JPH112048A - Vibration control device for large-space structure consisting of single layer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vibration control device for large-space structure consisting of single layer, which can effectively absorb and damp the vibrations in an out-of-plane direction generated in a single layer truss by the use of a TMD (tuned mass damper). SOLUTION: A TMD unit 14 is installed approx. in the center of a plane truss 4A and extends plumb in an out-of-plane direction, and its two ends are supported in the plane truss 4A by four diagonals 16 extending to the nodes 6 of the truss 4A. Each diagonal 16 is coupled by pin with each node 6, and also the connection of the diagonal 16 with the TMD unit 14 is accomplished as pin coupling at the node 6a. The plane truss 4A in which the TMD unit 14 is installed, is fixed to a framing in its specified position, and a unit structure of rectangular three-dimensional form is built by joining the diagonals 16 together, but the truss framing as a whole has merely a structural plane consisting of a single layer of skeleton formed from plane truss 4A, so that it remains a single layer truss fundamentally.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a single-layer truss in which a minimum number of plane trusses, which are basic elements, are framed in the form of a mesh, and the entire structure is formed into a frame having a desired shape as a whole. The present invention relates to a single-layer vibration control device for a large space structure which absorbs and attenuates out-of-plane vibrations using a tuned mass damper unit.

[0002]

2. Description of the Related Art Conventionally, a multi-layer truss has been often used for a roof of a large space structure or the like. This multi-layer truss is a frame structure of a frame formed by assembling a large number of net three-dimensional trusses as basic elements into a mesh-like structure, and the frame forming the frame of the frame is composed of two or more layers. .

In a multi-layer truss having two or more layers of surfaces with this space truss as a minimum unit, the force transmission in each truss member is in two directions and the load is transmitted to the entire frame, so that a large concentrated load is applied. It is advantageous for asymmetrical loads, and is lightweight and has high in-plane rigidity. Further, since the indeterminate constant order is high, even if a large damage occurs in a part, the whole structure is not collapsed, and the structure reliability is high.

There are triangular pyramids, quadrangular pyramids, and the like as the shape of the minimum unit space truss as a basic element. The roof shape of the entire frame formed by assembling these basic elements is as follows.
As shown in FIG. 8, flat plate, gable, square, ridge,
There are various forms such as a partial cylinder and a spherical shell dome.

[0005] A single-layer truss is one that has a single frame that forms the surface of the frame and does not have a three-dimensional truss member. This single-layer truss is a framed structure constructed by assembling a large number of these into a single-layer mesh, with the minimum unit being a planar unit being the basic element. The buckling strength of each truss member has a large effect on the overall buckling strength because of its low stiffness, so it has not been widely adopted in the past. In recent years, attention has begun to attract attention because simplification and the like are possible.

[0006]

By the way, in recent years, as the span of large space structures is becoming longer and longer, it is necessary to consider the effects of vibrations due to earthquakes and winds on the out-of-plane direction of the single-layer truss. The dynamic response of the vibration is being studied by mathematical analysis. As a result of the study, it has been reported that incorporating a tuned mass damper (hereinafter abbreviated as TMD) into a single-layer truss to absorb and attenuate out-of-plane vibrations is effective for vibration suppression measures. I have.

Here, regarding the multi-layer truss, T
As a vibration damping device incorporating an MD unit, for example, a technique disclosed in Japanese Patent Application Laid-Open No. 5-332050 has been proposed. In other words, this proposal includes supporting both ends of an upper chord and a lower chord of a truss beam forming a two-layer structure on the roof of a large space structure, and absorbing out-of-plane vibration therebetween. It is shown that a TMD unit is provided to attenuate the pressure.

However, for a single-layer truss having a single-layer structure and no upper / lower chords, a feasible concrete method for incorporating a TMD unit into the single-layer truss has not yet been shown. In this single-layer truss, the buckling strength of the individual truss members is lower than that of the truss, and the buckling strength of the individual truss members greatly affects the overall buckling strength. Is an important issue.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a single-layer truss capable of effectively absorbing and attenuating out-of-plane vibration generated in a single-layer truss using a TMD. A vibration control device for a large space structure comprising:

[0010]

In order to achieve the above-mentioned object, in the vibration damping device for a large space structure having a single layer according to the present invention, a plane truss of a minimum unit, which is a basic element, has a large number of meshes. In a single-layer truss formed into a frame having a desired structure as a whole, the frame is formed into a frame having a desired shape. A TMD unit that absorbs and attenuates directional vibrations is provided, and the TMD unit is supported by the minimum unit planar truss via a node provided outside the plane.

