How to design a panel

Abstract

To provide a joint structure for a panel excellent in wind pressure resistance without any damage on a joint part by screws even when receiving strong wind such as wind producing large outersurface reaction force at an edged part.SOLUTION: A joint structure of a panel for jointing a panel 2, having a generally L-shaped edge part in a cross-sectional view formed around a generally rectangular plane, to a support member with screws is provided with a plurality of standard screw joint parts 3 arranged apart with specific intervals on then edge part to be brought into contact with the support member, and reinforcement screw joint parts 4 provided to be adjacent to the standard screw joint parts provided on a corner part 21 of the panel.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a panel joining structure and a panel design method in which a panel having an approximately L-shaped cross-sectional edge formed around the periphery of a substantially rectangular plane is joined to a support material with screws. [Background technology]

[0002] As disclosed in Patent Document 1, a construction method is known in which walls and ceilings are constructed by arranging multiple rectangular, including square, flat panels on the wall or ceiling and fixing them to the building's framework or base material.

[0003] For example, the exterior of a building or civil engineering structure is formed by joining metal wall panels such as aluminum alloy or stainless steel to supporting materials such as studs or furring strips that span between the studs using drill screws that are screwed in at a specified interval (pitch).

[0004] The exterior wall panels are thus subjected to wind pressure, especially during strong winds such as typhoons, which can cause strong out-of-plane forces, so the joints between the wall panels must be designed and constructed to withstand such external forces. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2018-178553 [Non-patent literature]

[0006] [Non-Patent Document 1] "Design and Manufacturing Guidelines for Aluminum Alloy Exterior Panels for Bridges" (Japan Aluminum Association, Civil Engineering Product Development Committee, January 2005) Summary of the Invention [Problem to be solved by the invention]

[0007] However, for example, in Non-Patent Document 1, as will be described in detail later, the deflection and stress level at the center of the flat plate are examined using a large deflection method for the flat part of the panel, but the out-of-plane reaction force acting on the edge of the panel that is joined to the support material has not been examined at present.

[0008] Therefore, the present invention aims to provide a panel joint structure with excellent wind pressure resistance, which will not damage the screw joints even when subjected to strong winds that generate large out-of-plane forces at the edges, and a panel design method. [Means for solving the problem]

[0009] In order to achieve the above-mentioned object, the panel joining structure of the present invention is a panel joining structure in which a panel having an edge portion that is approximately L-shaped in cross section formed around a substantially rectangular plane is joined to a support material by screws, and is characterized by having a plurality of normal screw joints provided at predetermined intervals on the edge portion that contacts the support material, and reinforcing screw joints provided adjacent to the normal screw joints provided at the corners of the panel.

[0010] Here, the reinforcing screw joints may be spaced apart from adjacent normal screw joints by a distance of 1 / 3 to 1 / 2 of the spacing between the normal screw joints. Also, the reinforcing screw joints may be provided at the ends of a strip-shaped reinforcing plate that spans between adjacent members.

[0011] Furthermore, it is preferable that the reinforcing screw joint is formed by screwing a screw having a flat washer or a flange into an elongated hole drilled in the edge portion. The reinforcing screw joint may be provided on the edge portions of a pair of long sides of the panel, with the elongated hole provided in one of the edges and a round hole provided in the other edge portion.

[0012] Furthermore, the invention of a panel design method is a panel design method in which a panel having an edge that is approximately L-shaped in cross section formed around a substantially rectangular plane is joined to a support material with screws, and is characterized by comprising the steps of: setting the load acting due to wind; setting the specifications of the panel; setting whether or not to provide reinforcing screw joints at the corners of the panel; calculating the out-of-plane reaction force acting on the edge; and comparing the stress generated at the edge of the corner with the allowable strength. [Effects of the Invention]

[0013] The panel joint structure of the present invention, configured in this manner, not only provides a plurality of regular screw joints at predetermined intervals when joining the edges of a roughly rectangular, planar panel to a support material with screws, but also provides reinforcing screw joints adjacent to the regular screw joints at the corners of the panel.

[0014] By adding reinforcing screw joints to the corners of the panel in this way, even when subjected to strong winds that generate large out-of-plane forces at the edges, the stress is distributed to the reinforcing screw joints, preventing the screw joints from breaking, resulting in a panel joint structure with excellent wind pressure resistance.

[0015] These reinforcing screw joints are particularly effective when placed at the corners of panels, separated from adjacent regular screw joints by 1 / 3 to 1 / 2 the distance between regular screw joints. Furthermore, by placing reinforcing screw joints at the ends of strip-shaped reinforcing plates spanning between adjacent members, the bearing area can be increased, allowing stress caused by wind pressure to be dispersed.

[0016] Furthermore, if the reinforcing screw joints are provided in the slotted holes, they can also accommodate interlayer displacement that occurs in the in-plane direction of the panel during thermal expansion and contraction, earthquakes, etc. In this case, by providing an elongated hole on one edge of the panel and making a larger round hole on the other edge that overlaps it, it is possible to prevent excessive in-plane force from acting on the reinforcing screw joints even when interlayer displacement occurs.

