Device and method for measuring dynamic lateral strain of test piece through liquid volume

Abstract

The invention discloses a device and method for measuring the dynamic lateral strain of a test piece through liquid volume. Acquisition device for obtaining liquid elevation dynamic change information, and a fixing device for fixing the conversion device on the SHPB test bench and adjusting the vertical height of the conversion device. The invention converts the lateral strain of the test piece into the change of the measured liquid volume, and further converts it into the change of the liquid elevation, and the high-speed dynamic signal acquisition instrument collects the elevation signal received by the elevation signal sensor, and converts the liquid elevation signal into digital The signal is transmitted to the computer, and the curve of the volume change with time is formed on the computer, and then the curve of the lateral strain of the test piece with time under dynamic load can be obtained according to the specific size information of the test piece. The invention can measure the dynamic lateral strain of the test piece accurately, and the measuring method is reasonable and reliable.

Description

technical field [0001] The invention relates to the technical field of testing the dynamic mechanical properties of brittle materials such as coal and rocks by using an SHPB experimental system, in particular to a device and method for measuring the dynamic lateral strain of a test piece through liquid volume. Background technique [0002] In practical engineering applications, materials such as coal and rock are often subjected to high-intensity dynamic impacts. When materials are impacted by high-intensity dynamic loads in a short period of time, they exhibit mechanical properties that are completely different from static loading. Due to the simple structure and novel design idea of ​​the separated Hopkinson strut device, it has been the research field of high strain rate (10 2 ~10 4 ) The most important experimental method for the mechanical properties of materials. When measuring the mechanical properties of brittle materials such as coal and rock under dynamic load co...

AI Technical Summary

Problems solved by technology

This method has certain limitations. First, the lateral strain of the specimen is often uneven under the impact of dynamic load. The method of pasting strain gauges can only measure the strain at a certain point on the side of the specimen. It is inaccurate to represent the overall lateral strain of the specimen in this way

Second, for dynamic load impact, the lateral strain of the specimen increases sharply in a short period of time, which can easily cause the disconnection of the strain gauge, resulting in inaccurate lateral strain measurement

Third, for brittle materials such as coal and rock, due to the relatively rough arc surface, the strain gauge is not easy to stick, and cannot fit the surface of the test piece well, and the strain gauge is easy to fall off under the action of dynamic load, which affects Integrity of experimental data

Fourth, the strain gauge is pasted on the surface of the test piece, which is difficult to reuse

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