JP2016205474A - Method for designing high strength bolt friction joint part and high strength bolt friction joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for designing a high strength bolt friction joint capable of realizing a rational number of high strength bolts and arrangement of high strength bolts and provide a high strength bolt friction joint designed on the basis of the method.SOLUTION: This invention relates to a high strength bolt frictional joint subjected to a frictional surface treatment where a coefficient of friction is dependent on a contact pressure, and it satisfies a relation of μ=14×10×t+4×10×(l+w-1.35×2×r)+0.24, where l(mm) is a frictional surface length per one high strength bolt in a stress applying direction, w(mm) is a frictional surface length per one high strength bolt in a stress crossing direction, t(mm) is a doubling plate thickness, and μ is a sliding coefficient when relations of l≤1.35×2×rand w≤1.35×2×rare applied. Since a target sliding coefficient μ and ts are set in advance and land wcan be set to cause this sliding coefficient μ and ts to be satisfied, it is possible to attain a high strength bolt frictional joint where a rational high strength bolt can be arranged.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a high-strength bolt friction joint design method and a high-strength bolt friction joint with a friction surface treatment whose friction coefficient depends on contact pressure.

Conventionally, in the field of construction and civil engineering, as a joining structure of steel materials that constitute the framework of steel structures (buildings, bridges, etc.), the steel material is fastened with a fastening tool such as a high-strength bolt, and the friction generated by this tightened compressive force Friction welding that joins steel materials with resistance is generally used.
In general friction welding, the friction coefficient is secured by performing the following processing on the joining surfaces of steel materials such as base materials (columns, beams, bracing, etc.), accessory plates (splice plates), and gusset plates. That is, after removing the black skin with a sander or a grinder, it is left to generate red rust, or a method of roughening the joint surface by shot blasting or the like is used.
However, the friction coefficient of the joint surface obtained by such a method is relatively small and it is difficult to secure a stable frictional resistance. Therefore, a low value (for example, floating rust is removed) taken as a safe side in designing. In the case of a red rust surface, μ = 0.45, in the case of a blasted surface, μ = 0.45, etc.) must be adopted, and when the member cross section becomes large, it is difficult to realize a rational design. The solution is desired.

As an example for solving such a problem, a high-strength bolt friction joint structure described in Patent Document 1 is known. This high-strength bolt friction joint structure is made of a metal such as aluminum sprayed so as to include a plurality of pores in at least one of the joining surfaces of the steel materials constituting the joint when joining steel materials with high-strength bolts. Thermal spraying is performed, and the porosity of the metal sprayed layer is 5% or more and 30% or less.
According to such a high-strength bolt friction joint structure, the frictional force between one joint surface on which the metal sprayed layer is formed and the other joint surface is increased, so that the frictional resistance is reliably increased and a rational design can be achieved. Can be realized. Accordingly, for example, the number of fasteners such as high-strength bolts can be reduced, and the area of the joining surface can be reduced, so that the friction joining structure can be made compact.

As another example for solving the above problem, a high-strength bolt friction joining splice plate described in Patent Document 2 is known. This is because, in the splicing plate for high-strength bolt friction welding in which a thermal spray layer is formed by metal spraying on the friction welding surface, the porosity of the surface side thermal spray layer located on the surface side of the thermal spray layer is higher than that of the surface side thermal spray layer. The interface-side sprayed layer located on the interface side with the splice plate base material has a high porosity.
According to such a high-strength bolt friction joining splice plate, a high friction resistance, specifically, a slip coefficient (friction coefficient) of 0.7 or more can be reasonably stably obtained in high-strength bolt friction joining. It is possible to stabilize the joint strength and life of the high-strength bolt friction joint at a high level.

  Also, in the high-strength bolt friction joint where the friction surface treatment whose friction coefficient depends on the contact pressure, such as the above-mentioned aluminum spraying treatment, is applied to the joint surface, the lower the contact pressure, the higher the friction coefficient. It is known that the thicker the thickness, the larger the contact pressure distribution area on the surface of the base material.

JP 2009-121603 A JP 2012-122229 A

By the way, in a high-strength bolt friction joint where a friction surface treatment whose friction coefficient depends on the contact pressure, such as the above-described aluminum spraying treatment, is applied to the joint surface, the slip coefficient has a high strength bolt diameter, high strength bolt strength, additional strength. It is known that it depends on the plate thickness and the sprayed layer thickness. Further, when the thickness of the accessory plate is decreased, the slip coefficient is decreased, and a sufficient effect may not be obtained.
Therefore, the present inventors diligently studied the slip coefficient in the high-strength bolt friction joint, the slip coefficient is in addition to the above-described high-strength bolt diameter, high-strength bolt strength, accessory plate thickness, sprayed layer thickness, It has been experimentally clarified that it also depends on the friction surface length per high-strength bolt.
Based on this experiment, the present inventor formulated the relationship between the slip coefficient μ, the friction surface length per high-strength bolt, and the thickness of the accessory plate. As a result, the present inventor has obtained the knowledge that an economical high-strength bolt friction joint can be provided because a reasonable number of high-strength bolts and high-strength bolts can be arranged.

