Structural Scheme Research Articles

MODELING OF THE FLOW ADAPTIVE SYSTEM FOR CONTROLLING THE SOIL TILLAGE

It is well known that one of the significant disadvantages of the development of modern technological processes is the use of aspects of thinking associated with the use of already used design positions. From a practical point of view, there is no single optimal solution for tillage in agriculture. The methodology for solving complex, multipolar problems of quality and efficiency of technology must take into account a significant number of factors and be presented in an accessible form for the response of the working bodies of tillage machines. Precision tillage has great potential. The result of tillage operations can be improved depending on the optimal solution of construction working bodies and technological parameters of cultivating, which, in addition, can be adapted to the tillage technology depending on the local agro-climatic conditions. The article presents the results of the synthesis of the system of adaptive control of soil cultivation by creating a complex technological system with modeling of the structural-matrix schemes and on-stream technological influences of working bodies of machines and external agro-climatic conditions on the agrophysical state of the soil. The research methods are methods of analysis of structural schemes of technological process control systems; system-analog modeling of tillage control systems; structural analysis and synthesis of technological changes in agrophysical indicators of soil tillage. The main results are the structural diagram of the on-stream adaptive control system of the tillage unit for the requirements of precise agriculture; matrix diagram of the imaging and generalized system of equations of on-stream adaptive control of working bodies of tillage machines; system-analog model of the machine-tractor unit with the adaptive control system of working bodies.

Закони керування авіаційним газотурбінним двигуном з турбовентиляторною приставкою

The main aspects of the general task of integrating an aviation engine (AE) with a turbofan additional unit (TAU) of a multi-mode aircraft are the selection of the scheme and design parameters of the AE with the TAU (including parameters of the work process), as well as methods and means of automatic control of the AE with the TAU for better matching its characteristics with certain flight modes. These two tasks are closely interrelated: on the one hand, when determining the appearance of the aircraft and its power plant (PP), it is necessary to consider what means will ensure the adaptation of its characteristics to the variable flight mode, and on the other hand, the purpose of the aircraft, its parameters and parameters of the PP, and the flight modes mostly determine the choice of control laws. The subject of the research is the formation of the laws of control of the aviation gas turbine engine with TAU. The goal is to improve the dynamic characteristics of the aviation gas turbine engine by applying adaptive control of the gas turbine engine with the use of wireless information exchange technologies. Objectives: to generalize the concept of adaptive control at the stage of determining the appearance of an engine with TAU; to determine the methods of regulating the GTE with TAU and their influence on the speed characteristics; to describe the process of formation of the laws governing AE with TAU; to investigate thermal processes in order to find functional dependencies in the optimal control of gas turbines with TAU. Research methods: system analysis, mathematical and computer modeling were used in the formation of control laws; the methods of philosophical knowledge were used to build an approach to the design of adaptive control systems of gas turbines with TAU. The theory of aircraft engines, the theory of differential equations, difference grids, and numerical methods were used to optimize the control of gas turbines with TAU. Results: methods of regulating the GTE with TAU and their influence on the speed characteristics of the aviation engine; formulas for researching the thermal processes of the working blades of the GTE with TAU in order to form the influence of the regulator on the executive mechanisms. Scientific and practical novelty: formation of a paradigm for the development of models of adaptive control of GTE with TAU, considering different flight modes of the aircraft and engine operation modes. The selection of control laws using multi-parameter optimization methods for finding the relationship between structural and component schemes of the gas generator and turbofan additional unit. The character of the engine thrust change depending on the input temperature is shown, which in turn, will allow to increase the efficiency of the fan and obtain a thrust reserve. The research directions of the temperature field and stress field were formed.

