SU1609529A1 - Method of producing metal perforated beam - Google Patents

Abstract

The invention relates to the processing of metals by pressure, in particular to the manufacture of perforated metal beams used in construction. The aim of the invention is to increase the carrying capacity by creating a prestressing during assembly. The method includes cutting two initial blanks in broken zigzag lines and subsequent joining and welding parts from each of the blanks. The side portions of the broken zigzag line of the blank forming the lower part of the beam are inclined relative to the normal to the longitudinal axis of the beam by an angle equal to half the angle between the normals to the longitudinal axis of the beam bent under the operational load in the zone of maximum bending moment. The method allows to obtain prestressed beams, which under load are parallel to the ca. 4 il.

Description

The invention relates to the processing of metals by pressure, in particular to the manufacture of perforated metal beams used in construction.

The aim of the invention is to increase the bearing capacity of the beam by creating a prestressing during assembly.

FIG. Figure 1 shows the workpiece forming the upper part of the beam with the cut line applied: FIG. 2 — billet forming the lower part of the beam; Fig. 3 shows the beam obtained; in fig. 4 is a diagram of the layout of the workpiece.

The method is carried out as follows.

The marking of the workpiece 1, which forms the upper part of the beam with height hf), is made by applying sections of the broken line 2 located along and normal to the axis. The height h of the projections 3 and 4 and their pitch

determined from the calculation of the bearing capacity of the beam, after which the workpiece is cut into two parts, which have the same height h and the pitch of the projections. To mark the workpiece 5. forming the lower part of the beam, first calculate the angle (p between the normal to the beam axis and the cutting line 6.) which should be equal to half the angle between the normals to the longitudinal deformed beam axis located in the zone of maximum bending moment arising from the operational load. At this step, the protrusions 7 and 8 are taken in accordance with the pitch of the projections 3 and 4 of the upper part of the beam, and the height of the projections h is calculated on the basis of the carrying capacity of the beam. the lower part of the beam is taken to be (0.02-0.08) h less than the length of the workpiece 1. forming the upper part of the beam. In each specific case, these are opOs

ABOUT

you ate you

determined by calculation. After cutting each of the blanks 1 and 5 into two parts, the parts from each of them are combined. For this, they are first given a return curvature, the value of which is equal to the deflection of the resulting beam from the operational load. In this case, the rectangular cuts in the upper part of the beam become trapezoidal, with a large base of the trapezium in the zone adjacent to the bottom of the beam, @ the trapezoidal cuts in the part that surrounds the lower part of the beam are rectangular. After this, part 1 and The 5 beams in the deformed state match each other, i.e. The trapezoid protrusions 7 and 8 of the lower part are inserted into the resulting trapezoidal cuts of the upper part of the beam by the deformation by ensuring the coincidence of the planes of the walls of the joined parts. The size of the contact line 9 edges of the projections 3, 4 and 7, 8 is taken from the calculation of the strength of the butt weld. The welding of the beam parts is carried out in ways that ensure the equal strength of the weld and the base metal.

PRI me R 1. It is required to make a perforated beam from two identical original I-beams. The span of beam I, the height of the protrusions of both I-beams is the same, the height of the cross-section of the beam is h. 2N. where bn is the distance from the neutral axis to the outer edge of the shelf. The beam is pivotally supported at the ends and is designed to work on a uniformly distributed load of intensity q, the relative deflection does not exceed 1/2001. To manufacture the beam, it is necessary to determine the angle p between the inclined cutting line 6 of the workpiece, forming the lower part of the beam and the normal to the beam axis, as well as the lengths of the workpieces 1 and 5.

Considering that the deflection of a beam from a uniformly distributed load is equal to f

gl

2g4 E ® turn sections on

support (ro -XV

E y

where EY is flexural

stiffness of the beam, found in the corner of noiOpOTa

.f

Wo from where

384

one

24

 3.2 I,

Elongation of the upper (shortening of the lower) fiber (across sa) beam during bending D1 .htg 0 where Q is the angle of rotation of the section

beams on the support. Substitute value here

angle 0. we get D | htg (3.2 j 57.3). Teach that f

200

get

0,016h.

(3.2 From here we find the length of the lower part of the beam. It is equal to 1–1–2D1, and the top is 1 in 1 + 2D1.

At a height h (5 100 cm A, 6 cm, i.e., the length of the workpiece forming the bottom along the beam, is less than the length of the workpiece forming the top of the beam, 5 cm. From the expression Al htgy7 we find the angle between the cut line and the normal to the beam axis

 arctg -.

With h (5 100cM у7 arctg- "1.0. °

EXAMPLE 2. It is required to make a perforated beam, carrying a concentrated load applied in the middle of a span, the relative deflection of which is 1/400 I. The remaining parameters are the same as in Example 1.

Similar to the previous we have:

1 WG EY

one

48

L f

one

RI

Wg

-) / 16 E Y 1 P | 2

one

EY 16 EY

I,

3.0j,

htg (3.0 - -j- 57.3) 0.008h;

one

rctg

 arctg 0.008 0.5 °.

With a height h (5 100 cm, 8 cm, a, 6 cm; 6 cm, i.e., the length of the workpiece, forming the bottom along the beam, should be less than the length of the workpiece, forming the top along the beam, 3.2 cm.

The examples show that according to the proposed method can be made of all the main types of beams.

This method makes it possible to obtain prestressed beams, which under load will have parallel lines. The manufacture of beams is technologically advanced and is carried out without waste.

Claims (1)

Invention Formula A method of manufacturing perforated metal / beams, comprising cutting two initial blanks into broken zigzag lines, one of which has inclined side walls, bending parts of the workpieces, and then docking and welding of these parts, characterized in that, in order to increase the carrying capacity by creating prestressing during assembly, the side portions of a broken zigzag line of the workpiece forming the lower part of the beam are positioned at cutting relative to the normal to the longitudinal the beam axis is at an angle equal to half the angle between the normals to the longitudinal axis of the beam bent under the operating load in the zone of action of the maximum bending moment, and bending is performed by the value. equal to the deflection of the beam from the operational load in the direction opposite to the deflection of the beam in the working position. 1 5,678 (Rig.y. Fyz, 4