SU1495678A1 - Method of impact test of materials - Google Patents

Abstract

The invention relates to the study of the strength properties of materials under shock loading. The aim of the invention is to improve the accuracy of determining the strength properties of materials. A sample of the test material is tested according to the Hopkinson composite rod method and subjected to loading with successive shock pulses. The time shift between pulses is determined from the condition of loading the sample with a subsequent pulse before the pulses reflected from the free ends of the rods come to the sample. The sample can be modulated with both longitudinal and torsional loads. An increase in the accuracy of determination is achieved by eliminating the influence of interference pulses reflected from the free ends of the rods. 5 il.

Description

The invention relates to a testing technique, and specifically to methods for studying the strength properties of materials under shock loads.

The aim of the invention is to improve the accuracy of determining the strength properties of materials.

This goal is achieved due to the fact that, when a sample is subjected to successive shock pulses, the sample is loaded with a subsequent pulse before the sample is subjected to pulses reflected from the free ends of the rods, with a previous load.

Figures 1-5 show the test patterns of the sample according to the Hopkinson composite rod method: compression (figure 1), compression-torsion (figure 2-5), as well as the distribution circuits of the loading and reflected pulses.

The method is as follows.

Sample 1 is installed between two rods 2 and 3 and subjected to successive loading by shock pulses, applying a subsequent pulse after the sample has been deformed by the previous pulse, while the time shift between the pulses is set according to the condition of the sample loading by the pulse reflected from the free ends of the rods .

P. Merger, The method is carried out under loading with two successive compressive pulses (Fig. 1).

Sample 1 is installed between two measuring rods 2 and 3. The loading impulse is reproduced with the electric detonator 4 under pressure,

The loading impulse, (t) compression spreads over the measuring rod 2

four

with

01

O5

oo

3-.1495678

and at time t, where L, C is the length and speed of sound in the material of the first age, respectively, acts on sample 1. At a given time t (assuming that to 0), electric detonator 5 is undermined, as a result of which A pulse propagates), which Q at the moment of time ti t for (. where L ,, С is the length and speed of sound in the material of the second rod, respectively, acts on sample 1. 1 pulse passing through the sample is 15 5 (t) is reflected from the free end of the BTOpord of the measuring rod 3 and in the form of a pulse & t act on sample 1, later, acting on the sample impulse 6 (t). Similarly, tests can be carried out with other types of loading, such as compression-torsion (Figures 2-5), impulses 6, (t), 62 (t) squeezing when the electric detonators 4 and 5 and 5 are squeezed with twisting pulses (), 6kg (b) when the electric detonators 6 and 7 are blown up in various combinations of them. ) can be applied both to both measuring rods, and to one stern (Fig. 4 and 5).

When testing samples of materials after the first loading pulse (i -, (t), both elastic and elastoplastic deformation of the sample can be achieved. After the loading pulse passes through the sample through time t, the reflected pulse 6 acts on the sample 40 , (t), which leads to the re-deformation of the sample with

smaller amplitude due to the loss of reflection, refraction and energy dissipation in the material of the measuring rod.

The impact on the sample by the second loading pulse 6j (t), which arrives earlier reflected, allows the sample to be retested with the specified loading parameters.

At the same time, data on the behavior of materials under repeated and repeated loads of both elastic and elastoplastic can be fully obtained with M1 minimum errors, and such effects as, for example, the Bauschinger effect at strain rates can be studied. carried out under both longitudinal loading and sequential loading with longitudinal and torsional loads, for example, when a sample previously deformed by compression or stretching is subjected to loading by twisting pulses .

Claims (1)

Claims A method of percussion testing of materials, in which a sample of a test material is placed between two rods and subjected to successive loading with shock pulses, is impacted by a subsequent pulse after the sample has been deformed by a previous pulse, characterized in that, in order to improve accuracy, the time shift between pulses is set conditions of loading the sample with a subsequent impulse until the arrival of Ko to the sample of the pulses reflected from the free ends of the rods ... FIG. five