FIELD: measuring instrumentation.
SUBSTANCE: strain-gauge converter includes loading element attached to the monitored object, pieso-optic converter converting tension value in stress-optical element attached in preloaded state into electrical signal, and signal processing unit. Loading element is a plate with cylindrical hole where stress-optical element of cylindrical form is clamped adjustably in direction of measured deformations by two rods made of material with thermal expansion factor larger than respective factor of the plate. Rod length is designed so as to ensure independence of preloading compression from temperature.
EFFECT: enhanced measurement accuracy, simpler device design.
7 cl, 3 dwg
The technical field
The invention relates to the control and measurement technology, in particular, to measure the strain (stress) in various designs through the polarization-optical converters, and can be used in construction, transportation, industrial production, instrumentation.
The level of technology
It is known that piezooptical transducers used to measure deformations (strains)that have the greatest sensitivity in comparison with others, for example, piezoresistive transducers (Slesinger I.I. Piezooptical transducers. Measurement technology, 1985, No. 11, p.45-48) .
The closest in technical essence to the proposed strain sensor is piezooptical strain-gauge transducer (Patent No. 2422786 dated 23.04.2010) . The Converter consists of a load element, mounted on a controlled object, piezooptical Converter that converts the magnitude of the stresses on the photoelastic element into an electrical signal and block signal processing. The load element is a plate that provides a stress concentration on a photoelastic element, a photoelastic element fixed in the plate in the notoriously Laden condition and thus is m, what action is the source of power of the load is carried out in two mutually perpendicular directions. Fixing a photoelastic element in the initially loaded condition allows to measure both strain compression and tensile strain. Action source power load in two mutually perpendicular directions provides temperature compensation of the transducer, as when the temperature of the plate photoelastic element is compressed equally in opposite directions, i.e. isotropic, that did not result in a false signal at the output piezooptical Converter.
The disadvantages of this strain transducer are: a) the consolidation of a photoelastic element in the plate is carried out using a cone Morse, which requires very high precision in manufacturing as a photoelastic element, and a taper hole in the plate, coinciding with the dimensions of the photoelastic element; b) plate design is not symmetric in the areas of application of the initial load on a photoelastic element, and therefore, has a different stiffness in mutually perpendicular directions, which cannot ensure the isotropy of compression photoelastic element when the temperature changes, and therefore, may not provide sufficient temperature compensation strain gauge pre is brazaletes.
Disclosure of inventions
The objective of the invention is to create such a design strain-gauge transducer, in which, first, the consolidation of the photoelastic element in the initially loaded condition is more simple in comparison with Morse taper, by the way, and secondly, the temperature compensation was provided a more reliable method.
The technical result - the simplification of the structure, increasing its reliability and accuracy deformation measurements.
The problem is solved due to the fact that in the known device, comprising a load element mounted on a controlled object, piezooptical Converter that converts into an electrical signal the magnitude of stresses on the photoelastic element, which is fixed in an obviously loaded condition, and the unit signal processing, according to the invention, the load element is a plate with a cylindrical hole in the center, in which the photoelastic element of cylindrical shape adjustable clamped in the direction of action of the measured strains using two rods made of a material with a coefficient of thermal expansion greater than the corresponding coefficient of the plate, the length of rods designed in such a way that preserves the value of initial compression changed from what I temperature.
The material of the rods and their length are selected so that with the change of temperature change of the total length of the rods Lcmand the width of the photoelastic element of LFewas equal with sufficient accuracy the change of the distance between the places of attachment of the rods in the load element (plate) LPL. In other words, the elongation of the plate is equal to the relative lengthening of the structure of the rod-photoelastic element is a rod. If the plate is made of a material with a coefficient of linear expansion αPLthe rods have a coefficient of linear expansion αarticleand the coefficient of linear expansion photoelastic element αFethen the above condition can be written as follows:
Given that LPL=Lcm+LFereceived total length of the rod:
Thus, under the conditions according to equation (3), when the temperature of the transducer on a photoelastic element will not experience additional stress and, thus, the effect of the independence of the readings of the transducer from the temperature.
For example, consider a plate, made of steel SHKH15 with a coefficient of linear thermal expansion αPL=11.9×10-6K-1; photoelastic element diameter LFe=6 mm, made of fused silica with αFe=0.395×10-6K-1; rods made of stainless steel with αcm=16.6×10-6K-1. Tog is a, substituting values in the formula (3), we get the total length of the rods Lcm=At 14.68 mm If the rods are the same length, the length of one rod is Lcm/2=7.34 mm
The initial load on the photoelastic element is provided, for example, screws, Cruciferae in the plate, and clamping rods, between which is located a photoelastic element. The screws are made of a material plate.
