卷 37, 编号 5 (2017)

The efficiency of balanced drives, chain drives, and linear rack and pinion drives is compared for sucker rod pumps. An approach to energy-efficient oil extraction using the kinetic energy of the descending drilling stem is developed, and the corresponding mathematical model is derived. The results of numerical modeling are outlined.

The gas dynamics of a choked-flow turbine is considered. An uncooled choked-flow turbine may be used in a limited-power gas-turbine engine without marked impairment of its mass and size and with considerable decrease in cost.

The dependence of the hydrogen supplied to the hydrogenation reactor on the acetylene concentration is simulated. An algorithm is proposed for automatic cascade control of selective hydrogenation. That permits optimization of the hydrogen supply on the basis of the actual acetylene concentration in the ethane—ethylene fraction and the input of raw materials to the reactor.

The boundary problem in the mechanics of superplasticity is formulated on the basis of a standard superplasticity power law and the Perzyna viscoplasticity model. Methods of identifying these models on the basis of the same input data are proposed.

The stress in the critical section of a punch extruding the stepped cavity of a cylindrical part is analyzed. In extrusion with actively directed contact-friction forces, the punch life is increased by a factor of about 1.5.

The high concentrations of harmful materials within vehicles is studied. An air-purification system is developed. Bench tests are conducted. Technical specifications must be developed for filters and air purifiers so as to improve the air quality within vehicles, including electric vehicles.

Mathematical description of the geometric deviation of components in multicomponent mechanisms permits correction of the influence of such deviations on the precision of multicoordinate machine tools and industrial robots.

Machining centers and multifunctional machine tools are used in computerized integrated production. They are equipped with a large number of cutting tools for production of a specific batch of parts. In such automatic systems, monitoring and control systems replace the human operator. Monitoring of the state of machining systems is essential today in monitoring and control of the machining operations [1, 2]. It is important to create monitoring systems to support reliable tool operation in multifunctional machine tools. The goals of such systems are to minimize the damage from serious disruption of tool operation and to ensure timely tool replacement. To that end the multifunctional machine tools and/or the numerical control system must be equipped with sensors and various monitoring devices. A strategy must be developed for the prevention of disruption of the machining process and tool failure.

The stress–strain state in chip is investigated by the finite-element method. In addition, the cutting process and the mechanics of chip formation are studied experimentally over the whole temperature range of metal cutting.

A new method is proposed for the design of grinding operations—that is, the selection of tool characteristics and machining conditions. In this approach, tool performance is predicted, and combinations of wheel characteristics and grinding conditions are selected on that basis, with simultaneous satisfaction of all the constraints on the grinding operations and the specifications in the drawing of the part. By variant design of the grinding operations, the tool best suited to specific grinding conditions may be identified during preproduction.

A new method is proposed for ongoing measurement of the dissipative properties of an elastic element in a mechanical system. The theoretical basis of the method is outlined.