According to the vibration damping device for a large space structure composed of a single layer, the planar truss into which the TMD unit is incorporated supports both ends of the TMD unit extending in the out-of-plane direction at out-of-plane nodes. Although it is a unit with a rectangular three-dimensional structure, the frame as a whole only has a structure with a single frame formed by a plane truss, it basically remains a single-layer truss, and A TMD unit that absorbs and attenuates out-of-plane vibrations without having a lower chord material can be incorporated. Therefore, the TMD unit can be incorporated into the single-layer truss to effectively exert the vibration-damping effect without impairing the advantage of the single-layer truss, such as a small number of parts and the resulting light weight. Can promote the practical use of

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a single-layer truss vibration damping device according to the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 is a schematic perspective view conceptually showing the entire frame of a dome roof of a large space structure constructed by a single-layer truss incorporating a vibration damping device according to the present invention.
Is a perspective view schematically showing a minimum unit planar truss which is a basic element of a frame of the single-layer truss, and FIG. 3 incorporates a TMD unit disposed at a required portion of a dome roof constructed by the single-layer truss. FIG. 4 is a side view showing a schematic configuration of the TMD unit.

As shown in the figure, the dome roof 2 is formed by combining a large number of minimum unit planar trusses 4 which are basic elements in a mesh shape vertically and horizontally to form a dome-like frame having a more curved surface as a whole. Have been.

Here, the basic structure of the plane truss 4 as a basic element in the single-layer truss of this embodiment is a rectangular shape in which four truss members 41 are joined by pins at the nodes 6 (FIG. 2).
(See (a)), a large number of the flat trusses 4 are connected vertically and horizontally to form a curved frame-shaped dome roof 2 having a single-layer frame. The dome roof 2 has a hybrid single-layer truss structure as a structure capable of achieving self-balancing and increasing rigidity against bending.

That is, the tension-stable truss 8 is shown in FIG.
As shown in (b), a post member 10 extending on both sides in the out-of-plane direction is arranged at the center of a rectangular planar truss 4 forming a basic form, and this post member 10 is connected to four nodes of the planar truss 4 from both ends thereof. The cable 12 is provided with tension by introducing tension to the cable 12, and a film (not shown) is stretched on the cable 12. The unit has a rectangular three-dimensional structure combined with the flat truss 4. To form However, the entire frame of the dome roof 2 has only one frame of the frame formed by the flat truss 4 and is basically a single-layer truss.

The flat truss 4 and the tension stable truss 8
The above-mentioned unit has a function of resisting an external force by a combination of the tension of the cable 12 and the membrane and the axial compressive force of the post member 10 and the truss member 41, and converting the bending resistance to the axial force resistance. In addition, a self-balancing structure is completed, the rigidity in and out of the plane is large, and a structure having high stability against buckling load can be constructed.

The dome roof 2 generates out-of-plane vibrations due to an earthquake, wind, or the like. In order to reduce the out-of-plane vibrations, the flat truss 4 at a required portion is provided with the tension. Instead of the stable truss 8, a device incorporating a TMD unit is provided. FIGS. 3 and 4 show a planar truss 4A incorporating the TMD unit.

As shown in FIG. 3, the TMD unit 14
Are arranged at substantially the center of the center of the plane truss 4A and extend vertically in the out-of-plane direction, and both ends of the four truss diagonal members 16, 16 extending to each node 6 of the plane truss 4A, respectively.
Is supported by the plane truss 4A. Here, each truss diagonal member 16, 16... Is pin-connected to the node 6 of the plane truss 4A, and each truss diagonal member 16, 16.
The connection with the MD unit 14 is also a pin connection at the node 6a. That is, the TMD unit 14 is connected to the nodes 6a, 6a provided on both sides of the plane truss 4A in the out-of-plane direction, and is supported by the plane truss 4A via this.

Therefore, the flat truss 4A into which the TMD unit 14 is incorporated becomes a unit having a rectangular three-dimensional structure by joining the truss diagonal members 16, 16,.... However, similar to the case where the tension stable truss 8 is incorporated,
The entire frame of the dome roof 2 is a flat truss 4, 4A
Has only a single-story framing formed by the same and remains essentially a single-layer truss.

As shown in FIG. 4, the TMD unit 14 includes an additional mass body 18 and an elastic body 20 for elastically supporting the additional mass body 18 so as to be movable in an out-of-plane direction (vertical direction in FIG. 4). And a cushioning member 22 for suppressing the movement of the additional mass body 18. The additional mass body 18 is disposed substantially at the center of the plane truss 4A, and two elastic members connected to both sides in the out-of-plane direction. The elastic members 20 and 20 are elastically supported so as to be able to vibrate in an out-of-plane direction, and the vibration is absorbed and attenuated by a buffer member 22 arranged in parallel with the elastic members 20 and 20.

FIG. 5 shows a specific configuration example of the TMD unit 14. As shown in the figure, a telescopic air damper 24 constituting the cushioning member 22 is attached to each of two opposing end faces of the additional mass body 18. The air damper 24 includes a cylinder 28 forming an air chamber 26 and a piston rod 30 slidably fitted to the cylinder 28. The cylinder 28 has an orifice 32 for communicating the air chamber 28 with the atmosphere. Is formed.

The cylinder 28 and the piston rod 30
The spring seats 34 and 36 are formed so as to expand in the radial direction outward, respectively.
A coil spring 38 constituting the elastic body 18 is mounted between the coil springs 4 and 36. The piston rod 30 is integrally fixed to the additional mass body 18 via the spring seat 36 provided at the end of the piston rod 30. The cylinder 28 has the four truss ends. Node 6 which is a joining point of diagonal members 16, 16,.
a. Here, an oil damper or a friction damper may be employed instead of the air damper 24.