As a photoelastic material element can be used, for example, fused silica, having a high damage threshold in compression, which provides a high dynamic range measurements of deformations and reliability of the Converter. In addition, the processing technology of fused silica is well developed, which reduces the design strain of the Converter.
A load element (plate) with piezooptical Converter is attached to the test object so that the axis of the rod coincides with the direction of the measured deformation of the test object. The deformation of the test object is transmitted to the plate, then to the rods and the photoelastic element piezooptical Converter, the optical axis of which lies in a plane perpendicular to the direction of the measured strain.
The load element is provided with a mounting hole the threads for attachment to a controlled object. To improve the reliability of fastening of a load element on its surface in contact with the controlled object may be fulfilled by the teeth lying in the same plane.
To increase the sensitivity of the strain gauge transducer to deformation, the plate can be made grooves that do not violate its integrity, which reduce the stiffness of the plate in the direction of the measured deformations and without introducing distortion in the transmission of deformation in a photoelastic element.
To ensure reliable contact of the rods with a photoelastic element, on the surface of the cylinder can be performed symmetrically located flat platforms (flats), which rest against the bars.
The rationale put signs
As a photoelastic element is clamped by means of cores having a flat end face, there is no need to make a Morse taper, which is associated with serious technological difficulties. As a photoelastic element is initially compressed, the strain gauge transducer with the same sensitivity works both in compression and in tension. The length of the rods is chosen in such a way as to satisfy the condition of formula (3), while resizing elements load element associated with changes in temperature do not cause additional stress on the photoelastic element, t what is the effect of temperature compensation.
By mounting a photoelastic element using rods calculated length is achieved by simplifying the design and provide more reliable compensation of the stresses associated with the temperature change of strain of the Converter.
Thus, the proposed set of characteristics that defines the design of the strain gauge Converter, allows to achieve the stated technical result: simplify the construction, increase its reliability and precision of measurement of the deformations of the test object.
Description strain gauge transducer
The description of the device illustrated by figures 1, 2 and 3, where:
figure 1 shows the design of the strain gauge transducer with a photoelastic element made in the form of a cylinder with two symmetrically arranged attened;
figure 2 shows the load element (plate) top (view A-a in figure 1);
figure 3 shows a General view of the load element (plate).
On the figures the figures showing: 1 - load element (plate), 2 - mounting holes, 3 - photoelastic element, 4 - flats. In the plate made two holes 5, which are inserted rods 6, which are clamped by screws 7. To improve the reliability of fastening of a load element 1 to the controlled object on the surface of the plate facing the load El is the COP, made the teeth 8. To reduce the stiffness of the load element in the direction of the measured deformations in the plate made the grooves 9. The optical axis of piezooptical Converter is shown by a line 10.
Description of the device
Strain the Converter operates as follows.
A load element 1 is fixed on the object surface by means of mounting holes 2 and the teeth 8 so that the axis of the plate coincides with the axis of loading X. Deformation of tension or compression that occurs in a controlled object in the X-direction is transferred to the plate 1 through the attachment 2. The deformation of the plate is transferred to a photoelastic element 3 through the rods 6, which leads to additional compression (+Δ) or stretching (-Δ) photoelastic element. As a result, in piezooptical Converter, an additional phase difference of ±Δ between mutually perpendicular polarization components of the beam passed through a photoelastic element, which leads to the change of the electric signal at the output of the photodetector piezooptical Converter, which is detected and processed by the processing unit of the signal.
Used sources of information
1. Slesinger I.I. Piezooptical transducers. Measurement technology, 1985, No. 11, p.45-48.
3. RF patent №222786 dated 23.04.2010.
1. Strain gage transducer comprising a load element mounted on a controlled object, piezooptical Converter that converts into an electrical signal the magnitude of stresses on the photoelastic element, which is fixed in an obviously loaded condition, and the processing unit of the signal, wherein the load element is a plate with a cylindrical hole in which a photoelastic element of cylindrical shape adjustable clamped in the direction of action of the measured strains using two rods made of a material with a coefficient of thermal expansion greater than the corresponding coefficient of the plate, the length of the rods is designed in such a way that preserves the value of initial compression from temperature changes.
2. The Converter according to claim 1, characterized in that to increase the efficiency of the transfer of the measured strain on the photoelastic element plate is purified in a place of fastening of a photoelastic element.
