JP6174976B2 - Protective structure - Google Patents

Description

  The present invention relates to a protective structure. More specifically, the present invention relates to a protective structure used to protect buildings, warehouses, heavy oil tanks, water tanks, and other buildings from external impacts.

In Japan, strong winds are usually generated with the approach and landing of typhoons, and this strong wind causes damage such as the collapse of buildings and trees.
However, although strong winds caused by typhoons may have a maximum wind speed of 60 m / s or more, even if such strong winds cause collapse of houses and trees, the structure of a collapsed building (such as a steel frame) There is not enough energy to scatter heavy objects.
For this reason, conventionally, strong wind countermeasures in Japan have been mainly to weaken the wind blown to the building by windbreak forests or to increase the strength of the building to prevent collapse due to wind pressure.

  On the other hand, when a tornado occurs, it may have more energy than a typhoon, and if the wind speed is 70 m / s or more (F3 or more tornado), there is a possibility that the structure or automobile of a collapsed building will be scattered. is there. In the United States and the like, a large tornado occurs every year, and a large damage is caused by buildings scattered by the large tornado.

  Although tornadoes are seen in Japan, the tornadoes that have occurred so far are relatively small in scale, and no special measures have been taken against tornadoes.

  However, in recent years, large-scale tornadoes have been generated in Japan, and the tornadoes have caused great damage. For example, a tornado rolls up a structure of a building (for example, a roof or wall material) or a car, and the structure or the car collides with the building, causing a disaster that causes the building to collapse or be damaged. ing. For this reason, even in Japan, when a large tornado occurs and the structure of the building is scattered, the scattered structure, etc. (hereinafter referred to as a flying object) collides with the building, etc. Measures to prevent damage are needed.

  As such a countermeasure, it is conceivable to prevent a flying object from colliding with a building or the like. For example, a method for preventing a falling object from colliding with a building or the like by providing a falling rock prevention net or the like around the building or the like and receiving the flying object by the falling rock prevention net can be considered.

  This method directly prevents the flying object from colliding with the building, etc., so it is highly effective in protecting the building, but the rock fall prevention net may interfere with the use of the building. There is. Further, if the building or the like is a heavy oil tank or the like, a rock fall prevention net cannot be provided around the building or the like because of the Fire Service Act.

On the other hand, if a structure that absorbs the impact force when a flying object collides is provided in a building, etc., even if the flying object collides with the building, damage to the building can be minimized. I think I can.
However, at present, a structure as described above, that is, a structure that absorbs an impact force when a flying object collides and is installed in a building or the like has not been developed.

By the way, in the automobile etc., many techniques which absorb the impact force at the time of a collision are developed (for example, patent documents 1-4).
Patent Documents 1 to 4 and the like utilize a phenomenon (see Non-Patent Document 1) that a cylindrical structure is deformed into a bellows shape when a load from the axial direction is applied to the cylindrical structure. A technique for absorbing impact force at the time of collision is disclosed.

JP 2009-96261 A JP 2011-111113 A JP 2012-35771 A JP2013-87880A

Hiroyuki Mitsuishi, “Energy Absorption Characteristics of Thin-Structured Members during Axial Crushing”, Automobile Research, Vol.

However, the techniques of Patent Documents 1 to 4 are based on the assumption of collision between automobiles or between an automobile and a wall surface, and shock absorption is assumed when a flying object with a high penetration force such as a steel material collides with a building or the like. Not done.
In other words, even if the techniques of Patent Documents 1 to 4 are adopted as a structure that absorbs the impact force when a flying object having a high penetrating force collides with a building or the like like steel, the impact when the flying object collides. It is impossible to absorb power.

  As described above, structures that absorb impact force when a projectile with high penetrating force collide and that are installed in a building have not been developed at present. It is desired.

  In view of the above circumstances, an object of the present invention is to provide a protective structure that can absorb an impact force when a flying object collides.

The protection structure of the first invention includes a cylindrical portion having a plurality of cylindrical members having a circular cross section, and the plurality of cylindrical members have inner cylindrical shapes whose central axes are parallel to each other and located inward. The outer cylindrical member is disposed so as to be nested between the outer surface of the inner cylindrical member and the outer surface of the outer cylindrical member positioned outward. A spacer is provided between the inner surface of the cylindrical member to maintain a gap between the two, and the spacer is configured such that when a force is applied to compress the cylindrical portion from the axial direction of the cylindrical portion, the inner cylindrical shape is applied. The member is a member that is axially crushed together with the member and the outer cylindrical member .
A protective structure according to a second aspect of the present invention includes, in the first aspect, a box-shaped member having two opposing walls, and the plurality of cylindrical portions arranged between the two walls of the box-shaped member. The plurality of cylindrical portions are arranged such that both ends thereof are in contact with two walls of the box-shaped member.
The protection structure of the third invention is that in the first or second invention, the protection object is a building, and the plurality of cylindrical members are arranged along the surface of the building. Features.
The protection structure according to a fourth aspect of the present invention is characterized in that, in the first, second or third aspect , the cylindrical portion is composed of a plurality of cylindrical members having different lengths.
The protection structure according to a fifth aspect of the present invention is the first, second, third, or fourth aspect, wherein the plurality of cylindrical members can be deformed into an accordion shape when a compressing force is applied from the axial direction. The gap between the outer surface of the cylindrical member positioned at the outer surface and the inner surface of the cylindrical member positioned at the outer side is applied with a force for compressing the cylindrical member from the axial direction, so that the plurality of cylindrical members are in a bellows shape. When deformed, the outer surface of the cylindrical member positioned inward and the inner surface of the cylindrical member positioned outward are disposed in a non-contact state.
A protection structure according to a sixth aspect of the present invention is the first, second, third, fourth, or fifth aspect, wherein the cylindrical portion is formed of a pair of cylindrical members, and is an outer cylinder positioned outward. The cylindrical member is an aluminum pipe having an outer diameter of 80 mm and an inner diameter of 72 to 74 mm, and the inner cylindrical member positioned inward is an aluminum pipe having an outer diameter of 50 mm and an inner diameter of 44 to 46 mm. To do.

