Panel material

Abstract

To provide a panel material configured to improve thermal insulation performance by employing a lip channel steel, as a low-heat-transfer steel, having a perforated web and a thickness of 2.3 mm or smaller, thereby suppressing reduction in bearing force due to buckling specific to the low-heat-transfer steel.SOLUTION: A panel material 10 includes: a lip channel steel 12 having a thickness of 2.3 mm or smaller, configured to include a web 12A, a pair of flanges 12B, and a pair of lips 12C, the web 12A having perforations (slits 16) for improving thermal insulation performance of the channel steel; and a surface material 14 jointed to a plate surface of at least one of the flanges 12B. The length of the lip 12C connected to the flange 12B with the surface material 14 jointed thereto is equal to or longer than an effective length [mm] defined by 240 / √F)×t, wherein F is an F value [N / mm2] of the lip channel steel 12 and t is a plate thickness [mm] of the lip channel steel 12.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to paneling. [Background technology]

[0002] Low heat-conductive steel is known as a steel material used for paneling of exterior walls, flooring, etc. Low heat-conductive steel can be produced by drilling one or more holes in the web of a channel steel stud, which acts as a thermal bridge in an exterior wall.

[0003] The holes extend the length of the heat transfer path through the web located between the pair of flanges and reduce the cross-sectional area of ​​the transfer path. As a result, the thermal conductivity of the web is reduced, thereby improving the thermal insulation performance of low-heat-transfer steel sections that use perforated webs. For example, when comparing channels of the same shape and size, the thermal insulation performance of low-heat-transfer steel sections that use perforated webs is improved compared to channels with non-perforated webs.

[0004] In this specification, for the sake of convenience, lip channel steel having a perforated web will be referred to as "low heat transfer steel", and lip channel steel having a non-perforated web will be referred to as "normal steel".

[0005] As a technology relating to low heat-conductive steel sections, for example, Patent Document 1 discloses lip channel steel as a frame material used for panel materials such as wall materials for buildings. In the lip channel steel of Patent Document 1, the thermal conductivity of the web is reduced by making the cross-sectional area of ​​the web at the center in the web height direction smaller than the cross-sectional area at positions near the flanges on both ends when the cross-sectional area of ​​the web is cut along a plane perpendicular to the material axis. Patent Document 1 also discloses a technique of drilling holes in the plate surface of the web as an example of a method for reducing the cross-sectional area.

[0006] Patent document 2 also discloses a low heat-transfer steel section in which the web of a channel steel, which is a metal plate for construction, is cut and raised at the sides, thereby forming cuts in the web to reduce thermal conductivity. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-87505 [Patent Document 2] Japanese Patent Application Laid-Open No. 2002-146936 Summary of the Invention [Problem to be solved by the invention]

[0008] In low-heat-conductivity channel steel, the holes in the web act as cross-sectional defects in the web, improving the thermal insulation performance of the panel material. However, in terms of structural performance, the bending strength of a channel steel with a perforated web is lower than that of a channel steel with a non-perforated web. In particular, it has been found that low-heat-conductivity channel steel with a thickness of 2.3 mm or less is prone to distortional buckling, i.e., localized web deformation, when bending loads due to wind pressure or other factors are applied to the flange through the face material joined to the flange.

[0009] In this regard, Patent Document 1 does not disclose any technology for suppressing buckling that is specific to low heat transfer steel and improving strength when a bending load is applied to the channel steel. Therefore, the technology in Patent Document 1 alone cannot solve the problem of reduced strength caused by buckling that is specific to low heat transfer steel in lip channel steel with a plate thickness of 2.3 mm or less.

[0010] Furthermore, although Patent Document 2 is a technology related to low heat transfer steel, the inventors have found that even when a side wall is provided, it may not be possible to fully solve the problem of strength reduction caused by buckling, which is unique to lip channel steel made of low heat transfer steel. Therefore, a new technology is needed that can suppress the reduction in strength caused by buckling in lip channel steel made of low heat transfer steel.

