UA132878U - DEVICES FOR MEASUREMENT OF DEFORMATION OF ELEMENTS OF LARGE SIZE STRUCTURES - Google Patents

Abstract

A device for measuring deformations of large structural elements includes a laser, a photodetector and a processing and recording unit. The device also includes an optical collimator, sweep unit, switching unit and n-1 photodetectors, which are n consecutively deformed strain gauges located at supports at a certain equal distance from each other horizontally fixed to the structure, rigidly fixed to the structure deformable structures. The first and nth photodetectors, a laser connected through an optical collimator to a laser beam scanner assembly, are made outside the deformable structure. All n photodetectors are at one height above the surface of the deformable structure, and the laser, collimator and sweep are on the opposite side of the structure at the same height from the horizontal surface opposite the photodetectors, the sensitive surface of which is rotated in the direction of the sweep. The scanner node scans the laser beam in the horizontal plane on the surface of the deformation sensors, and the switching unit is connected to the processing and registration unit.

Description

A useful model belongs to the measurement of deformations of elements of large structures, such as bridges, by optical methods.

To control and forecast the state of the bridge structure using ASDM, optical methods of deformation measurement have become widespread. So, for example, in a device for measuring deformation, which contains n sequentially located deformation sensors, rigidly fixed on a deformable structure, each of which contains a translucent mirror, a cross-shaped mark and a light source, a light receiver, a focusing node, a light scanning node, a switching unit and the recorder, and are located sequentially along the optical axis between the light receiver and translucent mirrors of n cross-shaped marks, located along the optical axis of each sensor, perpendicular to the main optical axis between the translucent mirror and the light source, the switching unit, the input of which is connected to the light receiver, and its outputs are connected to the focusing node, n light sources and recorders, containing a measuring circuit and a computing unit (1.21.

The disadvantage of these devices is insufficient accuracy and insufficient functional capabilities and the practical inoperability of the device on sunny days, because it is difficult for the light receiver to distinguish the light beam used in the device from the sun's beam, especially since the light source in the analogue also passes through a translucent mirror . Referring to the rejection of the laser beam in the analogue, where a beam of a certain wavelength is not used and the entire spectrum of sunlight is easily cut off with the help of a suitable filter, except for a beam of a certain wavelength, the authors significantly limit the functional capabilities of the analogue.

The closest analogue is a device that contains a light source in the form of narrowly directed light pulses, a photodetector made in the form of a matrix of photocells with the number of rows and columns equal to 2M--1, where M-1,2,..., and, a processing unit and registration, connected to the photoreceptor, a pulse generator, connected to the light source, a delay unit, the input of which is connected to the pulse generator, and its output to the processing and registration unit. The light source and the photoreceptor are fixed on a deformable structure.

The disadvantage of this device is that deformation control is performed at one point of the structure, which limits the scope of application of this device. If you need to control large structures, such as bridges, then you need a certain number of matrices

From photoreceptors and light sources in the form of narrowly directed light pulses, for which it is necessary to use several similar devices, which greatly complicates the design.

The useful model is based on the task of developing a device for measuring the deformations of large structures of a simplified design with increased functionality.

The problem is solved by the fact that an optical collimator, a scanning unit, a switching unit and n-th photoreceptors, which are n serially located deformation sensors located on supports located on at a certain equal distance from each other horizontally throughout the structure rigidly fixed on the deformable structure, and the first and nth photodetectors, the laser connected through an optical collimator to the laser beam scanning node are placed outside the deformable structure, all n the photodetectors are at the same height above the surface of the deformable structure, and the laser, collimator and scanning node are on the opposite side of the structure at the same height from the horizontal surface of the structure opposite the photodetectors, the sensitive surface of which is turned in the direction of the scanning node, and the scanning node performs scanning of the laser beam in the horizontal plane p about the surface of the strain sensors, and the switching unit is connected through the processing and registration unit.

In Fig. 1 shows the general view of the device and the position of the photoreceptors on the structure without deformation.

Figure 2 shows the general view of the device and the position of the photoreceptors on the structure with deformation.

In Fig. C shows the design of a photoreceiver with K elements.

In Fig. 4 shows the laser beam traveling through the i-th element of the photodetector Zt before the deformation of the structure.