[0017] In addition, the panel design method invention calculates the out-of-plane reaction force acting on the edge of the panel and checks the allowable strength, making it possible to create panels with excellent wind pressure resistance that will not damage the screw joints. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is a front view of an exterior wall provided with a panel joint structure according to the present embodiment. [Figure 2] FIG. 2 is a perspective view illustrating the configuration of a panel and a support material that joins the panel. [Figure 3] FIG. 2 is an explanatory diagram showing an enlarged view of a corner portion of a panel. [Figure 4] FIG. 10 is an explanatory diagram showing the process of installing the panel. [Figure 5] 1A and 1B are diagrams illustrating the joining structure of the panel of this embodiment, in which (a) is a front view showing an enlarged view of the area around the corner, and (b) is a front view of the area around a conventional corner shown for comparison. [Figure 6] 1 is a cross-sectional view illustrating the joining structure of a panel according to the present embodiment using a bent panel. [Figure 7] 1 is a cross-sectional view illustrating the joining structure of a panel according to the present embodiment using a cut panel. [Figure 8] FIG. 10 is an explanatory diagram for explaining a conventional large deflection type. [Figure 9] This figure explains the results of a numerical analysis conducted to confirm the out-of-plane reaction force acting on the panel. (a) shows the analysis results of a four-sided pin support model, which is a large deflection condition, and (b) shows the analysis results of a 300mm interval support model. [Figure 10] These figures explain the wind pressure resistance test conducted to confirm the effect of additional reinforcement at the ends of the panels. (a) is an explanatory diagram of the test specimen, and (b) is a diagram showing the test results in terms of the relationship between von Mises stress and pressure. [Figure 11] These figures explain the model of the numerical analysis conducted to confirm the effect of additional reinforcement at the edge of the panel, where (a) is an explanatory diagram of an unreinforced panel, and (b) is an explanatory diagram of an additional reinforced panel at the edge. [Figure 12] 10A and 10B are diagrams illustrating the results of numerical analysis, where (a) shows the analysis results for an unreinforced panel, and (b) shows the analysis results for an edge-reinforced panel. [Figure 13] 10 is a flowchart illustrating a process flow of a panel design method according to the first embodiment. [Figure 14] 1A and 1B are diagrams illustrating the study conducted to derive the panel design method of Example 1, in which (a) shows the analysis results in terms of the relationship between displacement and pressure, and (b) shows the analysis results in terms of the relationship between stress and pressure. [Figure 15] FIG. 10 is an explanatory diagram showing the analysis results in terms of the relationship between the von Mises stress and pressure. [Figure 16] 1A and 1B are diagrams for explaining various coefficients used in the panel design method of Example 1, where (a) is an explanatory diagram of the displacement magnification factor α1 and the reinforcement reduction coefficient α2, and (b) is a diagram showing the relationship between the central displacement and the end stress calculated using them. [Figure 17] 1 is an explanatory diagram of a reaction force magnification γ1 and a reinforcement reduction coefficient γ2 used in the panel design method of the first embodiment. FIG. [Figure 18] 10 is an explanatory diagram comparing calculated values ​​according to the bending panel design formula used in the panel design method of Example 1 with experimental values ​​in terms of the relationship between displacement and pressure. FIG. [Figure 19] 1 is an explanatory diagram comparing calculated values ​​according to a bending panel design formula used in the panel design method of Example 1 with experimental values ​​in terms of the relationship between stress and pressure. FIG. [Figure 20] FIG. 10 is an explanatory diagram showing an enlarged view of a corner portion of a panel in the panel joint structure of Example 2. [Figure 21] FIG. 10 is an explanatory diagram showing a process of installing a panel according to a second embodiment. [Figure 22] FIG. 10 is a front view illustrating the joining structure of the panel of the second embodiment with an enlarged view of the periphery of the corner portion. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a front view of an exterior wall 1 provided with a panel joining structure according to this embodiment. Fig. 2 is a perspective view illustrating the configuration of a panel 2 and furring strips 12 that serve as supporting members for joining the panels. Fig. 3 is an explanatory view showing an enlarged view of a corner 21 of the panel 2.

[0020] The panel joint structure of this embodiment is applied when, for example, an exterior wall 1 is constructed by arranging a plurality of panels 2 that are generally rectangular when viewed from the front, as shown in Fig. 1. The application of the panels 2 is not limited to forming vertical wall surfaces such as the exterior wall 1, but can also be applied when forming roofs, eaves ceilings, sloping walls, etc.

[0021] For example, when constructing an exterior wall 1 that will serve as the exterior material for a civil engineering structure such as a building or bridge, a panel 2 is fixed to furring strips 12, which serve as supporting material, as shown in Figure 2. The furring strips 12 are placed horizontally, perpendicular to studs 11, which are erected vertically at intervals along the exterior surface of the structure, for example. Here, when fixing the panel 2 to the studs 11, the studs 11 serve as supporting material. Alternatively, post-installed anchors can be driven into the surface of an existing concrete exterior wall, etc., to attach fasteners 13, and the furring strips 12 can be attached to the fasteners 13 to serve as supporting material.