3. The Converter according to claim 1, characterized in that on a photoelastic element made in the form of a cylinder made two symmetrically located the flats facing the clamping bars.
4. The Converter according to claim 1, characterized in that the plate is made of a threaded screw holes rests on the rods, clamping photoelastic element, and the screws are made from a single plate material.
5. The Converter according to claim 1, characterized in that the plate is made grooves, reducing the rigidity of the plate in the direction of the measured strain.
6. The Converter according to claim 1, characterized in that on the surface of the plate in contact with the controlled object, performed the teeth lying in the same plane.
7. The Converter according to claim 6, characterized in that to ensure contact between the plate and the controlled object along the plane of the plate facing toward the object, the shape and size of teeth are selected in such a way that when the mounting plate on the object, the teeth are completely submerged in the body of the test object.
SUBSTANCE: invention relates to temperature compensating mechanisms of multiple use damping vibration of operating item and having definite rigidity when item is out of operation. This invention may be used in different engineering industries for the items operating under high temperatures. Compensator consists of elastic damper from metal rubber located between two cylindrical box-type items installed with annular gap as regard to each other and between end surfaces. Elastic damper from metal rubber is impregnated with low-melting metal to achieve rigidity and dimensional integrity of non-operating item and to ensure low-melting metal escape to additional volume in the form of metal bellow when item is heated to operating temperature and its return for metal rubber elastic damper impregnation. All box-type items, bellow and elastic damper are made of high-temperature corrosion-proof steel. Compensator design is a leak tight structure.
EFFECT: improvement of compensator rigidity on non-operating item; manufacturability, user-free design and possibility of multiple use.
2 cl, 2 dwg
FIELD: method and device belongs to aids for protection of internal spaces having optical surfaces and it can be used for protection of optical surfaces from icing.
SUBSTANCE: method consists of creation of internal space to be protected and on formation of protection barrier around it. Internal protected space is air-proof and transparent to optical radiation. Protection barrier is formed of single-layered thin transparent film material. Film material has low adhesion factor. Barrier is mounted between internal and external frames connected together. Bead is produced along entire perimeter of film by means of melting. To settle bead onto edges of internal and external frames, V-shaped deepening is made; hollows between bead and edges of frames are filled with compound. External frame has protrusion at side of V-shaped deepening. To seal protection structure and to connect frames, sealing compound is used. Protrusion is forged-rolled in direction to edge of internal frame. Stable reception and/or transmission of signal, belonging to optical range is provided due to elimination of icing onto surface of optical system under conditions of their usage at positive temperatures after transportation of flying vehicle under conditions of low temperatures, for example, after landing operation from board of flying vehicle.
EFFECT: improved stability; improved reliability of operation.
2 cl, 1 dwg
FIELD: mechanical engineering, possible use in device for thermo-compensation of cylindrical covers.
SUBSTANCE: in accordance to invention, mounting of thermo-compensating elements between cylindrical covers, having varying linear expansion coefficients, includes mounting resilient elements. Compensating elements are preliminarily stretched, decreasing their original thickness. After mounting elements into radial gaps of covers and following reduction of elements, elements are reduced to thickness, appropriate for value of gap between covers, while forming given force on covers. Device for thermo-compensation of covers of cylindrical shape, with different linear expansion coefficients contains compensating elements, positioned symmetrically along circle in the gap between covers. Compensating elements are made in form of strip of resilient material with shelves alternating on the surface, positioned along element, elements are positioned along whole length of covers.
EFFECT: decreased radial dimensions of compensating element, decreased gaps between covers, increased compactness of assemblage of covers during operation for overloads in side direction, decreased specific pressures on cylindrical covers, stable total reduction force on covers at given operation temperatures.
2 cl, 4 dwg
SUBSTANCE: invention relates to the system of "smart" cable for bridge with the use of built-in sensors based on fibre Bragg gratings (FBG) and can be used in cable load-bearing structures of cable, suspension, arched and other types of bridges. System comprises anchor glass, plate for separating wires, connecting clutches, sensor based on fibre diffraction grating and cable itself. Sensor based on fibre diffraction grating comprises strain gauge 9 with fibre diffraction grating and temperature sensor with fibre diffraction grating. The ends of optical fibres of strain gauge 9 and temperature sensor are led outwards. Assembled strain gauge 9 is rigidly connected with the steel wire in the connection coupling. Assembled temperature sensor is suspended on the steel wire in the connection coupling. Openings are punched in the plate to separate wires. Protective steel tube is dipped in advance in the front part into the connecting sleeve and anchor glass.
