SU1486778A1 - Method for determining strain in model in dispersed light - Google Patents

Description

The invention relates to measuring equipment, to the determination of stresses in structures on models using the polarization-optical method. The purpose of the invention is to improve the accuracy and the expansion of the use of

The invention relates to measuring equipment, to the determination of stresses in structures on models using the polarization-optical method.

The purpose of the invention is to improve the accuracy and expand the scope of use due to the expansion of the class of investigated objects and types of loading.

The drawing shows the optical system that implements the proposed method.

The system contains a laser 1, a telescopic system 2, an opaque screen 3, slots 4 and 5 with varying width and distance between them, which can independently of each other

2

account of the expansion of the class of investigated objects and types of loadings. The method consists in the fact that the model of construction is illuminated by a flat beam of polarized light; a plane is distinguished in the model parallel to the beam of polarized light and located at such a distance from it that the difference between the quasi-head voltages and their orientation does not change. This plane is illuminated with a flat beam of polarized light, then the model is illuminated with both parallel beams of light at the same time, with each of these three translucencies emitted by the polarizer in the light plane of the projections of the light vector on the axis, the angles are 90, 135 and 180 °, and the interference patterns are recorded with each translucent and determine the voltage on them. 1 il.

open and close, a rectangular cuvette 6, whose faces are parallel to the coordinate axes ΟΧ, ΟΥ, ΟΖ, with an immersion liquid, is a spatially stressed model 7. The light planes 8 and 9, formed by the beams in model 7, have a thickness equal to, respectively, the width of the slits 4 and 5, which is about 10 or more times less than the thickness of the investigated section emitted by the light planes 10, equal to the distance between the slits, which is determined by the condition of providing a flat-stressed state in the section, i.e. the invariance of the difference of quasi-head stresses and their orientation through the thickness of the studied section.

»Zi 1486778 A1

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On the optical axis parallel to the 0Ζ axis, there is a polarizer 11, which has the ability to rotate around the optical axis, a block 12 for receiving and processing optical information.

The method is as follows.

The beam of laser light 1 is expanded by a telescopic system 2, passes an open slit 4 and is scattered in the light plane 8. Light scattered parallel to the 0Ζ axis is linearly polarized, and the oscillations of the light vector are parallel to the OX axis and are described by the Jones method with a column vector

where £ "is a column vector of light scattered in the light plane20

ty 8;

B - the amplitude of the light scattered in the light plane 8. The scattered light, passing the model section from the light plane 8 to the border of the model's 25, undergoes a change in polarization, which is described by the matrix

. -1Ό

d, sozts> e-81SH "e.

N = (,

so ^ e-sozue

thirty

where N is the matrix for changing the polarization of light by the model section from the light plane 8 to the model border;

ψ, and, \ H parameters characterizing 35 "medium from the light plane 8

to the border of the model.

From the cuvette 6 light comes out with polarization

E '= O _G , ⁴⁰

where K. _£ is a column vector scattered in the light plane of 8 light; one coming out of the cuvette 6.

Establishing the axis of transmission of the field-45 rizatora 11 at an angle of 0 ° to the axis OX (90 ° to the direction of transmission of light), thereby distinguishing the projection of the light vector on the axis, which is an angle with the direction of transmission of light and block 12 receive and process optical information light intensity in the ΧΟΥ plane, i.e. interference pattern, which is described by the formula

1 ° = B ² cos ² n>, | .

t °

where is the light intensity, describing the interference

picture scattered in the light plane 8 light, when the axis of transmission of the polarizer 11 is set at an angle of 0 ° to the axis OX.

Setting the axis of transmission of the polarizer 11 at an angle of 45 ° to the axis of the OX (135 ° to the direction of transmission of light), the interference pattern is fixed by the unit 12 for receiving and processing optical information, which is described by the formula

45 V * ’~

= 2 ^- G ^{1 + cos} ( ^{and +} ^) 3Ϊη2ψ.

where I is the light intensity, describing the interference pattern in the light scattered in the light plane 8, when the transmission axis of the polarizer 11 is set at an angle of 45 ° to the OX axis.