[0022] In Fig. 2, L-shaped fasteners 13 are attached at predetermined intervals in the vertical direction to the outer surface of stud 11. As shown in Fig. 4, fasteners 13 are fixed to stud 11 via joints 131 made up of bolts and nuts, and furring strips 12 are placed on the top surfaces of fasteners 13 and fixed by joints 132. In this embodiment, panels 2 are joined to the side surfaces of furring strips 12 extending horizontally.

[0023] As shown in Fig. 2, the panel 2 is formed in a generally rectangular plane when viewed from the front, with edges (22A, 22B, 23) provided around the periphery. In this embodiment, a rectangular panel 2 with a long side to short side ratio of 2:1 will be described as an example, but the long side to short side ratio is not limited to this and can be set arbitrarily. It may also be a square with a ratio of 1:1.

[0024] Here, a pair of opposing edges on the long side of the panel 2 are referred to as edge portions 22A and 22B, and the edge on the short side is referred to as short side edge portion 23. Each of the edges (22A, 22B, 23) is formed to have a substantially L-shape in cross section.

[0025] Here, we will explain the bending panel as an example, which is manufactured by bending metal plates such as aluminum alloy plates, stainless steel plates, steel plates, titanium alloy plates, copper alloy plates, etc. For example, metal plates with a thickness of 2 mm or more can be used.

[0026] More specifically, as shown in Fig. 3, the edge portions (22A, 22B, 23) are formed by bending the side edges of a metal plate such as an aluminum alloy into an L shape. That is, the upper edge portion 22A of the panel 2 is formed in an L shape by an upright portion 222 and a flat portion 221A perpendicular to the upright portion 222, and the lower edge portion 22B is also formed in an L shape by an upright portion 222 and a flat portion 221B perpendicular to the upright portion 222.

[0027] Similar to the edges 22A and 22B, the short side edge 23 is formed by bending the side edge of the metal plate into an L-shape, and the corners where the short side edge 23 meets the edges 22A and 22B are joined by welding.

[0028] The panel 2 described in this embodiment is fixed by joining only the edges 22A, 22B on the long sides to the furring strips 12. In other words, the panel 2 is supported on two sides. The edges 22A, 22B that come into contact with the furring strips 12, which serve as support, are provided with normal screw joints 3 and reinforcing screw joints 4, as shown in Figure 1.

[0029] The normal screw joints 3 are provided at a predetermined interval in the extension direction of the edge portions 22A, 22B. For example, if the short side of the panel 2 is 900 mm or less and the long side is 1800 mm or less, the normal screw joints 3 are provided at an interval (pitch) of 230 mm to 300 mm along the entire length of the edge portions 22A, 22B.

[0030] Meanwhile, a reinforcing screw joint 4 is provided at each of the four corners 21 present in the rectangular panel 2. That is, at the corners 21 of the panel 2, a reinforcing screw joint 4 is provided adjacent to a normal screw joint 3. In this embodiment, a reinforcing screw joint 4 is provided on both sides of the normal screw joint 3 at the corners 21.

[0031] 3 shows that the elongated holes 31 that constitute the normal screw joints 3 are drilled in the flat portion 221B at intervals (pitch) of 230 mm to 300 mm in the lower edge portion 22B of the panel 2. In addition, elongated holes 41 that constitute the reinforcing screw joints 4 are drilled on both sides of the elongated holes 31 in the flat portion 221B of the corner portion 21.

[0032] The distance between the elongated holes 31 and 41 can be set to, for example, 100 mm. In other words, the reinforcing screw joints 4 are provided at a distance from the adjacent normal screw joints 3 that is 1 / 3 to 1 / 2 the distance between the normal screw joints 3 (230 mm to 300 mm).

[0033] The long holes 31, 41 are oval loose holes whose horizontal length is longer than the diameter of the drill screws 33, 43 that are screwed into them. If the normal screw joint 3 and the reinforcing screw joint 4 are configured by screwing the drill screws 33, 43 into the long holes 31, 41, they can accommodate interlayer displacement that occurs in the in-plane direction of the panel 2 due to thermal expansion and contraction, earthquakes, etc.

[0034] When threading the drill screw 43 into the elongated hole 41, it is preferable to increase the bearing area by using a flat washer or by using a flanged drill screw. Note that flat washers and flanged drill screws can also be used for the drill screw 33 of the regular screw joint 3.

[0035] Meanwhile, round holes 42 are perforated in the flat portion 221A of the upper edge 22A of the panel 2 at positions directly above the elongated holes 41 of the lower edge 22B. That is, when the distance between the elongated holes 31, 41 is 100 mm, the distance between the round holes 42, 42 is 200 mm.

[0036] Additionally, a long hole 32 is drilled in the flat portion 221A at a position directly above the long hole 31 in the lower edge portion 22B. This long hole 32 is a load-receiving hole for initially supporting the panel 2, and by making it oval, the panel 2 can be easily attached to the furring strip 12 in an accurate position.

