SU1752895A1 - Prestressed arch structure - Google Patents

Abstract

Use: for structures of collapsible prestressed arched trusses. The essence of the invention: the arched structure contains the upper prestressed flexible in c, the lower hard in c, the lattice elements that form with themselves quadrilateral cells, the opposite sides of which are made of rigid rods hinged to the lower part of the Bottom by with formed from hingedly connected rods. Each cell has a flexible diagonal with the intersection of the extension of the axes along its length in the zone of acute-angled sectors formed by the axis of tightening and the extension of the axis of the corresponding diagonal. 3 hp f-ly, 8 ill.

Description

WITH

with

The invention relates to the construction, in particular to the structures of collapsible prestressed building elements such as arched trusses, suitable for covering buildings of various purposes on both rectangular and polygonal planes and can be used in supporting structures of automatically opening reflectors of space antennas. .

The pre-stressed arched structure with a rigid upper catfish in the form of hingedly coupled rods with a flexible bottom catfish and braces is known.

The disadvantage of this design is that for the geometrical immutability of the structure it is necessary to mount the supports to a rigid base or to have a spacer connecting the supports, which significantly complicates the design and limits its scope.

The closest solution to the technical essence of the present invention is a pre-stressed arched structure, including the upper pre-stressed flexible in c, the lower hard e, the lattice elements located between themselves, and the supporting assemblies with flexible tightening.

A disadvantage of the known construction is that it does not fold due to the presence of a rigid arched belt with flexural stresses and the making of all the lattice elements in the form of rigid squeezed rods.

The purpose of the invention is to provide a compact design.

In the pre-stressed arched design, the lattice elements from to saXI

cl

hO 00

about cl

They form quadrangular cells, the opposite sides of which are made of rigid rods that are hingedly connected to the lower stem, made in the form of hingedly connected rods, while each cell has a flexible diagonal intersecting the continuation of its axes in the area of acute sectors and the continuation of the axis of the corresponding bracing, the length of the rigid rods of the lattice is less than the distance between the hinges of the rods of the lower bar. At least one of the rigid bars of the lattice is adapted to vary the length. In addition, the hinges of the rigid rods of the lower belt are spring-loaded for mounting.

FIG. 1 depicts a collapsible precursors-Go-stressed arched structure in the design position, side view; in fig. 2 - the same, in the process of folding; in fig. 3 - the same, in folded form (flexible elements are not shown), side view; in fig. 4 is a plan view of the antenna reflector of elements in the form of radial trusses; in fig. 5 - the same, side view; in fig. 6 - a fragment of a collapsible pre-stressed structure; in fig. 7 is a view A of FIG. 6; in fig. 8 is a diagram of the location of the points of intersection of the extensions of the axes along the sharp and acute-angle sectors.

The pre-stressed arched structure includes a lower rigid-in with rods 1 connected in the hinges 2, an upper pre-stressed flexible in c 3, flexible braces A and rigid rods 5. To the supporting nodes 6 a bending knot 7 is attached, rigid to C of the rods 1 is located between the flexible catfish 3 and the puff 7. The rigid rods 5 are hingedly attached to 1 and 3 themselves with the formation of quadrilateral cells 8. The flexible braces 4 are located diagonally of the cells 8. The rods 1 have axes 9 (Fig. 8 ), the continuation of which intersect with the axes 10 ibkih chord 3 at points 12, 11. The axis 7 and tightening continuation axes 13 4 struts intersect at points 14. The points 11 are positioned in acute sectors zone 15 with vertices 14.

For convenience of installation, the rigid rods 5 are made shorter than the distances between adjacent hinge nodes 2 of the lower rigid strip of rods 1.

Figs 1-6 show a structure, one of the rigid rods of the grid 16 of which is designed with the possibility of changing the length.

FIG. 4 and 5, an example is given of the formation of radial trusses of the same type of folding elements 17 of a system with a total length 16 of the rod 16 and an annular tightening 18.

To rods m 1 lower hard

can be attached reflective mesh 19.

Pre-stressed arched

construction (Fig. 6 and 7) in the hinge nodes

2 is provided with springs 20, due to which the structure is spring-loaded onto the opening.

When the bend is not tight, the design changes. It gives the chance due to hinged connections in

nodes fold the structure (Fig. 2 and 3) in the overall transport volume.

The layout of the structure in the design position can be made by releasing the spring-loaded hinges.

on the opening or by stretching the structure in length manually or with the help of the simplest mechanisms.