USE OF THE WORKING BODY OF THE UNIVERSAL VIBRATORY MILL FOR DRYING GRAIN MATERIAL

One of the most perspective directions of intensification of heat and mass transfer in the processes of drying plant materials and increasing the energy efficiency of drying plants is the application of a vibration field for mixing grain material while moving in the drying chamber. The analysis of existing vibration installations has revealed that the most promising is the usage of vibratory grinding chambers with spatial circulation of material for the implementation of grain heat treatment, in particular drying. As a result, it is proposed to use the proven element base of a vibratory mill as a working body of which grinding chambers with spatial circulation of the load are used. The article presents the structural and technological scheme of a vibratory thermal drying unit, the structural parameters of the unit, and a mathematical description of the grain drying process. The obtained differential equations constitute a mathematical model of the nonstationary process of continuous drying of grain material and determine the change in time, parameters of grain and steam-gas mixture at the outlet of the grain drying chamber. The constructed mathematical model of the drying process makes it possible to determine the modes of heating and dehydration of grain material during circulation in a vibrating chamber with a conductive energy supply and partial vacuuming of the chamber, to expand the technological capabilities of the "vibrating mill" type installations. The graphical dependences of the temperature and moisture content of grain over time, the data for which were determined experimentally, are presented when a monolayer of grain of mass m is heated on a heating surface of area F at a stabilized surface temperature θn. In this work, the kinetics of drying and heating of grain were obtained, which were used to calculate the parameters of the vibrothermal drying unit. Also, using the results of the experiments, the performance indicators of the vibration dryer created on the basis of the grinding chamber of the vibrating mill were determined.

Neurocontrolled Car Speed System

The features of the synthesis of neural controllers for the car speed control system are considered in the article. The task of synthesis is to determine the weight coefficients of neural networks that provide the implementation of proportional and proportional-integral-derivative control laws. The synthesis of controllers is based on an approach that uses a reversed model of the standard. A model of the car speed control system with the use of permitting subsystems has been developed, with the help of which one of the synthesized controllers is connected under certain specified conditions. Using the iterative programming and mathematical modeling environment in MATLAB and using the Simulink package, a structural scheme for controlling the speed of the car was constructed and simulated using synthesized neural controllers.

THE MODEL OF THE ADAPTATION MECHANISM OF THE DISCHARGED MILITARY FROM THE ARMED FORCES OF THE REPUBLIC OF AZERBAIJAN

A serviceman discharged from the Army faces various concerns and problems while integrating into civilian society. The integration of people belonging to this category into society and making their lives easier has become a priority. While the transition from military to civilian life works out well for many, for some the transition is extremely difficult. The development of a complex model of the social adaptation process of personnel discharged from military is considered one of the most important issues in the process of integrating people who change their profession and lifestyle into a new environment. The article reviews all possible elements involved in the process of social adaptation of servicemen released from the Armed Forces of the Republic of Azerbaijan and presents a structural scheme (model) for the development of the mechanism of this process.

A Generalized Nomenclature Scheme for Graphene Pores, Flakes, and Edges, and an Algorithm for Their Generation and Numbering.

In the present study, we generalize our recently proposed nomenclature scheme for porous graphene structures to include graphene flakes and (periodic) edges, i.e., nanographenes and graphene nanoribbons. The proposed nomenclature scheme is a complete scheme that similarly treats all these structures. Beyond this generalization, we study the geometric features of graphene flakes and edges based on ideas from the graph theory, as well as the pore-flake duality. Based on this study, we propose an algorithm for the systematic generation, identification, and numbering of graphene pores, flakes, and edges. The algorithm and the nomenclature scheme can also be used for flakes and edges of similar honeycomb systems.

Structural Optimization Design of Microfluidic Chips Based on Fast Sequence Pair Algorithm.

The market for microfluidic chips is experiencing significant growth; however, their development is hindered by a complex design process and low efficiency. Enhancing microfluidic chips' design quality and efficiency has emerged as an integral approach to foster their advancement. Currently, the existing structural design schemes lack careful consideration regarding the impact of chip area, microchannel length, and the number of intersections on chip design. This inadequacy leads to redundant chip structures resulting from the separation of layout and wiring design. This study proposes a structural optimization method for microfluidic chips to address these issues utilizing a simulated annealing algorithm. The simulated annealing algorithm generates an initial solution in advance using the fast sequence pair algorithm. Subsequently, an improved simulated annealing algorithm is employed to obtain the optimal solution for the device layout. During the wiring stage, an advanced wiring method is used to designate the high wiring area, thereby increasing the success rate of microfluidic chip wiring. Furthermore, the connection between layout and routing is reinforced through an improved layout adjustment method, which reduces the length of microchannels and the number of intersections. Finally, the effectiveness of the structural optimization approach is validated through six sets of test cases, successfully achieving the objective of enhancing the design quality of microfluidic chips.