According to the first invention, when the cylindrical portion is installed in a building or the like so that the flying object collides from the axial direction, when the flying object collides with the cylindrical portion, the plurality of cylindrical members of the cylindrical portion. Transforms into a bellows shape and absorbs the impact energy of flying objects. Therefore, even if a flying object collides with a building or the like, the main body of the building or the like can be prevented from being damaged, and the force applied to the building or the like can be reduced. And since the cylindrical part is formed with the several cylindrical member, if the combination of a cylindrical member is adjusted, the collision energy which can be absorbed can be adjusted according to a building etc. or a flying object assumed. And since the spacer is provided, it can prevent that the relative position of an inner side cylindrical member and an outer side cylindrical member shifts | deviates. In addition, when a plurality of cylindrical portions are provided, any cylindrical portion can be in substantially the same state, so that any cylindrical portion can be axially crushed in substantially the same situation.
According to the second invention, since the plurality of cylindrical portions are held inside the box-shaped member, if the box-shaped members are arranged in front of the object to be protected, the object to be protected is protected from collisions such as scattered objects. be able to.
According to the 3rd invention, the force added to the surface of a building can be reduced.
According to the fourth invention , since the load peak at the initial stage of the collision can be kept low, the effect of reducing the force applied to the building or the like can be enhanced.
According to the fifth aspect of the present invention , when the plurality of cylindrical members are deformed in a bellows shape, each cylindrical member can be smoothly deformed, so that the efficiency of absorbing collision energy can be increased.
According to the sixth invention , if there is no protective structure, the impact force applied to the building or the like is about 30 G, but the impact force applied to the building or the like can be reduced to 2 G or less by installing the protective structure. . Therefore, even if a flying object collides with a building or the like by a tornado having a wind speed of about 100 m / s, damage to the building or the like can be suppressed.

It is a schematic explanatory drawing of the cylindrical part 10 in the protection structure 1 of this embodiment, (A) is a top view, (B) is a side view, (C) is a schematic side view after axial crushing. is there. BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic explanatory drawing of the axial crushing condition of the cylindrical part 10 in the protection structure 1 of this embodiment, (A) is an initial schematic sectional drawing in which the load F was added to the cylindrical part 10, (B) is It is a schematic sectional drawing after the cylindrical part 10 is axially crushed, (C) is a schematic plan view of the cylindrical part 10 after axially crushed. (A) is a schematic external view of the heavy oil tank T which provided the protection structure 1 of this embodiment, (B) is a BB schematic sectional drawing of (A). (A) is a schematic longitudinal cross-sectional view of the heavy oil tank T which provided the protection structure 1 of this embodiment, (B) is a principal part schematic enlarged view of (A). FIG. 6 is a schematic explanatory diagram of a situation where a load F is applied to the protective structure 1 when the inner cylindrical member 12 has a shorter axial length than the outer cylindrical member 11. (A), (B) is a schematic explanatory drawing of the cylindrical part 10 which provided the spacer 15, (C), (D) is a schematic explanatory drawing of the cylindrical part 10 in the state where the inner side cylindrical member 12 was eccentric. It is. It is a schematic explanatory drawing of the protection plate 20 using the protection structure 1 of this embodiment, (A) is a schematic perspective view, (B) is a schematic expanded sectional view. (A) is a photograph of the experimental apparatus of the example, and (B) is a photograph showing a situation in which the cylindrical portion is compressed. It is the graph which showed the experimental result of the Example. It is the graph which showed the experimental result of the Example. It is the graph which showed the experimental result of the Example. It is the graph which showed the experimental result of the Example.

  The protective structure of the present invention is installed on the wall surface of a building in a thermal power plant, nuclear power plant, manufacturing plant, etc., and when a flying object collides with the wall surface of the building, the impact It absorbs and prevents damage to the building.

  In addition, the building etc. in which the protection structure of this invention is attached are not specifically limited. For example, the steel frame surface part of a steel structure building, the reinforced concrete building wall surface, etc. can be mentioned. Especially suitable for buildings such as tanks that store flammable fuels such as heavy oil, etc., where a protective structure such as a rockfall prevention net cannot be provided around buildings due to regulations of the Fire Service Act, etc. .

  Below, the case where the structure where the protection structure of this invention is attached is a heavy oil tank is demonstrated as a representative.

(Protective structure 1 of this embodiment)
In FIG. 3 and FIG. 4, the code | symbol T has shown the heavy oil tank which installed the protection structure 1 of this embodiment. This heavy oil tank T is comprised from the cylindrical main-body part TB and a pair of end plate TM and TM provided in the both ends of the main-body part TB.
As shown in FIGS. 3 and 4, the heavy oil tank T is provided with the protective structure 1 of the present embodiment on the surface of the main body TB (portion excluding the lower part) and the surfaces of the pair of end plates TM and TM. Is provided. Hereinafter, the surface on which the protective structure 1 of the present embodiment is provided, that is, the surface of the main body portion TB and the surfaces of the pair of end plates TM and TM are simply referred to as an installation surface.

