Vol 48, No 4 (2019)

This article provides analysis of a robot-assisted system, an alternative to the da Vinci system. The diagram of the developed mechanism with a parallel–series structure is provided. The problem of the positions has been solved.

The static and dynamic properties of self-similar branched structures (lattices) in which each subsequent cell replicates the structure of the previous one on some scale are investigated. The trichotomous lattices in which each element in each subsequent line divides into three self-similar ones are analyzed. The analytical conditions of static and dynamic self-similarity are found. The conditions of the same static deformation of each element are obtained. It is proved that the lattice is a band-pass filter, and its pass band depends on the similarity factor. It is shown that in the lattice there are multiple natural frequencies equal to the partial frequency of the generating element.

The numerical results of studying the impact of an axisymmetric liquid jet upon a flat rigid wall covered by a layer of similar liquid are presented. Primary attention is paid to the effect the layer thickness on the wall has on loading in the range of impact velocities 150–350 m/s. The loading character is studied, and the estimations of wall pressure are obtained in the case of a small layer thickness, which are topical for the applications associated with the droplet and cavitation erosion. It is shown that under the conditions considered the known results of two-dimensional modeling overestimate the maximum of the average pressure on the wall by 1.8 times.

The applicability of the energy approach to evaluation of the adhesive strength of thin coatings that exfoliate in the course of instrumental indentation is analyzed. The effect of the coating thickness exerted on the value of adhesive strength is theoretically established. Analytical dependences are obtained that make it possible to calculate the contribution of deformation of the elastic substrate to the adhesive strength of the layered system. It is proposed to introduce the concept of the effective value and that of the true value of adhesive strength in order to assess the contribution of the coating thickness to the maintenance of thin coating serviceability.

The way heat processes influence the structural elements of an electric motor is analyzed, and the factors determining the residual lifetime of the traction electric motor are revealed. A procedure for predicting the residual lifetime of induction traction electric motors based on the information on their heat state is presented.

The loading pattern of a transport-loading facility of a flexible manufacturing system for the treatment of base members was proposed in this article. The dependences allowing determination of the loading coefficient of the transport-loading facility for different types of work were found. Methods for loading reduction of the transport system and optimization of its operation were proposed.

In this paper, the mathematical simulation of laser melting of wear-resistant plasma coatings is considered. The results of numerical study of the influence of the heat flow and thermophysical properties of the materials on the heating and melting processes are presented. Application programs are developed to optimize the process of laser melting of the surface layer for surfacing the wear-resistant coatings and surface melting using the additive laser technology.

In this work, features of the characteristics of alloys with the shape memory effect and hyperelasticity are considered. The principles of evaluation of the thermomechanical characteristics of the blank material before its immediate application are presented. In this work, the ultrasonic method for evaluation of the phase transformations in blanks of thermomechanical joint sockets is discussed.