SU1101672A1

SU1101672A1 - Device for touch=free measuring of deformations

Info

Publication number: SU1101672A1
Application number: SU802873225A
Authority: SU
Inventors: Анатолий Прокопьевич Быков
Original assignee: Предприятие П/Я Г-4903
Priority date: 1980-01-18
Filing date: 1980-01-18
Publication date: 1984-07-07

Abstract

УСТРОЙСТВО ДЛЯ БЕСКОНТАКТНОГО ИЗМЕРЕНИЯ ДЕФОРМАЦИЙ, содержащее установленные вдоль оптического , пучка лазер, коллиматор, расщепитель , формирующий два пучка света, и дифракционную решетку, предназначенную дл установки на исследуемой поверхности в зоне пересечени пучков перпендикул рно биссектрисе угла между ними, и фотоаппарат, отличающеес тем, что, с целью увеличени чувствительности и точности, оно снабжено оптическим частотным модул тором, размещенным между лазером и коллиматором , фотоприемным блоком, выполненным из двух жестко св занных друг с другом фотодетекторов, установленных в плоскости расщеплени симметрично относительно биссектрисы угла между пучками, и электронным фазометром, опорный и измерительный входы которого подключены к выходам фотодетекторов.g (Л о: юDEVICE FOR CONTACTLESS MEASUREMENT STRAIN comprising installed along an optical, beam laser collimator splitter forming two beams of light, and the diffraction grating designed for installation on the examined surface in the zone of intersection of the beams perpendicular to the bisector of the angle between them, and the camera, wherein that, in order to increase sensitivity and accuracy, it is equipped with an optical frequency modulator placed between the laser and the collimator, a photo-receiver unit made of two x photodetectors rigidly connected to each other, installed in the splitting plane symmetrically with respect to the bisector of the angle between the beams, and the electronic phase meter, the reference and measurement inputs of which are connected to the outputs of the photodetectors.g (L

Description

Изобретение относится к измерительной технике, в частности к устройствам измерения деформации, и . может быть использовано при аттестации тензорезисторов.The invention relates to measuring equipment, in particular to devices for measuring strain, and can be used for certification of strain gauges.

Известно.устройство для бесконтактного измерения деформации, содержащее установленные вдоль оптического пучка лазер, коллиматор, расщепитель, формирующий два пуч;ка света и дифракционную решетку, предназначенную для установки на исследуемой поверхности в зоне пересечения пучков перпендикулярно биссектрисе угла между ними С1].A device for non-contact strain measurement is known that contains a laser, a collimator, a splitter that forms two beams installed along the optical beam, a light beam and a diffraction grating intended to be installed on the surface under study in the zone of intersection of the beams perpendicular to the bisector of the angle between them C1].

Известно также устройство для бесконтактного измерения деформаций, содержащее установленные вдоль оптического пучка лазер', коллиматор, •расщепитель, формирующий два пучка света, и дифракционную решетку, предназначенную для установки на исследуемой поверхности в зоне пересечения пучков перпендикулярно биссектрисе угла между ними,и фотоаппарат (2].A device for non-contact strain measurement is also known, which contains a laser 'installed along the optical beam, a collimator, • a splitter that forms two light beams, and a diffraction grating designed to be installed on the surface under study in the zone of intersection of the beams perpendicular to the bisector of the angle between them, and a camera (2 ].

Однако известные устройства не обеспечивают требуемую чувствительность и точность измерений,, ограниченные разрешающей способностью и абберациями объектива.However, the known devices do not provide the required sensitivity and measurement accuracy, limited by the resolution and aberrations of the lens.

Целью изобретения является увеличение чувствительности и точности измерения, ц) Поставленная цель достигается' ' тем, что устройство снабжено оптическим частотным модулятором, размещенным между лазером и коллиматором, фотоприемным блоком, выполненным иэ двух жестко связанных друг, с другом фотодетекторов, установленных в плоскости расщепления симметрично относительно биссектрисы угла между пучками,и электронным фазометром,опорный и измерительный входы которого подключены к выходам фотодетекторов. .The aim of the invention is to increase the sensitivity and accuracy of measurement, c) The goal is achieved `` by the fact that the device is equipped with an optical frequency modulator located between the laser and the collimator, a photodetector made of two photodetectors rigidly connected to each other, installed symmetrically in the splitting plane relative to the bisector of the angle between the beams, and an electronic phase meter, the reference and measuring inputs of which are connected to the outputs of the photodetectors. .