  The present invention has been made on the basis of such knowledge. A design method for a high-strength bolt friction joint capable of arranging a reasonable number of high-strength bolts and high-strength bolts, and high-strength bolt friction designed based thereon. The aim is to provide a joint.

In order to achieve the above object, a high-strength bolt joint design method of the present invention is a high-strength bolt friction joint design method in which a friction surface treatment whose friction coefficient depends on contact pressure is performed,
The friction surface length per one high-strength bolts in the stress direction l _{b (mm),}
添板thickness of _t s (mm),
If the slip coefficient is μ,
When l _b ≦ 1.35 × 2 × r ₀ , the following expression (1) is satisfied,
When l _b > 1.35 × 2 × r ₀ , the following expression (2) is satisfied.
_{^{μ = 14 × 10 -3 × t}} s + 4 × 10 -3 × l b +0.24 (1)
_{^{μ = 14 × 10 -3 × t}} s + 4 × 10 -3 × (1.35 × 2 × r 0) +0.24 (2)
However,
l _b = (2 × e ₁ + (n−1) × p) / n
When the high-strength bolt is a hexagonal bolt: r ₀ = r ₂
If the high strength bolt of torque shear _{bolt: r 0 = r 1/2} + r 2/2
r ₁ (head _{side) = Dh 1/2 + t} s
r ₂ (nut _{side) = Dn 1/2 + t} ws / 2 + t s
e ₁ : Edge distance in the stress direction (mm)
p: Distance between high-strength bolts in the stress direction (mm)
n: Number of high-strength bolts in the stress direction r ₀ : Radius of contact pressure distribution (mm)
Dh ₁ : Torcia bolt head side bearing surface diameter (mm)
Dn ₁ : Nut bearing surface diameter (mm)
t _ws : Washer thickness (mm)
And

Here, the stress direction means the longitudinal direction of the base material when the base materials are connected to each other using the accessory plate in the longitudinal direction.
The edge distance in the stress direction means the distance from the end of the base material to the nearest bolt hole center with respect to the stress direction and the distance from the end of the accessory plate to the nearest bolt hole center.

In the present invention, for example, when the yield strength for the effective cross section or the entire cross section of the base material is the design external force of the joint, the minimum necessary plate thickness ts is calculated by setting the base plate width as the base material width. can do. Further, by setting the slip coefficient mu _t to select the high-strength bolts diameter and high-strength bolts intensity used target, determine the allowable friction high-strength bolts, the allowable friction design force and high-strength bolts The necessary number n of high strength bolts can be calculated. By using these conditions and the expressions (1) and (2), it is possible to set the friction surface length (l _bt ) per high-strength bolt in the target stress direction.
The friction surface length (l _b ) is defined by l _b = (2 × e ₁ + (n−1) × p) / n. Thus, per one high-strength bolt in the target stress direction. friction surface length (l _bt) from the friction surface length per one stress direction high strength bolts (l _b) becomes large as high-strength bolts stress direction of the edge distance (e _1), and the stress Determine the distance (p) between the high strength bolts in the direction. Here, it is desirable that 2e ₁ ≧ p.
From the friction surface length per high-strength bolts one stress direction (l _b), wherein (1), (2) determine the coefficients μ slip using equation greater slip coefficient μt slip coefficient μ is the targeted By confirming this, or by confirming that the allowable frictional force of the high-strength bolt is greater than the design external force, it is possible to design a high-strength bolt friction joint where a reasonable number of high-strength bolts and high-strength bolts can be arranged.
And if acceptable friction high strength bolt is not greater than the design external force, if e ₁ and p is not properly set, again,添板thickness, high strength bolt diameter, re-select a high strength bolts strength and the like, high Design force bolt friction joints.
Expressions (1) and (2) may be used for all slip coefficients required in the design of high-strength bolt friction joints, or may be used for specific slip coefficients.