  In FIGS. 3 and 4, the protective structure 1 of the present embodiment is not provided at the lower surface of the main body portion TB (see FIG. 3B). Of course, the lower surface of the main body portion TB is also provided. You may provide the protective structure 1 of this embodiment. However, the lower part of the surface of the main body TB is provided with legs BM for fixing the heavy oil tank T to the base B, so that it is difficult to install the protective structure 1, and the front (outside) is usually made of reinforced concrete. There is an oil breakwater and it is considered that there is a low possibility of flying objects colliding. Therefore, the protective structure 1 of the present embodiment may be appropriately attached to the lower surface of the main body portion TB in consideration of the location conditions of the place where the heavy oil tank T is installed.

(Protective structure 1)
As shown in FIGS. 3 and 4, the protective structure 1 according to this embodiment includes a base member 2, an outer surface member 3, and a plurality of cylindrical portions 10.

(Basic member 2 and outer member 3)
The base member 2 is a plate-like member fixed to the installation surface, and is formed so that the shape thereof is the same as that of the installation surface. The same shape means that the surface of the base member 2 is the installation surface when the protective structure 1 is installed on the installation surface when the installation surface is a curved surface on the surface of the main body TB or the pair of end plates TM, TM described above. And a shape that is a substantially parallel curved surface.

  The outer surface member 3 is also a plate-like member, and is formed so as to have the same shape as the base member 2. That is, the outer surface member 3 is formed so that the surface thereof is a curved surface parallel to the surface of the base member 2. In other words, the outer surface member 3 is formed in a shape whose surface becomes a curved surface parallel to the installation surface when the protective structure 1 is installed on the installation surface.

(Cylindrical part 10)
A plurality of cylindrical portions 10 are provided between the base member 2 and the outer surface member 3. One end (base end) in the axial direction of the plurality of cylindrical portions 10 is connected to the outer surface of the base member 2 (the surface opposite to the surface facing the installation surface), and the other end in the axial direction ( The tip is connected to the inner surface of the outer member 3 (the surface facing the base member 2). In other words, the base member 2 and the outer surface member 3 are connected to each other by the plurality of cylindrical portions 10.

  As shown in FIG. 1, each cylindrical part 10 is comprised from the hollow outer cylindrical member 11 formed in the cross-sectional circle shape, and the hollow inner cylindrical member 12 formed in the cross-sectional circle shape. Each tubular portion 10 is disposed such that the outer tubular member 11 and the inner tubular member 12 are nested with each other. Specifically, each cylindrical portion 10 is disposed in a hollow space of the outer cylindrical member 11 so that the inner cylindrical member 12 is coaxial with the outer cylindrical member 11. That is, each tubular portion 10 is a double tube formed by the outer tubular member 11 and the inner tubular member 12 so that the cross-sectional shape is concentric.

  And each cylindrical part 10 is arrange | positioned so that the axial direction may correspond with the normal line direction (in other words normal line nv direction of the outer surface member 3 inner surface) of the surface of the base member 2, and it adjoins. It arrange | positions so that the space | interval of the cylindrical parts 10 may become the substantially same distance. For example, when viewed from the normal nv direction of the surface of the base member 2, the plurality of cylindrical portions 10 are arranged in a lattice shape or a zigzag shape.

  Since the protective structure 1 of the present embodiment has the above-described configuration, if the protective structure 1 is provided on the installation surface of the heavy oil tank T, flying objects will fly toward the heavy oil tank T. However, the force applied to the heavy oil tank T can be reduced for the following reasons, and damage to the heavy oil tank T can be prevented.

  First, when the protective structure 1 of the present embodiment is provided on the installation surface of the heavy oil tank T, the surface of the heavy oil tank T is covered with the protective structure 1, and the outer surface member 3 is positioned on the outermost surface. Even if a flying object comes to the heavy oil tank T, the flying object first collides with the outer surface member 3 of the protective structure 1. When the flying object collides with the outer surface member 3, collision energy is applied to the outer surface member 3, and a force for deforming the outer surface member 3 and a force for moving the outer surface member 3 toward the heavy oil tank T are generated.

  On the other hand, in the protective structure 1, since the plurality of cylindrical portions 10 are provided inside the outer surface member 3, the force applied to the outer surface member 3 is a cylindrical shape near the position where the flying object collides with the outer surface member 3. Part 10 (hereinafter referred to as a pressurized cylindrical part 10) is added. At this time, since the plurality of cylindrical portions 10 are provided such that the axial direction thereof coincides with the normal direction of the inner surface of the outer surface member 3, the force is mainly generated in the axial direction of the pressurized cylindrical portion 10. The pressurized cylindrical portion 10 is added so as to be compressed along the axial direction.

  Then, when the magnitude of the force applied from the axial direction of the pressurized cylindrical portion 10 becomes equal to or greater than the force causing axial crush in the pressurized cylindrical portion 10 (the force causing buckling), the cylindrical portion 10. The outer cylindrical member 11 and the inner cylindrical member 12 cause axial crushing (see FIG. 2A). Then, the outer cylindrical member 11 and the inner cylindrical member 12 are folded in a bellows shape while repeating buckling, and deformed so that the length in the axial direction is shortened (see FIGS. 1C and 2B). ). That is, since the energy applied to the pressurized cylindrical portion 10 is absorbed by the pressurized cylindrical portion 10 when the outer cylindrical member 11 and the inner cylindrical member 12 are axially crushed, the flying object is the outer surface member 3. The collision energy at the time of collision is absorbed by the pressurized cylindrical portion 10.

  As described above, when the protection structure 1 according to the present embodiment is provided, even if the flying object flies toward the heavy oil tank T, the collision energy is absorbed by the deformation of the pressurized tubular portion 10 of the protection structure 1. Therefore, the force applied to the heavy oil tank T can be reduced, and damage to the heavy oil tank T can be prevented.