In the TMD unit 14, the additional mass body 18 moves and vibrates due to the out-of-plane vibration of the dome roof 2, and the vibration is attenuated by the air damper 24 so that the TMD unit 14 is installed. Of the plane truss 4A in the out-of-plane direction is reduced.

FIGS. 6 and 7 show the above TMD unit 1 respectively.
FIG. 4 is a plan view showing an example of an arrangement form of the flat truss 4 </ b> A into which the truss 4 is incorporated on the dome roof 2, showing the curved dome roof 2 flatly developed. In FIGS. 6 and 7, small rectangles shown by solid lines vertically and horizontally on the paper are plane truss 4 and 4A, respectively. Lumber 1
The TMD unit 14 is indicated by a white circle at the intersection of 6. The oblique broken line in the rectangle of the flat truss 4 is the cable 12 of the tension stable truss 8, and the intersection of the cable 12 is the post member indicated by a black circle.

In the arrangement shown in FIG. 6, the flat truss 4A incorporating the TMD unit 14 and the tension stable truss 8
Are arranged alternately vertically and horizontally in a checkered pattern over the entire surface of the dome roof 2 so as to exert a vibration damping effect over the entire surface.

In the arrangement shown in FIG. 7, the dome roof 2
In the out-of-plane vibration pattern generated in the whole, the TMD unit 14 is incorporated in the plane truss 4A at a portion where the vibration increases, and in the illustrated example, the center of the dome roof 2 and an annular shape so as to surround the center. It is arranged. That is, the TMD unit 14 is provided only in the plane truss 4A at the portion where the vibration in the out-of-plane direction becomes particularly large.
Is incorporated, the increase in the number of components and the overall weight of the dome roof 2 can be suppressed as much as possible, rational vibration control can be performed, and the construction cost can be further reduced. In addition,
Here, in the illustrated example of FIG.
The units 14 are provided continuously, but are not limited to this, and can be provided with an interval as needed.

In the above description, the case where the plane truss of the minimum unit, which is a basic element of the single-layer truss, is formed in a rectangular shape, but the plane truss of the minimum unit is triangular or hexagonal. The shape may be a polygon, and the shape may be any polygonal shape.

Further, the frame structure formed by the single-layer truss is not limited to the dome, but may be formed by a truss other than a flat plate, a gable, a square, a ridge, a partially cylindrical shape as shown in FIG. It can be of any shape.

[0030]

As described above in detail, according to the vibration control device for a large space structure composed of a single layer according to the present invention, the TM
The flat truss in which the D unit is incorporated is a unit having a rectangular three-dimensional structure because the two ends of the TMD unit extending in the out-of-plane direction are supported through out-of-plane nodes, but the entire frame is formed by the flat truss. Basically, it has a single-layer truss only with a single-layer frame, and absorbs and attenuates out-of-plane vibrations even if it does not have upper and lower chords like a multi-layer truss. A TMD unit can be incorporated. Therefore, the TMD unit can be incorporated into the single-layer truss to effectively exert the vibration-damping effect without impairing the advantage of the single-layer truss, such as the small number of components and the resulting light weight. , Which can promote the practical use of single-layer trusses.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view conceptually showing an entire frame of a dome roof formed by a single-layer truss into which a vibration damping device according to the present invention is incorporated.

FIG. 2 (a) is a perspective view schematically showing a minimum unit planar truss which is a basic element of the single-layered large space frame, and FIG. 2 (b) is a tension truss added to the plane truss. It is a perspective view showing a compound unit.

FIG. 3 is a perspective view schematically showing a flat truss incorporating a TMD unit disposed at a required portion of a dome roof by the single-layer truss.

FIG. 4 is a side view showing a schematic configuration of a TMD unit.

FIG. 5 is a side sectional view showing a specific configuration example of a TMD unit.

FIG. 6 is a plan view showing an example of an arrangement of a plane truss incorporating a TMD unit.

FIG. 7 is a plan view showing another example of an arrangement of a plane truss incorporating a TMD unit.

FIG. 8 is a perspective view schematically showing a form of a roof of a conventional large space structure.

[Explanation of symbols]

 2 Dome roof 4, 4A Plane truss 6, 6a Node 8 Tension stable truss 10 Post member 12 Cable 14 TMD unit 16 Truss diagonal material 18 Additional mass 20 Elastic body 22 Buffer member 24 Air damper 38 Coil spring

Claims (1)

[Claims] 1. A single-layer truss in which a minimum unit flat truss serving as a basic element is framed in a mesh form to form a frame having a desired structure as a whole in a single-layer truss. A tuned mass damper unit that absorbs and attenuates out-of-plane vibrations of the plane truss is disposed at a central portion of the plane truss of the minimum unit in the portion, and the tuned mass damper unit is provided out of the plane. A vibration control device for a large space structure consisting of a single layer, wherein the vibration control device is supported by the minimum unit planar truss via a node.