In the design method of the high-strength bolt friction joint, the slip coefficient is described only when the high-strength bolt is arranged along the stress direction. However, in the actual high-strength bolt friction joint, the stress direction and the stress direction are orthogonal to each other. In many cases, high-strength bolts are arranged along the stress orthogonal direction.
Therefore, in this case, the design method of the high-strength bolt joint of the present invention is a design method of the high-strength bolt friction joint subjected to the friction surface treatment whose friction coefficient depends on the contact pressure,
The friction surface length per one high-strength bolts in the stress direction l _{b (mm),}
The friction surface length per high-strength bolt in the direction perpendicular to the stress is w _b (mm),
添板thickness of _t s (mm),
If the slip coefficient is μ,
In the case of l _b ≦ 1.35 × 2 × r ₀ and w _b ≦ 1.35 × 2 × r ₀ , the following expression (3) is satisfied:
When l _b > 1.35 × 2 × r ₀ and w _b ≦ 1.35 × 2 × r ₀ , the following expression (4) is satisfied:
When l _b ≦ 1.35 × 2 × r ₀ and w _b > 1.35 × 2 × r ₀ , the following expression (5) is satisfied:
When l _b > 1.35 × 2 × r ₀ and w _b > 1.35 × 2 × r ₀ , the following expression (6) is satisfied.
_{^{μ = 14 × 10 -3 × t}} s + 4 × 10 -3 × (l b + w b -1.35 × 2 × r 0) +0.24 (3)
_{^{μ = 14 × 10 -3 × t}} s + 4 × 10 -3 × w b +0.24 (4)
_{^{μ = 14 × 10 -3 × t}} s + 4 × 10 -3 × l b +0.24 (5)
_{^{μ = 14 × 10 -3 × t}} s + 4 × 10 -3 × 1.35 × 2 × r 0 +0.24 (6)
However,
l _b = (2 × e ₁ + (n−1) × p) / n
w _b = (2 × e ₂ + (m−1) × g) / m
When the high-strength bolt is a hexagonal bolt: r ₀ = r ₂
If the high strength bolt of torque shear _{bolt: r 0 = r 1/2} + r 2/2
r ₁ (head side of the torque shear _{bolt) = Dh 1/2 + t} s
r ₂ (nut _{side) = Dn 1/2 + t} ws / 2 + t s
e ₁ : Edge distance in the stress direction (mm)
p: Distance between high-strength bolts in the stress direction (mm)
n: number of high-strength bolts in the stress direction e ₂ : edge distance in the direction perpendicular to the stress (mm)
g: Distance between high-strength bolts in the direction perpendicular to stress (mm)
m: number of high-strength bolts in the direction perpendicular to stress r ₀ : radius of contact pressure distribution (mm)
Dh ₁ : Torcia bolt head side bearing surface diameter (mm)
Dn ₁ : Nut bearing surface diameter (mm)
t _ws : Washer thickness (mm)
And

Here, the stress orthogonal direction means a direction orthogonal to the longitudinal direction of the base material when the base materials are connected to each other in the longitudinal direction using the accessory plate.
The edge distance in the direction perpendicular to the stress means the distance from the end of the base material to the center of the bolt hole closest to it.

In the present invention, for example, when the yield strength to the effective cross-section or the entire cross-section of the base material and the design force of the joint, the minimum necessary添板thickness t _s by setting the添板width as the base material width Can be calculated. Further, by setting the slip coefficient mu _t to select the high-strength bolts diameter and high-strength bolts intensity used target, determine the allowable friction high-strength bolts, the allowable friction design force and high-strength bolts The required number of high-strength bolts can be calculated, and the number of columns n and the number of rows m can be set.
By using these conditions and the above equations (3) to (6), the friction surface length (l _bt ) per one high strength bolt in the target stress direction and one high strength bolt in the stress orthogonal direction The hit friction surface length (w _bt ) can be set.
The friction surface length (l _b ) is defined by l _b = (2 × e ₁ + (n−1) × p) / n. Thus, per one high-strength bolt in the target stress direction. friction surface length (l _bt) from the friction surface length per one stress direction high strength bolts (l _b) becomes large as high-strength bolts stress direction of the edge distance (e _1), and the stress Determine the distance (p) between the high strength bolts in the direction. Here, it is desirable that 2e ₁ ≧ p.
Since the friction surface length (W _b ) is defined by W _b = (2 × e ₂ + (m−1) × g) / m, one high-strength bolt in the direction perpendicular to the stress is thereby obtained. The edge distance (e ₂ ) of the high-strength bolt in the stress orthogonal direction so that the friction surface length (W _b ) per high-strength bolt in the direction orthogonal to the stress is greater than the friction surface length (W _bt ) per contact, And the distance (g) between the high-strength bolts in the direction perpendicular to the stress. Here, it is desirable that 2e ₂ ≧ g.
Friction surface length per high-strength bolts one stress direction (l _b) and the friction surface length per one high-strength bolts in the stress direction perpendicular used to design the (W _b), wherein (3) to (6 ) To obtain the slip coefficient μ and confirm that the slip coefficient is greater than the target slip coefficient, or confirm that the allowable friction force of the high-strength bolt is greater than the design external force. It is possible to design a high-strength bolt friction joint where the number of high-strength bolts and high-strength bolt arrangement is possible
If the allowable friction force of the high-strength bolt is not greater than the design external force, or if e ₁ and p, e ₂ and g cannot be set appropriately, the thickness of the accessory plate, high-strength bolt diameter, high-strength bolt strength, etc. Redesign and design a high strength bolt friction joint.
Expressions (3) to (5) may be used for all slip coefficients required in the design of a high-strength bolt friction joint, or may be used for specific slip coefficients.