Constancy of construction is achieved after its layout to the design position.

by tightening. Due to the hinge joints of rigid rods in the nodes, the tension of the tightening causes stretching in the flexible elements and compression in the rigid rods, and, conversely, stretching any one of the flexible rods or compressing one of the rigid ones causes a corresponding tension zhki. Thus, a given stress state, ensuring the stabilization of the structure

(its prestress) can be achieved by tightening the tension or by imposing the required amount of force on any of the rods, and this pointing can be achieved by shortening the expanded or elongated-compressed rod.

Ensuring the stretching of flexible prestressed braces is achieved by choosing the appropriate

the geometrical configuration of the truss, which is the proposed construction.

The necessary conditions for selecting the geometry of the structure (Fig. 8) are as follows.

Three sections I, II, and III have been carried out to determine the forces in flexible spacings of Si, 82 and 8h, respectively. Consider the sections of the farm from the left support to the section. Thus, for example, for such a region limited by section I, the point AI at which they intersect

The 5 axis axis is the torque point for the force in the diagonal st. By making a moment equilibrium equation for m. AI, you get

H-drn -Srdsi 0; Si H

dHi

Similarly, for sections II and III (in other quadrangular truss cells) with respect to point A2,

H-dH2-S2ds2 0; S2 H -;

0S3

H-dH3-S2ds3 0;

dH3 dss

It follows from the relationships obtained that stretching in flexible braces Si, S2 and 5h from thrust H is provided when the points AI and Aa intersections along the owls of the corresponding cells are located in acute sectors 15 with vertices 14 formed by intersection of axis 12 of puff 7 with extension 13 the axis of the brace 4 belonging to the same cell (in Fig. 8, sectors 15 are shaded); for a cell with a diagonal Si, this sector is designated Ci. CM, D; for bracing Sz - € 2, 02, D; for bracing Zs - Sz, Oz, D).

In the case when the points AI and A2 of the intersection over the joint go beyond the limits of the indicated acute-angled sectors, the forces of spreading H applied to the supports and bringing them together cause compression in the bracings. When the points of intersection along the line lie on the line of support, the forces in the bracings of force H are zero. The location of the points of intersection along the owl on the line of the corresponding bracing is devoid of geometric meaning.

The design can be used both as a single arched truss and as a radial arched system: in the first case, the tie connects the supports along the straight, in the second case the supports can be connected with the ring pull.

In the case of construction for coating buildings of various purposes, the element in the form of a flat arched truss is mounted in its own plane, aligned with the horizontal one, it is stabilized with one of its rods, which transmits a preliminary voltage to the entire structure. Then the arched truss is installed in the design

position, combining its own plane of the farm with the vertical.

Effective use of the design for the folding frame of the reflector antenna, including space. In this case, the frame made in the form of a system of radial arched trusses, is provided with a common variable along the length of the rod 16 in the form of a stand. Due to the hinge connection of 10 m rods, the skeleton folds into overall volume. Then, due to the springs, the frame opens to a position close to the design, then the drive is activated, and the rod 16 is extended to the desired

15 magnitudes, for example, by rotating a screw pair 21 (Figures 1 - 3, 6). This achieves design stabilization of the framework. The grid 19, attached to the rods 1 in the factory, creates the reflective surface of the antenna reflector.

Claims (1)

The formula isobrege 1. The prestressed arched structure, including the upper prestressed flexible over, 5 bottom rigid with s, the lattice elements located between themselves, and supporting nodes with a flexible tightening, characterized in that, in order to ensure the compactness of the structure, the lattice elements gradually form quadrangular cells, the opposite sides of which are made of rigid rods pivotally connected to the lower catfish, made in the form of pivotally connected rods, 5, each cell has a flexible strut with the intersection of the extension of the axes along its length in the zone of acute-angled sectors formed by the axis of tightening and offering the axis of the corresponding strut. O 2, Structures according to claim 1, characterized in that the length of the rigid rods of the lattice is less than the distance between the hinges of the rods of the lower lattice. 3. The structure according to claim 1, clause 5 and 5 with the fact that at least one of the rigid rods of the lattice is made with the possibility of changing the length. 4. The designs in accordance with claim 1, which is connected with the fact that the hinges of rigid rods 0 bottom sa sa spring loaded for installation. 1752895 3Purk Fm / g 5 21 Fig 6 Vida (rig 7 s