[0037] In other words, between adjacent panels 2, 2, the lower edge 22B of the panel 2 installed above is placed on top of the upper edge 22A of the panel 2 installed below. Figure 4 is an explanatory diagram showing a cross section of the process of installing the panels 2.

[0038] As shown in this figure, the lower panel 2 is fixed to the furring strip 12 by a drill screw 33 threaded into the elongated hole 32 in the upper edge 22A. By making the edge 22A of the panel 2 to be installed first into the elongated hole 32, it can be positioned on-site and easily fixed to the furring strip 12.

[0039] The elongated hole 32 and the head of the drill screw 33 screwed into it are provided above the flat portion 221A so as not to overlap with the flat portion 221B of the panel 2 to be attached later. Then, the flat portion 221B of the edge portion 22B of the upper panel 2 is overlapped with the flat portion 221A of the edge portion 22A, and the drill screw 43 is screwed into the elongated hole 41.

[0040] The tip of the drill screw 43 screwed into the long hole 41 passes through the round hole 42 in the flat portion 221A of the lower panel 2 and is screwed into the furring strip 12. In other words, the flat portion 221B of the overlapping edge portion 22B and the flat portion 221A of the edge portion 22A are joined together to the furring strip 12 by the drill screw 43.

[0041] 5(a) is an enlarged front view of the periphery of a corner 21 of a panel 2 provided with the panel joint structure of this embodiment. As shown in this figure, a pair of reinforcing screw joints 4 are provided at 100 mm intervals in the corner 21 of the panel 2, adjacent to normal screw joints 3 provided at 300 mm intervals.

[0042] On the other hand, Figure 5(b) is a front view of the corner area of ​​a conventional panel a2 shown for comparison. Conventional panel a2 only has regular screw joints 3 at 300 mm intervals, and the corner area is not reinforced.

[0043] Figure 6 shows a cross-sectional view of the state shown in Figure 5(b). The panel 2 shown in this figure is a bent panel made by bending the side edges of a metal plate, and a sealing material 14 is interposed between the edges 22A and 22B of the upper and lower panels 2, 2.

[0044] 7 is a cross-sectional view of a cut panel 2A to which the panel joining structure of this embodiment is applied. The cut panel has a rectangular flat plate portion 20 made from a metal plate such as an aluminum alloy, and a frame 24, which is a separate member, attached to the four side edges of the flat plate portion 20. The frame 24 is fixed to bolts 242 stud-welded to the flat plate portion 20 using nuts.

[0045] The generally L-shaped cross-sectional portion of the frame 24 protruding from the flat plate portion 20 becomes the edge portion 241 of the panel 2A. Similar to the edges 22A and 22B described for the bent panel, the edge portion 241 is perforated with the long holes 31, 32, and 41 and the round hole 42.

[0046] Drill screws 33, 43 are screwed into the elongated holes 31, 32, 41 and the round holes 42, and the upper and lower panels 2A, 2A are joined to the furring strip 12 in a state where the edge portions 241, 241 of the panels are overlapped.

[0047] Next, the operation of the panel joint structure of this embodiment will be described. First, the conventional large deflection method will be described with reference to Fig. 8. As described above, the large deflection method is applied to the design of exterior panels made of aluminum alloy, as described in Non-Patent Document 1.

[0048] The large deflection formula is a calculation formula for when a rectangular flat plate with a vertical length of a and a horizontal length of b is supported by pins on all four sides, as shown in the top of Figure 8. The calculation formula finds the deflection at the center of the flat plate (point A), where the displacement is greatest, and the stress at the central underside of the flat plate (point B), where the stress is greatest.

[0049] On the other hand, the design method described in Non-Patent Document 1 does not mention the reaction force at the edge of the flat plate. Furthermore, as described above, the panel 2 actually used may be supported on two sides by the upper and lower furring strips 12, and further, the panel is joined via the edges 22A, 22B, 241 that are approximately L-shaped in cross section, so a design that applies the large deflection method for flat plates is not sufficient.

[0050] Therefore, we will consider a joint structure that can ensure high wind pressure resistance performance that is suited to the actual shape of the panels 2 and 2A. First, the out-of-plane force acting on panel 2 will be considered.

[0051] The out-of-plane reaction force was confirmed by using a numerical analysis, FEM analysis, to determine the out-of-plane reaction force of an aluminum plate supported by pins on all four sides and an aluminum plate supported by pins at 300mm intervals on only the two long sides. Figure 9 explains the results of the numerical analysis, with Figure 9(a) showing the analysis results for the four-side pin support model, which is the large deflection condition, and Figure 9(b) showing the analysis results for the 300mm interval support model.

[0052] In Figure 9, the horizontal axis represents the out-of-plane reaction force (N) and the vertical axis represents the Y coordinate (longer side coordinate) from the center of the panel upward. The analysis was performed by applying a uniform distributed load of 1 kPa to 5 kPa to the entire surface of the aluminum plate.