On the Role of Seismic Damage Tolerance on Costs and Life Cycle of CLT Buildings

This paper presents a contribution to reviewing the most common seismic design procedures of CLT buildings and their implications on structural features and technological solutions. Attention is particularly focused on the overall seismic performance, damage tolerance, construction costs and environmental impact. It is intended as a baseline for a more comprehensive study, thus the assessment is made with reference to a real building, representative of a class of common buildings recently designed and erected in many Italian regions exposed to low and moderate seismic hazards. As usual, the analysis was carried out according to a two-dimensional model of the panels, assumed to be elastic, varying the type of connections at the base, the presence of pre-stressing steel bars for rocking control and dissipative devices. The main outcomes of the study can be summarized as follows: (i) the structural seismic behavior of CLT buildings is significantly influenced by the structural schemes adopted for walls and connections; (ii) construction costs and environmental impact decrease whenever damage tolerance is accounted for in design procedures.

ORBITAL STRUCTURE OPTIMIZATION TECHNIQUE OF THE LOW-ORBIT COMPLEX OF ON-ORBIT SERVICE

Most of the currently planned on-orbit servicing (OOS) missions involve the use of disposable OOS spacecraft. The use of disposable OOS spacecraft may be profitable in the near future. But it is not a reliable solution for OOS in the long term. As an alternative, a more useful concept is the use of reusable OOS complexes, which allow responding to scheduled and random requests from OOS clients. This concept can ensure the timeliness and efficiency of OOS implementation during planned services and random requests of OOS clients. However, despite the potential advantage of a reusable OOS, the design of its orbital structure and operational maintenance is much more complicated in comparison with the traditional concept of the organization of OOS. This is because when planning the response of reusable OOS complexes to requests, it is necessary to distribute OOS client service operations between space vehicles of the reusable OOS complex. Now the space industry is switching its attention to the area of low Earth orbits. This causes an increase in deployed and planned low-orbit satellite groups, the number of satellites in them, the difference in structural schemes of satellite groups, and the significant influence of the environment on orbital parameters. As you know, the orbital parameters of low orbits of space vehicles can differ significantly, and the difference between them can reach tens or even hundreds of degrees in the longitude of the ascending node. This leads to unacceptably high energy costs for modern OOS spacecraft for active rotation of the planes of their original orbits to the planes of the destination orbits. In some works, the possibility of reducing these energy costs due to the use of the difference in the speed of the nodal precession of the parking and destination orbits of the OOS spacecraft due to the non-centrality of the Earth’s gravitational field is considered. However, due to the long wait of the OOS spacecraft in the parking orbit, the flight time with the wait between the parking and destination orbits increases significantly. Its reduction can be achieved by increasing the number and rational selection of the semi-major axis and inclination of the parking orbits of the OOS spacecraft. The purpose of the article is to develop a technique for the optimal synthesis of the orbital structure and optimal operational planning of the low-orbit OOS complex in near-Earth orbits with a small eccentricity. Methods for solving the problem are the averaging method, the branch-and-bound method, and the multiobjective optimization method. The novelty of the obtained results lies in the development of a technique for optimal synthesis of the orbital structure and optimal operational planning of the low-orbit space OOS complex in near-Earth orbits with low eccentricity. The developed technique can be used in the previous planning and design of space OOS complexes in low near-Earth orbits with a small eccentricity.

Research on instrument structure scheme for improving the sensitivity of wireline D-T source porosity logging

Utilizing a D-T source to replace the chemical source is the development trend of nuclear logging technology. However, the wireline porosity logging with a D-T source has a lower sensitivity. To solve this problem, the key factors on the sensitivity of neutron porosity logging are analyzed. Combining the numerical simulation method, special structures such as neutron-source deceleration block and detector shielding sleeve are designed to improve the sensitivity of D-T source wireline porosity logging tool, and the detector-spacing selection of the improved instrument was discussed. Study indicates that the sensitivity of neutron porosity logging mainly depends on the fast-neutron deceleration length, the proportion of formation information in the detector count and the detector-spacing. In the instrument design, the tungsten neutron-source deceleration block is adopted to reduce the energy of neutrons emitted by source, thereby shortening the fast-neutron deceleration length and improving the logging sensitivity. Additionally, the detector shielding sleeve made of boron carbide can absorb thermal neutrons from the borehole to increase the proportion of formation information in the detector count, which can also effectively improve the sensitivity. Based on the above structure design, it was found that when the near detector-spacing was set at 30 cm and the far detector-spacing was set at about 70 cm, the performance of the instrument can reach the best. This study can provide theoretical guidance for the application of D-T source in the wireline porosity logging tool in the future.

