A. L. Vorontsov, D. A. Lebedeva (The Bauman Moscow State Technical University, Moscow)

The study of combined extrusion of tumblers with a co-bottom part.
Part 19. Methodology for calculating technological parameters at initial set by constrained free backward extrusion

The method for calculating the energy-power and deformation parameters of the process of constrained backward extrusion of tumblers with a co-bottom part is presented. The extrusion of both non-hardening and hardening materials is considered. In the latter case, the consideration of hardening of the extruded material is described in detail. The above formulas make it possible to determine such important parameters of the stamping process as the total and specific deforming force, the maximum pressure on the die wall, and the increase in yield stress.
Keywords: forging; tumblers with the co-bottom part; combined extrusion; stresses; deformations.

V. V. Mironenko, M. V. Lavrenteva (Irkutsk National Research Technical University, Irkutsk)

Mathematical model for calculation of the main parameters when forming non-standard lateral locks on sheet parts to eliminate the defect of the type «under stamping»

The article deals with a non-standard lateral undercut, which goes beyond the limits of OST 1.52468–80 and for which there are no methods for calculating the main technological parameters. The article shows that standard methods from the scientific literature do not provide a solution for the main parameters for shaping a given element of a part. In particular, the calculation of the parameters of the minimum thickness and the required pressure is shown (the linear law of approximation of the true stress diagram was used) proposed by E. I. Isachenkov. The paper proposes methods for finding the parameters of shaping and technological characteristics of a part containing a non-standard undercut. The assumption is made that the surface area built on the basis of four vertices and the curve related to the top of the undercut is the initial shaping area for the undercut before the manufacturing process and that the metal is not thinned before this stage. To verify the results and verify the proposed analytical dependencies, we carried out simulation modeling of the shaping process based on the finite element method in the PAM-STAMP software package. A method of shaping is also proposed, which makes it possible to eliminate a defect of the «understamping» type. This method divides the process into two transitions (at the second transition it is necessary to apply an additional tooling element that will move) and changes the stress-strain state in the process of shaping. A comparison of the results with finite element analysis of shaping and natural experiment was carried out and no significant differences were revealed.
Keywords: mathematical model; sheet stamping; stretch bending; springing; undercutting.

A. E. Tsibulko, E. A. Romanenko (PJSC «NKZM», Kramatorsk, Ukraine)

Improved first condition of a reliable strength criterion for materials in a brittle state

An improved first condition for a reliable strength criterion for materials in a brittle state is proposed for consideration, in the structure of which the loading stiffness parameter is built in, based on octahedral tangential and normal stresses.
Keywords: strength; deformation; octahedral, normal, tangential stresses, loading stiffness parameter.

Yu. N. Loginov, Yu. V. Zamaraeva (The Ural Federal University named after the first President of Russia B. N. Yeltsin, Institute of Physics of Metals named after M. N. Mikheev Ural Branch of the Russian Academy of Sciences, Ekateriburg)

Cylinder article compression in the cavity of a deformable shell by small diameter punches

A description is given of experiments on compression of an assembly consisting of a cylindrical billet placed in a hollow of a shell. A feature of the process is that the compression is carried out by punches having a diameter smaller than the diameter of the assembly. The experimental data are supplemented by the results of numerical modeling using the finite element method. It was established that such a deformation scheme leads to an increase in the level of compressive stresses, as a result of which the ductility of the metal increases.
Keywords: compression of a cylindrical workpiece; stress; strain; ductility; finite element method.

V. V. Mironenko, M. V. Lavrentieva (Irkutsk National Research Technical University, Irkutsk)

Tooling compensation by springback for parts made by transverse «covering»

The article deals with the problem that arises when compensating for springback in the tooling of parts manufactured by longitudinal tight and its negative consequences associated with the direction of the elastic response of the material. On the example of one typical part, simulation modeling was carried out using the finite element method of the process of shaping the longitudinal cover. The problem of the direction of movement of the part, which occurs during springback, its influence on the compensation of the tooling, is shown. A method is proposed to eliminate this effect by changing the method of shaping to a transverse tight. The details were analyzed using the least squares method in the places of the most important sections. Based on the theory of probability and characteristics of the distribution of a random variable, the threshold values of the cross sections at which negative effects occur are calculated. On the basis of the calculations performed, a method has been developed for determining the occurrence of a problem with tooling compensation for springback based on the geometry of the part.
Keywords: sheet stamping; tensile bending; springback; simulation; springback compensation.

J. N. Nizomov (Institute of Geology, Earthquake Engineering and Seismology of Academy of Sciences of the Republic of Tajikistan, Dushanbe, Republic of Tajikistan), A. I. Dadoboev (Khujand Polytechnic Institute of the Tajik Technical University named after academic M. S. Osimi, Khujand, Republic of Tajikistan)

On methods of mathematical modeling of the stress-strain state of stiffening diaphragms

This article considers various methods of mathematical modeling of the stress-strain state of stiffening diaphragms of multi-storey residential buildings. A comparison is made of the calculation options for mathematical modeling of the stress-strain state of stiffening diaphragms. The accuracy of describing a phenomenon by a mathematical model is sometimes limited only by the available computing power.
Keywords: deformation; element; program; diaphragm; stiffness; efficiency; model; approbation; task; analysis.

A. S. Govorkov, M. V. Lavrenteva (Irkutsk National Research Technical University, Irkutsk)

Working environment as the basis of a digital enterprise

Currently, the basis of the structure of any manufacturing enterprise that produces a wide range of products is the production environment. It is a set of production, information, management, support processes that are designed for efficient and safe production, as well as to meet consumer requirements. Innovations in the development of industrial enterprises can be noted at all levels of the hierarchical ladder: from building design to the start of production of finished products. The paper considers a digital enterprise that meets the requirements of the "Digital Economy of the Russian Federation" program, according to which the work of such an enterprise is regulated. Regulation includes personnel and education, the formation of research competencies and technical groundwork, information infrastructure, as well as information security. The digital enterprise forms the digital economy, which includes: digital data, digital infrastructure and digital models. Recently, the concept of a digital enterprise has begun to be widely introduced at enterprises in the military-industrial complex. The article presents the production system, which is a hierarchical structure, at each level of which there is a strictly defined set of objects, which are combined with each other according to their purpose and functions.
Keywords: production environment; hierarchy; constructive solutions; enterprise; information process; efficiency; organizational structure.