SU1298645A1 - Acoustical method and apparatus for studying article properties - Google Patents

Abstract

This invention relates to the field of acoustic non-destructive testing methods. The aim of the invention is to provide the possibility of controlling the quality of polluted cylindrical articles due to the formation of a powerful acoustic impulse with a uniform circular front in the cavity of the article by choosing a certain quantity. fe S CO 00 about from

Description

spraying wires and their uniform arrangement around the circumference. In the cavity of the product 12 filled with liquid 11, a coaxial input 3 is installed, a high voltage pulse is output from the storage tank 1 through the terminals 2, the input 3 with the central electrode 4 and the disks 5 is fed to the wires 9. The electric explosion of the wires 9 is accompanied by the generation of a shock wave. Under the action of high voltage layer 8

one

The invention relates to acoustic methods of non-destructive testing and can be used to control hollow cylindrical articles, for example, when visualizing the internal structure of thick-walled pipes.

The purpose of the invention is to provide the possibility of controlling the quality of hollow cylindrical products due to the formation in the cavity of a controlled product of a powerful pulse of acoustic oscillations with a uniform circular front coaxially with the cavity of the controlled product.

Figure 1 shows a device for acoustic investigation of product properties; figure 2 is a view of And figure 1; on fig.Z - graph of the return of stored energy E, reduced to the maximum value

energy e

on the diameter ratio

d J disk to the diameter D of the cavity of the controlled product; Fig. 4 shows a qualitative graph of the distribution of the pressure field P in the near zone of breaking wires in reduced distance coordinates, determined by the ratios of the diameter d of the circle on which the exploding wires are located, to the diameter d of the disk.

The acoustic method of studying the properties of the products is carried out as follows.

In the liquid-filled cylindrical cavity, the products are evenly spaced around the circumference with a diameter dp of exploding wires and are connected via a discharge circuit to a storage dielectric on the electrode 4 and also generates a counter shock wave, which protects the destruction layer 8 and the electrode 4 from destruction. the wave does not fall due to the washers 7. The acoustic pulse through the fluid 11 is transmitted to the product 12 and is received from the outside by the receiver 10. The quality of the output is determined by the intensity of the received signal. whether 2 rf f-ly, 4 ill.

bulk capacity. Diameter of the number of p delays vybrorazheny

d, 0.765D;

0.15

n

Lo.as ..

I-r-d

P, 6. (

0 where D is the cavity diameter;

C - the value of storage capacity;

I is the current value; g - electrical resistance 5 wires;

L is the discharge inductance; P - pressure in the shock front

waves; 0 d, is the diameter of the wire.

R as a result of supplying the stored energy capacity, an electrical explosion of wires occurs, accompanied by the generation of a shock wave. 5 Through the liquid, a powerful acoustic pulse is transmitted to the controlled product, and is received from the outside of the last 1 €. The intensity of the received pulse is measured and the quality of the item being monitored is determined using the measurement results.

A device for acoustic investigation of the properties of the products contains. storage capacitor 1, terminals 2 35 of the power supply and coaxial input 3 with the central electrode 4. The device also contains two flat conductive disks 5 with holes 31

6, evenly spaced circumferentially with diameter d, coaxial with Central electrode 4. Liski 5 are mounted coaxially on coaxial input 3 and electrically connected to terminals 2. In addition, the device contains spacer washers 7 mounted on central electrode 4 and one of disks 5 , a polar dielectric layer 8 surrounding the central

the electrode 4, the wires 9 installed in the holes 6 of the disks 5, and the receiver 10. The diameter d of the disks 5 is 1.1 d.

A device for acoustic investigation of the properties of the products works as follows.