  The high-strength bolt friction joint of the present invention is designed by the design method described above.

  By using the design method according to the present invention, a high-strength bolt friction joint having a reasonable number of high-strength bolts and high-strength bolt arrangement can be obtained.

1 is a front view showing an embodiment of a high-strength bolt friction joint according to the present invention. FIG. The high strength bolt and nut used for the high strength bolt friction joint part which concerns on this invention are shown, (a) is a side view of a hexagon bolt, (b) is a side view of a torcia bolt, (c) is a side view of a nut. It is. In high-strength bolted joint according to the present invention, for each添板thickness is a graph showing the relationship between the coefficient and slip friction surface length l _b per one high-strength bolts mu. The other embodiment of the high strength bolt friction junction part which concerns on this invention is shown, and it is the bottom view. It is a perspective view which shows the example applied when connecting the H-shaped steel to the high strength bolt friction joining structure part which concerns on this invention. It is the figure which compared the high strength bolt friction joining part designed by the design method of the high strength bolt friction joining part which concerns on this invention, and the high strength bolt friction joining part designed by the normal design method.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
1 and 2 show the high-strength bolt friction joint of the first embodiment. FIG. 1 is a front view and FIG. 2 is a bottom view.
1 and 2, reference numeral 1 denotes a material to be joined, and reference numeral 2 denotes an accessory plate. In this Embodiment, the to-be-joined material 1 is a flange of H-section steel. In addition, the to-be-joined material 1 may be a web of H-section steel, and may be other steel materials.
In the present embodiment, when connecting the H-shaped steels in the longitudinal direction, the two H-shaped steels are arranged coaxially with a predetermined gap, and the one-side flanges (joined materials, base materials) 1, 1 are connected to each other. Are connected by the accessory plate 2.

In this case, a pair of upper and lower accessory plates 2 and 2 are arranged with a one-side flange (material to be joined) 1 interposed therebetween, and the accessory plates 2 and 2 are stretched over the adjacent one-side flanges 1 and 1, respectively. After contacting the upper and lower surfaces of the one-side flange 1, it is joined to the one-side flange 1, 1.
The joint surface 1a of the one-side flange 1 with the accessory plate 2 is blasted so that the surface roughness (maximum height Rz) is 50 μm or more. Alternatively, the joint surface 1a of the one-side flange 1 may be covered with iron oxide (red rust, black skin, etc.).

A friction surface treatment is applied to the joint surface 2 a of the accessory plate 2 with the one-side flange 1. In this friction surface treatment, the ground coating is applied to such an extent that the sprayed metal is fixed, and the aluminum, which is a low-strength metal, is sprayed in a molten state to form an aluminum sprayed layer. In the ground treatment, for example, blasting is performed so that the surface roughness (maximum height Rz) is 50 μm or more.
The aluminum sprayed layer is formed in the circumference on the joint surface around the bolt hole through which the high-strength bolt 5 is inserted. The diameter of this circumference is set to, for example, three times the shaft diameter of the high strength bolt 5. Further, the thickness of the aluminum sprayed layer is set within a range of 200 μm or more and 500 μm or less, for example, 300 μm.
In the present embodiment, the high strength bolt 5 is a torcia bolt, but may be a hexagon bolt. The strength of the high strength bolt is 1400 MPa in terms of tensile strength, but any strength of 800 to 1400 MPa may be used.

  A plurality of pores (not shown) are uniformly dispersed throughout the aluminum sprayed layer, and the porosity indicating the ratio of the total volume of the plurality of pores to the volume of the aluminum sprayed layer is 5%. As described above, it is set within a range of 30% or less, and is, for example, 21%. The aluminum sprayed layer is formed by an arc spraying method using a wire-shaped sprayed material having an aluminum component of 99.5%.

Thus, the aluminum sprayed layer formed on the joining surface 2a of the accessory plate 2 is subjected to a friction surface treatment such that the lower the contact pressure (average contact pressure), the higher the friction coefficient.
Such a joining portion between the accessory plate 2 and the one-side flange 1 is a high-strength bolt friction joining portion subjected to a friction surface treatment whose friction coefficient depends on contact pressure. In other words, it is a high-strength bolt friction joint that has been subjected to a friction surface treatment such that the lower the contact pressure, the higher the friction coefficient.
Note that a washer 7 is externally inserted and a nut 8 is screwed and fastened to the high-strength bolt 5 inserted through the one-side flange 1 and the accessory plates 2 and 2. The flange 1 and the accessory plate 2 are friction-joined by the frictional resistance generated by the tightened compressive force.