Moreover, in the protection structure 1 of the present embodiment, the cylindrical portion 10 is formed by a plurality of cylindrical members (a pair of cylindrical members 12 and 13 in the above example). As compared with the case where it is used as a shock absorbing effect, it can be improved. For example, it has the cylindrical part 10 which consists of a pair of cylindrical members 12 and 13 compared with the case where the cylindrical member (single tube) of the same board thickness as the total board thickness of a pair of cylindrical members 12 and 13 is used. The protective structure 1 of this embodiment can improve the impact absorption effect. That is, the protective structure 1 of the present embodiment is simply formed with the tubular portion 10 so that a plurality of tubular members are nested, but the tubular member (single tube) is simply used as the shock absorber. The impact absorption effect can be improved compared to the case of using it.
In the present specification, the total plate thickness means the sum of the plate thicknesses of all the cylindrical members constituting the cylindrical portion 10.

For example, considering a case where about 100 kg of steel frame collides as a flying object due to a wind of 100 m / s class tornado, in this case, the collision force when the flying object collides with a building or the like is about 30G.
In such a case, when an aluminum pipe (single pipe, length 170 mm) having an outer diameter of 80 mm and a thickness of 5 to 7 mm is used as an impact absorbing member, the impact force applied to the heavy oil tank T is reduced to 2 G or less. I can't do it.
On the other hand, as the inner tubular member 12 of the pressurized tubular portion 10, an aluminum pipe (outer diameter 50 mm, inner diameter 44 to 46 mm (plate thickness t = 2 to 3 mm), length 170 mm) is used. As the outer cylindrical member 11, an aluminum pipe (outer diameter 80 mm, inner diameter 72 to 74 mm (plate thickness t = 3 to 4 mm), length 170 mm) is used. Then, even if the total plate | board thickness of the to-be-pressurized cylindrical part 10 is the same as the said single pipe | tube, collision energy is absorbed with the protective structure 1, and the collision force added to the heavy oil tank T is reduced to about 2G or less. Can do.

  And when the cylindrical part 10 is formed so that a plurality of cylindrical members are in a nested state, when the shaft is crushed in a bellows shape, the width of the load fluctuation is larger than that of the cylindrical member (single pipe). It can be made smaller (see FIG. 9B). When designing the cylindrical portion 10 as described above, load fluctuation (that is, absorption performance) at the time of deformation (axial crushing) of the cylindrical portion 10 is confirmed by numerical calculation. The numerical calculation is performed assuming that the load in the crushing process is a constant value. For this reason, if the width of the load fluctuation at the time of shaft crushing becomes small (if the load fluctuation becomes smooth), the difference between the actual machine and the result of numerical calculation (design) can be reduced. That is, when the cylindrical portion 10 is formed so that a plurality of cylindrical members are nested, the width of the load fluctuation is smaller than that of the cylindrical member (single tube), and thus the cylindrical portion 10 in the actual machine is used. Can be evaluated more accurately at the design stage. In other words, when the cylindrical portion 10 is formed so that a plurality of cylindrical members are nested, the cylindrical portion 10 can be made to have a performance closer to the design. The advantage that desired performance can be exhibited is also obtained.

(Arrangement of the inner cylindrical member 12 and the outer cylindrical member 11)
The inner cylindrical member 12 and the outer cylindrical member 11 are not particularly limited in outer diameter (inner diameter) and plate thickness, and when the inner cylindrical member 12 is disposed in the outer cylindrical member 11, it is between It suffices if it can be arranged so that a certain gap is formed. “A certain amount of gap between the two” means that the outer cylindrical member 11 and the inner cylindrical member 12 can be deformed into a bellows shape. That is, when “a certain amount of gap is formed between the two”, as described above, the inner cylindrical member 12 and the outer cylindrical member 11 are arranged so as to be coaxial, and the outer surface of the inner cylindrical member 12 is arranged. The present invention is not limited to the case where a uniform gap is formed between the outer cylindrical member 11 and the inner surface of the outer cylindrical member 11.

  For example, the outer surface of the inner cylindrical member 12 and the inner surface of the outer cylindrical member 11 are not in contact with each other. This is applicable. Moreover, even if the outer surface of the inner cylindrical member 12 and a part of the inner surface of the outer cylindrical member 11 are in contact with each other, a portion (gap) that is not in contact with each other is formed. If it can be deformed into a shape, that state also corresponds to the case where “a certain amount of gaps” are formed in this specification (see FIGS. 6C and 6D).

  In addition, when the inner cylindrical member 12 and the outer cylindrical member 11 are axially crushed, the inner cylindrical member 12 and the outer cylindrical member 11 have a gap so that they do not contact each other. It is desirable that they are arranged. That is, even if the inner cylindrical member 12 and the outer cylindrical member 11 are axially crushed, the outer cylindrical surface of the inner cylindrical member 12 and the inner surface of the outer cylindrical member 11 have a gap that is maintained in a non-contact state. It is desirable that the inner cylindrical member 12 is disposed in the outer cylindrical member 11 (see FIGS. 1C, 2B, and 2C). Then, when the inner cylindrical member 12 and the outer cylindrical member 11 are crushed axially, both can be smoothly deformed, so that an advantage that the efficiency of absorbing collision energy can be increased.