Setting the transmission axis of the polarizer 11 at an angle of 90 ° to the axis OX (180 to the direction of transmission of light), the interference pattern is fixed by the receiving and processing unit 12 of optical information, which is described by the formula

I * = В ² 3ίη ^ζ ψ, t

where I £ is the light intensity, describing the interference pattern in scattered light in the light plane 8, when the transmission axis of the polarizer 11 is set at an angle of 90 ° to the OX axis.

In addition, a plane is distinguished in the model parallel to a beam of polarized light and located at such a distance from it, at which the difference between the quasi-head voltages and their orientation do not change. Translucent along this plane with a flat beam of polarized light. To do this, close slit 4 and open slit 5. The beam of laser light 1 expands with a telescopic system 2, passes an open slit 5 and scatters in the light plane 9. Light scattered parallel to the 0 оси axis is linearly polarized, and the oscillations of the light vector are parallel to the axis and are described by the vector column

ε- ( ^Αθ )

five

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where is the column vector of light scattered in the light plane 9;

And the amplitude of the light scattered in the light plane 9;

/ - the optical phase difference between the light scattered in the light planes 8 and 9. The scattered light, passing the section under study, undergoes a change in polarization, which is described by the matrix.

ίί

M = 1

L

where is m

^g (e ¹ cos ² (D + e ¹ δίη ² οί) 3Ϊη ^ 8Ϊη2 «')

.4 ν

ψ 'at h ₁ 131p-31p2 ₀ / (e 5Ϊη ² + e ¹ cos ² oO

- the matrix describing the change of polarization in the section under study;

- parameters characterizing the optical anisotropy of the cross section under study, which are associated with stresses as follows:

Where

- wavelength of light;

C is the model material constant; b - thickness of the studied layer; a <5 is the difference of quasi-head stresses in the plane;

o (- angle of orientation of quasi-cap stresses.

From the cuvette 6 light comes out with polarization

E _th = Ν. Μό ,; ,

where E, γ is the column vector of light scattered in the light plane 9, coming out of the cell 6.

Installing the transmission axis of the polarizer 11 at an angle of 0 ° to the axis of the OX, the interference pattern is fixed by the receiving and processing unit 12 of optical information, which is described by the formula

I * = A ² [0032 ^ (1-3142 ^ 310 ² 2о () + ΐ ¹ λ

+ 3Ϊη ² φ 5Ϊη ² ^ 3Ϊη ² 2νί ~

V g 7

-5ΐη2ψ3ΐη-8Ϊπ2οί [cos-z зη (π-λ)) +

50

+ 51P ^ cos2o / cos (u55

where is the light intensity describing the interference pattern in the light plane scattered in the light plane 9

ten

15

>,

light when the transmission axis of the polarizer 11 is set at an angle of 0 ° to the axis OX.

Setting the axis of transmission of the field of the polarizer 11 at an angle of 45 ^° to the axis OX, the interference pattern is fixed by the receiving and processing unit 12 of optical information, which is described by the formula

A 0 *

1 ^ = 2 {1 + 3Ϊη ² h> (1-3ΪΠ ² ^ δΐπ ² 2οί) +

20

25

thirty

35

+ СО3 ² ({/ £ ϊη ² T ^ POP ² 2b (+

+ 31P ² -51p4o / [cos ² fsoz2i-z1p ² schsoz24] +

+ zgls ^ ίη2ο £ [so3 ² ψ з ίη2ιι + 3ίη ² ψзίη2]},

where I is the light intensity, describing the interference pattern in the light scattered in the light plane 9, when the transmission axis of the polarizer 11 is set at an angle of 45 ° to the OX axis.

Setting the transmission axis of the polarizer 11 at an angle of 90 to the axis of the OX, the interference pattern is fixed by the receiving and processing unit 12 of optical information, which is described by the formula

1? ° = A ² [είη ² 4> (1 -είη ² ^ είη ² 2y () +

+ cos ² uznp ² ^ cos ² 2о1 +

p, r θ ’

+ 3Ϊη ² 2tsz1n-z1n2o1 [so5231n (and — 0) + + 31p ^ cos2 <^ cos (and-0) 5},

40

45

where Ι, γ is the light intensity, describing the interference pattern in the light scattered in the light plane 9, when the transmission axis of the polarizer 11 is set at an angle of 90 ° to the OX axis.