[0011] In view of the above problems, the present disclosure aims to provide a panel material that has improved insulation performance by using lip channel steel with a perforated web and a plate thickness of 2.3 mm or less as low heat transfer steel, and that can suppress the decrease in strength due to buckling that is unique to low heat transfer steel. [Means for solving the problem]

[0012] A panel material according to one embodiment of the present disclosure has a web, a pair of flanges, and a pair of lips, and the web has holes for improving the thermal insulation performance of the channel steel, the lip channel steel has a plate thickness of 2.3 mm or less, and a face material joined to the plate surface of at least one of the flanges, and the length of the lip that is continuous with the flange to which the face material is joined is determined by the F value [N / mm 2 ] is F and the thickness of the lip channel steel [mm] is t, the effective lip length [mm] is equal to or greater than the formula (240 / √F) × t.

[0013] The inventors investigated the length of the lip that connects to the flange to which the face plate is joined and that is subjected to compression when an external bending load is applied to the flange to which the face plate is joined, in low-heat-conductivity steel sections that use lip channel steel with a perforated web and a plate thickness of 2.3 mm or less. As a result of the investigation, it was found that when the lip length is equal to or greater than the effective lip length [mm], the bending stress increases compared to lip channel steel of the same specifications, except that the lip length is the required lip length.

[0014] Here, the bending stress refers to the distortional buckling strength of the lip channel steel. The formula for defining the effective lip length is the same as the formula for calculating the effective lip width listed in Table 3.4.4 on page 56 of the "Guidelines for the Design of Lightweight Steel Buildings, Second Edition" (Japan Iron and Steel Federation). Furthermore, as a result of the inventors' research, it was found that in the case of non-perforated ordinary steel sections, even if the lip length is extended beyond the effective lip length, the bending stress of the ordinary steel section does not increase compared to the bending stress when the lip length is the required lip length.

[0015] Therefore, in a panel material according to one embodiment of the present disclosure, it is possible to suppress the reduction in strength due to buckling, which is unique to low heat transfer steel, in lip channel steel made of low heat transfer steel with improved thermal insulation performance. [Effects of the Invention]

[0016] Therefore, according to the present disclosure, a panel material can be provided that has improved insulation performance by using lip channel steel having a perforated web and a plate thickness of 2.3 mm or less as low heat transfer steel, and that can suppress the decrease in strength due to buckling that is unique to low heat transfer steel. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 1 is a perspective view illustrating a panel material according to an embodiment of the present disclosure. [Figure 2] FIG. 2(A) is a front view of the outer surface of the web of the lip channel steel of the frame member according to this embodiment, and FIG. 2(B) is a cross-sectional view taken along line 2B-2B in FIG. 2(A). [Figure 3] FIG. 10 is a front view of the outer surface of the web when the slit joints are arranged in series. [Figure 4] 10 is a graph illustrating the relationship between the slit ratio and the rate of decrease in the coefficient of overall heat transmission, with different slit arrangement patterns. [Figure 5] FIG. 2 is a diagram illustrating an outline of an analytical model of a lip channel steel of a low heat-transfer steel according to Example 1. [Figure 6] Figure 6(A) is a diagram explaining the cross-sectional deformation at the center in the material axis direction of the analysis model according to Example 1, Figure 6(B) is a diagram explaining the cross-sectional deformation at the center in the material axis direction of the analysis model according to the first comparative example, and Figure 6(C) is a diagram explaining the cross-sectional deformation at the center in the material axis direction of the analysis model according to the second comparative example. [Figure 7] FIG. 10 is a diagram illustrating the relationship between displacement and load at the center of each of the analysis models of Example 1, the first comparative example, and the second comparative example. [Figure 8] 10 is a graph illustrating the relationship between the ratio of effective lip length to short-term bending strength in the analysis model of Example 2. [Figure 9] 10 is a graph illustrating the relationship between the ratio of effective lip length to maximum bending strength in the analysis model of Example 2. [Figure 10] 10 is a graph illustrating the relationship between the ratio of effective lip length to short-term bending strength in the analysis model of the second comparative example. DETAILED DESCRIPTION OF THE INVENTION

[0018] An embodiment of the present disclosure will be described below. In the following description of the drawings, identical or similar parts are designated by the same or similar reference numerals. However, the relationship between thickness and planar dimensions in the drawings, the thickness ratios of each device and each component, etc., differ from the actual ones. Therefore, specific thicknesses and dimensions should be determined with reference to the following description. Furthermore, parts with different dimensional relationships and ratios are included among the drawings.

