RU2293979C1 - Method of determination of rise of internal disorders in contiguity of viscous hermetic materials at multi-cycle loading - Google Patents

Abstract

FIELD: metrology.

SUBSTANCE: fine dispersed ferromagnet powder is added to sample of tested hermetic material. To find arise of changes in internal structure of hermetic during multi-cycle deformations it is subject to, magnetic field is created by means of concentrated inductance coil of resonant circuit. Magnetic field changes as ferromagnet particles re-distribute, which particles were added into hermetic sample, which causes changes in resonant frequency of circuit. Arise of internal disturbances in continuity is judged from change in frequency of measuring oscillator.

EFFECT: improved reliability of results.

1 dwg

Description

The present invention relates to the field of metrological measurements and can be used in practice as a basis for the development and construction of various devices for determining the occurrence of internal discontinuities in viscous sealing materials (sealants) under high-cycle loads.

A known method of determining discontinuity inside the sealant by direct impact [1]. The disadvantages of the method include: the differentiability of the resulting damage in depth and the difficulty of detecting defects of small size.

There are methods for determining the quality of materials by transmission through a radiation source and registration with the help of a detector that has passed through a controlled material or is reflected from it, rigidly connected to a source of radiation [2, 3, 4]. The main disadvantages of these methods is the high degree of attenuation of any electromagnetic waves in the considered sealants.

Also known is a method using ultrasonic sensing of sealants. The disadvantage of this method can be considered a high absorption coefficient of ultrasonic waves, which makes it possible to study only thin samples.

The closest in technical essence and the achieved result to the proposed one is a method for determining the volume concentration of ferromagnetic components, which measure the magnetic susceptibility of the medium alternately in a stationary mode at different values of the external magnetic field [5]. The disadvantage of this method is that when you try to use it in an unsteady mode (with multi-cycle loads), the effect of an abrupt change in the strength of the external magnetic field arises, not related to the occurrence of defects inside the sealant under study.

The essence of the proposed method consists in the fact that finely dispersed ferromagnetic powder is added to the sample of the investigated sealant during polymerization. During the polymerization process, the sample rotates at an angular speed that ensures uniform distribution of the powder in the volume. The uniformity of the distribution of the powder also contributes to its fineness. After polymerization, the resulting sample is placed in the inductance coil of the resonant circuit of the measuring generator. The first pass of the generator coil along the sample allows us to estimate the primary distribution of the ferromagnetic powder in the volume of the sealant sample by the magnitude of the frequency deviation of the measuring generator. With further deformations (ε), the powder will redistribute along the length of the sample, and the closer to the central axis of the deformation, the more redistribution will be more noticeable, due to the visco-plastic properties of the sealant. After the application of N-load cycles, microdefects will begin to appear inside the sealant sample and, accordingly, a sharp change in the concentration of magnetic powder will be observed in these areas, which will immediately affect the change in the frequency of the measuring generator. To implement the method, it is recommended to use the magnetic field of a concentrated inductor of an oscillatory circuit connected to a high-frequency measuring generator.

The drawing shows a block diagram for implementing the proposed method, where 1 is a test sample of sealant, 2 is a measuring circuit of the device, 3 is a measuring generator, 4 is a limiter, 5 is a frequency meter, 6 is a moving mechanism of the measuring circuit.

Using the proposed method provides the ability to determine the occurrence of internal discontinuities of viscous sealing materials under high-cycle loads.

Information sources

1. A.S. USSR No. 1270654, M. cl. 4 G 01 N 19/08 from 04.01.85, publ. Bull. No 42 on 11/15/86

2. A.S. USSR No. 404004, M. cl. G 01 N 23/18 from 03/17/65, publ. Bull. No 43 on 10/26/73

3. A.S. USSR No. 323724, M. cl. G 01 N 23/18 from 06.24.68, publ. Bull. No 1 on 01/10/72

4. A.S. USSR No. 1264052, M. cl. 4 G 01 N 22/02 from 06/11/85, publ. Bull. No 38 on 10/15/86

5. A.S. USSR No. 565243, M. cl. G 01 N 27/76 from 08/07/70, publ. Bull. No 26 on 07/15/77

Claims (1)

A method for determining the occurrence of internal discontinuities in viscous sealing materials (sealants) under high-cycle loads by changing their magnetic permeability, characterized in that a magnetic field is created in the sealant using a concentrated resonance circuit inductor that changes as the redistribution of ferromagnetic particles added to the sealant sample which affects the resonant frequency of the circuit, and the desired parameter is judged by the change in the frequency of the measuring generator.