In order to keep the relative positions of the inner cylindrical member 12 and the outer cylindrical member 11 or to accurately position the relative positions of the inner cylindrical member 12 and the outer cylindrical member 11, A spacer may be provided in the gap between the inner cylindrical member 12 and the outer cylindrical member 11. If such a spacer is provided, any cylindrical part 10 can be in substantially the same state when a plurality of cylindrical parts 10 are provided, so that any cylindrical part 10 can be axially collapsed in substantially the same situation. If the spacer is provided, the relative positions of the inner cylindrical member 12 and the outer cylindrical member 11 can be prevented from shifting when the cylindrical portion 10 is installed. There is also an advantage that the work becomes easier. The shape of the spacer and the like are not particularly limited, and it is sufficient that the inner cylindrical member 12 and the outer cylindrical member 11 do not interfere with axial crushing. For example, a thin corrugated plate can be disposed between the inner cylindrical member 12 and the outer cylindrical member 11 to form the spacer 15 (see FIGS. 6A and 6B). In this case, the position at which the spacer 15 is provided is not particularly limited. As shown in FIGS. 6A and 6B, three spacers 15 may be provided, or only the intermediate spacer 15b in the vertical direction may be provided. Only the upper and lower spacers 15a and 15c may be provided.

(About the material of the cylindrical part 10)
The inner cylindrical member 12 and the outer cylindrical member 11 of the cylindrical portion 10 are hollow cylindrical members that are deformed into a bellows shape by being axially crushed when pressurized from the axial direction. There is no particular limitation as long as it is present. For example, the above-described aluminum pipe, steel pipe, and stainless steel pipe can be used as the inner cylindrical member 12 and the outer cylindrical member 11.

  In particular, if a commercially available aluminum pipe is used as the inner cylindrical member 12 or the outer cylindrical member 11, the advantage that the protective structure 1 can be installed in the heavy oil tank T or the like at a low cost is also obtained. For example, when the protective structure 1 is provided in the heavy oil tank T, about 40,000 cylindrical portions 10 must be provided in order to maintain the above-described performance (performance that reduces the collision force of 30 G to about 2 G or less). I must. Then, when a non-commercial product (such as a custom-made product) is used, the delivery time of the product becomes very long, and the cost of the product becomes very high. However, if a commercially available aluminum pipe or the like is used, the protection structure 1 can be installed in the heavy oil tank T or the like inexpensively and quickly because it can be easily obtained at low cost.

  Further, in the above example, the inner cylindrical member 12 and the outer cylindrical member 11 of the cylindrical portion 10 are the same except for the inner diameter, but those other than the inner diameter (for example, material, plate thickness, etc.) are different. May be used.

(Axis length change)
In order to reduce the collision force applied to the heavy oil tank T, it is desirable that the inner cylindrical member 12 and the outer cylindrical member 11 have different lengths.

  When a projectile collides with the protective structure 1, after the projectile collides with the protective structure 1, the period before the pressurized cylindrical portion 10 starts to deform (pre-deformation period) is pressurized. Since the cylindrical part 10 functions like a rigid body, the force applied to the protective structure 1 is directly applied to the heavy oil tank T via the pressurized cylindrical part 10. And in the period before a deformation | transformation, since the force added to the protection structure 1 from a flying object increases, the force added to the heavy oil tank T also increases (refer FIG. 9). In particular, immediately before the end of the pre-deformation period, the maximum force is usually applied to the heavy oil tank T including the pre-deformation period and the period (deformation period) in which the pressurized tubular portion 10 is deformed in a bellows shape. Therefore, after the flying object collides with the protective structure 1, it is preferable that the pressurized cylindrical portion 10 starts to be deformed with the lowest possible load.

  As described above, if the lengths of the inner cylindrical member 12 and the outer cylindrical member 11 are different, when a flying object collides with the protective structure 1, a force is applied only to one cylindrical member. . Then, since the deformation of the cylindrical member can be started with a low load, the force applied to the heavy oil tank T during the first period of deformation can be reduced, and the heavy oil tank T can be prevented from being damaged during this period. .

  For example, as shown in FIG. 5, the outer cylindrical member 11 is made longer than the inner cylindrical member 12. In this case, the force F when the flying object impacts is first applied only to the outer cylindrical member 11. Then, since only the outer cylindrical member 11 receives the force F, axial crushing of the outer cylindrical member 11 occurs with a smaller force than when the force is applied to both the inner cylindrical member 12 and the outer cylindrical member 11. (FIG. 5B). Therefore, the force applied to the heavy oil tank T in the pre-deformation period can be reduced.

  In the case of the above configuration (the outer cylindrical member 11 is longer than the inner cylindrical member 12), since the outer cylindrical member 11 is deformed with a small force, only the outer cylindrical member 11 is deformed. Can absorb less energy. However, if the outer cylindrical member 11 is deformed to have the same length as the inner cylindrical member 12, thereafter, both the outer cylindrical member 11 and the inner cylindrical member 12 are deformed and collide by axial crushing of both. Energy can be absorbed (see FIG. 5C). Therefore, even if the outer cylindrical member 11 is longer than the inner cylindrical member 12, it absorbs collision energy having a magnitude equivalent to that when the outer cylindrical member 11 and the inner cylindrical member 12 have the same length. can do.

  In the above example, the case where the outer cylindrical member 11 is longer than the inner cylindrical member 12 has been described. However, even if the inner cylindrical member 12 is longer than the outer cylindrical member 11, the same effect can be obtained. Can do.

(Other examples of arrays)
In the above example, the case where the plurality of cylindrical portions 10 are regularly arranged in the protective structure 1 has been described, but the arrangement method of the plurality of cylindrical portions 10 is not particularly limited, and is arranged at random. Also good. Further, the arrangement method and the density may be changed depending on the location of the protective structure 1. In this case, the protective structure 1 suitable for the portion can be formed in accordance with the strength of the structure and the importance of the portion to be protected. For example, in the protective structure 1 installed on the surface of a less important part or a higher strength part, the density of installing the plurality of cylindrical parts 10 is reduced (the number is reduced), and the plurality of cylindrical parts 10 If the thickness of the cylindrical member is reduced, the protective structure 1 can be reduced in weight and the manufacturing cost can be reduced.