[0019] <Panel material> First, the panel material according to this embodiment will be described with reference to Figures 1 to 4. As shown in Figure 1, the panel material 10 according to this embodiment has a lip channel steel 12 as a frame material, a face material 14 joined to the upper flange 12B, and a face material 22 joined to the lower flange 12B. A filler member 24 is disposed between the upper face material 14 and the lower face material 22. Note that in Figure 1, portions of the face materials 14, 22 are exemplarily cut away to make the lip channel steel 12 easier to see.

[0020] (Lip channel steel) The lip channel steel 12 has a web 12A, a pair of flanges 12B, and a pair of lips 12C. The lip channel steel 12 can be made from a single steel plate by, for example, bending. In the present disclosure, the steel plate has a thickness of 2.3 mm or less.

[0021] In this embodiment, the lip channel steel 12 may be formed using a high-strength steel plate of 500 MPa or more. In this specification, "high-strength steel plate" refers to a steel plate (steel material) having an F-value, as a strength, of 500 MPa or more and 1000 MPa or less. In addition, in contrast to "high-strength steel plate," a steel plate having an F-value of less than 500 MPa may be referred to as "normal steel plate." In this embodiment, for example, a steel material may be used in which the F-value of 400 material as a normal steel plate is 280 MPa and the F-value of a high-strength steel plate is 500 MPa, or a steel material in which the F-value of a high-strength steel plate is 500 MPa may be used.

[0022] If the F-value, which is the strength of the steel plate, exceeds 1000 MPa, the strength becomes too high, and the workability decreases when the steel plate is formed into the lip channel steel 12, for example, by roll forming. For this reason, in this embodiment, the strength of the high-strength steel plate is specified to be 1000 MPa or less. However, in the present disclosure, the strength of the high-strength steel plate is not limited to this and can be changed as appropriate.

[0023] (lip) In this embodiment, the lip lengths L of the pair of lips 12C are equal to each other, but in the present disclosure, the lip lengths of the pair of lips may be different from each other. The "lip length L" is the maximum length of the lip 12C measured in a cross section perpendicular to the material axis direction D of the lip channel steel 12, as shown in Figure 2(B).

[0024] In this embodiment, it is assumed that the flange 12B joined to the face material 14 is subjected to an external compressive force along the out-of-plane direction of the face material 14, that is, bending.

[0025] (surface material) As shown in FIG. 1 , the face material 14 is a rectangular building component when viewed from the front. The face material 14 is, for example, a plate-shaped base material or gypsum board. In this embodiment, the face material 14 is an exterior wall material, but the present disclosure is not limited to this and may be other panel materials such as flooring. Furthermore, in this embodiment, the face material is joined to both of the pair of flanges 12B, but the present disclosure is not limited to this and may be joined only to the upper flange 12B in FIG. 1 or only to the lower flange 12B.

[0026] 1 may be members having the same function or different functions. The face material 14 may be joined to the plate surface of at least one of the flanges 12B by the joining member 20.

[0027] (Filling material) In this embodiment, the filler member 24 is a heat insulating material such as glass wool or cellulose fiber, but the present disclosure is not limited to this and can be changed as appropriate. Also, the filler member is not essential in the present disclosure.

[0028] (jointing material) The connecting members 20 are, for example, screws or the like, and are architectural components that connect the flange 12B and the face material 14. In Fig. 1, when the wall surface of the face material 14 is viewed from the front, multiple connecting members 20 are arranged linearly along the material axis direction of the lip channel steel 12. Note that in the present disclosure, the number of rows of connecting members 20 can be set as desired, such as one row, two rows, or more.

[0029] (web) As shown in FIG. 2(A), in this embodiment, the web 12A is provided with a row of slits 16 arranged linearly at approximately equal intervals G along the material axis direction D. The slits 16 are holes that improve the thermal insulation performance of the channel steel. Three rows of slits 16 are formed at approximately equal intervals G along the vertical direction in FIG. 2(A). Note that the "material axis direction D" is the direction in which the web 12A and flange 12B of the lip channel steel 12 extend along the left-right direction in FIG. 2(A). In other words, the material axis direction D is the same as the longitudinal direction.