As described above, the slip coefficient in the high-strength bolt friction joint is determined by the friction surface length per high-strength bolt in addition to the bolt diameter, bolt strength, splice thickness, and sprayed layer thickness of the high-strength bolt. The present inventor has experimentally clarified that this also depends on the above.
Based on this experiment, the relationship between the slip coefficient μ, the friction surface length per high-strength bolt, and the thickness of the accessory plate was formulated as follows.

That is, the high-strength bolt friction joint of the present embodiment has a friction surface length of 1 _b (mm) per high-strength bolt in the stress direction and a friction surface length per high-strength bolt in the stress orthogonal direction. In the case of l _b ≦ 1.35 × 2 × r ₀ and w _b ≦ 1.35 × 2 × r ₀ where w _b (mm) is the thickness, t _s (mm) is the plate thickness, and the slip coefficient is μ And the following expression (3) is satisfied.
_{^{μ = 14 × 10 -3 × t}} s + 4 × 10 -3 × (l b + w b -1.35 × 2 × r 0) +0.24 (3)

However,
l _b = (2 × e ₁ + (n−1) × p) / n
w _b = (2 × e ₂ + (m−1) × g) / m
When the high-strength bolt is a hexagonal bolt: r ₀ = r ₂
If the high-strength bolts of torque shear _{bolt: r 0 = r 1/2} + r 2/2
r ₁ (head _{side) = Dh 1/2 + t} s
r ₂ (nut _{side) = Dn 1/2 + t} ws / 2 + t s
e ₁ : Edge distance in the stress direction (mm)
p: Distance between high-strength bolts in the stress direction (mm)
n: number of high-strength bolts in the stress direction e ₂ : edge distance in the direction perpendicular to the stress (mm)
g: Distance between high-strength bolts in the direction perpendicular to stress (mm)
m: number of high-strength bolts in the direction perpendicular to stress r ₀ : radius of contact pressure distribution (mm)
Dh ₁ : Torcia bolt head side bearing surface diameter (mm)
Dn ₁ : Nut bearing surface diameter (mm)
t _ws : Washer thickness (mm)
And

Here, the hexagonal bolt has a bolt head shape shown in FIG. 3 (a), and the torcia bolt has a bolt head shape shown in FIG. 3 (b). The bolt head side seating surface diameter Dh ₁ of the torque shear bolt, as shown in FIG. 3 (b), a diameter of the lower surface flush circle head 5a. Further, a diameter of the seat surface 5b of the seating surface diameter Dn ₁ of the nut is provided to protrude from the nut lower surface as shown in Figure 3 (c).

In addition, as shown in FIGS. 1 and 2, the stress direction is a base material in the case where base materials (flanges) 1 and 1 that are materials to be joined are connected to each other using the accessory plate 2 in the longitudinal direction ( It means the longitudinal direction of the flanges 1 and 1 (the left-right direction in FIGS. 1 and 2).
As shown in FIGS. 1 and 2, the stress orthogonal direction means that the base materials (flange) 1, 1 when the base materials (flange) 1, 1 are connected to each other using the accessory plate 2 in the longitudinal direction. It means a direction (vertical direction in FIG. 2) orthogonal to the longitudinal direction.

The edge distance (e ₁ ) in the stress direction is the longitudinal direction of the base material (flange) 1, 1 when the base materials (flange) 1, 1 are connected to each other using the accessory plate 2 in the longitudinal direction. The high-strength bolt 5 located at one end of the accessory plate 2 and the distance between one end of the accessory plate 2 and the high-strength bolt 5 located at the other end of the accessory plate 2, and the base material (Flange) The distance between the joint ends of 1 means.
The edge distance (e ₂ ) in the direction perpendicular to the stress is the base material (flange) 1, 1 when the base materials (flange) 1, 1 are connected to each other using the accessory plate 2 in the longitudinal direction. This means the distance between the high-strength bolt 5 located at the end of the accessory plate 2 and one end of the accessory plate 2 in the direction orthogonal to the longitudinal direction.

In addition, l _b ≦ 1.35 × 2 × r _{0 in the} equation (2) means the maximum value of the friction surface length per high-strength bolt in the stress direction, and l _b is more than this. Then, the slip coefficient μ is constant in the equation (1). This is the case where the overlap of the contact pressure distribution does not occur between the high-strength bolts l _b are adjacent large enough, because the correlation between slip coefficient μ and l _b is eliminated.
Similarly, w _b ≦ 1.35 × 2 × r _{0 in the} equation (3) means the maximum value of the friction surface length per high-strength bolt in the direction perpendicular to the stress, and w _b If it becomes above, in (1) Formula, slip coefficient (mu) will become fixed.

