A. D. Khvan (Voronezh State University, Voronezh); D. V. Khvan, A. A. Sidorenko (Voronezh State Technical University, Voronezh)

Plastic stability under compression of a plate

The article considers the stability of a compressive flat wall. Based on the criterion of the positivity of the work of the additional load, a formula is obtained for calculating the supporting force that prevents the curvature of the workpiece when it is compressed by a longitudinal force. The magnitude of the supporting force depends on the mechanical properties of the workpiece material and its geometric parameters. It is established that with an increase in the relative deformation of compression, the supporting force increases monotonously. Knowledge of this force is necessary to calculate the design dimensions of the die for the implementation of the technological process of settling a flat billet without curvature.
Keywords: stability; flat sample; stress; supporting force; stability criterion; compressive force; deflection.

A. I. Kanareykin (Russian State University for Geological Prospecting (MGRI), Moscow)

Independent statistical criterion of plasticity of construction materials

The article is devoted to the statistical criterion of plasticity of structural materials. Plasticity criteria are a measure of the stress state that determines the conditions for the material to reach its limit state, i.e., from the elastic state to the plastic state. The article discusses the statistical criterion of fracture hazard proposed by D. M. Shur. This approach is based on the assumption that the resistance to detachment does not depend on the tangential stress, and the resistance to detachment in different directions is a random variable, with a zero probability of damage when the stress is compressive.
Keywords: statistical approach; strength; tension; stress hazard criterion; energy theory of strength.

A. I. Kanareykin (Russian State University for Geological Prospecting (MGRI), Moscow)

Determination of heat transfer in a rod for the case of a linear change in thermal conductivity

The article is devoted to the theoretical issues of heat transfer through a rod. The paper considers the case of a linear change in the thermal conductivity of the rod material. At the same time, there are no heat sources in the rod, as well as in the coating layer. The process itself is stationary. The solution to the problem is given using the Frobenius method. The Frobenius method allows us to find a solution to a second-order differential equation in the form of power series.
Keywords: core; heat transfer; thermal conductivity; Frobenius method; Bessel functions.

V. E. Ovsyannikov, R. Yu. Nekrasov, Yu. A. Tempel, A. I. Starikov, A. S. Gubenko (Tyumen Industrial University, Tyumen)

On the issue of theoretical determination of the printing speed of items in additive manufacturing

The issues of developing an approach to assigning rational values of the printing speed in additive manufacturing, which provides a combination of productivity, as well as ensuring the required dimensional accuracy and surface quality of products, are considered. The solution to the problem is based on modeling the oscillatory processes occurring in the technological system.
Keywords: additive technologies; surface quality; productivity; accuracy; printing speed.

B. A. Romantsev, M. M. Skripalenko (Baikov Institute of Metallurgy and Materials Science; NUST MISIS, Moscow); M. N. Skripalenko, V. V. Panasyuk (NUST MISIS, Moscow); S. A. Stebunov (Qantorform LLC, Moscow); V. S. Yusupov, V. A. Andreev (Baikov Institute of Metallurgy and Materials Science, Moscow); V. P. Kuznetsov (Ural Federal University named after the first President of Russia B. N. Yeltsin, Ekaterinburg)

Estimation of the hollow shells torsion while screw piercing using computer simulation

Finite element method (FEM) computer simulation of two- and four-high screw piercing was carried out using QForm software. Obtained results allowed estimation of hollow shells’ material torsion due to different rotational velocities of adjacent cross-sections inside the deformation zone. It is shown that torsion moment 47–48 % decreases while four-high piercing compared to two-high one. Torsion moment decreasing allows fracture risk decreasing while four-high piercing: normalized Cockroft-Latham damage criterion is up to 25 % less along the outer surface and up to 37 % less along inner surface of the hollow shell at the stationary stage compared to two-high piercing.  
Keywords: torsion; moment; two-high screw piercing; four-high screw piercing; computer simulation; hollow shell surface. 

