Vol 23, No 2 (2024)

The article describes the experience of applying the methodology of Model-Based Systems Engineering (MBSE) in the organization of ground tests of the on-board equipment complex of unmanned aerial vehicles at Kronshtadt JSC. This methodology was successfully used in the development of various complex control systems such as embedded control systems, digital signal processing, computer vision, radar and communications. The analysis of the on-board equipment testing process using an existing ground test bench was performed, and a method for automating its operation has been proposed. The calculation of economic efficiency was performed.

The problem of ensuring the specified thermo-dimensional stability of structures from laminated polymer composite materials for the service life period is considered. A method of reliability-oriented design of a thermo-dimensionally stable composite structure is proposed, according to which its design parameters are set with regard to the possibility of obtaining thermal strain properties under specific processing and the changes of these properties for the operational conditions and duration of using the article as intended. Within the framework of the presented approach, the features of design upon the dimensional accuracy and stability criterion when meeting the requirements of strength and stiffness are discussed, an algorithm of a packaged solution of the design task is given.

The article discusses a method for calculating, as a first approximation, the take-off weight of a light aircraft with a hybrid power plant based on piston and electric engines. A brief overview of organizations dealing with hybrid power plants is given.  The influence of the degree of hybridization of the power plant on the take-off weight of the aircraft is shown. The degree of hybridization of a power plant is understood as a relative value characterizing the distribution of the total power of all engines installed on the aircraft between piston and electric engines. The main parameters necessary to determine the take-off weight of an aircraft to a first approximation are presented. The take-off weight of the aircraft is determined to a first approximation from the equation of its existence. Statistical data of aircraft with different types of power plants are provided on the basis of which calculations are carried out. As a first approximation, the relative mass of the hybrid power plant is determined by analyzing the statistical data of light aircraft with piston and electric engines, from which the corresponding graphs are constructed. After the calculations, conclusions were drawn about the optimal range of characteristics of a light aircraft with a hybrid power plant.

The paper presents the design of a damper based on a multilayer magnetorheological elastomer that has high load capacity, up to 500 N. The damper is able to operate in all vibration control modes, depending on its control signal. The damper cooling system is presented. Vibration tests were carried out and the damper amplitude-frequency characteristics were obtained. The transition process of damper displacement with a control step signal was analyzed.

The problem of monitoring the performance of technical systems is considered, corresponding to the stage of final control during the production of a product, as well as the stage of testing the product before its use. Based on the generalization and development of the existing approaches, models and methods for monitoring the performance of complex technical systems were developed, and models for predicting the parameters of their control were proposed. Methods of optimizing the number of tests of units of technical systems when monitoring their performance were developed. Methods for estimating the optimal level of the total defect rate are proposed. The efficiency of the proposed approaches is illustrated using a specific numerical example. The methods and models presented in the article can be useful for engineering and technical workers of design bureaus, research institutes, research and production associations and enterprises in ensuring the reliability of products and technical systems.

The creation of new and improvement of existing machines and mechanisms requires the development of drive engineering and the creation of new drive systems capable of competing with currently known circuit solutions. Under these conditions, the creation of combined pneumatic-mechanical drives is an important scientific and technical task. The purpose of this work is to increase the speed at a given accuracy of auxiliary movements of the target mechanisms of technological machines by creating a pneumatic-mechanical drive with improved energy and dynamic characteristics. The technical solution of a positioning pneumatic-mechanical drive of executive movements of technological equipment is presented, mathematical and computer models are developed. In this case, the method of solving the differential equation in the SimInTech program is used. As a result, an oscillogram of transients is obtained. The developed models allow for dynamic analysis of pneumatic-mechanical systems.

Gearbox is the most stressed component in an aircraft gas-turbine engine. This implies the need for finding ways to monitor its technical condition. Practice shows that the most efficient method is vibration-based diagnostics. However, this method requires the use of sophisticated measurement systems and highly skilled personnel. This paper shows that errors of gear coupling manufacture and assembly, characteristics of machine operating mode, design factors, frequency modulation of the carrier of the engine rotor speed in the stationary mode of its operation, and wear of teeth flanks determine the width of the spectral component of the gearbox output shaft speed. Using the results obtained from the developed model of the width of gear tooth spectral component, ratios for width of the spectral component of the signal of the “standard” tachometric speed sensor of the gearbox output shaft speed and the corresponding spectral component of its vibration were obtained. Models for repaired and newly manufactured gearboxes and gearboxes with tooth flank wear were proposed. This allowed the development of a number of new diagnostic indicators of a defect. Several examples of the use of these new diagnostic indicators are given for the gearbox of one of turbo-prop engines. The results obtained provide an opportunity to assess the gearbox technical condition in operation.