EFFECT: system improves survival of sensors and optic fibre during manufacture and operation of cable, provides reliable sealing of sensors and permits to transmit signals effectively and accurately from fibre diffraction gratings outward from cable.
SUBSTANCE: problem is solved by designing a fibre-optic pressure sensor, having a housing with two tubular elements, having at least one plugged end, mounted in the housing such that the second end of the first tubular element is connected to the housing and is linked with a channel for feeding working medium, and the second end of the second tubular element is open and linked with the inside of the housing through which is passed an optical fibre with two Bragg gratings, attached by areas with the Bragg gratings directly to the outer cylindrical surface of the tubular elements such that one of the gratings is located on the first tubular element and the second grating is located on the second tubular element. The problem is also solved by mounting the second tubular element to the inner wall of the housing and by mounting the second tubular element to the inner wall of the housing coaxially to the first tubular element. The tubular elements are made of the same material and have identical geometrical dimensions. The problem is also solved directing portions of the optical fibres equipped with Bragg gratings along the edge of the cylindrical surface of the tubular elements. The disclosed design of the fibre-optic pressure sensor enables to solve the problem of quality and reliable measurement of pressure of working medium of remote objects with transmission of information over a fibre-optic link for long-term operation, up to several years, without intermediate maintenance and adjustment procedures.
EFFECT: simple design of a fibre-optic pressure sensor, assembly thereof and avoiding the need to adjust sensor elements thereof during assembly, smaller size of the sensor and high reliability and accuracy of measuring pressure.
6 cl, 3 dwg
FIELD: engines and pumps.
SUBSTANCE: proposed system comprises light source to transmit light onto shaft surface via multiple optic fibres made at multiple points nearby said surface in, in fact, axial direction between the ends of at least one shaft, high-temperature reflection probe built around fibre bundle to detect light reflected from shaft surface and mechanism to measure torque or oscillation at the shaft. The latter comprise coding mechanism composed of changed texture shaped to wedge-like groove on shaft surface of variable depth. Said depth generates the front and rear working point signals so that appropriate time delay can be detected from whatever two positions of said groove for determination of shaft twist angle by differentiation of reflection pattern characteristics during every rotation cycle.
EFFECT: higher precision of measurements.
23 cl, 24 dwg
FIELD: measuring equipment.
SUBSTANCE: invention belongs to fibre-optical sensors and can be used for check and measurement of parameters of voltage. The fibre-optical sensor of spiral structure is the multi-turn spiral element created by a spring wire. The set of a teeth of deformation is continuously distributed on the top surface and the bottom surface of a spring wire in the longitudinal direction along a spring wire; in two adjacent turns of the spring wire the deformation teeth on the bottom surface of the top turn of the spring wire and deformation teeth on the top surface of the bottom turn of the spring wire are arranged in staggered order to each other. An alarm optical fibre is clamped between deformation teeth on the bottom surface of the top wire of the spring wire and deformation teeth on the top surface of the bottom turn of the spring wire and is connected to the test facility by the optical fibre of transfer.
EFFECT: increase of accuracy of measurement.
10 cl, 10 dwg
FIELD: measuring equipment.
SUBSTANCE: invention belongs to area of instrumentation and can be used for creation of distributive systems of measurement of temperature and deformation. The Brillouin system for tracking of temperature and deformation contains one - or bilateral fibre with a set of fibre Bragg gratings (FBG) on different lengths of waves and a laser system with the setting excitation, adjusted in a range essentially bigger, than Brillouin shift. FBG are distributed along the length of the placed fibre and serve as chosen reflectors of length of the wave, allowing to support operation of the device even in case of a rupture of fibre.
EFFECT: increase of accuracy and reliability of these measurements.
7 cl, 4 dwg
SUBSTANCE: invention is referred to electric cable with in-built strain-gage fit specifically to measure static and dynamic deformations, in particular, bending strain. Method of bending strain control for electric cable includes stages of the cable equipment with peripheral and mechanically unsymmetrical bearing element having higher resistance to tensile loads than to compression ones and with fibre-optical sensor.
EFFECT: invention provides for high duty cables, in particular, in mobile units, controllability and traceability of bending strain area.
9 cl, 15 dwg
SUBSTANCE: electric cable with strain-gage located longitudinally along the cable and containing strain-gage optical fibre installed in flexible neutral area that surrounds and includes flexible neutral longitudinal axis of the electric cable, and at least two longitudinal structural elements where at least one of at least two longitudinal structural elements represent a core containing electric conductor with strain-gage in-built into filler resistant to strain; it connects at least one of at least two longitudinal structural elements with strain-gage. By means of open cable structure strain endured by at least one of at least two longitudinal structural elements can be transmitted to strain-gage at least in stretched state. In preferred variants of implementation the electric cable represents high-duty cable. Invention is also related to control method of strain and, preferably, temperature of electric cable.
