Vol 21, No 1 (2019)

Due to the complexity of the created organizational structure of specific systems and service production in General, the physical implementation, and then its development in order to assess the resulting structure, is costly. Therefore, taking into account this factor to solve the problems of building an organizational structure and production processes, it is necessary to use mathematical modeling, i.e. the creation of a model that can be used to study various options for building and optimizing it. Today, however, the problem is the lack of a universal model underlying many specific maintenance tasks.

The current lack of a regulatory database on the designation of controlled parameters of the centerless external grinding mode for new hard-to-work powder construction materials, which include Relit, a two-component material, does not allow reasonably designate a combination of centerless grinding mode parameters that would provide the required quality indicators for surface roughness. On the basis of the developed optimization model, including technical limitations on the ranges of variation of the controlled parameters of the centerless grinding mode and the required roughness of the ground surface, supplemented by the adopted optimization criterion - maximum performance, polygons for solving the system of equations of the optimization model were established. On the basis of their developed quality maps on the parameter Ra of surface roughness, which are normative guidance materials for technologists on the choice of a combination of controlled mode parameters in the design of centerless grinding operations.

Calculated dynamic models are developed at the design stage of an aircraft and are used to estimate operational loading, to provide strength, controllability and aeroelastic stability of the aircraft. These models accompany experimental investigations, trial and serial operation of the aircraft. Wherein the calculated dynamic models are updated by the results of ground modal tests. The calculated model of the aircraft is as a rule the model of the free dynamic system. While the aircraft vehicles are set on landing gears or are installed on the special system of elastic hanging to perform the modal tests, and the space structures are set on the offloading (zero-G) system. In the present work the method of freeing a fixed dynamic model of an aircraft after the procedure of direct updating its stiffness and/or mass matrices has been proposed. This model updating leads to the fact that it is impossible to free the model by direct returning of the degrees of freedom which were removed during the process of fixing the model. The proposed method allows to free the model from fixations in the case of the inertia characteristics of the free structure are known. As in, mass and moments of inertia regarding some point, for example, center of mass. The method is based on the fact that the fixed model is set on a virtual mobile platform which has the inertia characteristics of the input free structure. It allows to describe the movement of the structure as a rigid body in the model. Movement of the platform influences on the fixed model through inertial forces. Reverse impact is performed through the sum of all the inertial forces which is the reaction in the fixation basically. The system of equations which describes movements of the fixed model was extended by the equations of movements of the platform. The inertial forces which are conditioned by the movement as a rigid body are added to each equation of motion of the model. Moreover, transition from the local coordinate system, which is linked to the fixed model, to the global coordinate system is executed. The obtained equations do not violate the symmetry of the stiffness and mass matrices. The eigenfrequencies and eigenforms are close to the corresponding frequencies and forms of the free model. The implementation of the method has been shown on the mathematical model of linear oscillators. The example of freeing of the conditional beam model of the aircraft, which is set on the landing gears, is presented.

A mathematical formulation of the direct problem of maintenance of complex systems and complexes of them in a symbolic form has been carried out. This task arises in assessing the state of these systems and complexes, carried out at an acceptable time (usually part of an hour) and making a decision by using a measure of a set of characteristics that satisfy the relations “norm” and “abnorm” in the final case. An analysis of existing approaches to solving this problem has been carried out and a new approach has been proposed that considers this problem within the framework of the exact formalism of the representation of objects’ images and maintenance systems as a conceptual basis based on the synthesis and analysis of the images of the serviced systems that makes it possible to create a universal estimation and estimation algorithm in general, which the authors will propose in the next publications, planned in the near future.

In the article, a study of modern means of delivering spacecraft as objects of execution of the stage of transportation of the payload in space in the process of delivering the payload of the space vehicle has been conducted. The space transport system is considered as the next level in the development of the payload transportation stage in outer space. Based on the results of the analysis of the tasks that are presented in the Federal Space Program of the Russian Federation for 2016-2025, the preliminary composition of the space transportation system based on modern space products was considered.

The article presents a theoretical and probabilistic model of the turbine wheel assembly, which allows to complete the wheel disk with working blades in accordance with the required assembly parameters. The model includes a complete set of blades under the conditions of weight, pitching in the free position, the main gaps and the turn of the bandage shelf relative to the lock. On the basis of the intermediate results of the model, calculations of the necessary backlog of work in progress of blades are made, the reduction of which will reduce the cost of production and improve the efficiency of the process.

An analytical solution to the problem of calculating the temperature field in the workpieces for belt grinding operations using different types of tapes: with a continuous working surface, discontinuous, composite with areas containing abrasive grains and solid lubricant, combined, containing areas filled and not filled with abrasive grains, and solid lubricated areas.

The article deals with the system of measuring the fuel level of various modifications of the carrier rockets “Soyuz” at the «Baikonur» and «Vostochny» space launch center. A comparative analysis of the principles of construction of fuel level control systems and a General view of the rocket refueling scheme is given. The methods of measurement and processing of capacitive sensors signals associated with obtaining and taking into account the climatic and electrophysical parameters of the environment are described. The design of a tripled capacitive level sensor with a compensation section for the «Vostochny» space launch center, its connection scheme and formulas for calculating the current value of the fuel level are considered.

When automating an enterprise through the introduction and further use of information systems, a number of typical problems arise. As a result of the review of emerging difficulties in the implementation, analysis of typical problems of system implementation, the prospect of finding alternative solutions to the problems that have arisen appears.

This paper concerns basic principles for developing parallel-algorithm models based on a visual programming style. The visual modeling of parallel computational processes has the advantage of presenting information visually and so agrees with the nature of human reception much better than conventional textual-programming methods. The proposed technique and the resulting language for the visual presentation of parallel algorithms are of significant practical importance because they simplify and accelerate the development of parallel-computation algorithms.

The article offers variants of designs of anatomically shaped vertebral implants. We assume that the vertebral implant has a foramen vertebrale. For this reason, we made the implants detachable. We have investigated two options for fixing the components of the structure: the dovetail groove and using asymmetric surfaces. Taking into account the existing medical practice, for fixing the components of the implant, we proposed the conjugation of the components with the help of asymmetric surfaces and the fastener. This is necessary to ensure the rigidity of the implant structure assembled. We have formulated criteria for the evaluation of the design, including the proximity of the weight to the weight of a natural vertebra and the possibility of resistance to the external loads. We analyzed the proposed design of the anatomically shaped vertebral implant on the basis of the formulated evaluation criteria. In order for the implant not to be rejected by the immune system and its components can grow together, it is supposed to make implants from blocks of allogenic osteoplastic material.

The article is devoted to the study of the efficiency of vortex matrices application in gas turbine cooling systems. Various variants of cooling intensification for which author’s certificates are received are given.