SU1509656A1 - Method of determining pressure in the front of cylindrical wave - Google Patents

Abstract

The invention relates to a test technique and allows an expansion of the range for determining the pressure formed by detonation products and shock waves in a closed volume when an explosive charge explodes. For this purpose, a cylindrical shell 1 is installed coaxially with charge 2 with the plates 4 glued on its surface. As a result of the explosion of charge 2, shell 1 begins to oscillate. The movement of the wall of the shell is recorded optically and the pressure inside the shell is determined by it. From the speed of expansion of the plates 4, the pressure pulse in the shock wave front is determined, thereby specifying the initial pressure value. 1 hp ff, 4 ill.

Description

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The invention relates to an experimental technique and can be used to create experimental installations for determining the pressure produced by detonation products and shock waves in a confined space during the explosion of an explosive charge.

The aim of the invention is to expand the range of pressure determination by ensuring the integrity of the sensitive element in the presence of a shock wave in the frolt, and

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First, plates 4 of lead foil are photographed after separation from the shell at equal intervals of time, which makes it possible to establish the rate of expansion of each plate and calculate the magnitude of the pressure pulse.

Due to the use of an indestructible cylindrical shell as a sensitive element, the recording of pressure continues even after the passage of a shock wave. The use of a shell of considerable size and strength does not reduce the sensitivity

also increase the reliability of the result-15 carry, as the measured pressure

by determining the pressure pulse in the shock front.

FIG. I shows a device for implementing the proposed method; in fig. 2 is a shell loading circuit} in FIG. 3 is a graph of pressure versus time; in Fig. A, a graph of the vibrations of a shell in the explosion of an explosive charge placed along its axis.

The device for implementing the method is a cylindrical shell 1, coaxially with which an elongated charge 2 of explosive with a fuse 3 is installed. On the side surface of the shell there are plates 4 of lead lead that can be held onto the shell by wetting or sticking.

The method is implemented as follows.

An explosion of charge 2 is effected. At the same time, an optical method begins to record the displacement W extr 40 coaxally to the cylinder surface of shell 1. The pressure can be determined by the equation of motion of the shell

the explosive charge, and the deformation of the sensitive element are determined by measuring the displacement of the outer surface of the shell in the middle part along its length.

(t) -phf-.bG (t),

where t is time;

p is the density of the shell material; h is the thickness of its wall; r is the radius; d

(j is the normal stress in the circumferential direction. If necessary, the circumferential stresses should be optically refined and the points at the ends of the shell are also recorded.

The initial pressure is refined by the magnitude of the pressure pulse in the shock front. For this0

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acts simultaneously over the entire inner surface of the cylindrical shell, and this allows to obtain reliable results in a wide range of pressures created in a closed volume with the explosion of an explosive charge.

Formula and 3 gains

Claims (2)

1. The method of determining the pressure in the front of a cylindrical wave, which consists in the fact that on the path of propagation of the pressure set a sensitive element in the form of an elastic body with a known stiffness and determine its deformation under the action of pressure, which is judged on the magnitude and pressure change over time characterized in that, in order to expand the range of measured pressures, a symmetrical cylindrical shell is used as a sensitive element. 40 coaxally cylindrical 45 d The magnitude of the explosive charge and the deformation of the sensing element are determined by measuring the displacement of the outer surface of the shell in the middle part along its length. 2. The method of claim 1, which, in order to increase the reliability of the result by determining the pressure pulse in the front of the shock wave, foil plates are attached to the outer surface of the shell at a medium length, and their speeds are recorded. after separation from the shell surface as a result of its interaction with the shock wave, and determine the magnitude of the pressure pulse in the shock wave front, which is used to judge the maximum pressure in the shock wave front. Fi9.2