[0053] Looking at the analysis results in Figure 9, we can see that even though a uniformly distributed load is applied to the entire surface of the flat plate, the distribution of the out-of-plane reaction force is not uniform, and the reaction force value is slightly larger at the end (Y coordinate 1500 mm or more) in Figure 9(b), which is closer to the actual support structure. As will be explained later, in the case of a curved panel, the difference in reaction force between the end and the center becomes even larger.

[0054] Furthermore, because the reaction force at the end exceeds the value obtained by multiplying the pressure force by the pressure-receiving area and dividing by the number of supports, as shown by the dotted and dashed lines in the diagram, it was confirmed that the out-of-plane reaction force based on the assumption of uniform burden underestimates the reaction force acting on the end. Here, the "uniform burden assumption" is a design concept that calculates the load borne by each screw by multiplying the wind pressure by the pressure-receiving area of ​​the panel and dividing by the number of fastening screws.

[0055] Assuming that the strength of the exterior wall 1 formed by the panels 2 is determined by the out-of-plane reaction force at the edges (corner sections 21) of the panels 2, the most effective and efficient method would be to reinforce only those sections with additional fastening screws to disperse the stress (reaction force). Therefore, the effectiveness of the edge reinforcement was confirmed through further wind pressure resistance tests.

[0056] Figure 10 is a diagram illustrating a wind pressure test conducted to confirm the effect of additional reinforcement at the end (corner 21) of panel 2, and Figure 10(a) is an explanatory diagram of the test specimen. In all of these test specimens, only the long sides of the curved panel were joined to the support material with drill screws (positions marked with circles) at 300 mm intervals.

[0057] The "end reinforcement" specimen on the right has two more drill screw connections (marked with circles) at each of the four corners compared to the "unreinforced" specimen. Wind pressure tests were conducted using these two specimens, and the displacement and stress generated in the specimens were measured.

[0058] Figure 10(b) shows the test results in terms of von Mises stress (N / mm 2 ) and pressure (kPa). The measurement location was "G1 position" which is the corner of the specimen as shown in Figure 10(a).

[0059] The test results show that the stress is smaller in the "end reinforcement" than in the "unreinforced" case. Although not shown in the figure, the displacement measured at the center of the specimen was also smaller in the "end reinforcement" case.

[0060] In addition, the stress at the end of the "unreinforced" specimen was calculated based on the results of a tensile test of aluminum material (A1100P-H14) conducted separately, and was found to be nominal strength (σ y =95N / mm 2 ) and the tensile test yield strength (R p0.2 =119N / mm 2 ) was reached.

[0061] In such wind pressure resistance tests, it is not possible to obtain the force (reaction force) acting on the panel fastening parts due to limitations in the experimental equipment, such as the size of the supporting furring strips 12. Therefore, we will conduct an investigation using numerical analysis (FEM analysis) in addition.

[0062] Figure 11 shows models of numerical analysis conducted to confirm the effect of additional reinforcement at the end (corner 21) of panel 2, with Figure 11(a) being an explanatory diagram of an "unreinforced panel" and Figure 11(b) being an explanatory diagram of an "end-reinforced panel." The numbers such as "3424" written in each model indicate the numbers of the nodes focused on in the FEM analysis.

[0063] Figure 12 explains the results of the FEM analysis, with Figure 12(a) showing the analysis results for the "unreinforced panel" and Figure 12(b) showing the analysis results for the "end reinforced panel."

[0064] Figure 12 shows the analysis results for the node of interest, with the vertical axis representing pressure (kPa) and the horizontal axis representing out-of-plane force (N). Figure 12(a) shows that for the "unreinforced panel," a large out-of-plane force is generated at node 3424, which corresponds to the location of the end fastening.

[0065] In contrast, in the "end reinforced panel" of Figure 12(b), the out-of-plane reaction force of node 3424, which corresponds to the position of the end fastening part, is reduced to about 1 / 2 to 1 / 3 of that of the "unreinforced panel," and it was found that a high effect can be obtained simply by reinforcing the area around the corner part 21 of panel 2.

[0066] In short, the panel joining structure of this embodiment provides a plurality of normal screw joints 3 at predetermined intervals when joining the edge portions 22A, 22B, 241 of the approximately rectangular planar panel 2 to the support material (furring strip 12) with drill screws 43, and further provides reinforcing screw joints 4 adjacent to the normal screw joints 3 at the corner portions 21 of the panel 2.

[0067] By adding reinforcing screw joints 4 to corners 21 of panel 2 in this way, even when subjected to strong winds that generate large out-of-plane forces at edges 22A, 22B, and 241, the stress is dispersed to reinforcing screw joints 4, resulting in a panel joint structure with excellent wind pressure resistance that does not damage the screw joints. In short, with just the minimal reinforcement of adding reinforcing screw joints 4, it is possible to obtain two to three times the wind pressure resistance of conventional unreinforced panels.

[0068] Such reinforcing screw joints 4 are particularly effective when provided at corners 21 of the panel 2, away from adjacent normal screw joints 3 by a distance of 1 / 3 to 1 / 2 (e.g., about 100 mm) of the distance between the normal screw joints 3, 3 (e.g., 230 mm to 300 mm).

