


Vol 37, No 5 (2017)
- Year: 2017
- Articles: 22
- URL: https://journal-vniispk.ru/1068-798X/issue/view/14021
Article
Shakedown of pressure vessel components under cyclic loading
Abstract
The limiting load is determined on the basis of the shakedown of structures in cyclic loading, by means of Melan’s theorem and the finite-element method in a shell formulation. For the example of a cylindrical vessel with a branch pipe under cyclic internal pressure, the formulation of the finite-element model and the solution algorithm is considered.



Energy-efficient oil extraction by sucker rod borehole pumps in low-yield fields
Abstract
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.









Predicting the fatigue strength of structural elements
Abstract
The development of models relating the fatigue strength of materials to their static strength and plasticity is considered. Statistical strength theories were developed to describe the results of fatigue tests and to predict the strength of machine components with variable loads. Experiments show that the strength of materials depends significantly on structural defects, and the limiting stress is a statistical quantity.



Control of the selective hydrogenation of acetylene compounds
Abstract
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.






Modeling of superplastic structural materials
Abstract
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.



Model of tool life based on fuzzy sets
Abstract
The influence of the statistical distribution of technological factors on the life of a cutting tool is investigated. A mathematical model is developed for determining the mathematical expectation and distribution of the tool life as a function of the distribution of the technological factors.






Strengthening of low-alloy steel by extrusion, helical pressing, and equal-channel angular pressing
Abstract
Metals may be strengthened by a combination of extrusion, helical pressing, and equal-channel angular pressing. The mechanical properties of 09G2S low-alloy steel with and without such strengthening are presented. The steel is subjected to failure tests under uniaxial tension.



Air quality within vehicles
Abstract
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.



Automated standardization of primary and auxiliary materials in order-based production
Abstract
Automated standardization of materials consumption in order-based production is considered. The proposed approach is based on automated information systems for optimal layout of expensive bar and sheet materials, so as to improve the precision in calculating how much material is required and also to reduce material costs in high-tech production.









Monitoring and control of tools in multifunctional machine tools
Abstract
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.









Improvements in surface precision by automated design of machining trajectories
Abstract
Automated design of the machining trajectories in multifunctional machine tools (compact production systems) may be used to ensure the required surface precision of machine parts. The approach proposed is based on automated generative synthesis of individual processes.



Variative designing of grinding operations
Abstract
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.



Properties of powder produced by a high-speed method
Abstract
A high-speed method of powder production is analyzed. X-ray, chemical, and granulometric analysis indicates that the particle size of the powder obtained depends on the grinding conditions. The properties of the powder are basically the same as those of the initial sample.





