Abstract
An algorithm for calculating elastic rod systems under the action of impulse loads, using a complex model of internal friction in the material, has been developed and implemented in ...software. Very short (instantaneous) and extended in time impulses are considered as variants of impulse action. The importance of taking into account the vibration energy dissipation due to internal friction in the material of the structure is shown, considering impulse effects. The implemented software module is used to calculate the dynamic responses of the system in the search for the optimal solution of the control program for the selected variable parameters, target and restrictive functions. The problem of optimizing a flat frame system loaded with static and impulse loads has been posed and solved. An algorithm for finding an optimal solution is considered. Variants of dividing variable parameters into generalized groups are discussed. The minimum volume of material, spent on the structure, is taken as an optimality criterion. Analysis of the influence of the pulse duration of a given value on the calculation results without and with internal friction, as well as a comparative analysis of the optimal designs obtained without and with internal friction in the material and various tolerances for horizontal displacements. The results obtained indicate a significant effect of internal friction on the characteristics of the optimal design, especially with active movement restrictions.
Vibrations of a thin-walled cantilever rod of a box-shaped profile were studied. The natural vibrations frequencies of a rod with a crack of different depth and located in different places of the rod ...were determined. The method of conducting an experiment using a vibration analyzer is given. A variant of determining the location of the crack depending on the change in the natural vibrations frequency is proposed. The resulting expression for estimating the location of the crack has an error of no more than 2.7 percent of the length of the rod, which makes it effective in practical application. The puchnost points of each oscillation form of the cantilever rod are determined, taking into account internal friction, which allowed us to specify the locations of sensors for maximum efficiency in evaluating the influence of crack parameters on natural frequencies. We found that when the crack is located in the places where the puchnosty for the corresponding vibration form causes noticeable energy dissipation due to friction in the crack.
The aim of the work is to study the problem of optimizing energy consumption and practical application of methods for improving energy efficiency in the housing sector. Optimization of ...energy efficiency management allows to reduce the expenditure of energy resources in the performance of various works, heating of buildings, etc. The creation of optimization methods will make it possible to reduce payments for utilities in a short time, and in general for the industry, will help reduce the consumption of various resources and improve the ecological state of the region. Unlike other approaches, the emphasis in this paper is on the convenience and simplicity necessary for using this technique by the population in households. The proposed integrated approach uses methods of probability theory, linear programming, heat exchange models. The conducted research confirms the effectiveness of the solution obtained and can serve as a basis for the creation of training and research stands. The article consists of two parts: the first part analyzes the leading works in this field and identifies the reasons that make it difficult to apply the solutions proposed in these papers. Further, the statement of the problem was proposed and justified, and a number of basic requirements to the mathematical model of energy consumption, necessary for the constructed technique to be used to optimize energy consumption in households, were formulated. In the second part, a mathematical model of their functioning is proposed using examples of specific household electrical appliances. When researching existing methods for optimizing energy consumption in households, problems were identified that were difficult to apply these methods in practice and recommendations were obtained that allowed to formulate the basic principles of constructing an optimization technique that was convenient for practical application. It was shown that when constructing such a technique, the primary question is the data that the user can provide. The minimum composition of input data was determined, according to which the necessary algorithms for optimizing energy consumption were designed. A number of algorithms for determining some input indicators that are easy to use in households have also been proposed. Thus, the general plan of research in this paper is as follows:• carry out grouping of devices by the way of setting functionalrequirements;• determine the acceptable composition and type of input data forthe user;• define the minimum set of input data for formalizing the limitationof the total power consumption;• design optimization algorithms that work with the input dataspecified above. The most important results of the work performed are the following:• the methodology for forecasting the graph of the maximum totalpower consumption has been developed.• methods for optimizing energy consumption for each of the selected subsets of household appliances have been developed.• the optimization algorithms obtained have been simulated, which showed their operability, efficiency and the possibility of their practical application without any adaptation.Thus, the article proposes the solution of the problem of optimization of energy consumption in the housing sector, oriented to practical application.
Addressing the combination of features and properties, characterizing technical systems, and various factors and effects that influence the functionality of technical objects. It is shown that for ...territorially dispersed clusters functionality analysis, it is necessary to take into account external adverse effects and requires the use of probabilistic models, complemented by principles of the situation-based approach to searching the most crucial objects and revealing the most damaging effects.
We consider the problem of reliability of energy-and resources supplies of large consumers receiving power or resources from a heterogeneous network infrastructure. We analyze the problem of finding ...damaged network components, leading to loss of functionality of major customers and proposed methods of its solution.
We considered the problem of creating combinatorial algorithms for analyzing the safety of engineering infrastructure objects, which makes it possible to automate the process of solving the problems ...of providing resources to a multitude of consumers.
Consideration was given to efficient mechanisms to reduce dimensions of the problem of seeking the critical power plant nodes built in the classical algorithms for seeking on graph a network ...endangered by negative actions.
In our opinion the beginning of the 21st century is marked by three most important and indirectly connected changes which are capable to influence essentially the destinies of mankind as a whole, and ...in particular the part of it which lives in the circumpolar zone of the Northern hemisphere. First of all it is global changes of climate, the reduction, and probably exhaustion of stocks of oil and gas on the earth, and also changes in mass consciousness of millions and millions of people on the planet.
The cross section of the process e + e − → π + π − has been measured in the center-of-mass energy range from 0.32 to 1.2 GeV with the CMD-3 detector at the electron-positron collider VEPP-2000. The ...measurement is based on an integrated luminosity of about 88 pb − 1 , of which 62 pb − 1 represent a complete dataset collected by CMD-3 at center-of-mass energies below 1 GeV. In the dominant region near the ρ resonance a systematic uncertainty of 0.7% was achieved. The implications of the presented results for the evaluation of the hadronic contribution to the anomalous magnetic moment of the muon are discussed. Published by the American Physical Society 2024
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