[0069] Furthermore, if the reinforcing screw joints 4 are provided in the elongated holes 41, they can also accommodate interlayer displacement that occurs in the in-plane direction of the panel 2 during thermal expansion and contraction, earthquakes, etc. In this case, by screwing the drill screws 43 into the elongated holes 41 via flat washers or by using drill screws with flanges, it is possible to ensure a bearing area sufficient for reinforcement.

[0070] Furthermore, if a long hole 41 is provided in one edge 22B of the panel 2, the other edge 22A that overlaps it can be made into a larger round hole 42 with a diameter of approximately 10 mm, thereby preventing excessive in-plane forces from acting on the reinforcing screw joint 4 even if interlayer displacement occurs. [Example]

[0071] A panel design method for designing the panel joint structure of the above-described embodiment will be described below with reference to Figures 13 to 19. Note that the same terms or the same reference numerals will be used to describe the same or equivalent parts as those described in the above-described embodiment.

[0072] 13 is a flowchart illustrating the flow of processing in the panel design method of Example 1. First, how the design equations for the bent panel used in the panel design method of Example 1 are derived will be described.

[0073] Figure 14(a) shows the results of the FEM analysis in the case of no reinforcement, as a relationship between displacement and pressure, and Figure 14(b) shows the results of the FEM analysis in the case of no reinforcement, as a relationship between stress and pressure. Figure 14 also shows the "large plate deflection," which is the value calculated using the large plate deflection formula mentioned above, as well as the "flat plate FEM," which is the result of FEM analysis of a flat plate model, and the "bent panel FEM," which is the result of FEM analysis of a bent panel.

[0074] For the "large deflection of flat plate," "flat plate FEM," and "bending panel FEM" values, the displacement is the displacement at the center of the panel, and the stress is the stress on the underside of the center of the panel. When comparing only the flat plate, the displacement and stress showed almost the same values ​​for "large deflection of flat plate" and "flat plate FEM." Strictly speaking, the FEM analysis value was slightly smaller than the calculated value using the large deflection formula, but this is because the large deflection formula is an approximate calculation and not an exact solution.

[0075] On the other hand, when comparing "large flat plate deflection" and "bending panel FEM," the displacement is significantly larger with "bending panel FEM," and there is a risk that the simplified calculation formula for "large flat plate deflection" will underestimate the actual displacement that occurs.

[0076] Figure 15 is an explanatory diagram showing the analysis values ​​obtained by FEM analysis as a relationship between von Mises stress and pressure. Here, the "flat plate FEM analysis value" indicates the von Mises stress on the central lower surface of the flat plate, and the "bent panel FEM analysis value" indicates the von Mises stress on the upper surface of the end (corner) of the bent panel.

[0077] As can be seen from this figure, the von Mises stress is much greater at the end of the bent panel than at the center of the plate. In other words, it can be concluded that the bottleneck of the exterior panel system is the out-of-plane strength of the end fastenings.

[0078] Therefore, we organized the magnifications of the analysis results of the "bent panel FEM" and "flat plate FEM" and by multiplying the displacement (center) and stress (center) obtained from the large deflection formula by a scalar, we derived a design formula that can safely evaluate the displacement (center) and stress (end) of the bent panel.

[0079] In short, the design formula that can evaluate the central displacement where large displacement of the bending panel occurs and the end stress where large stress occurs from the displacement (center) and stress (center underside) calculated from the large deflection formula is defined as follows:

[0080] <Central displacement δ' (mm)> δ'=δ×α1×α2 Here, α1 = 0.411ln(P) + 2.351, α2 = -0.012ln(P) + 0.975. However, in the case of no reinforcement, α2 = 1.0. Furthermore, P is the applied pressure (kPa).

[0081] <Edge stress σ' (N / mm 2 )> σ'=β1×δ' β2 Here, β1=0.106 and β2=2.025.

[0082] <End surface reaction force R' (N)> R'=10 3 ×P×p×a / 2×γ1×γ2 Here, p is the pitch of the fastening screws (m), a is the width of the short side of the bent panel (m), γ1 = 0.201ln(P) + 2.078, γ2 = 0.05ln(P) + 0.441. However, in the case of no reinforcement, γ2 = 1.0.

[0083] The α1 and α2 in the above equation are coefficients to be multiplied by the displacement δ (mm) calculated using the large deflection formula, and are calculated from the applied pressure P (kPa). α1 is called the displacement magnification factor for the flat panel and the curved panel, and α2 is called the reinforcement reduction coefficient due to additional reinforcement.

[0084] On the other hand, the edge stress σ' is expressed as a function of displacement, just like the large deflection formula, and once the central displacement δ' of the bent panel is determined, the maximum stress intensity (Mises stress) at the edge (corner) can be determined using β1 and β2. In other words, β1 and β2 are coefficients for determining the panel edge stress from the central displacement of the bent panel.