[0030] As shown in FIG. 2B, the "web height HW" is the vertical linear distance from the end of one flange 12B to the end of the other flange 12B. The "flange width WF" is the horizontal linear distance from the end of the web 12A to the end of the lip 12C in FIG. 2B. The "lip length L" is the vertical linear distance from the end of one flange 12B of the lip 12C to the end of the other lip 12C in FIG. 2B. For example, the lip length L of the upper lip 12C in FIG. 2B is the linear distance between the upper surface of the upper end, which is located at the same height as the upper surface of the upper flange 12B, and the lower surface of the lower end of the upper lip 12C.

[0031] In addition, in the present disclosure, the number of rows including the slits 16 is not limited to three rows, and may be one row, or any number of rows of two or more rows, such as five rows. From the viewpoint of improving the heat insulating performance, it is desirable to form three or more rows of the slits 16.

[0032] In addition, in the present disclosure, the intervals G in the material axis direction D between adjacent slits 16 in one row are not limited to being equal, but may be different. The intervals G between adjacent rows in the web height direction are also not limited to being equal, but may be different. To avoid stress concentration, the shape of the longitudinal end of the slit 16 is preferably arc-shaped, as shown in FIG. 1.

[0033] (joint part) In this embodiment, a connecting portion 18 that connects the plate members of the web 12A in the height direction is formed in the portion of the web 12A where a gap G in the material axis direction D is formed between adjacent linear slits 16 having a constant length M in one row.

[0034] In the present disclosure, the shape and dimensions of the holes formed in the web 12A are not limited to slits and can be changed as appropriate. Also, in the present disclosure, the number of slits included in one row is arbitrary as long as it is two or more. In the present disclosure, it is sufficient that at least one connecting portion is formed, as long as the necessary strength as a member is ensured.

[0035] In this embodiment, in a plan view of the plate surface of the web 12A seen from the front, the arrangement pattern of the multiple joints 18 included in the three rows of slits 16 is staggered. Specifically, the slits 16 included in each of the three rows are arranged so as not to overlap on a straight line along the web height direction.

[0036] In other words, when the slits 16 are arranged in a staggered pattern, the path along which heat moves from one flange 12B side to the other flange 12B side when viewed from the front of the web 12A is prevented from being the shortest distance equal to the web height HW. Note that when "the slits 16 are arranged in a staggered pattern," there may arise a case where "the joints 18 are arranged in a staggered pattern."

[0037] In addition, in the present disclosure, "a state in which the slits are staggered" is not limited to a case in which the slits are staggered in all rows of slits 16 formed in the web 12A. In the present disclosure, a case in which the staggered slits are partially formed in at least one of the material axis direction D and the web height direction can also be included in the "staggered slits" state.

[0038] In the present disclosure, the arrangement pattern of the plurality of slits is not limited to a staggered arrangement. As shown in Fig. 3, the slits 16 may be arranged in series so as to overlap each other on a straight line along the web height direction (the vertical direction in Fig. 3).

[0039] (Slit ratio) In the present disclosure, the slit ratio is defined as the sum of the spacing G between adjacent slits 16 in the material axis direction D of the web 12A divided by the sum of the lengths M of the slits 16. Note that in the present disclosure, the "slit spacing" includes both the spacing formed between two slits and the spacing formed between one slit and the end of the web in the material axis direction.

[0040] (Analysis test of heat transfer coefficient decrease rate) 4 illustrates the heat transmission coefficient reduction rate calculated from the results of analyzing the heat transmission coefficient of panel materials using low heat transfer steel for lip channel steel 12 with different slit ratios using finite element numerical analysis (FEM). Specifically, the heat transmission coefficient reduction rate of an analytical model of lip channel steel 12 in which the joints 18 are arranged in a series pattern, and the heat transmission coefficient reduction rate of an analytical model of lip channel steel 12 in which the joints 18 are arranged in a staggered pattern are illustrated.

