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卷 37, 编号 6 (2017)
- 年: 2017
- 文章: 22
- URL: https://journals.rcsi.science/1068-798X/issue/view/14022
Article
Diagnostics of electrical components by means of their external magnetic field
摘要
The external magnetic field of idling three-phase induction motors in electrical systems is investigated in the following cases: with no faults; with a turn-to-turn short-circuit in a stator phase; with rupture of a stator phase; and with static eccentricity. The field is modeled by the finite-element method on the basis of the Laplace equations and Ansoft Maxwell v.14 software.
467-470
Predicting the limiting strength of chaotically reinforced polymer composites with dispersed antifrictional additives
摘要
The limiting strength of antifrictional polymer composites in uniaxial compression is investigated as a function of their components, by numerical modeling.
471-474
Orientation mechanism with linear drives for robot manipulators and limb prostheses
摘要
The design of an orientation mechanism with linear drives is considered. The matrix method is used for kinematic determination of the displacements and speeds in linear drives that ensure specified motion of the output element around a fixed point, with three, two, and one degrees of freedom. On that basis, the forces of the drives are determined for specified torques at the output element.
475-478
Optimizing pump-drive operation to improve the energy-efficiency of oil extraction
摘要
Equivalent systems (analogs) are employed in developing a model of the drive mechanism in a sucker-rod borehole pump. Normal and emergency pump operation is simulated on the basis of Matlab-Simulink software. The rod column is regarded as a coupled sequence of active quadrupoles. The results of the simulation are compared with experimental data, and recommendations are made for reducing the energy consumption.
479-484
Innovative suspensions for caterpillar vehicles
摘要
A semiempirical method may be used to determine the optimal rigidity and damping of the suspension of a caterpillar vehicle with controllable track tension. Simulation of its resonant motion confirms the applicability of the method.
485-489
Production of rings for gas-turbine engines by the hot rolling of welded blanks
摘要
The manufacture of rings for gas-turbine engines is considered. The rings are obtained from folded and welded steel sheet, with subsequent strengthening of the weld seam by forging and rolling (with 30–50% deformation). Metallographic data confirm that uniform structure is obtained by hot rolling at the weld seam; its grain size is optimal and its mechanical properties are good.
490-493
Running-in of metal–polymer frictional systems with a composite coating
摘要
A universal criterion is proposed to determine when the nonsteady running-in of a frictional pair has ended. An algorithm is developed for identification and statistical evaluation of the running-in parameters in the case of a metal–polymer frictional system.
494-497
Microhardness and tribological characteristics of coatings
摘要
The hardness and frictional coefficients of two-layer coatings are investigated. The coating life of steel samples is investigated on the basis of its elastoplastic deformation and the microhardness before and after testing on a frictional machine. The two-layer Mo2N + Mo coating considerably outperforms the steel in terms of microhardness. The life is greatest for TiC coatings.
498-501
Target cleaning for faster CrN/AlN coating growth in magnetron sputtering
摘要
Metallic sputtering may be used to clean the target surface in the course of coating application by reactive magnetron sputtering. The introduction of additional stages of metallic sputtering in reactive magnetron sputtering increases the growth rate of CrN/AlN coatings by around 23%, with little change in physicomechanical properties.
502-504
Optimization of vibrational cutting
摘要
The cutting speed and vibrational acceleration have the greatest influence on the tool life in turning. Promising directions for further improvement in tool life are identified by analysis of a mathematical model.
505-508
Cutting forces on the tool blade
摘要
If the cutting force acting on the tool blade at the rear surface is divided into the chip-formation force and the elastic-recoil force of the machined material, formulas may be obtained for calculating these components. The formulas take account of all the relevant factors and permit the determination of the loads on the system components when parts are machined in a metal-cutting machine.
509-512
ISO 25178 standard for three-dimensional parametric assessment of surface texture
摘要
Analysis of the surface texture in accordance with the ISO 25178 standard is described. Potential applications of the ISO 25178 parameters to machining are considered.
513-516
Modeling of hydrostatic bearings by electrical analogy
摘要
Models of various dynamic systems may be constructed by electrical analogy. As an example, the operation of an open hydrostatic guide is analyzed. The optimal relations between the dynamic parameters are established on the basis of modeling.
517-522
The problem resolution of designing of cycles in the conditions of modern automated production
摘要
The design of machining cycles in automated production entails the development of a theory regarding the selection of optimal automatic cycles for numerically controlled metal-cutting machines. This theory is based on dynamic programming and permits optimization of an unlimited number of control parameters for all types of machining operations.
523-529
Chip combustion in metal grinding
摘要
The microstructure of spherical inclusions (globules) in grinding sludge is analyzed, and the inclusions are classified. Their basic defects are considered. The formation of the spherical inclusions and their defects is explained in terms of the theory of physicochemical combustion of metal. Typical stages of chip combustion in the course of grinding are identified.
530-535
Surface microgeometry of structural-steel samples after diamond burnishing
摘要
The influence of diamond burnishing on the surface microgeometry of 30ХГСН2А-ВД structural alloy steel is considered. Empirical formulas are presented for the surface roughness as a function of the burnishing parameters.
536-538
Residual stress in the surface layer of ground parts
摘要
A method is outlined for calculating the residual stress in the surface layer of ground parts as a result of heating and structural changes.
539-544
Surface quality of turbine blades in multicoordinate grinding
摘要
The influence of multicoordinate creep-feed grinding on the surface quality of gas-turbine blades is studied. The influence of the grinding conditions on the roughness and residual stress in the surface layers of the turbine blades is established. The conditions in which scorch marks and cracks appear at the machined surfaces are determined.
545-548
Hole shaping in the honing of thin-walled cylinders
摘要
The possibility of obtaining specified hole geometry in a thin-walled cylinder by honing is studied. One promising option is the deliberate deformation of the workpiece when it is attached by means of disk springs.
549-553
Calculations of tool hardness in the aviation industry
摘要
For the aviation industry, a formula is proposed for converting the Brinell hardness of metals and alloys to values of the relative hardness according to the Mohs scale. As an example, the Mohs hardness is calculated for the basic tool steels.
554-556
Temperature fields in grinding by abrasive wheels
摘要
A method is proposed for calculating the temperatures at the surface of the workpiece and within its interior on grinding by abrasive wheels of different design (discontinuous, composite, or hybrid wheels). On that basis, the temperature fields in the cutting zone are calculated.
557-560
Diamond-based pressure sensors
摘要
Instruments for pressure monitoring are widely used today, in fields such as the aerospace industry, machine tools, and automated control systems. The pressure sensors employed must meet high standards in terms of their range, precision, reliability, and operational stability. Sensors are essential to measuring instruments and to monitoring and control systems. In the present work, a diamond-based pressure converter is described.
561-564