[0085] The end surface reaction force R' of the end fastening can be calculated from the reaction force calculated based on the assumption of uniform load and the coefficients γ1 and γ2 determined from the applied pressure P (kPa). Here, γ1 is called the reaction force multiplier for the flat panel and curved panel, and γ2 is called the reinforcement reduction coefficient due to additional reinforcement.

[0086] Figure 16(a) shows the values ​​of the displacement magnification α1 and reinforcement reduction coefficient α2 versus the applied pressure P (kPa), and Figure 16(b) shows the relationship between the central displacement δ' and the end stress σ' calculated using the displacement magnification α1 and reinforcement reduction coefficient α2. Finally, Figure 17 shows the values ​​of the reaction force magnification γ1 and reinforcement reduction coefficient γ2 versus the applied pressure P (kPa).

[0087] These coefficients (α1, α2, β1, β2, γ1, γ2) were obtained from the results of FEM analysis of the flat plate and bent panel. Note that γ1 and γ2 were calculated based on the assumption of uniform load. As mentioned above, the displacement and stress values ​​of the flat plate calculated using the large deflection formula are larger than the FEM analysis values, so multiplying the calculation results of the large deflection formula by the coefficients mentioned above is believed to enable a generally safe evaluation.

[0088] As shown in Figure 18, the values ​​calculated using the above-mentioned design formula for the bent panel are almost the same as the experimental values ​​for the bent panel. To summarize the above results, the experimental value is the largest in terms of displacement, followed by the FEM analysis value for the bent panel, the calculated value using the large deflection formula, and the FEM analysis value for the flat plate.

[0089] Next, with regard to stress, the experimental values ​​and the FEM analysis values ​​for the bent panel are almost the same, with the values ​​decreasing in the order of the calculated values ​​for the large deflection formula and the FEM analysis values ​​for the flat plate. As shown in Figure 19, the values ​​calculated using the above-mentioned bent panel design formula are larger than the experimental values ​​for the bent panel and are on the safe side.

[0090] Regarding the reaction force, the FEM analysis value for the bent panel is larger than that for the flat plate, and in the case of uniform load, it is smaller than that for the flat plate. In other words, the value calculated using the above-mentioned bent panel design formula is larger than the uniform load value and is on the safe side.

[0091] Next, the processing flow of the panel design method of the first embodiment will be described with reference to FIG. First, in step S1, we start examining the wind pressure resistance of the metal exterior panel 2. In other words, we start examining how to construct an exterior wall 1 by arranging multiple panels 2 vertically and horizontally, as shown in Figure 1.

[0092] To carry out the design, design conditions are set, such as the construction site for the exterior wall 1 (step S21), the installation position (step S22) of the exterior panel (panel 2), such as the installation height (number of floors of the building), and the design return period (step S23) for determining the scale of strong winds. Then, in step S3, the design wind load (acting load) of the exterior panel is calculated based on the design conditions.

[0093] Next, in step S4, the specifications of the exterior panel are set, such as the material, shape, cross section such as thickness of the panel 2, the support interval for joining to the support material, and the panel type such as a bent panel or a cut panel.

[0094] In step S5, it is determined whether or not reinforcing screw joints 4 are to be provided as end reinforcement at the corners 21 of the panel 2. If two reinforcing screw joints 4 are to be provided at each corner 21, the process proceeds to step S61. On the other hand, if end reinforcement is not to be performed, the process proceeds to step S62, where the reinforcement reduction coefficient α2 is set to 1.0 and the reinforcement reduction coefficient γ2 is set to 1.0.

[0095] Then, in step S7, the out-of-plane reaction force R is calculated based on the uniform load assumption. Next, in step S8, the panel type set in the specification setting in step S4 is confirmed, and if it is a cut panel, the process proceeds to step S81. In the case of a cut panel, the above-mentioned design formula does not apply, so the displacement δ' and stress σ' are examined using FEM analysis or the like.

[0096] On the other hand, if the panel type is a curved panel, the central displacement δ of the plate is calculated using the large deflection formula in step S9. Next, various coefficients (α1, α2, γ1, γ2) and coefficients (β1, β2) corresponding to the design wind load calculated in step S3 are set using Figures 16 and 17 (step S10).

[0097] Then, the central displacement δ' of the bent panel is calculated using the above-mentioned design formula (step S11), and the end stress σ' of the end (corner portion 21) is calculated based on the central displacement δ' using the above-mentioned design formula (step S12). In addition, in step S13, the out-of-plane force of the outermost end support portion of the end (corner portion 21) of panel 2 is calculated as the end out-of-plane force R' using the above-mentioned design formula.

[0098] The end stress σ' and end surface reaction force R' calculated in this way are compared with the allowable strength of the exterior panel, etc. in step S14, and if they fall within the allowable strength range, construction can be carried out (step S15).

[0099] Next, the operation of the panel design method of the first embodiment will be described. The panel design method of Example 1, which is carried out in this manner, calculates the out-of-plane reaction forces acting on the edges 22A, 22B of the panel 2 and checks the allowable strength, thereby making it possible to create a panel 2 with excellent wind pressure resistance, in which the reinforcing screw joints 4 using drill screws 43 and the normal screw joints 3 are not damaged.