Here, based on the experiment, for each添板thickness, the relationship between the coefficient and slip friction surface length l _b per one high-strength bolts μ shown in FIG.
As shown in FIG. 4, according to the friction surface length l _b becomes longer, sliding coefficient gradually increased, it can be seen that the friction surface length l _b is constant it exceeds a predetermined maximum value.
That is, when the friction surface length _{l b} is _{l b> 1.35 × 2 × r} 0, the slip coefficient ^{μ, μ = 14 × 10 -3} × t s + 4 × 10 -3 × (1.35 × 2 × r ₀ ) +0.24 and constant.
Although not shown, the relationship between the friction surface length w _b per high-strength bolt and the slip coefficient μ is the same, and the slip coefficient increases as the friction surface length w _b increases. go, the friction surface length w _b is constant exceeds a predetermined maximum value.
That is, when the friction surface length _{w b} is _{w b> 1.35 × 2 × r} 0, the slip coefficient ^{μ, μ = 14 × 10 -3} × t s + 4 × 10 -3 × 1.35 × 2 × It becomes constant at r ₀ +0.24.
_{Further, l b> 1.35 × 2 ×} r 0, if the _{w b ≦ 1.35 × 2 × r} 0, μ = 14 × 10 -3 × t s + 4 × 10 -3 × w b +0.24 next , a _{l b ≦ 1.35 × 2 × r} 0, w b> 1.35 × case of _{2 × r 0, μ = 14} × 10 -3 × t s + 4 × 10 -3 × l b +0.24 .
Also, the friction surface length (joint lengths) l _b, if w _b is reduced, shortens the length of添板can reduce steel weight.
Further, when the slip coefficient μ is increased, the number of high-strength bolts can be reduced.

Further, it is found that a positive correlation between the slip coefficient μ and添板thickness t _s. This is because the contact pressure distribution radius r ₀ increases as the splicing plate thickness increases, and as a result, when the bolt tension is the same, the contact pressure is relatively reduced and the slip coefficient is increased.

A specific design example is shown using FIG. 1 and FIG. As a premise, the base material width Wb = 200 mm, the base material thickness tb = 36 mm, the base material and the attached plate both have a steel material with a yield point of 325 MPa, the high strength bolt 5 is a 1400 MPa class torcia bolt with a diameter of 24 mm, and high strength in the direction perpendicular to the stress. The number of bolts is m = 2. As for the accessory plate, if the accessory plate width is set to 200 mm, which is the same as that of the base material, and the thickness of the accessory plate is selected so that the yield strength is equal to or greater than that of the base material, ts = 19 mm. When the slip coefficient is set to 0.7, the required number of high-strength bolts is the yield strength bPey = (200 mm−2 × 26 mm) × 36 mm × 325 MPa / 1000 = 1732 kN in the base metal effective section of one high-strength bolt. The slip resistance Ps = 349 kN × 2 surfaces × 0.7 = 489 kN divided by 3.54 or more is necessary, so there are four. That is, the number of high-strength bolts in the stress direction is n = 2. Here, since the base material width and the accessory plate width are determined, Wb = 200 mm / 2 = 100 mm. Regarding e ₂ and g, e ₂ = 50 mm and g = 100 mm can be set based on the relationship of 2e ₂ ≧ g. Also. For e ₁ and p, l _b = 58.53 mm from the above condition and the equation (1). Here, r ₁ = 43 mm / 2 + 19 mm = 40.5 mm, r ₂ = 38 mm / 2 + 6 mm / 2 + 19 mm = 41 mm, and r ₀ = 40.5 mm / 2 + 41 mm / 2 = 40.75 mm are used. If e ₁ and p are set in consideration of the relationship of 2e ₁ ≧ p, a reasonable length of the accessory plate can be obtained by setting e ₁ = 30 mm and p = 60 mm. In this example, bolt diameter,添板thickness ts, high-strength bolts the number m of the stress perpendicular direction has been set to e ₁ and p of high-strength bolts the number and direction of stress by setting the slip coefficient mu, high strength bolt arrangement May be determined first to determine the slip coefficient and the number of high-strength bolts.

In this embodiment, the case where the number m of high-strength bolts in the direction perpendicular to the stress is 2 has been described as an example, but the friction surface sufficient in the width direction of the flange 1 (the direction perpendicular to the stress) when m is 1 When the length (w _b ) can be secured, the friction surface length (w _b ) is 1.35 × 2 × r ₀ which is the maximum value in the equation (3). Is
the _{^{μ = 14 × 10 -3 × t}} s + 4 × 10 -3 × l b +0.24.
Therefore, in this case, it is possible to design a high-strength bolt friction joint with a reasonable high-strength bolt shaft diameter, number of high-strength bolts, and placement of high-strength bolts by performing a similar design based on this formula. it can.

