opening T. The dimensions of each part are set to the following values. Circular opening diameter: d = 250mm, 500mm Enlarged inner diameter of annular member: dr = d ~ 950 mm Annular member thickness: tr = 12 mm Height of ring member (protrusion): Wr = 100 mm

[0025] 12 shows the comparative results of elastic buckling analysis of the structural member 100. As shown in the figure, in two calculation results for the structural member 100 with different diameters d of the opening T, the elastic buckling strength increases in both cases until the inner diameter of the annular member 2 reaches approximately half the distance from the edge of the opening T to the flange portion S2, and as the inner diameter of the annular member 2 increases beyond that, the stiffening effect gradually decreases.

[0026] 13 shows the results of a large deformation analysis when the diameter of the opening T of the structural member 100 is fixed at 250 mm. As shown in the figure, when the inner diameter dr of the annular member 2 is changed from 250 mm to 700 mm, the maximum reinforcement effect is obtained when the inner diameter dr of the annular member 2 is 600 mm.

[0027] 14 shows the results of a large deformation analysis when the diameter of the opening T of the structural member 100 is fixed at 500 mm. As shown in the figure, when the inner diameter of the annular member 2 is changed from 500 mm to 900 mm, the elastic buckling strength increases until the inner diameter of the annular member 2 is approximately halfway between the edge of the opening T and the flange portion S2, and as the inner diameter of the annular member 2 increases beyond that, the stiffening effect gradually decreases. With the structural member 100, the maximum reinforcing effect is obtained when the position of the inner diameter of the annular member 2 is approximately halfway between the edge of the opening T and the flange portion S2.

[0028] 15(A) to 15(E) show examples of arrangements of stiffening members 3 arranged around the annular member 2. The number and positions of the stiffening members 3 are set arbitrarily depending on the position and size of the buckling waveform that occurs depending on the load state of the web portion S1. The stiffening members 3 may be arranged at positions that break up the buckling waveform that occurs around the annular member 2 depending on the load state of the web portion S1.

[0029] FIG. 16 shows parameters corresponding to the dimensions of each part of the H-section member S and parameters corresponding to the dimensions of each part of the stiffening structure 1. An example of the set values ​​for each parameter is as follows. Each set value is an example and may be adjusted appropriately according to the actual design value. The height h of the H-section member S is set by equation (1). h=300~2000mm (1)

[0030] The ratio B / h of the height h of the H-shaped cross section member S to the width B of the flange portion in the short side direction is set by equation (2). B / h=0.10~1.0 (2) This setting value is set based on the dimensions of the H-shaped cross-section member S that actually exists. The ratio of the height h of the H-shaped cross-section member S to the diameter d of the opening: d / h is set by equation (3). d / h=0.10~0.75 (3) This setting value is set based on the range of diameters of the openings formed in the current H-shaped cross-section member S.

[0031] The ratio wr / B of the width B in the short side direction of the flange portion to the protrusion wr of the annular member 2 from the mounting surface is set by equation (4). wr / B=0.05~0.50 (4) The lower limit of this set value is set to obtain an effective stiffening effect, and the upper limit is set to prevent buckling of the annular member 2.

[0032] The ratio tr / tw of the thickness tr of the annular member 2 to the thickness of the web portion S1 is set by the formula (5). tr / tw=0.50~5.00 (5) The lower limit of this set value is set to obtain an effective stiffening effect, and the upper limit is set for reasons of joining the annular member 2 and the web portion S1.

[0033] The inner diameter dr of the annular member 2 is set by the formula (6). (dr-d) / (hd)=0.0~1.2(1-d / h) / 2 (6) The lower limit of this set value is set due to the geometrical constraints of the H-shaped cross section member and the annular member 2, and the upper limit is set in order to obtain an effective stiffening effect.

[0034] The ratio wh / B of the protrusion amount wh of the stiffening member 3 from the mounting surface to the width B of the flange portion in the short direction is set by equation (7). Wh / B=0.05~0.50 (7) The lower limit of this set value is set to obtain an effective stiffening effect, and the upper limit is set to prevent buckling of the stiffening member 3 itself.

[0035] The ratio lh / h of the width lh of the suppressing portion 5 of the stiffening member 3 to the height h of the H-shaped cross-section member is set by equation (8). lh / h=0.10~2.00 (8) The lower and upper limits of this set value are both set to obtain an effective stiffening effect.

[0036] The ratio th / tw of the thickness th of the stiffening member 3 to the thickness tw of the web portion S1 is set by equation (9). th / tw=0.50~2.00 (9) The lower limit of this setting value is set to obtain an effective stiffening effect, and the upper limit is set for reasons of joining the stiffening member 3.

[0037] As described above, the stiffening structure 1 can improve the out-of-plane rigidity of a plate-like body having an opening T and suppress buckling waveforms occurring in the plate-like body. The stiffening structure 1 can suppress buckling waveforms occurring in the plate-like body by providing the stiffening members 3 on the annular member 2. The stiffening structure 1 can reliably suppress buckling waveforms by attaching the stiffening members 3 in accordance with the positions of buckling waveforms occurring based on the stress state of the plate-like body. The stiffening structure 1 can efficiently suppress buckling waveforms by adjusting the number and positions of the stiffening members 3 according to the stress state of the plate-like body.

[0038] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are within the scope and spirit of the invention, as well as the scope of the invention and its equivalents as set forth in the claims. Furthermore, each configuration shown in the stiffening structure 1 exemplified in the embodiments and modifications may be replaced, modified, or added as appropriate. For example, while the stiffening structure 1 has been described as being applied to structural members made of steel, such as H-shaped cross-section members, it may also be applied to structural members made of other materials, such as wooden members or resin members. [Explanation of symbols]

[0039] 1 Stiffening structure 2. Annular member 3 Stiffening members 4 Fixed part 5 Suppression part 100 Structural members SH type cross section member S1 Web Department S2 flange SA front page SB other side T opening

Claims

1. an annular member attached to at least one mounting surface of a plate-like body having an opening, either on one side or the other side, and protruding from the mounting surface so as to surround the periphery of the opening; one or more stiffening members each including a fixing portion fixed to the annular member and a suppressing portion that suppresses displacement due to a buckling waveform generated in the plate-like body; Stiffening structure.

2. The suppression unit is The buckling waveform is fixed to the mounting surface, and suppresses the buckling waveform that is displaced so as to bulge toward the one surface side and the buckling waveform that is displaced so as to bulge toward the other surface side. The stiffening structure of claim 1 .

3. The suppression portion is not fixed to the mounting surface, and suppresses the buckling waveform that is displaced so as to bulge toward the mounting surface on which the annular member is provided. The stiffening structure of claim 1 .

4. The suppression unit is The annular member is disposed at a position that breaks the buckling wave that occurs around the annular member. The stiffening structure of claim 1 .

5. The one surface side includes the annular member and one or more stiffening members, The other surface side is provided with the annular member and one or more stiffening members. The stiffening structure according to claim 2 or 3.

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