[0100] The other configurations and effects are substantially the same as those of the above-described embodiment or other examples, and therefore the description thereof will be omitted. [Example]

[0101] Example 2, which is different from the embodiment described above, will be described below with reference to Figures 20 to 22. Note that the same terms or the same reference numerals will be used to describe the same or equivalent parts as those described in the embodiment or Example 1.

[0102] In the above embodiment, a case has been described in which a pair of reinforcing screw joints 4, 4 are added to both sides of the normal screw joint 3 at the corner 21. In this Example 2, a case in which a reinforcing plate 5 is placed at the corner 21 of the panel 2, as shown in Fig. 20, will be described.

[0103] Here, Fig. 21 is an explanatory diagram showing the process of installing the panel 2 of Example 2. Also, Fig. 22 is a front view illustrating the joining structure of the panel of Example 2, enlarging the periphery of a corner portion 21.

[0104] The reinforcing plate 5 is a strip-shaped plate material that is placed between the panel 2 and an adjacent member. For example, as shown in Fig. 22, the reinforcing plate 5 is placed between adjacent panels 2, 2 on the left and right. Note that the adjacent member is not limited to the panel 2, and may be a building frame, a pillar, or the like.

[0105] The reinforcing plate 5 is made of a metal plate such as stainless steel and is formed to a length that allows it to bridge two members. For example, it can be made of a stainless steel (SUS) plate approximately 1.5 mm thick, 150 mm long, and 15 mm wide. Furthermore, as shown in FIG. 20, the reinforcing plate 5 has round holes 511, 511 drilled at both end portions 51, 51.

[0106] The reinforcing screw joint 4A of Example 2 is provided at the end 51 of this reinforcing plate 5. This reinforcing screw joint 4A is provided adjacent to the normal screw joint 3 (position of the elongated hole 31). In the reinforcing screw joint 4A, as shown in FIG. 21 , the round hole 511 of the end 51 of the reinforcing plate 5 is aligned with the position of the elongated hole 41 of the flat portion 221B, and a drill screw 43 is screwed in.

[0107] The tip of the drill screw 43 screwed into the round hole 511 and the long hole 41 passes through the round hole 42 in the flat portion 221A of the lower panel 2 and is screwed into the furring strip 12. In other words, the overlapping reinforcing plate 5, the flat portion 221B of the edge portion 22B, and the flat portion 221A of the edge portion 22A are joined together to the furring strip 12 by the drill screw 43.

[0108] The reinforcing screw joints 4A provided in this manner are provided at the outermost ends of the corners 21 of the panel 2, as shown in Figure 22. For example, the distance between the reinforcing screw joint 4A and the short side edge of the panel 2 is about 50 mm, and the distance between the reinforcing screw joint 4A and the adjacent normal screw joint 3 is about 100 mm. In addition, the distance between the reinforcing screw joints 4A, 4A provided at the end portions 51, 51 on both sides of the reinforcing plate 5 is about 100 mm.

[0109] The panel joint structure of Example 2 configured in this manner has the reinforcing screw joint 4A provided at the end 51 of the strip-shaped reinforcing plate 5 that is bridged between adjacent members (panels 2), thereby increasing the bearing area and enabling the stress caused by wind pressure to be dispersed.

[0110] The other configurations and effects are substantially the same as those of the above-described embodiment or other examples, and therefore the description thereof will be omitted.

[0111] The embodiments of the present invention have been described above in detail with reference to the drawings, but the specific configuration is not limited to these embodiments or examples, and design changes that do not deviate from the gist of the present invention are included in the present invention.

[0112] For example, in the above embodiment and Examples 1 and 2, a panel 2 that forms a vertical exterior wall surface has been described as an example, but this is not limited to this, and the present invention can also be applied to panels that form roof surfaces, eaves ceiling surfaces, sloped wall surfaces, etc.

[0113] In addition, in the above-mentioned Example 2, an example was described in which the reinforcing plate 5 was applied to a bent panel, but this is not limited to this, and even when a cut panel is used, the reinforcing plate 5 can be used to provide a reinforcing screw joint 4A. [Explanation of symbols]

[0114] 12:Furring strip (supporting material) 2,2A: Panel 21: Corner 22A, 22B: Edge 241: Edge 3:Normal screw joint 33: Drill screw (screw) 4: Reinforced screw joint 41: Long hole 42: Round hole 43: Drill screw (screw) 4A: Reinforced screw joint 5: Reinforcement plate 51: Edge

Claims

[Claim 1] A panel design method for joining a panel having an edge portion with a substantially L-shaped cross section formed around a substantially rectangular plane to a support material with screws, comprising: establishing wind loads; setting specifications for the panel; determining whether or not to provide a reinforcing screw joint at the corner of the panel; calculating an out-of-plane reaction force acting on the edge; A panel design method comprising a step of comparing the stress generated at the edge of the corner portion with an allowable strength.

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