Further, in the present embodiment, the high-strength bolts 5 are arranged in a straight line along the stress direction and the stress orthogonal direction so as to be arranged in two columns and two rows, but as shown in FIG. If the length in the width direction is long, they may be arranged in a staggered pattern. FIG. 5 shows an example in a case where they are arranged in a zigzag pattern and have 4 columns and 2 rows.
In this case, high-strength bolts distance in stress direction rather than employing a distance p in the direction of stress, while adopting the distance p _m in the oblique direction intersecting the direction of stress, one row of such a staggered arrangement It is assumed that the number of high-strength bolts in the stress direction is n (n = 4).
Also, w _b = (2) where the width of one row is the distance g ₁ between adjacent high-strength bolts in the same row, and the distance between adjacent rows in this direction is the distance g ₂ between the high-strength bolts in the direction perpendicular to the stress. What is necessary is just to design as * e < ₂ > + (m-1) * g2 + m * g1) / m.

Therefore, the friction surface length w _b per high-strength bolts one friction surface length l _b and the stress perpendicular direction per one high-strength bolts in the stress direction is as follows.
l _b = (2 × e ₁ + (n−1) × p _m ) / n
w _b = (2 × e ₂ + m × g ₁ + (m−1) × g ₂ ) / m
Even when the high-strength bolts 5 are arranged in a staggered manner, the same effects as those of the first embodiment can be obtained.

For example, as shown in FIG. 6, the high-strength bolt friction joint portion according to the present embodiment is formed by connecting the steel beams 16, 16 made of H-shaped steel with the accessory plates 22, 23. This can be applied to the case where the flange 16b of the steel beam 16 is friction-joined and the case where the accessory plate 23 and the web 16a are friction-joined.
In this case, for example, the auxiliary plate 22 and the flange 16b are fastened by tightening the high strength bolt 5 with the washer 7 and the nut 8 after the auxiliary plate 22 is stretched over and in contact with the upper and lower surfaces of the adjacent flanges 16b and 16b. The high-strength bolt can be friction bonded.
Further, the auxiliary plate 23 is stretched over and abutted against both surfaces of the adjacent webs 16a and 16a, and the high strength bolt 5 is tightened with the washer 7 and the nut 8 to thereby fix the auxiliary plate 23 and the web 16a to the high strength bolt. Can be friction bonded.

  Next, referring to FIG. 7, the high-strength bolt friction designed by the design method of the high-strength bolt friction joint subjected to the friction surface treatment (aluminum spraying treatment) whose friction coefficient depends on the contact pressure according to the present invention. The effect of the present invention will be clarified by comparing the joint and a high-strength bolt friction joint designed by a normal design method.

As shown in the left column of FIG. 7, the slip coefficient μ between the friction plate and the flange plate and the flange subjected to the normal blasting process is μ = 0.45.
On the other hand, in the present invention, the accessory plate is subjected to a friction surface treatment (aluminum spraying treatment) in which the friction coefficient depends on the contact pressure.
In addition, the attachment board and the web which used the attachment board to which the normal blasting process etc. were given were used.

Then, on the friction surface between the accessory plate and the flange, the friction surface length per high-strength bolt in the stress direction is l _b (mm), and the friction surface length per bolt in the stress orthogonal direction is w _b ( mm), the thickness of the accessory plate is t _s (mm), the slip coefficient is μ, and the high-strength bolt friction joint is designed to satisfy the above-described formulas (1) to (3).
The accessory plate thickness is 36 mm, and the flange thickness is 37 mm.

First, as shown in the right column of FIG. 7, Torcia bolts were used as high-strength bolts.
In the case of torque shear bolt _{r 0 = r 1/2 +} r 2/2
Cranial r ₁ = 41/2 + 36 = 56.5 mm
Nut side r ₂ = 38/2 + 6/2 + 36 = 58 mm
Therefore,
r ₀ = 56.5 / 2 + 58/2 = 57.25 mm.

Also, the friction surface length _{l b} is
l _b = (2 × e ₁ + (n−1) × p _m ) / n
= (2 × 40 + (4-1) × 60.2) /4=65.15 mm
l _b ≦ 1.35 × 2 × 57.25 = 154.575 mm.

The friction surface length w _b is
w _b = (2 × e ₂ + m × g ₁ + (m−1) × g ₂ ) / m
= (2 × 33 + 40 + (1-1) × 40) / 1 = 106 mm
w _b ≦ 1.35 × 2 × 57.25 = 154.575 mm.

