SU1245989A1 - Method of ultrasonic inspection of material conditions - Google Patents

Abstract

The invention relates to a measurement technique and can be used for structural analysis of media. The aim of the invention is to enhance the functionality by detecting acoustic birefringence. In the method, a sample in the form of a cuboidal hedron is cut out of the controlled medium. Ultrasonic transducers of longitudinal waves and ultrasonic transducers of transverse linearly polarized waves, the planes of polarization of which are mutually perpendicular, are installed on the cuc of the bocto octahedron. The sample is probed in the direction perpendicular to the face of the cubooctahedron, one longitudinal and two transverse linearly polarized waves. The velocity of the longitudinal 1 /, k transverse linearly polarized waves G and tj is measured. For each of these nine directions, the acoustic constants tensor values are determined. Solving the system of characteristic equations, we obtain the eigenvalues of the tensor of acoustic constants, which determine the elastic matrix of constants. From the values of these elastic constants, the state and acoustic birefringence of the material are determined. With S IW Is :) 4 recounted O 00 with

Description

f

The invention relates to a measurement technique and can be used for structural analysis of media.

The purpose of the invention is to expand the functionality by registering acoustic birefringence.

The method of ultrasound monitoring the state of the material is as follows.

From a controlled medium, an az-aztec is formed in the shape of a cubooctahedron.

Ultrasonic transducers of longitudinal waves and ultrasonic transducers of transverse linearly polarized waves, the polarization planes of which are mutually perpendicular, are installed on the facets of the cuboid octal. The sample is probed in the direction perpendicular to the face of the cubooctahedron, one longitudinal and two transverse linearly polarized waves. Measured along these nine directions is the velocity of longitudinal C and transverse linearly polarized waves of CG and U. For each of these nine These directions determine the value of the tensor / w of acoustic constants according to the equation

h

. (Y,

for which the system of characteristic equations written as B is valid

(i.f - ,,

(one)

where X is the principal sought direction (i f is the Kronecker symbol; 1. is the eigenvalue of the acoustic constant tensor.

Solving the system of characteristic equations (1), we obtain the eigenvalues L of the tensor f, j of acoustic constants. For example, for sillimanite slate, the condition is observed indicating its rhombic structure. The matrix of elastic constants for media of such symmetry is:

tkf

.

12459892

Know that the acoustic tensor is G,

equals

whom tensor

de

ijK t-h.n, matrix is acoustically written in fork-g

43.

moreover,

eleven

Oh g

23

- oh g with

I j

 ABOUT

55

We have for this case a longitudinal

wave with speed vj

- Sc

R

the pope

/ G / G river waves Vj, V ,, / -.

Substituting the successively found values of the equation (1), we find the CL about the displacement vector of the longitudinal wave and. coincides with the direction of the wave normal, i.e. it coincides with the direction of the Xj axis - (x). Displacement vectors dws x transverse waves U and пер are perpendicular to this direction and coincide with the main coordinate system

is polarized along the xj axis (y), and V is C,

ALONG THE AXIS Xj (z).

Since С V, --7 V ,,

55 (, 6 therefore 2... ,,, as required to be proved. If in the direction of the x (x) axis, using a piezo-transducer, send an ultrasonic transverse-oscillation pulse whose displacement vector is parallel to the axis, then the receiving piezoelectric transducer is oriented exactly the same If it takes a transverse wave V, If both pre-formers that emit a wave are transversely oriented with displacement vectors along the z axis (Xj), then the transverse wave will be recorded. And finally, if oriented at an angle of 45 to the yz directions ( x2X), then two pulses will be recorded.

Claims (1)

Invention Formula The method of ultrasonic control of the material state, which consists in that in the material along non-equivalent arbitrarily given directions, the propagation velocities of ultrasonic longitudinal and two transverse linearly-polarized waves, whose polarization planes are mutually orthogonal, are measured and the components of the acoustic tensor, distinguishing 312459894 so that, in order to expand the speeds of ultrasonic waves of real-life capabilities, they exist along nine directions of recording acoustic two-rays, and taking into account the matrix of 5 other constants, excitation and measurement determine the state of the material.