Reliability based bi-directional evolutionary topology optimization of geometric and material nonlinear analysis with imperfections

This paper aims to present a novel computational technique for using reliability-based design while taking into account the effect of geometrically and materially nonlinear imperfect analysis. Consequently, a new bi-directional evolutionary structural optimization scheme is developed. A comparison is made between perfect geometrically and materially nonlinear analysis and imperfect geometrically and materially nonlinear analysis topology optimization designs for both deterministic and probabilistic analysis. In the case of probabilistic analysis, relevant parameters such as volume fraction (including manufacturing imprecisions), material properties, and geometrical imperfections (for stability calculations) are assumed to be random variables that follow a normal distribution to represent the uncertainties. The considered numerical examples have successfully illustrated that the proposed method can find the optimal topology for a reliability-based design using perfect geometrically and materially nonlinear analysis and imperfect geometrically and materially nonlinear analysis. Additionally, the results of the topology optimization according to the mean stress and the final optimized shapes have been influenced by introducing a reliability-based design, considering the reliability index as a bound governing the process.

Анализа зарубежного опыта обеспечения продовольственной безопасности в условиях мирового кризиса, а также существующих возможностей и ресурсов его адаптации в российской практике

The article presents the results of the analysis of foreign experience in ensuring food security in the context of the global crisis, as well as the existing opportunities and resources for its adaptation in Russian management practice at the national, regional and corporate levels. Structural and logical schemes for ensuring food security in countries with developing and developed economies are presented.

Systems with optimal geometric shapes

Objective. In this paper, buildings of various shapes that have high seismic resistance are considered. Such seismic resistance is provided by the rational shape and outlines of the building itself. Here, the influence of the torsion of the building in the plan is minimized, thereby eliminating large stresses at the ends of the designed building. At the same time, the translational movement of the building in the plan is preserved.Method. By optimizing the shape and shape of buildings for various purposes, high efficiency of the structure is ensured under seismic effects. By comparing the shape and outlines of various buildings, the best variant of their layout is selected.Result. Structural schemes of buildings and structures with high resistance to seismic effects are given. A comparative analysis and recommendation for the design of earthquake-resistant buildings are given. Structural schemes for buildings and structures of various outlines have been developed: round, square, rectangular; constructive schemes of volumetric seismic-resistant structures, pyramidal, conical of various shapes, have been drawn up. Recommendations for the design of earthquake-resistant buildings and structures with optimal geometric shapes are made.Conclusion.The design schemes proposed in the article can be used in the design of earthquake-resistant buildings and structures for various purposes.

Modularize-and-Conquer: A Generalized Impact Dynamics and Safe Precollision Control Framework for Floating-Base Tree-Like Robots

Flexible and versatile mobile robotic coworkers are becoming an indispensable commodity for helping humans with repetitive or physically demanding work. A key challenge with these systems is respecting the strict safety requirements in shared and collaborative workspaces. This inevitably requires solving their whole-body dynamics to obtain the necessary inertial impact properties. In this article, we present an integrated impact dynamics and safe precollision control framework to address the discussed challenge. We propose a novel modular dynamics approach that provides efficient formulations for reusing the uncoupled subsystem dynamics when evaluating the coupled system. Our approach is generalized for deriving the whole-body impact dynamics of any articulated floating-base robot. Furthermore, it outperforms classical monolithic approaches for computing the dynamics, making it favorable for systems with more than two dynamic subsystems while allowing decentralized computations. Finally, based on the proposed modular and generalized impact dynamics and extending our previous work, we introduce the generalized safe motion unit as a unified safety scheme for floating-base robotic structures with branched manipulation extremities. The proposed concepts are evaluated on an exemplary wheeled mobile manipulator, considering realistic use cases in simulation and real-world experiments. The obtained results validated the efficacy of our framework and developed methods.

Straw harvesting equipment for combine harvesters in dry land harvesting

Currently, in Uzbekistan, wheat and barley grown in dry lands are harvested with a combine harvester, and the straw is piled on the ground. However, due to their low yield (12-16 t/ha) in dry lands, straw is not suitable. As a result, most of the straw, especially the small ones, remains on the ground when it is collected with straw baler, and there is a lot of destruction. This is the reason for low accumulation of the important roughage used for feeding livestock for farms engaged in cattle breeding in dry lands. Taking this into account, the structural and technological scheme of the device that collects straw directly into trailers for grain harvesters was developed. In order to determine the parameters of the straw harvesting device installed on grain combines, which ensure the required performance and performance, the researched parameters of its working parts and their intervals were determined. Now, by making an experimental copy of the device, installing it on a grain combine, work will be carried out to determine the optimal parameters of the working parts.