In Fig. Fig. 5 shows the path of the i-th element of the photodetector Zp after the deformation of the structure by the laser beam.

The device works as follows. To measure the deformation of a large-sized structure, n photodetectors 3:1,...,Zi are used, which are n serially located deformation sensors located on supports 21,...,2y, rigidly fixed to the structure, 60 located on some specific equal distance 4 from each other horizontally along the structure 1 (Fig. 1 and Fig. 2) and at the same height from the horizontal surface of the structure (Fig. C and

Fig. 4). Moreover, photoreceptors 3: and Zy are placed outside the design. In addition, the laser 4, the optical collimator 5 and the node b of the laser beam scan 7 are placed outside the structure, which are located on the support at the same height as the photoreceptors, but on the opposite side of the structure opposite the deformation sensors, the sensitive surface of which is turned in the direction of the scan node laser beam. The device uses a laser with continuous emission of a beam of a certain wavelength. An optical collimator is placed in series with the laser, which consists of a lens, in the focal plane of which the output of the laser beam 7 is placed. The optical collimator 5 ensures the parallelism of the laser beam and therefore, due to practically zero divergence, all the energy of the laser beam will be concentrated on the sensitive surface of each multi-element photodetector, made in the form of a line of elements of a certain length | (Fig. 3), and each photoreceptor has the same number of elements. Each element of the photodetector is made of a certain material that passes the laser beam 7 without any particular obstacles. All n photodetectors, consisting of k elements, contain photodiodes, in front of which there is a sensitive surface and an optical filter that passes a beam of only a certain wavelength of the laser. All elements of the photo receiver are placed in a sealed housing. The scanning unit 6, for example, is a motor, on the shaft of which a mirror or a prism with a mirror face is located at an angle of 45" to the laser beam, or a rotating optical wedge, due to which the laser beam is expanded in a horizontal plane.

The unfolding optical signal from the scanning node 6 sequentially passes over the sensitive surface of the element with the corresponding identical number and each Zi. ..., Zp photo receiver (Fig

C, Figure 4). The electrical signal from the photodiode enters the amplifier of the electrical signal of the photoreceiver, which, after amplification, enters the switching unit 8 (Fig. 1 and Fig. 2).

If the structure is deformed (dashed line 10 in Fig. 2 and Fig. 4). then photo receivers

Z2,..., Zp ZmChange their position relative to the expanding laser beam, and the laser beam 7 will go around a different numbered (for example, |) element of the corresponding photodetector, and the number of the element does not change on photodetectors 3rd, Zy. Amplified electrical signals from the corresponding elements of the photodetectors 3:1,..., Zly arrive through the switching unit 8 to the unit 9

From processing and registration. The difference between the number and element of the photoreceptor 3: or C" and the number of the element of the corresponding photoreceptor located on the deformed surface of the structure, multiplied by a certain length of the element, will give the amount of deformation of the part of the structure on which the corresponding photoreceptor is located.

Ait-(I-, where DiIp is the amount of deformation under the tth photoreceptor, and is the number of the photoreceptor element Zt before the deformation (number of the photoreceptor element 3: or

Zp), - element number of the photoreceptor 3; after deformation, is the length of the photoreceptor element.

The device can be used in the automated deformation monitoring system (ASDM) of bridge structures and other elements of large-sized structures, which will allow to quickly monitor their condition, displacement and deflections that occur as a result of the influence of external natural and climatic influences, as well as intensive traffic load.

Sources of information: 1. Vhemei a'ipmepiyop. Me2.153.798 Egapse s 01 V 11/00. Oivroviiyi oriidne de sopigoie reppapepi a'aidpetepi. - 24.09.1971. 2 As. Mo1216642 USSR IPC sio01 V 16/11. A device for determining structural deformations // Bogatyrenko K.I., Denysenko O.V. -3728163/25-28. Application April 18, 1984; published 07.03.1986. Bul. Me9.

With As Mo1441193 USSR MOPC sat; 01 In 11/16. The device for determining sample deformations // V.N. Gavrykov, A.V. Babenko, O.A. Fuzhenko - 42444991/25-28. Application 14, 05.87; published 30.11.88. Bul. Mo44.

Claims (1)

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