(Different cylindrical part 10)
Moreover, the plurality of cylindrical portions 10 do not need to use the cylindrical portions 10 having the same structure, and may use the cylindrical portions 10 having different structures. In the protective structure 1 installed on the surface of the less important part or the higher strength part, one having reduced deformability with respect to the initial load may be used. For example, if the plate thickness of the inner cylindrical member 12 or the outer cylindrical member 11 is increased, the deformability of the cylindrical portion 10 at the initial stage of the collision can be reduced (start of axial crushing is delayed). On the contrary, if the deformability with respect to the initial load is improved, the axial crush can be rapidly advanced from the initial stage of the collision by reducing the thickness of the inner cylindrical member 12 or the outer cylindrical member 11.

(Multiple pipe)
In the above example, the case where the tubular portion 10 is a double tube having the inner tubular member 12 and the outer tubular member 11 has been described. However, the tubular portion 10 has three or more tubular members nested therein. It is good also as the multiple tube made. Even in this case, if the number of cylindrical members is adjusted, the collision energy absorbed by the protective structure 1 can be adjusted in accordance with the type of building or the like where the protective structure 1 is installed or the expected flying object. Further, as in the case of the double pipe described above, if cylindrical members having different lengths are provided, the axial crush can be rapidly advanced from the initial stage of the collision. Furthermore, if the combination of the thickness of each cylindrical member is adjusted, the collision energy absorbed by the protective structure 1 is adjusted according to the type of building or the like where the protective structure 1 is installed or the expected flying object. it can.

(Installation example of protective member 1)
In the above example, the case where the installation surface is a curved surface has been described. However, if the installation surface is a flat surface, the foundation member 2 and the outer surface member 3 may be formed so that the surfaces thereof are parallel to the installation surface. Good.

Moreover, the surface of the base member 2 and the outer surface member 3 does not necessarily have to be a parallel surface or a parallel curved surface with the installation surface, and may be an appropriate shape according to the shape of the installation target and the surrounding situation. For example, when there is an obstacle (a tree or other structure) in the vicinity of the installation target, the shape of the base member 2 or the outer surface member 3 may be adjusted so as not to contact the structure.
However, if the surface of the foundation member 2 or the outer surface member 3 is formed so as to be a parallel surface or a parallel curved surface with the installation surface, the protection structure 1 can be easily installed on the installation surface, and the protection structure 1 Can be fixed to the installation surface in a stable state. Moreover, it is also preferable in that the impact load is evenly transmitted to the protected equipment.

  Furthermore, you may use the protection member 1 independently, without installing in another member. For example, when a plurality of protection members 1 are arranged so that a plane is formed by the base member 2 and the outer surface member 3 to form a plate-like or box-like member, a protection plate composed of the plurality of protection members 1 is formed. Can do.

  Moreover, you may attach the cylindrical part 10 to the surface of a target object directly as the protection member 1, without providing the base member 2 and the outer surface member 3. FIG. In this case, since the protective member 1 can be reduced in weight compared with the case where the base member 2 and the outer surface member 3 are provided, an advantage that the burden on the building or the like where the protective member 1 is installed can be reduced.

  Further, as shown in FIG. 7, the protective member 22 may be formed by accommodating only the tubular portion 10 as the protective member 1 in the hollow box-shaped member 23. Specifically, a plurality of cylindrical shapes are provided between the two opposing walls 23a and 23b of the box-shaped member 23 so that the normal direction of the two walls 23a and 23b and the axial direction of the cylindrical portion 10 are parallel to each other. The parts 10 are arranged side by side. Then, when another object collides with the protection member 22 from the normal direction of the two walls 23a and 23b, the plurality of cylindrical portions 10 are axially crushed and can absorb the collision energy. For example, as shown in FIG. 7, a protection plate 20 having a plurality of protection members 22 can be formed by providing a frame 21 formed in a cross beam shape and attaching a protection member 22 to the frame 21. If the protective plate 20 is installed in front of a wall surface to be protected, the wall surface can be protected from collision with scattered objects.

  Furthermore, you may comprise the protection member 1 only with the cylindrical part 10 and the base member 2, or only the cylindrical part 10 and the outer surface member 3. FIG. When the protection member 1 is configured only by the tubular portion 10 and the base member 2, there is an advantage that the protection member 1 can be easily installed and reduced in weight. Further, when the protective member 1 is configured only by the cylindrical portion 10 and the outer surface member 3, energy is dispersed and absorbed by a plurality of cylindrical portions as compared with the case where the cylindrical portion 10 is exposed while being reduced in weight. And the appearance can be improved.

  In order to confirm the collision energy absorption performance of the protective member of the present invention, the relationship between the deformation of the cylindrical portion and the load when a load was applied from the axial direction to the cylindrical portion constituting the protective member was confirmed.

In the experiment, various cylindrical parts were formed, and each cylindrical part was pressurized and compressed by applying a load from the axial direction, and the relationship between the deformation (compression amount) of the cylindrical part and the load applied to the cylindrical part was determined. Measurement was performed (see FIG. 8).
In the experiment, a cylindrical part was attached to a compression tester (manufactured by Shimadzu Corporation: hydraulic RH vertical type), and a compression load was applied. The amount of compression and the load during the compression test were measured with a load cell and a dial gauge provided in the compression tester.

