Ural Federal University (Ekaterinburg, Russia):

M. V. Erpalov, Cand. Eng., Assocoate Prof., Chair “Metal Forming”, e-mail: m.v.erpalov@urfu.ru
D. A. Pavlov, Cand. Eng., Associate Prof., Chair “Metal Forming”, e-mail: d.a.pavlov@urfu.ru

The paper is devoted to the new method of torsion testing with variable acceleration, which is conducted in order to determine the shear strain resistance of materials. In order to study the rheological properties of materials, which are sensitive to strain rate, with the use of proposed method, test control and experimental data processing algorithms have been developed. It is shown that two control parameters c and k determine the ranges of the strain and strain rate values in which the rheological properties of materials are studied. They also determine the duration of testing. For the case of testing samples with a cylindrical working part of a solid circular cross section, formulas are given for calculating the values of the sample twist angle at each time point. Changing the twist angle of the sample in accordance with these values provides a reliable determination of the rheological properties of materials, which are sensitive to strain rate. In order to verify the new testing method, mathematical modeling of the torsion test was performed using the Wolfram Mathematica software. The simulation results indicate the consistency of the proposed method for testing materials, which are sensitive to strain rate.

The application for the invention № 2018132149 dated 07.09.2018 was submitted on this method of testing samples.
The investigation was supported by the program 211 of the Government of the Russian Federation (agreement № 02.A03.21.0006).

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