V. V. Glebov, A. V. Platonov, M. V. Kangin, V. A. Sharov (Arzamas Polytechnic Institute, branch of the Nizhny Novgorod State Technical University named after R. E. Alekseev, Arzamas); K. A. Shchegletov, I. I. Klokov, E. M. Kangin (Nizhny Novgorod State Technical University, Nizhny Novgorod)

A numerical simulation study of the «fixture-billet» kit during performing a slotting operation on an electric erosion machine (part 2)

The article presents the design of a special device for processing a shaped hole in the workpiece of a body part in an electroerosion treatment machine. Studies of the strength and stability of the «fixture-billet» kit for strength and stability using the «ANSYS» software package have been performed. The dependence of the values of stresses and displacements in the investigated set of «Fixture-billet» on various masses of workpieces was also revealed. The study showed the possibility of using such devices to secure workpieces weighing up to 200 kg. in electroerosion treatment machines.
Keywords: electroerosion treatment; numerical modeling; deformations and displacements; billet basing; adaptation.

V. S. Mamutov, X. S. Arsentyeva (Peter the Great St. Petersburg Polytechnic University, St. Petersburg); D. R. Kravtsov (Peter the Great St. Petersburg Polytechnic University, Morion, Inc., St. Petersburg); A. A. Stepanov (Morion, Inc., St. Petersburg)

Experience of design and manufacturing of small-scale tools for punching operations of sheet metal forming

In this article «Morion, Inc.» company’s experience of manufacturing of small-size punches for punching 0.17 mm wide holes in «Holder» parts is provided. Several variants of small-size punches design and their advantages and disadvantages are considered. Some variants of which manufacturing was attempted by company and herewith appeared issues are provided. Final design of punch which was approbated and showed its workability is proposed.
Keywords: sheet metal forming; die tools; punching operations; small-size tools.

M. M. Bakradze, O. A. Bazyleva, D. V. Kapitanenko, N. V. Moiseev, B. R. Nekrasov (National Research Center «Kurchatov Institute» – VIAM, Moscow), P. A. Ratman, D. A. Nadezhdin (OOO «Firm «Medel» Ltd., Shchyolkovo)

The use of the foundry structural alloy based on intermetallic compound Ni3Al for manufacturing high-temperature isothermal dies

The influence of the chemical composition of an intermetallic alloy based on Ni3Al compound, casting technology and hot isostatic pressing on the phase composition, microporosity and deformation resistance in order to use the material in as a stamping tool.
Keywords: intermetallides; Ni3Al compounds; die material; hot isostatic pressing.

Wu Tongyu (Peter the Great St. Petersburg Polytechnic University, St. Petersburg)

Optimization of technological process of manufacturing parts from titanium alloy VT19

The article deals with the issues of optimization of technological process of manufacturing parts from titanium alloy BT19, widely used in aviation, space and energy industries with the coverage of both mechanical and physical-technical processing methods.  The main attention is paid to the study of mechanical and physical-technical processing methods, including cutting, grinding, laser and ultrasonic processing. The problems arising in the processing of VT19 associated with its high strength, tendency to rivet and thermal damage to the surface are analyzed. The methods of experiments are described, the results of evaluation of the quality of the obtained surfaces, the influence of different processing modes on the physical and mechanical properties of the material are given. Recommendations on selection of optimal parameters of technological process providing increase of productivity and quality of processing of products from titanium alloy BT19 are formulated.
Keywords: titanium alloys; VT19; optimization of technological process; mechanical processing; physical and technical processing; laser processing; ultrasonic processing; surface quality.

Yu. N. Ivanov, L. I. Shemetov, M. E. Lebedeva, K. P. Zenin, A. O. Ulanov (Irkutsk National Research Technical University, Irkutsk)

Features of modern methods of manufacturing pipelines in aviation: review and development prospects

This article examines the features of modern methods of manufacturing pipelines in aviation, provides an overview of them, and considers development prospects. A detailed analysis is carried out for traditional and modern approaches, such as welding, molding, 3D printing and vacuum infusion, as well as their advantages and disadvantages. Particular attention is paid to innovative materials and technologies that provide resistance b lightness of pipelines to aggressive operating conditions. In conclusion, the article discusses the development prospects of pipeline manufacturing technologies in aviation, including the possibilities of process automation and digital solutions, which is a hot topic at the moment.
Keywords: pipe; 3D printing; pipeline; fatigue limit; thermoplastic composite material.