Structural response characteristics of TMA during water-entry procedure

This work presents a comprehensive numerical investigation of the structural responses of the Trans-Medium Aircrafts (TMA) during a water-entry event and the max mises-stress, the acceleration, and the water-entry deepness are analyzed and discussed. The simulating finite element model of the elastic field and the fluid field are imitated and solved by the coupled euler lagrange (CEL) method. The water-entry velocity is set from 0 m/s to 8 m/s. From the results, the max mises-stress is about 24 MPa and the max acceleration of all simulation conditions is 110000 m/s2. Considering the elastic effect of the TMA structure, the current research is of great importance to the TMA’s structural design scheme.

Overall Design of Multi-module Offshore Floating Bridge and a Method for Random Analysis of Anchor Tension

This paper proposes a multi-module floating bridge design for offshore applications and establishes a coupled motion response analysis method for the anchoring system of the floating bridge. Time-domain coupled analysis is performed under the combined effects of wind, wave, and current loads, resulting in the maximum tension of the anchor chain in random waves. Using the typical island and reef sea area of Zhoushan, China as an example, the randomness of waves is considered, and a random sampling method is adopted. The main configuration, connection structure, and mooring system design schemes are presented, and the maximum tension of the anchoring system is numerically calculated and analyzed. The random distribution of the maximum anchor chain tension is obtained, the goodness-of-fit test is conducted for the fitting results, and the main degree-of-freedom motion response is analyzed under different exceedance probabilities. The results show that the multi-module offshore floating bridge meets the design requirements, and the statistical characteristics of the maximum tension of the anchor chain under random waves conform to the Gumbel distribution. The mode of the random distribution of the maximum anchor chain tension increases by 7.65% when fully loaded compared to the unloaded condition. In different exceedance probability scenarios, there are significant differences in the maximum tension of the anchor chain and the motion response of the main degrees of freedom of the floating bridge.

INTEGRATED BUSINESS DEVELOPMENT FOR THE DEVELOPMENT OF SUSTAINABLE TOURISM IN UKRAINE

The article is devoted to highlighting the issues of integrative development of entrepreneurship in the tourism sphere to ensure the sustainable development of tourism in Ukraine. Theoretical aspects of the integrative development of entrepreneurship and economic integration in the form of a cluster are considered. The issue of the development of regional tourist clusters and the internal market of tourist services of Ukraine was studied. The structural and logical scheme of the cluster management mechanism is presented as the basis of the integrated development of entrepreneurship in the market of tourist services to ensure the sustainable development of tourism in Ukraine. Conclusions were made regarding the need for integrated development of entrepreneurship in the field of tourism and economic integration in the form of a cluster in the market of tourist services for the sustainable development of tourism in Ukraine in the post-war recovery of Ukraine's economy

Models for managing operational reliability of highly automated vehicles

In the presented article, the authors analyzed the implementation of autonomous and/or highly automated vehicles. A concept of integrated solution to the problems of managing the technical condition of highly automated vehicles, by developing and implementing adaptive management of individualization of regulations to ensure operational reliability, by means of numerical, informational and simulation modeling is proposed. The structural logical scheme of the stages of the highly automated vehicles life cycle has been developed. Theoretical and methodological bases of formation and management of stability of the system of management of operational reliability of highly automated vehicles, as a part of the polymodel complex of digital twin, within the concept of development of the fourth industrial revolution Industry 4.0 are offered. Keywords: highly automated vehicle, industry 4.0, operation, digital twin, cyber-physical systems

UNIVERSAL STRUCTURAL SYSTEM OF CLOSED KINEMATIC CHAINS OF MOVABLE LINKS AND ITS APPLICATION FOR THE SYNTHESIS OF STRUCTURAL SCHEMES OF THESE CHAINS

The article shows the possibility of developing the method of structural synthesis of flat closed kinematic chains by M. Grubler, into closed kinematic chains of moving links of all families and spaces. The universal structural system of Professor L. T. Dvornikov for closed kinematic chains of moving links of all families and spaces is given. A complete set of solutions has been found describing the organization of closed kinematic chains of movable links of the second, third and fourth subfamilies of the first family with the complexity of the basic chain link equal to two and three, the mobility of the chain equal to six and the total number of chain links from three to six. Combinations of kinematic pairs and links have been obtained, which make it possible to find all, without exception, structural schemes closed kinematic chains of movable links of the first family under given parameters, from which, by stopping a link connected to an adjacent link of the chain by a kinematic pair of the fifth class, single-moving assur mechanisms can be formed.