EFFECT: invention is oriented to creation of deformation control system to measure at least stretching strain for several electrical cables and, in particular, several high-duty cables.
30 cl, 12 dwg
FIELD: process engineering.
SUBSTANCE: glass fibre is introduced in composition used for forming controlled object as a material similar to that used as a filler for forming part carcass matrix, that glass fibre allows channeling light beam there through. Note here that glass fibre intact lengths, longer than said part, are used to be arranged to cross paths of probable defect development in part sections not subjected to processing. Occurrence of defect is detected by light beam passage or decreased in emergent light flux brightness.
EFFECT: efficient detection of defects.
6 cl, 1 dwg
SUBSTANCE: optical fibre structure with Bragg lattices is put into composite material during production thereof. The spectral position of peaks of the Bragg lattices is measured after making the structure from the composite material and distribution of mechanical and thermal deformations inside the structure of the composite material is determined by solving the system of equations: , where f(T,ε) is the distribution function of mechanical and thermal deformations on the structure made from composite material (T is the temperature value, ε is the deformation value); f(Ex, y, z) is the distribution function of elastic properties of the structure made form composite material, Ex, y, z is the Young 's modulus tensor; f(αx, y, z, vx, y, z) is the distribution function of thermal characteristics of the composite material (αx, y, z is the coefficient of volume expansion tensor, vx, y, z is the thermal conductivity coefficient tensor);f(Fload, FT) is the distribution of mechanical and temperature effects on the structure made from composite material (Fload is the value of the mechanical effect, FT is the value of the temperature effect); fFBG(T,ε) is the function of total deformation on the path of the optical fibre with Bragg lattices (T is the temperature value, ε is the deformation value); fi-FBG(Δλ) is shift transformation function of the position of the i-th peak of the Bragg lattice to the temperature value and deformation (Δλ is the displacement of the peak of the Bragg lattice). The optical fibre contains two or more Bragg lattices which are not more than 5 mm long. The distance between the Bragg lattices and one optical fibre is not less than 5 mm.
EFFECT: high measurement accuracy.
3 cl, 15 dwg
SUBSTANCE: proposed transducer comprises load secured on controlled element and strain-gage transducer to convert voltage across stress-optical element into electric signal, and signal processing unit. Load is made up of plate to concentrate strain at stress-optical element. Stress-optical element is fixed in said plate as-stressed so that initial stress force acts in two mutually perpendicular directions. Note that stress-optical element is fixed at plate thinned center by means of Morse taper. Note also that, additionally, two mutually perpendicular through cuts are made not corrupting plate integrity, cuts axes being directed at 45° to loads axis. Cuts axes are aligned with that of taper hole for stress-optical element attachment.
EFFECT: higher sensitivity, thermal compensation.
5 cl, 1 dwg
SUBSTANCE: invention refers to an operating method and a system equipped with an electric machine, which includes stator (4) and rotor (1), as well as with an infra-red temperature sensor. With that, detection field of infra-red temperature sensor is oriented along rotor housing surface. Infra-red temperature sensor represents thermoelectric column (6) and serves for contactless radiometric recoding of rotor (1) temperature. Infra-red sensor is located in the slot of stator (4) and is combined at erection with standard structural elements of a covering slot wedge of the electric machine.
EFFECT: improving operating efficiency of an electric machine owing to implementation of states matched as to capacity.
9 cl, 3 dwg
FIELD: physics, optics.
SUBSTANCE: invention relates to optics and specifically to devices for creating backlight without distortion of the background radiation spectrum, mainly for checking photosensitivity of the surface of a photodetector. Disclosed is a method and apparatus for simulating backlight without background radiation spectrum distortion, involving obtaining light flux from a backlight source, illuminating a set of pinholes with said light flux, said pinholes lying in a plane away from the backlight source such that light flux passing through each pinhole falls on the inner side surface of the cylindrical tube of the circular section of white light, whose axis passes through the backlight source, after reflection from which it is collected in the output face of the cylindrical tube, where the photosensitive surface of the photodetector is placed, lighting parameters of which are measured in the non-distorted spectrum of the lamp of the backlight source.
EFFECT: high accuracy of determining integral light sensitivity and non-uniformity of light sensitivity of a specific photodetector on a specific radiation source.
2 cl, 7 dwg