KSHP. OMD №7-2020

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

The study of combined extrusion of tumblers with the co-bottom part.
Part 8. Kinematic and stress states of the plastic area located under the central flat surface of the punch

For extrusion of tumblers with a conical bottom using the method of plastic flow by A. L. Vorontsov, the kinematic and stress states of the extruded metal in the area of the plastic deformation zone located under the central flat surface of the punch are determined. The formulas of the deforming force and the height of the zone of plastic deformation are obtained. In the future, the results of this mechanical and mathematical analysis will make it possible to formulate a scientifically grounded methodology for calculating the main technological parameters for extruding nozzles with a tapered bottom, as well as to investigate the issue of the presence of a punch taper that is optimal in terms of strength.
Keywords: tumbler with a flange; die forging; direct extrusion; stresses; deformation.

V. N. Chudin (Tula State University, Tula)

Crimping of body workpieces made from anisotropic hardening material

A technological scheme and calculations of the modes of technology for crimping thick-walled pipes for body workpieces are proposed. The operation pressure is determined as the upper limit according to the equation of the balance of the powers of external and internal forces. A calculated estimate of the damageability of the material of the original workpiece is given. Technological data, tooling and product samples are presented.
Keywords: plasticity; power; pressure; material damage.

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

A variant of the energy theory of strength

A version of the energy theory of strength and fracture of plastic materials under a complex stress state is proposed, based on the components of the specific potential energy of deformation, which are responsible for changing the volume and shape of an element.

Sh. A. Omarov (Daghestan State Technical University, Makhachkala)

Calculation of energy-power parameters of magnetic elastic-pulse forming

A method has been developed for calculating the energy-power parameters of magnetic elasto-pulse forming (MEIF) by jointly solving problems describing the deformation of the workpiece under the action of a given pressure, with the definition of the stiffness function of the «elastic medium-workpiece» system, and also taking into account electromechanical processes in the technological device of the MEIF for a given function stiffness with the definition of the law of pressure change. Numerical calculations show that the inductance and resistance of the discharge circuit change significantly during the action of an electromagnetic force on the moving element.
Keywords: power parameters; technological device; magnetic field; deformation of the workpiece; elastic medium; discharge circuit.

S. M. Vaytsekhovich, L. M. Ovechkin, A. Yu. Zhuravlev (Tekhnomash Scientific Production Association, Moscow)

Development of equal-channel pressing technology to obtain products made of hard-to-form materials

The data of experimental studies of equal-channel pressing (RK pressing) for the processing of semi-finished products from tungsten and molybdenum are presented. Based on the analysis of the stress-strain state of a simple shear of a plastically inhomogeneous body, the requirements for an instrument providing a simple shear are formulated. An assessment of the effectiveness of RK-pressing is given. An experimental device has been developed for testing technology that implements multi-stage plastic deformation by a simple shift.
Keywords: metal processing by pressure; plastic deformation; shear; metal flow; die tooling; matrix; punch; RC-pressing.

M. A. Petrov, D. A. Elesin (Moscow Polytechnic University, Moscow ), V. V. Isakov (Central institute of aviation motors, Moscow)

Stating the wear and fatigue of the tool for cold bulk forming applying numerical simulation

The assurance methods of wear and fatigue predictions of the punch and die are presented, whereby modern technique like microscopy and numerical simulation are applied. There is a nonlinear characteristics of the tool’s wear depends on the sizes of the downscaled tools’ and half-product geometry. Using topology optimization method the die was redesigned in software sT Inspire and returned into the material’s deformation simulating software QForm for repeating the process simulation with renewed tool set. This principle shows the development perspectives of the going through technology workflow with the software evolution into CAED software.
Keywords: forming tool’s wear; similarity theory; cold forming; backward extrusion; finite-element modeling; topology optimization.

A. A. Jomartov, A. K. Tuleshov, M. Zh. Kuatova (Institute of Mechanics and Mechanical Engineering named after U. A. Dzholdasbekov (IMME), Almaty, Kazakhstan)

The choice of the structure of the main working mechanism of the crank press

The paper gives the rationale for the use of flat linkages of high classes for the design of new main working mechanism (MWM) of crank presses. A new MWM of a crank press was designed on the basis of a flat linkage of class IV and its prototype was made.
Keywords: crank press; main working mechanism (MWM); linkage of class IV; connecting rod; slide.