The device and method of installation and debugging for improving the precision of arc Brazil test

Abstract

The invention discloses a device for improving the precision degree of a circular-arc Brazilian test. The device comprises an upper base which is mounted under an upper pressing head of a testing machine, and a lower base which is mounted above a lower pressing head of the testing machine, wherein the upper base and the lower base are arranged correspondingly; the lower side of the upper base is movably connected with an upper circular-arc pressing block and the upper side of the lower base is movably connected with a lower circular-arc pressing block; the structures of the lower circular-arc pressing block and the upper circular-arc pressing block are the same; an explosive test sample storing space is formed between the lower circular-arc pressing block and the upper circular-arc pressing block; the lower base is mainly composed of an upper assembly and a lower assembly; and the upper assembly and the lower assembly are movably matched. Meanwhile, the invention discloses an installation and debugging method of the device for improving the precision degree of the circular-arc Brazilian test; and the installation and debugging of a tool can be carried out by the central axis of the tool and a positioning cylinder, so that the lower circular-arc pressing block and the upper circular-arc pressing block are at a coaxial alignment state in a loading process, and furthermore, the testing precision degree of the circular-arc Brazilian test of crispy explosive is improved.

Description

technical field [0001] The invention relates to the technical field of material performance testing, in particular to a device and an installation and debugging method for improving the precision of a circular-arc Brazilian test. Background technique [0002] The tensile strength of solid brittle explosives is one of its important mechanical properties. Due to the limitations of the direct tensile test method for explosives, the sample size is large and the dosage is large, it is often difficult to sample during the development of explosive formulations and special parts. Satisfying the preparation requirements of the above-mentioned standard samples cannot obtain its mechanical performance data; in addition, the shape of the sample is relatively complex, the processing precision is high, and the sample preparation cycle is long, which seriously affects the progress of the research work; at the same time, the dumbbell-shaped tensile sample It is prone to loading eccentricity...

AI Technical Summary

Problems solved by technology

The traditional planar indenter Brazil test has the problem of stress concentration at the loading point, which leads to local failure of the sample. The test results are much lower than the standard tensile test results, even 50%, and the correlation with the direct tensile test results is poor. The strength The correlation coefficients with the strain are 0.879 and 0.568 respectively; regardless of the accuracy of the platform Brazil test, just processing the platform at both ends of the sample, the consistency of the dimensions of the two platforms and the requirements of good parallelism are also difficult to prepare the sample. problems; the rubber pad Brazil test has high requirements on the performance and size of the rubber pad itself, otherwise there will still be a problem of stress concentration at the loading point of the rubber pad, and the test results will be highly dispersed and poor in repeatability; at the same time, the patent number is ZL201420342600.1, and the patent name is A Brazilian test device, the publication date is 2014-10-29, the patent discloses a Brazilian test device, which improves the influence of stress concentration near the loading point of the traditional Brazilian test to a certain extent, and the test results are consistent with the direct tensile results It is closer, but because the upper indenter is bonded and fixed to the first arc pressure surface in this device, and the lower indenter is bonded and fixed to the second arc pressure surface, it is affected by the coaxiality of the testing machine and the connection eccentricity of the fixture. It is often difficult for the device to achieve precise coaxial and uniform loading on the upper and lower arc pressure surfaces, resulting in axial load deviation from the centerline of the explosive sample, large dispersion of test results, and even test failure

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