I

Open slits 4 and 5. The light beam of laser 1 is expanded by telescopic system 2, slits 4 and 5 open and scattered in light planes 8 and 9. Light scattered parallel to the 0Ζ axis is linearly polarized, and the oscillations of the light vector are parallel to the OX axis. From the cuvette 6 comes the light described by the formula

^E , nd = ^E T ^{+ E} , 1 '

where E _{) T (} is the scattered column vector

in the light planes 8 and 9 of light,

leaving the cuvette 6.

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Installing the transmission axis of the polarizer 11 at an angle of 0 ° to the axis of the OX, the interference pattern is fixed by the receiving and processing unit 12 of optical information, which is described by the formula

Ι ° ₍ = Ι ° + Ι ^ + АВ [2соз ² ф (cos ^ +

- · 005 _{2Λ'δίη2δίηεΙ ') - 3Ϊη2ι ί' 8ΪΠ23Ϊη2} <75Ϊη (π- \ ΐ + ιθ

+ cp)

where ~ light intensity

^ describing the interference pattern in the light scattered in the light planes 8 and 9, when the transmission axis of the polarizer 11 is set at an angle of 0 ° to the axis OX "

Setting the transmission axis of the polarizer 11 at an angle of 45 ° to the axis of the OX, the interference pattern is fixed by the reception and processing unit 12 of optical information 12, which is described by the formula

ΐΐ ⁵ = 1 ^ ⁵ + 1 ^ + AB {Г1 + з £ п2 ^ cos (and +

u I Sh 25

+ $)] [СО8 ^ СО8 (Р + 51П ^ 81П ^ СО52й (3 +

. ί / _g

+8 1p2o! Z1p2 [οο5 ² ψ 31p (2i + <G) + zgp ² for 3ίη (2 <^ 30

where I is the light intensity

describing the interference pattern in the light scattered in the light planes 8 and 9, when the transmission axis of the polarizer 11 is set at an angle of 45 ° to the OX axis.

Setting the transmission axis of the polarizer 11 at an angle of 90 ° to the axis of the OX, blocking the reception and processing of optical information with the optical information information block 12, which is described by the formula

1 ^ * = 1 ^ +1 + AB [2δϊπ ² hCcfd ^ soZChCH

+ СОз2с (81П ^ 81П << ') + 8Ϊη2ψ3Ϊη ^ 5Ϊη2θί8Ϊη (and- <45

-5) + (P),

-g 9o

where I, ϊι is the light intensity, describing the interference pattern in the light scattered in the light planes, 8 and 9, when the transmission axis of the polarizer 11 is set at an angle of 90 ° to the OX axis.

The interference patterns or intensity equations obtained in this way for each point of the cross section contain information about the scattered light, the flat-caged state of the cross section and changes in polarization when light passes through the model section located between the cross section and the border of the model. The decoding of data of nine interference patterns or the solution of the system of intensity equations carried out by the unit 12 for receiving and processing optical information allows determining the difference of quasi-head voltages and their orientation regardless of the distribution of the difference of quasi-head voltages and changes in their orientation throughout the model.

Claims (1)

Claim The method for determining stresses in the model in diffused light, which consists in that the loaded model is shined with a flat beam of polarized light, the interference pattern is recorded in the direction normal to the plane of the light beam and used as an information parameter in determining stresses, increase the accuracy and expand the field of use, additionally distinguish in the model a plane parallel to the beam of polarized light and located at such a distance from it, where the difference of quasi-head voltages and their orientation do not change, shine through this plane with a flat beam of polarized light, then shine the model with both parallel beams of light at the same time, with each of these three shineings, the polarizer in the light plane is projected on the light vector to the axes 90, 135 and 180 °, register three interference patterns with each translucence and use them as an information parameter. 1486778