Том 46, № 6 (2017)

A new contactless method for checking-up a net-shaped curtain’s tension of a radio-reflecting surface of a large umbrella reflector antenna is presented. The method is based on revealing the correlation between Moiré patterns and net-shaped curtain uniformity and tension. The advantages of the method are presented. Its main advantage lies in the fact that it is possible to set the netshaped curtain on the folding skeleton of an antenna reflector in the online mode. A way to apply the method is presented.

The problem of the movement of the load at a constant rate on an infinitely long beam superposed on the solid viscoelastic foundation has been considered. The load is considered to be an arbitrary function of the longitudinal coordinate. The impact of the load characteristics and the foundation on the critical speed value and the mean-square scatter of the beam deflection has been analyzed.

A technique for the backward analysis of the analytical and numerical estimates of the stressed state that logically explains the difference in the estimates (consequences) by formulating a list of plausible factors (causes) followed by the systemization and generalization of the latter is proposed. The application potential of the backward analysis is examined by examples of a number of widely used structurally complicated load-bearing components of machines and equipment.

The regularities of the formation of a friction transfer film (FTF) of polymeric composite materials on a metallic counterface are found. It is shown that in the friction process, the lubricants based on biodegradable base oils are able to form antifriction films, which are related to surface absorption structures.

During the projection of corrugated fillers for honeycomb panels, which are widespread in the aircraft industry, the machine industry, and other industries, the problem of modeling the transformation process of this filler in space upon the change of its particular geometric parameters is relevant. There are various approaches to designing kinematic models of fillers; however, all recent procedures are labor-intensive and hardly adaptable to specific types of fillers; for this reason, the development of a universal procedure is considered.

Investigations on the feasibility and development of the monitoring process for the lowtemperature plasma hardening of metal items are carried out. It is shown that it is reasonable to carry out monitoring according to the parameters of the signals registered in the plasma-item-stand-earth electric circuit and analyze it with the help of the value (Hurst exponent) numerically reflecting the main formation regularities and change of the signal structure in the hardening process. Requirements on the monitoring system providing the valid information support of low-temperature plasma hardening are formed. It is deduced from the experiments that the maximum hardened surface layer is formed if the hardening process is accompanied by signal generation with the minimal Hurst exponent values.

For manufacturing thin-walled shafts for gas turbine engines of heat-resistant steels and alloys, the labor-intensive multistage drawing of a sheet of the workpiece in dies is used. The following problem is posed in the work: to study the possibility of manufacturing such parts by a less labor-intensive method: the rotary drawing of a thick-walled workpiece (sheet) by a spinning lathe by rolling a roll under hot deformation conditions. For this purpose, the computer and physical modeling of the rolling process of hollow shafts of a thick-sheet steel workpiece was carried out. The important parameters of the technological process of manufacturing a geometrically complex shaft are determined: the initial workpiece shape and the changes in its shape when rolled on a mandrel mounted on the spindle of the spinning lathe of the PNC 600 type. The research results are used for rolling full-size shafts of chromium steel of the EI962-Sh grade.

The author’s name E. Snachez should read E. Sanchez.