На чертеже представлена схема устройства для бесконтактного измерения деформации.The drawing shows a diagram of a device for non-contact strain measurement.

Устройство содержит установленные вдоль оптического пучка лазер 1, коллиматор 2, расщепитель 3, формирующий два пучка света, оси которых пересекаются в плоскости расщепления и дифракционную решетку 4, предназначенную для установки на исследуемой поверхности в зоне пересечения пучков’ перпендикулярно биссектрисе угла между осями этих пучков, оптический частотный модулятор 5, фотоприемный блок 6, выполненный из двух жестко связанных друг с другом фотодетекторов 7, установленных в плоскости расщепления симметрично относительно биссектрисы угла между пучками, и электронный фазометр 8, опорный и измерительный входы которого подключены к выходам фотодетекВНИИПИ Заказ 4749/25The device comprises a laser 1, a collimator 2, a splitter 3 installed along the optical beam, forming two light beams whose axes intersect in the splitting plane and a diffraction grating 4 designed to be installed on the surface under study in the beam intersection zone 'perpendicular to the bisector of the angle between the axes of these beams, optical frequency modulator 5, photodetector unit 6, made of two photodetectors 7 rigidly connected to each other, mounted in the splitting plane symmetrically with respect to the bisectors the angle between the beams, and an electronic phase meter 8, the reference and measuring inputs are connected to outputs fotodetekVNIIPI Check 4749/25

Claims

DEVICE FOR CONTACTLESS MEASUREMENT OF DEFORMATIONS, containing installed along the optically studied surface in the zone of intersection of the beams perpendicular to the bisector of the angle between them, and a camera, characterized in that, in order to increase sensitivity and accuracy, it is equipped with an optical frequency modulator located between the laser and a collimator, a photodetector unit made of two photodetectors rigidly connected to each other, installed in the splitting plane symmetrically with respect to the bisector of the beam and laser collimator splitter forming two light beams, and the diffraction grating designed for installation on the angle between the beams, and an electronic phase meter, the reference and measuring inputs are connected to the outputs of the photodetectors.

tori 7. Splitter 3 consists of <polarizing beam splitter 9, half-wave plate 10 and adjustable mirrors 11.

The device operates as follows.

The radiation beam of laser 1 is modulated by an optical frequency modulator 5. At the output of the modulator, two radiation components are obtained with mutually orthogonal polarization and with frequencies that differ by the frequency of the master oscillator. Using a polarizing beam splitter 9, two radiation components are separated into two beams with mutually orthogonal polarization and different frequencies.

The half-wave plate 10 in one of the arms of the splitter rotates the plane of polarization of radiation in this arm by 90 °. Reflected from the mirror 11, the beams intersect. An object with a diffraction grating 4 is installed in the intersection zone, the strokes of which are perpendicular to the expansion plane 3. The angle between the axes of the beams is coordinated with the period of the grating in such a way that the reflected diffraction beams are collinear and perpendicular to the surface of the object. The diffraction beams interfere with each other, the resulting interference pattern is detected by the photodetector 7 at two points symmetrical about the bisector between the beams in the plane of the splitter. Electrical signals from photodetectors at the frequency of the master oscillator of the modulator 5 are fed to the reference and mes. Signal inputs of the electronic phasemeter 8, which measures the phase difference of these signals. Before the object is deformed, splitter 3 is tuned to an approximately infinite strip during interference of the beams, i.e. what- . the phase difference of the electrical signals would be approximately equal to · zero. When the object is deformed, the lattice period 4 changes and an angle appears between the diffracted beams, which leads to the formation of interference. pictures, with a finite step of strips. The phasometer 8 measures the phase difference within one period, and the integer number of periods, if necessary, can be an electronic counter. The magnitude of the deformation is determined by the measured phase difference and the known lattice period 4 and the distance between the points at which the optical signal is recorded.

Thus, the sensitivity and accuracy of measuring the deformation of objects is increased.

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