[0041] The lip channel steel 12 used in the two analysis models in Fig. 4 have the same shape and dimensions, except for the arrangement pattern of the joints 18. In Fig. 4, data points for the staggered arrangement pattern of the joints 18 are illustrated by five black circles, and data points for the serial arrangement pattern of the joints 18 are illustrated by seven white circles.

[0042] In analysis test 1, five exterior wall components with different slit ratios were set as analysis models. Each component was made of low-heat-conductivity steel lip channel steel 12 (a stud material), with one structural face panel 14, insulation material as filler member 24, and gypsum board as face panel 22 attached to the other. Specifically, in the shape of lip channel steel 12 having three rows of slits 16 as shown in Figure 2(A), the length M and spacing G of the slits 16 were changed to vary the slit ratio. The five joints 18 were all arranged in a staggered pattern. An analysis was then performed using the set analysis models to analyze the respective thermal transmittances.

[0043] In addition, a lip channel steel 12 having the same shape and dimensions as the analytical model and a non-perforated web 12A was set as a reference model for comparison. Then, an analysis was performed on the set reference model to analyze the thermal transmittance of the reference model.

[0044] The "decrease in thermal conductivity" on the vertical axis of the graph in Figure 4 is the value obtained by dividing the thermal conductivity of the analytical model with slits 16 by the thermal conductivity of the reference model. A larger decrease in thermal conductivity, i.e., the closer the decrease in thermal conductivity is to 1, the smaller the degree of decrease, meaning that the thermal insulation performance is not improved. On the other hand, a smaller decrease in thermal conductivity means a larger degree of decrease, meaning that the thermal insulation performance is improved.

[0045] As can be seen from the data points marked with black circles in Figure 4, when the joints 18 are arranged in a staggered pattern, the reduction in heat transmission coefficient is 85% or less when the slit ratio is 20% or less. In other words, it is possible to improve the heat insulation performance by 15% or more. On the other hand, when the slit ratio is more than 20%, the improvement in heat insulation performance is less than 15%.

[0046] Furthermore, from the viewpoint of thermal insulation performance, a smaller slit ratio is preferable, but if the slit ratio is too small, the strength of the lip channel steel 12 as a structural member, i.e., the structural performance, becomes unstable. For this reason, in this embodiment, the slit ratio is set in the range of 5% or more and 20% or less, which is a range that can achieve a good balance between structural performance and thermal insulation performance. Note that in the present disclosure, the range of the slit ratio is not limited to this, and can be changed as appropriate depending on the desired specifications of the lip channel steel 12.

[0047] Furthermore, as can be seen from the data points marked with white circles in Figure 4, even when the joints 18 are arranged in series, if the slit ratio is set within the range of 5% or more and 20% or less, the thermal insulation performance can be effectively improved. However, even with the same slit ratio, the analysis model of the lip channel steel 12 with the joints 18 arranged in a staggered configuration has a smaller rate of decrease in the thermal transmittance than the analysis model of the lip channel steel 12 with the joints 18 arranged in series, and therefore the thermal insulation performance is further improved.

[0048] (Lip length) Next, the lip length L of the lip 12C according to this embodiment will be specifically described. First, in a lip channel steel made of ordinary steel that is not low heat transfer steel, it is usually sufficient to ensure the required lip length as the lip length L. However, in this embodiment, the lip length L continuing from the flange 12B to which the face material 14 is joined is set to be longer than the required lip length, i.e., equal to or greater than the effective lip length.

[0049] (required lip length) The required lip length is defined by the following formula, based on the description on page 83 of "Guidelines for the Design of Lightweight Steel Buildings, Second Edition" (Japan Iron and Steel Federation, General Incorporated Association).

number

[0050] (effective lip length) The effective lip length is the same as the "effective lip width" listed in Table 3.4.4 on page 56 of the "Guidelines for the Design of Lightweight Steel Buildings, Second Edition" (Japan Iron and Steel Federation). Specifically, it is defined by the following formula: Effective lip length [mm] = (240 / √F) × t

[0051] The plate thickness t is set according to the design plate thickness described in "(1) Steel Plate Thickness" regarding the structural calculation of the effective section on page 52 of the "Guide to the Design of Lightweight Steel Buildings, 2nd Edition." In other words, as a general rule, a plate thickness of 90% of the nominal plate thickness is used.