Into a product 12 filled with a liquid 11, for example, water, with a cylindrical cavity with diameter D, a coaxial input 3 is inserted. The latter is installed so that the center of a circle with diameter d along which the exploding wires 9 are located coincides

thirty

40

with the axis of the product 12. The disks 5 form a practically closed volume around the wires 9. From storage tank 1, terminals 2 supplying electricity, coaxial input 3 with central electrode 4 and disks 5 to the wires 9 receive a high voltage pulse. As a result, electric wiring of wires 9 occurs, accompanied by the generation of a shock wave. At the same time, when a high voltage is applied to the surrounding central electrode A of the polar dielectric layer 8, around the latter a shock wave is received directed towards the shock wave from the exploding wires 9, which protects the layer 8 and the electrode 4 from being destroyed by a powerful pressure pulse. The washer 7 prevents the passage of a pressure pulse to the inside of the coaxial input 3.

Through fluid 11, a powerful acoustic pulse is transmitted to the test article 12, for example, a thick-walled metal pipe, and excites its crystal lattice. From the outer side of the article 12, a pulse is recorded by the receiver 10, for example by photographic film. The intensity of the received pulse is measured and the quality of the product 12 is limited therewith. The d of diameter of the disks 5 is equal to 1.1 o, which corresponds to

45

25

55

0.84 P, provides the maximum return of the stored energy E (fig.Z). The choice of the diameter d equal to 0.765 D, which corresponds to the equality 0.9 d, also provides the maximum amount of energy released E (Fig. 4). The diameter d of the wire 9 is also determined from the condition of the maximum energy released. The quality of the p wires 9 installed in the holes 6 of the disks 5 is chosen from the expression

P

1.1 С

0.15

IT-D

O.YO p 1.6. 0.5

0

0

five

five

five

(where D is the diameter of the cylindrical cavity of the product 12;

C is the value of storage tank 1; I - current value in bit

chains; g - electrical resistance

wires 9;

L is the discharge inductance of the coaxial input 3 inductance and the inductance of terminals 2; P is the pressure in the front created as a result of electric explosions of the 9 shock wave C, is the diameter of the wire 9. The determination of the number of n wires 9 was obtained by processing the experimental data with the help of a computer and ensures the symmetry of the load. Experimental data are obtained under the following conditions: wire diameter d - 0.6–0.8 mm; capacity of accumulative capacity 1 C 20-100 microns; discharge inductance L 40 10 G, current in discharge circuit I 240-480 kA, cavity cavity diameter 12 D 60 mm; voltage on storage capacity U 5-15 kV.

The use of an acoustic method for studying the properties of products allows one to increase the power of the probe pulse by increasing the efficiency up to 60%. The lifetime of the device for the acoustic study of the properties of the products is 10,000 pulses.

Claims (2)

1. Acoustic method for studying the properties of products, which consists in placing in a filled using a liquid hollow product, exploding wires, connecting them through a discharging circuit with a cumulative capacity, generating a shock wave in a liquid by exploding wires, accepting excited vibrations and measuring their intensity, which in order to control the quality of hollow cylindrical products, the wires are uniformly placed in the cavity of the product around the circumference of diameter d and the quality of the product is determined by the intensity of the oscillations passing through it, and the diameter d and the number of n wires are ajeny d 0.765 D; P 1 1-С ° - I-r-D - D is the diameter of the cavity; C - the value of storage capacity; I is the current value; g - electrical resistance of the wire; L is the discharge inductance; P - pressure in the shock front waves;  - diameter of the wire. 2. A device for acoustic investigation of the properties of products, containing an accumulative capacitance, electric power supply terminals, coaxial input with a central electrode, exploding wires and a receiver, which, in order to control the quality of hollow cylindrical products, is equipped with two flat conductive disks mounted coaxially on the coaxial input and electrically connected to the terminals, spacer washers mounted on the central electrode and one of the disks, and surrounding the central electrode with OEM polar dielectric disks are made with holes arranged uniformly on a circle of diameter d, soos- hydrochloric central electrode wire explosion vakitsies installed in openings disks, and the diameter d, drives selected to be 1.1 d, Vida fpUB.2 0.1 0.2 0.3 0. 0.5 0.6 0.7 0.8 0.9 7.0 d FaaL d yd 0.8 0.7 0.6 0.5 OC U2 Phage 4 d Editor M.Blanar Compiled by V. Gondarevsky Tehred L. Serdyukova Proofreader I. Musk Order 882/46 Circulation 777 Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, Uzhgorod, st. Project, 4