Therefore, the slip coefficient μ is
_{^{μ = 14 × 10 -3 × t}} s + 4 × 10 -3 × (l b + w b -1.35 × 2 × r 0) +0.24
= 14 × 10 ⁻³ × 36 + 4 × 10 ⁻³ × (65.15 + 106−1.35 × 2 × 57.25) +0.24
= 0.504 + 0.0663 + 0.24 = 0.81
Here, a slip coefficient of 0.81 can be employed for calculation, but 0.7 is employed for the safety side.
The formula for calculating the number n of high-strength bolts is omitted because it is well known.

  As shown in FIG. 7, in the present invention, the number of high strength bolts is reduced by increasing the slip coefficient on the friction surface between the accessory plate and the flange as compared with the prior art. You can see that the length is getting shorter.

1 Flange (material to be joined)
2,22,23 Adhesive plate 5 High-strength bolt 7 Washer 8 Nut

Claims (3)

A method of designing a high-strength bolt friction joint with a friction surface treatment whose friction coefficient depends on contact pressure,
The friction surface length per one high-strength bolts in the stress direction l _{b (mm),}
添板thickness of _t s (mm),
If the slip coefficient is μ,
When l _b ≦ 1.35 × 2 × r ₀ , the following expression (1) is satisfied,
In the case of l _b > 1.35 × 2 × r ₀ , the following formula (2) is satisfied.
_{^{μ = 14 × 10 -3 × t}} s + 4 × 10 -3 × l b +0.24 (1)
_{^{μ = 14 × 10 -3 × t}} s + 4 × 10 -3 × (1.35 × 2 × r 0) +0.24 (2)
However,
l _b = (2 × e ₁ + (n−1) × p) / n
When the high-strength bolt is a hexagonal bolt: r ₀ = r ₂
If the high strength bolt of torque shear _{bolt: r 0 = r 1/2} + r 2/2
r ₁ (head _{side) = Dh 1/2 + t} s
r ₂ (nut _{side) = Dn 1/2 + t} ws / 2 + t s
e ₁ : Edge distance in the stress direction (mm)
p: Distance between high-strength bolts in the stress direction (mm)
n: Number of high-strength bolts in the stress direction r ₀ : Radius of contact pressure distribution (mm)
Dh ₁ : Torcia bolt head side bearing surface diameter (mm)
Dn ₁ : Nut bearing surface diameter (mm)
t _ws : Washer thickness (mm)
And A method of designing a high-strength bolt friction joint with a friction surface treatment whose friction coefficient depends on contact pressure,
The friction surface length per one high-strength bolts in the stress direction l _{b (mm),}
The friction surface length per high-strength bolt in the direction perpendicular to the stress is w _b (mm),
添板thickness of _t s (mm),
If the slip coefficient is μ,
In the case of l _b ≦ 1.35 × 2 × r ₀ and w _b ≦ 1.35 × 2 × r ₀ , the following expression (3) is satisfied:
When l _b > 1.35 × 2 × r ₀ and w _b ≦ 1.35 × 2 × r ₀ , the following expression (4) is satisfied:
When l _b ≦ 1.35 × 2 × r ₀ and w _b > 1.35 × 2 × r ₀ , the following expression (5) is satisfied:
A design method for a high-strength bolt friction joint that satisfies the following expression (6) when l _b > 1.35 × 2 × r ₀ and w _b > 1.35 × 2 × r ₀ .
_{^{μ = 14 × 10 -3 × t}} s + 4 × 10 -3 × (l b + w b -1.35 × 2 × r 0) +0.24 (3)
_{^{μ = 14 × 10 -3 × t}} s + 4 × 10 -3 × w b +0.24 (4)
_{^{μ = 14 × 10 -3 × t}} s + 4 × 10 -3 × l b +0.24 (5)
_{^{μ = 14 × 10 -3 × t}} s + 4 × 10 -3 × 1.35 × 2 × r 0 +0.24 (6)
However,
l _b = (2 × e ₁ + (n−1) × p) / n
w _b = (2 × e ₂ + (m−1) × g) / m
When the high-strength bolt is a hexagonal bolt: r ₀ = r ₂
If the high strength bolt of torque shear _{bolt: r 0 = r 1/2} + r 2/2
r ₁ (head _{side) = Dh 1/2 + t} s
r ₂ (nut _{side) = Dn 1/2 + t} ws / 2 + t s
e ₁ : Edge distance in the stress direction (mm)
p: Distance between high-strength bolts in the stress direction (mm)
n: number of high-strength bolts in the stress direction e ₂ : edge distance in the direction perpendicular to the stress (mm)
g: Distance between high-strength bolts in the direction perpendicular to stress (mm)
m: number of high-strength bolts in the direction perpendicular to stress r ₀ : radius of contact pressure distribution (mm)
Dh ₁ : Torcia bolt head side bearing surface diameter (mm)
Dn ₁ : Nut bearing surface diameter (mm) t _ws : Washer thickness (mm)
And   A high-strength bolt friction joint that is designed by the design method according to claim 1.

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