[0052] Additionally, the arrangement of the effective cross section of the bending member is set according to the arrangement shown in Figure 3.4.5 on page 55 of the "Guidelines for the Design of Lightweight Steel Buildings, Second Edition," and in "(6) Effective Section Modulus Ze of Bending Members" on page 56. In other words, when calculating the allowable stress of a bending member, the arrangement of the effective cross section of the bending member differs depending on whether the flange 12B on the compression side of the lip channel steel 12 subjected to strong axis bending is evaluated with an ineffective section equivalent to that on the compression side, or whether the entire plate element is considered effective. [Example]

[0053] Next, examples 1 and 2 carried out on the lip channel steel 12 of the panel material 10 according to this embodiment, in which the lip length L is set to be equal to or greater than the effective lip length, will be described with reference to FIGS. 5 to 9.

[0054] Example 1: Relationship between displacement and load In Example 1, an analysis was performed using FEM to measure the resistance strength of the lip channel steel 12 against a compressive force acting along the out-of-plane direction. Note that, since bending is the dominant load acting on low heat-transfer steel, it is assumed here that the force acting on the lip channel steel 12 of the low heat-transfer steel does not include a compressive force along the material axis direction D, i.e., an axial force.

[0055] Specifically, an analytical model was set as shown in Fig. 5. The length in the material axis direction D of the analytical model was 3900 mm, the web height was 100 mm, the flange width WF was 50 mm, and the plate thickness was 1.6 mm. In Example 1, the lip length L was set as four parameters: 10 mm, 20 mm, 30 mm, and 40 mm.

[0056] In the analysis, it was assumed that face plate 14 was joined to the upper flange side of the lip channel steel of the analytical model in Figure 5. Furthermore, the lip channel steel was divided into four equal parts in the material axis direction D, and forced vertical displacement from top to bottom in Figure 7 was set at two points on both ends, and a four-point bending test was performed in which force was applied to the central part sandwiched between the two central points. Furthermore, displacement of the central part in the flange width direction was restrained to prevent lateral buckling. Furthermore, as a boundary condition, one end of the lip channel steel in the material axis direction D was set to be pin-supported, and the other end was set to be roller-supported.

[0057] A load was then applied to each of the set analysis models, and the deformation state at the center in the material axis direction D was analyzed. In addition, the bending strength of each model was measured based on the analysis results. Below, the analysis results of the lip channel steel 12 in which the lip length L is equal to or greater than the effective lip length will be described as Example 1. In addition, the analysis results of the lip channel steel 12 in which the lip length L is less than the effective lip length will be described as Comparative Example 1.

[0058] In addition, as a second comparative example, a normal section steel that is a lip channel steel having a non-perforated web 12A was subjected to the same analysis and measurements as in Example 1 and Comparative Example 1. The specifications of the lip channel steel according to the second comparative example are the same as those of the lip channel steel 12 according to Example 1, except that it is non-perforated and the lip length L is 12 mm.

[0059] 6(A) to 6(C), the cross-sectional shape of the center of the material in the material axis direction D before the compressive force is applied from above is shown by a dashed line, and the state of the cross-sectional shape that is deflected and deformed downward at the maximum yield strength after the compressive force is applied from above is shown by a solid line. FIG. 6(A) illustrates the cross-sectional shape of the analytical model according to Example 1, which has a lip length L equal to or greater than the effective lip length. FIG. 6(B) illustrates the cross-sectional shape of the analytical model according to Comparative Example 1, which has a lip length L less than the effective lip length. FIG. 6(C) illustrates the cross-sectional shape of the analytical model according to Comparative Example 2 of ordinary shaped steel.

[0060] As shown in Figures 6(A) and 6(B), the buckling deformation in Example 1 was suppressed more than in Comparative Example 1. In the analytical model of Comparative Example 2 illustrated in Figure 6(C), although the central portion in the material axis direction D was bent downward, the overall cross-sectional shape was not significantly deformed, and as a result, buckling deformation like that in Example 1 and Comparative Example 1 hardly occurred.