The following four tests were performed.
(1) Test to confirm the behavior of the double pipe (2) Test to confirm the effect of difference in plate thickness (3) Test to confirm the effect when changing the axial length (4) Confirm the effect of spacer test

(1) Test for confirming the behavior of the double pipe When a double pipe was used as the cylindrical portion, the amount of compression and the change of the load when pressure was applied by applying a load from the axial direction were compared.

The cylindrical part is made of an aluminum pipe (outer diameter 80 mm, plate thickness 3 mm, length 170 mm) and an aluminum pipe (outer diameter 50 mm, plate thickness 3 mm, length 170 mm). (Example 1) and an aluminum pipe (outer diameter 80 mm, plate thickness 3 mm, length 170 mm) in an aluminum pipe (outer diameter 50 mm, plate thickness 2 mm, length 170 mm) ) Was used to make a double pipe (total thickness 5 mm) (Example 2).
The single pipes to be compared include an aluminum pipe (outer diameter 80 mm, plate thickness 5 mm, length 170 mm, comparative example 1) and an aluminum pipe (outer diameter 80 mm, plate thickness 4 mm, length). 170 mm, Comparative Example 2) was used.

FIG. 9A shows the result.
In any case, the reason why the load increases rapidly after the compression amount of 110 mm is that it is not possible to compress any more (the state shown in FIG. 1C).

As shown in FIG. 9A, in both Example 1 and Comparative Examples 1 and 2, it can be confirmed that the load varies in a waveform as the compression amount increases. In Example 1, the peak load fluctuates so as to have a magnitude between Comparative Examples 1 and 2.
Considering that the pipe of Example 1 is thinner than Comparative Examples 1 and 2 but the total thickness is larger than Comparative Examples 1 and 2, the above results indicate that the pipe combination If adjusted, it is considered that there is a possibility that a cylindrical portion exhibiting a desired behavior with respect to the load may be formed.

Further, as shown in FIG. 9B, the total plate thickness of Example 2 and the plate thickness of Comparative Example 1 are the same, but the behavior is different.
First, the load at the first peak is slightly smaller in Example 2, and buckling starts earlier. That is, if the total plate thickness is the same, it can be confirmed that the multi-tube has higher impact absorption performance with respect to the initial load than the single-pipe pipe.
Next, when the behavior after the first peak is compared, the fluctuation period of Example 2 is shorter than that of Comparative Example 1. And the load of the part used as the peak of each period is about 20 to 30% smaller in Example 2 than the peak load in Comparative Example 1. Moreover, in Comparative Example 1, the load at the peak of each cycle is about the same as the load at the first peak, whereas in Example 2, the load at the peak of each cycle is at the first peak. It is about 30 to 40% smaller than the load. From this, in the process of deforming into a bellows after buckling occurs, if the total plate thickness is the same, the multiple pipe is smaller and smoother than the single pipe, and the impact is affected by smooth load fluctuations. It can confirm that it has absorbed.
And in the final compression amount, compared with the comparative example 1, Example 2 is compressed 15 mm or more largely. That is, if the total plate thickness is the same, it can be confirmed that the total shock absorption amount of the multiple tube is increased.

  As described above, it can be confirmed that the shock absorption performance of the multiple pipe is generally higher than that of the single pipe having the same thickness as the total thickness.

(2) Test for confirming the effect of difference in plate thickness When a double tube was used as the cylindrical portion, the effect of the plate thickness of each tube on impact absorption was confirmed. In the experiment, the total thickness of the two tubes was the same, and the thickness of each tube was changed for comparison.

In Examples 3 and 4 below, the total plate thickness was adjusted to 6 mm.
The cylindrical portion (Example 3) is obtained by placing an aluminum pipe (outer diameter 50 mm, plate thickness 3 mm, length 170 mm) in an aluminum pipe (outer diameter 80 mm, plate thickness 3 mm, length 170 mm). A double tube was used.
The cylindrical portion (Example 4) is obtained by placing an aluminum pipe (outer diameter 50 mm, plate thickness 2 mm, length 170 mm) in an aluminum pipe (outer diameter 80 mm, plate thickness 4 mm, length 170 mm). A double tube was used.

In Examples 5 and 6 below, the total plate thickness was adjusted to 7 mm.
The cylindrical portion (Example 5) is obtained by placing an aluminum pipe (outer diameter 50 mm, plate thickness 3 mm, length 170 mm) in an aluminum pipe (outer diameter 80 mm, plate thickness 4 mm, length 170 mm). A double tube was used.
The cylindrical portion (Example 6) is obtained by placing an aluminum pipe (outer diameter 50 mm, plate thickness 2 mm, length 170 mm) in an aluminum pipe (outer diameter 80 mm, plate thickness 5 mm, length 170 mm). A double tube was used.

  The results are shown in FIGS. 10 (A) and 10 (B).

  As shown in FIG. 10A, in Examples 3 and 4, although there are differences in the load that becomes the fluctuation cycle and the valley, the peak load is substantially the same after the first peak load, and the behavior is similar. This can be confirmed.

  On the other hand, as shown in FIG. 10B, in Examples 5 and 6, there is a large difference in peak load between the two, and in Example 6 using a pipe having a thickness of 5 mm, compared to Example 5. Thus, the peak load is greatly increased at all peaks. Moreover, in Example 6, when the amount of compression becomes about 105 mm, the load increases rapidly. In Example 5, considering that the timing at which the load increases is the compression amount of 110 mm or later, it can be confirmed that the amount that can be compressed is reduced in Example 6.

