Engineering, Energy, Transport AIC

Andrii SHTUTS – Candidate of Technical Sciences, Senior Lecturer, Department of Electric Power Engineering, Electrical Engineering and Electromechanics, Vinnitsa National Agrarian University (3, Solnechna str., Vinnitsa, 21008, Ukraine, email: shtuts1989@gmail.com, https://orcid.org/0000-0002-4242-2100).

The analysis of the construction of the curves of limit deformations of metals is carried out in the work. It was established that traditional methods of testing, such as deposition and stretching of cylindrical samples, do not ensure constancy of the stress state indicator, and therefore introduce the history of deformation into the construction of curves.
During deposition, there is an increase in the stress state indicator due to the curvature of the side surface of the sample (the formation of a barrel), which is caused by friction on the ends. And during stretching, the stress state indicator also increases, as a result of the formation of a neck due to the loss of deformation resistance. Therefore, measures were considered that would ensure obtaining reliable results when constructing the curves of limit deformations excluding the influence of deformation history. During deposition, such measures include the use of a plastic foil, softer than the sample material, on the ends of the samples and stepwise removal of the edges of the hole on their ends by grinding or deposition without foil. In addition, an experimental and computational method was considered, which involves the construction of deformation paths and correction of the limit deformation using the deformability criterion. During stretching, in the case of neck formation, the increase in deformation depends linearly on the ratio of the radius of curvature of the neck to its diameter.
An equation is presented, which can be used to take into account the influence of the neck parameters on the increase in limit deformations using the experimental and computational method. For the experimental determination of the ultimate deformation during stretching, a method of rolling cylindrical samples into a wedge with rolls, the radii of which increase during the rolling process, which allows to eliminate the appearance of a neck, is proposed. With sufficient accuracy for practice, the curves of limit deformations can be constructed based on the results of testing samples for torsion and sedimentation, and the values of limit deformations during stretching can be obtained using approximating dependencies tested for various metals. According to the above method, including the determination of plasticity by rolling, the curves of limit deformations of a number of steels were constructed.

1.    Matvijchuk, V., Shtuts, A., Kolisnyk, M., Kupchuk, I., Derevenko, I. (2022). Investigation of the tubular and cylindrical billets stamping by rolling process with the use of computer simulation. Periodica Polytechnica Mechanical Engineering, 66 (1), 51–58. [in English].
2.    Shtuts, A., Kolisnyk, M., Vydmysh, A., Voznyak, O., Baraban, S., Kulakov, P. (2020). Improvement of Stamping by Rolling Processes of Pipe and Cylindrical Blades on Experimental Research. Actual Challenges in Energy & Mining, 844, 168–181. [in English].
3.    Stuts, A.A. (2020). Computer modeling of the rolling stamping process of cylindrical and tubular blanks using the deform-3d software complex. Vibrations in engineering and technology, 4 (99), 101–113. [in Ukrainian].
4.    Shtuts, A.A., Sluzhaluk, M.O. (2020). Research of rolling stamping processes using surface heating of blanks. Vibrations in engineering and technology, 2 (97), 138–148. [in Ukrainian].
5.    Matviychuk, V.A., Kolisnyk, M.A., Shtuts, A.A. (2018). Study of the stress-strain state of the material of the blanks during direct extrusion by the rolling stamping method. Technology, energy, transport of agricultural industry, 3(102), 77–84. [in Ukrainian].
6.    Shtuts, A., Kolisnyk, M., Yavdyk, V. (2018). Improvement of processes of rolling stamping on the basis of investigation of technological parameters on the mechanics of workpieces formation. MOTROL. Commission of Motorization and Energetics in Agriculture, 20 (1), 19–25. [in Ukrainian].
7.    Matviychuk, V.A., Aliyev, I.S.. (2009). Improvement of processes of local rotational pressure processing based on the analysis of deformability of metals : monograph. Kramatorsk: DGMA. [in Ukrainian].
8.    Kraevsky, V.O., Matviychuk, V.A., Mikhalevich, V.M. (2003). Influence of technological parameters on the kinematics of cold end rolling. Improvement of pressure treatment processes and equipment in mechanical engineering and metallurgy. Kramatorsk-Slovyansk. [in Ukrainian].
9.    Mikhalevich, V.M., Dobranyuk, Yu.V. (2015). Analytical presentation of the maximum radius of cylindrical workpieces during axisymmetric deposition with barrel formation. Herald of mechanical engineering and transport, 1, 59–66. [in Ukrainian].
10.    Matviychuk, V.A., Mykhalevych, V.M., Dobranyuk, Yu.V., Bubnovska, I.A. (2016). Method of determining the plasticity of metals by rolling cylindrical samples into a wedge, IPC G01N 3/08 (2006/01). № 109984, September 26, 2016. [in Ukrainian].
11.    Kupchuk, I., Kolisnyk, M., Shtuts, A., Paladii, M. (2021). Development of the technological process of forming rings from sheet samples by stamping rollers and rotary hood. Bulletin of the Transilvania University of Braşov. Series I: Engineering Sciences, 14 (63), 2, 1–13. [in Ukrainian].
12.    Andrii Shtuts, Mykola Kolisnyk, Oleksandr Voznyak (2022). Studying the dynamic characteristics of closed system of gravity concrete mixer’s electric drive by means of computer simulation. AGRICULTURAL ENGINEERING, 54, 49–61. [in Ukrainian].
13.    Vozniak, O.M., Stuts, A.A., Kolisnyk, M.A. (2021). Modern systems of electric drives. Theory and practice (part 1): teaching manual. Vinnytsia: LLC "CREATIONS". [in Ukrainian].
14.    Shtuts, A.A., Matviychuk, V.A. (2016). Computer modeling of the rolling stamping process of pipe blanks. Technical sciences: Collection of scientific papers, 1 (95). 178–184. [in Ukrainian].
15.    Matviychuk, V.A., Kolisnyk, M.A., Shtuts, A.A. (2018). Study of the stress-strain state of the material of the blanks during direct extrusion by the rolling stamping method. Technology, energy, transport of agricultural industry, 3 (102), 77–84. [in Ukrainian].
16.    Matviychuk, V.A. (2007). On increasing the plasticity of metals in cases of the appearance of a neck during stretching. Forging and stamping production “Processing of metals by pressure”, 9, 18–22. [in Ukrainian].
17.    Mikhalevich, V.M., Dobranyuk, Yu.V. (2015). Analytical presentation of the maximum radius of cylindrical workpieces during axisymmetric deposition with barrel formation. Herald of mechanical engineering and transport, 1, 59–66. [in Ukrainian].
18.    Mikhalevich, V.M., Lebedev, A.A., Dobranyuk, Y.V. (2011). Modeling of plastic deformation in a cylindrical specimen under edge compression. Strength of Materials, 43 (6), 591–603. [in Ukrainian].
19.    Lebedev, A.A., Mikhalevich, V.M. (2003). On the Choice of Stress Invariants in Solving. Problems of Mechanics. Strength of Materials N 35 (3), Plenum Publishing Corporation (USA), May - June, 217–224. [in English].