[0061] FIG. 7 also illustrates trajectories showing the relationship between the vertical displacement δy at the center in the material axis direction D and the load P for Example 1, the first comparative example, and the second comparative example. The low heat-transfer steel with a lip length L of 10 mm illustrated by a dotted line in FIG. 7 is the lip channel steel of the first comparative example. The low heat-transfer steel with a lip length L of 20 mm illustrated by a dashed line in FIG. 7, the low heat-transfer steel with a lip length L of 30 mm illustrated by a thin solid line, and the low heat-transfer steel with a lip length L of 40 mm illustrated by a thick solid line are the lip channel steel 12 of Example 1. The lip channel steel illustrated by a dashed line in FIG. 7 is the lip channel steel of a normal section steel of the second comparative example.

[0062] As shown in Fig. 7, it can be seen that the low heat-transfer steel having a lip length L of 20 mm according to Example 1 was able to withstand a maximum load of approximately 85% of the maximum load of ordinary steel. Furthermore, the maximum load of the low heat-transfer steel having a lip length L of 30 mm according to Example 1 and the maximum load of the low heat-transfer steel having a lip length L of 40 mm according to Example 1 were both greater than the maximum load of ordinary steel. It was found that the lip channel steel 12 according to Example 1 was able to suppress a decrease in yield strength due to cross-sectional loss, even though it was a low heat-transfer steel having a perforated web 12A.

[0063] Example 2: Relationship between short-term bending strength increase rate and lip length Next, in Example 2, the short-term bending strength of the lip channel steel 12 when the lip length L was changed was analyzed using FSM (Finite Strip Method). The specifications of the analytical model were set to be the same as those in Example 1 except for the lip length L. Also, as shown in Fig. 8, in Example 2, the plate thickness of the analytical model was set to three different types: 1.2 mm, 1.6 mm, and 2.3 mm.

[0064] The vertical axis of the graph in Figure 8 represents the rate of increase in short-term bending strength. To calculate the rate of increase in short-term bending strength, first, the allowable bending stress is calculated from the buckling strength calculated by FSM. The calculated allowable bending stress is then multiplied by the section modulus of the effective cross-sectional area to calculate the short-term bending strength. The short-term bending strength is then divided by the short-term bending strength calculated from an analytical model with an effective lip length. The ratio to the effective lip length, set on the horizontal axis of the graph in Figure 8, is the value obtained by dividing the lip length L by the effective lip length.

[0065] 8, in Example 2, it was found that the increase rate of short-term bending strength increases as the lip length L becomes longer than the effective lip length, regardless of whether the plate thickness t is 1.2 mm, 1.6 mm, or 2.3 mm. In other words, it is found that in the low heat transfer steel of the lip channel steel 12 according to this embodiment, when the plate thickness t is 1.2 mm or more and 2.3 mm or less, the effect of increasing the bending strength can be obtained.

[0066] Furthermore, as shown in Figure 9, a similar effect was also confirmed by analysis using FEM (finite element method). As shown in Figure 9, for all plate thicknesses t of 1.2 mm, 1.6 mm, and 2.3 mm, the increase in maximum bending strength increases as the lip length L becomes longer than the effective lip length. Therefore, it can be seen that the maximum bending strength can be increased when the plate thickness t of the lip channel steel 12 made of low heat transfer steel is 1.2 mm or more and 2.3 mm or less.

[0067] Meanwhile, a similar analysis was performed on the short-term bending strength using an analytical model of a regular section steel having a perforated web 12A, as shown in Fig. 10. The analytical model of the regular section steel in Example 2 illustrated in Fig. 10 has the same specifications as the second comparative example described in Example 1. In the case of the regular section steel in the second comparative example, it was found that, contrary to Example 2, the longer the lip length L is than the effective lip length, the smaller the short-term bending strength becomes.