Considering the above results, it was confirmed that if the thicknesses of the pipes to be assembled are approximately the same, if the total thickness is the same, a behavior approximated when compressed is produced.
On the other hand, if a pipe with a large plate thickness (that is, a pipe with high strength against compressive load) is used, it is strongly affected by the properties of the pipe with a large plate thickness. I was able to confirm.

For reference, FIG. 11A shows the result when the cylindrical portion is a triple tube so that the total plate thickness is 7 mm. Even in the case of a triple pipe, it can be confirmed that if an axial load is applied, the load changes into a waveform, and each pipe is deformed into a bellows shape.
On the other hand, even if the total plate thickness is the same, the peak load and the like in the triple pipe are slightly different from those in Examples 5 and 6 (double pipe). This indicates that even if the total plate thickness is the same, if the number of tubes constituting the cylindrical part and the plate thickness are adjusted, it is possible to form a cylindrical part that exhibits the desired behavior with respect to the load. It is thought that there is.

(3) Test for confirming the effect when the axial length is changed When the double pipe is used as the cylindrical portion and the pipe having a different axial length is used, the state of shock absorption was confirmed.

  The cylindrical portion (Example 7) is obtained by placing an aluminum pipe (outer diameter 50 mm, plate thickness 3 mm, length 165 mm) in an aluminum pipe (outer diameter 80 mm, plate thickness 3 mm, length 170 mm). A double tube was used. That is, the inner tube was shortened.

FIG. 11B shows the result.
For comparison, the results of Example 1 are shown in the same graph.
As shown in FIG. 11B, in Example 7, the initial peak load is smaller than in Example 1, and it can be confirmed that the deformation of the pipe starts earlier with a small load.
On the other hand, when the amount of compression exceeds 5 mm, the behavior of Example 1 and Example 6 shows almost the same behavior thereafter.

  From the above results, it was confirmed that when the axial length of the double pipe is changed, the impact absorbing performance in the initial stage when the load is applied can be improved.

(4) Test for confirming the influence of the spacer In the case of a double pipe, the influence of the positions of the outer pipe and the inner pipe in the cross section on the state of shock absorption was confirmed.

In the experiment, the same pipe as in Example 1 was used, and the corrugated plate (plate thickness 0.4 mm) was used as a spacer in the gap between the outer tube and the inner tube (Examples 8 and 9, FIG. 6A). , (B)) and when the inner tube is arranged so as to contact the outer tube (see Example 10, FIGS. 6C and 6D), the behavior when compressed is confirmed. did.
In Example 8, only one spacer was disposed in the middle of the pipe in the axial direction, and in Example 9, one spacer was disposed above and below the pipe in the axial direction (two in total).

The results are shown in FIG.
As shown in FIG. 12, it can be confirmed that Examples 8 to 10 show almost the same behavior. Further, even when compared with the behavior of Example 1 (see FIG. 9A), it can be seen that the behavior is almost the same.

From the above results, it was confirmed that if each tube can be deformed in a bellows shape, the positions of the outer tube and the inner tube and the spacers have little influence on the shock absorbing performance.
However, in Example 10, since the load is higher than the other examples after the compression amount is 100 mm or more, when the inner tube and the outer tube are in contact with each other, the impact absorbing performance is slightly increased. It is assumed that there will be an impact on

  The protective structure of the present invention is suitable for installation on the wall surface of buildings such as buildings, warehouses, heavy oil tanks, and water tanks.

DESCRIPTION OF SYMBOLS 1 Protective structure 2 Foundation member 3 Outer surface member 10 Cylindrical part 11 Outer cylindrical member 12 Inner cylindrical member 15 Spacer 20 Protection plate T Heavy oil tank

Claims (6)

It has a cylindrical portion having a plurality of circular cylindrical members,
The plurality of cylindrical members are:
The central axes are parallel to each other so that a gap is formed between the outer surface of the inner cylindrical member positioned inward and the inner surface of the outer cylindrical member positioned outward. Arranged ,
A spacer is provided between the outer surface of the inner cylindrical member and the inner surface of the outer cylindrical member to maintain a gap therebetween.
The spacer is
The protective structure according to claim 1, which is a member that axially collapses together with the inner cylindrical member and the outer cylindrical member when a force for compressing the cylindrical portion is applied from an axial direction of the cylindrical portion .   A box-shaped member having two opposing walls;
A plurality of the cylindrical portions disposed between two walls of the box-shaped member,
The plurality of cylindrical portions are
The both ends are arranged so as to be in contact with the two walls of the box-shaped member.
The protective structure according to claim 1.   The object to be protected is a building,
The plurality of cylindrical members are arranged along the surface of the building.
The protective structure according to claim 1 or 2, wherein The cylindrical part is
Claim 1, 2 or 3 protection structure, wherein the <br/> that is composed of a plurality of tubular members having different lengths. The plurality of cylindrical members are:
When a force compressing from the axial direction is applied, it can be deformed into a bellows shape,
A gap between the outer surface of the cylindrical member positioned inward and the inner surface of the cylindrical member positioned outward adds a force for compressing the cylindrical member from the axial direction, and the plurality of cylindrical members are bellows. when deformed into Jo, claims, characterized in that the inner surface of the tubular member located on an outer surface and an outer tubular member positioned inwardly are disposed so as to maintain a non-contact state Item 5. A protective structure according to item 1, 2, 3 or 4 . The cylindrical portion is formed of a pair of cylindrical members;
The outer cylindrical member located outside is an aluminum pipe having an outer diameter of 80 mm and an inner diameter of 72 to 74 mm.
6. The protective structure according to claim 1, wherein the inner cylindrical member positioned inward is an aluminum pipe having an outer diameter of 50 mm and an inner diameter of 44 to 46 mm.