[0068] Specifically, as shown in Figure 10, in ordinary steel sections, when the lip length L is shorter than the effective lip length, the longer the lip length L, the greater the short-term bending strength. However, when the lip length L reaches the effective lip length, the peak strength of the lip channel steel is reached, and local buckling occurs. Furthermore, when the lip length L exceeds the effective lip length, the short-term bending strength tends to decrease as the lip length L becomes longer than the effective lip length. In other words, in the case of ordinary steel sections, it is not necessary to extend the lip length L beyond the effective lip length.

[0069] (Action and effect) In the low heat transfer steel using the lip channel steel 12 according to this embodiment, the lip length L continuing from the flange 12B, to which the face material 14 is joined and which is subjected to compression, is equal to or greater than the effective lip length. Therefore, in this embodiment, the bending strength is higher than that of a lip channel steel made of low heat transfer steel with the same specifications, except that the lip length L is the required lip length. As a result, the panel material 10 according to this embodiment can suppress the decrease in strength due to buckling, which is unique to low heat transfer steel, in the lip channel steel 12 made of low heat transfer steel with improved thermal insulation performance.

[0070] In addition, in this embodiment, the lip lengths L of the pair of lips 12C are equal to each other, so the cross-sectional shape of the lip channel steel 12 is symmetrical compared to when the pair of lip lengths L are different from each other. Therefore, the panel material 10 using the lip channel steel 12 is well-balanced as a building component and has excellent design and construction properties.

[0071] In this embodiment, the slit ratio, which is defined by dividing the sum of the spacing G of the slits 16 in the material axis direction D of the web 12A by the sum of the lengths of the slits 16, is 5% or more and 20% or less. This makes it possible to realize a lip channel steel 12 that is a low heat transfer steel with ensured heat insulation performance.

[0072] Furthermore, when the slits 16 are arranged in a staggered pattern, the distance between the joints 18 that form the heat path is longer than when the slits 16 are arranged in series, improving the heat insulating performance of the panel material 10. This makes it possible to more effectively achieve both structural performance and heat insulating performance.

[0073] In this embodiment, the low heat-transfer steel of the lip channel steel 12 is formed using a high-strength steel plate having an F-value of 500 MPa or more. By using a high-strength steel plate for the low heat-transfer steel, it is possible to achieve a yield strength equal to or greater than that of a normal steel plate in the low heat-transfer steel, even if the plate thickness is thinner than that of a normal steel plate.

[0074] <Other embodiments> Although the present disclosure has been described by the above embodiments, this description does not limit the present disclosure, and it should be understood that various alternative embodiments, examples, and operating techniques will become apparent to those skilled in the art from the present disclosure.

[0075] For example, the present disclosure can be configured by partially combining the configurations shown in Figures 1 to 10. The present disclosure includes various embodiments not described above, and the technical scope of the present disclosure is defined only by the invention-specifying matters in the claims that are appropriate from the above description. [Explanation of symbols]

[0076] 10 Panel material 12 Lip channel steel 12A Web 12B flange 12C Lip 14 Surface material 16 Slit 18 Joint 20 Joint material 22 Surface material 24 Filler material D Material axis direction G interval HW Web height L Lip length M slit length WF flange width t Plate thickness δy displacement

Claims

1. a lip channel steel having a plate thickness of 2.3 mm or less, the lip channel steel having a web, a pair of flanges, and a pair of lips, the lip channel steel improving the heat insulating performance of the channel steel and having holes in the web that cause local deformation of the web in response to a bending load applied to the flanges; a face material joined to the plate surface of at least one of the flanges, The length of the lip that is continuous with the flange to which the face material is joined is determined by the F value [N / mm ２ ] is F and the thickness [mm] of the lip channel steel is t, the effective lip length [mm] defined by the formula (240 / √F) × t is equal to or greater than Panel material.

2. The pair of lips have equal lengths. The panel material of claim 1.

3. the hole is a slit, A slit ratio defined by dividing the sum of the slit intervals in the material axis direction of the web by the sum of the slit lengths is 5% or more and 20% or less. The panel material according to claim 1 or 2.

4. When the plate surface of the web is viewed from the front, the plurality of slits are arranged in a staggered pattern. The panel material of claim 3.

5. The lip channel steel is formed using a high-strength steel plate having an F value of 500 MPa or more. The panel material according to any one of claims 1 to 4.

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