scholarly journals Possibilities of Using Frequency Energy Functions in Problems of Dynamics of Machines for Transport and Technological Purposes

2021 ◽  
Vol 346 ◽  
pp. 03073
Author(s):  
Andrey Eliseev ◽  
Sergey Eliseev ◽  
Nikolay Kuznetsov ◽  
Roman Bolshakov
Keyword(s):  
Natural Vibration ◽  
System Analysis ◽  
Dynamic Properties ◽  
Block Diagram ◽  
Mechanical Vibration ◽  
Oscillatory System ◽  
Stationary Mode ◽  
Energy Functions ◽  
Frequency Properties ◽  
Frequency Functions

New approaches to the evaluation of the dynamic properties of mechanical vibration systems are proposed, which consider as the design schemes for technical objects operating under dynamic vibration loads. The purpose of the study is to develop ideas for the use of frequency energy functions. In this case, the frequency functions represent the ratio of the potential and kinetic energies in a specific form, based on the use of the relations of the coordinates of the system in the stationary mode. The technologies of system analysis and structural mathematical modeling are used. In this approach, the mechanical oscillatory system is correspond with the block diagram of the automatic control system, which is equivalent in dynamic terms. It is proposed to use the analytical apparatus to take into account the features of interpartial relations, to evaluate the specific modes of dynamic interaction of system elements. A method for determining the natural vibration frequencies of the system based on the use of the frequency energy function is proposed. Methodological bases of approaches to solving problems of system dynamics related to the assessment of the influence of system parameters on their frequency properties are developed. The results of computational modeling are presented.

Features of the system concepts of the dynamics of mechanical vibrational structures under asymmetric connections

2021 ◽  
pp. 4-16
Author(s):  
А. V. Eliseev ◽  
Keyword(s):  
Degrees Of Freedom ◽  
System Analysis ◽  
Viscous Friction ◽  
Oscillatory System ◽  
Gear Ratio ◽  
Topological Approach ◽  
Oscillatory Systems ◽  
Support Surfaces ◽  
Frequency Functions ◽  
Damping Functions

The paper is devoted to a new approach to the formation of the methodological basis of system analysis in application to problems of the dynamics of mechanical oscillatory systems taking into account the forces of viscous friction. A mechanical oscillatory system with two mass-inertia elements connected to the support surfaces and to each other by elastic-dissipative elements is considered. A method for estimating the free movements of a mechanical oscillatory system is developed based on the characteristics expressed in terms of the parameters of the lever connections between the partial blocks in the form of a gear ratio. Mathematical models are built on the basis of Lagrange formalism, algebraic methods, and the theory of functions of a complex variable. A matrix method is proposed for constructing frequency functions and damping functions for mechanical oscillatory systems with two degrees of freedom based on the ratio of the potential and kinetic energy of the system, taking into account the forces of viscous friction. For a mechanical system in which the connection of elements with a single reference surface is reset, a graphic analytic analysis of the extreme properties of the corresponding frequency functions and damping functions is performed. A topological approach is proposed.

scholarly journals Building lifecycle management based on 4D modelling as the main workspace for building risk assessment

2020 ◽  
Vol 224 ◽  
pp. 02023
Author(s):  
R Kazaryan ◽  
N Galaeva ◽  
R Avetisyan ◽  
Sh Aliev
Keyword(s):  
Information Technology ◽  
Life Cycle ◽  
System Analysis ◽  
Planning Process ◽  
Block Diagram ◽  
Labour Productivity ◽  
Development Trend ◽  
Basic Block ◽  
Mathematical Methods ◽  
Element Base

The use of information technology in the management of construction projects has become a decisive factor for the successful completion of projects, taking into account time, quality and financial costs. There are challenges in visualizing the planning process and integrating information between stakeholders. The paper considers some aspects of the development trend of information technology in construction. The element base, including the risks arising during the design and construction, associated with the direct use of computer and mathematical models of the object in the design is considered. The generated information models will provide basic information for the participants in the design process, which ultimately will be the basis of the element base of an effective tool for ensuring project life cycle management. The following methods were used: system analysis, logical-mathematical modelling, systems theory, economic-visual modelling, research methods of operations, economic and mathematical methods. A basic block diagram of 4D modelling is presented to minimize the occurrence of risks during design. The model allows considering the possibility of assessing the duration of the project, the level of labour productivity, as well as visualizing the construction process. The presented analysis indicates the importance of using 4D modelling in relation to the life cycle of the object in order to prevent the possibility of construction risks.

scholarly journals Determination of Period of RC Buildings by the Ambient Vibration Method

2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
Mehmet Inel ◽  
Hayri Baytan Ozmen ◽  
Bayram Tanik Cayci
Keyword(s):  
Natural Vibration ◽  
Dynamic Properties ◽  
Shear Walls ◽  
Vibration Signal ◽  
Analytical Models ◽  
Ambient Vibration ◽  
Seismic Behaviour ◽  
Infill Wall ◽  
Infill Walls ◽  
Vibration Period

Determining the dynamic properties of structures is important for understanding their seismic behaviour. Ambient vibration signal measurement is one of the approaches used to determine the period of structures. Advantages of this method include the possibility of taking real-time records and presenting nondestructive and rapid solutions. In this study, natural vibration periods are calculated by taking ambient vibration signal records from 40 buildings. The height of the building, infill wall effect, presence of seismic retrofit, and presence of damage are taken into consideration, and their effects on natural vibration periods are investigated. Moreover, the results are compared with the analytical methods to reveal the differences. A significant correlation between the period and height of the building is observed. It is seen that the natural vibration periods of the buildings decrease by 7% to 30% (15% on average) due to infill wall contribution. However, the efficiency of infill walls decreases as the building height increases. Another significant result is that adding shear walls substantially decreases the vibration period values by 23% to 33% with respect to the shear wall ratio. When the analytical estimates and measured building period results are compared, it is seen that analytical models have closer period estimates before infill walls are implemented. The limited data in scope of the study suggest that significant differences may present in the analytical and measured periods of the buildings due to infill wall contributions.

Nonlinearity in the Dynamic Properties of Vulcanized Rubber Compounds

1954 ◽  
Vol 27 (1) ◽  
pp. 209-222 ◽  
Author(s):  
W. P. Fletcher ◽  
A. N. Gent
Keyword(s):  
Simple Shear ◽  
Dynamic Modulus ◽  
Dynamic Properties ◽  
Mechanical Vibration ◽  
Frequency Range ◽  
Vulcanized Rubber ◽  
Rubber Compounds ◽  
Chemical Combination ◽  
Wide Range ◽  
Static Shear

Abstract Measurements are described of the dynamic properties of rubber, loaded with various amounts and types of filler, when subjected to mechanical vibration in simple shear at amplitudes from 0 to 3 per cent shear in the frequency range 20 to 120 c.p.s. The decrease of dynamic modulus with increasing amplitude is shown, for a wide range of filler types and concentrations, to be determined by the amount of stiffening produced by the filler. This relationship is not influenced by variations in the vulcanizing ingredients, reasonable variations in state of vulcanization, addition of softener, or imposition of static shear strain. Rubber compounds stiffened by mixture with, or chemical combination of, other polymers exhibit a smaller order of nonlinearity than that described above and also exhibit much lower hysteresis values within the amplitude range 0 to 3 per cent shear.

Machine Tool Axis Dynamics

2006 ◽  
Vol 220 (4) ◽  
pp. 403-419 ◽  
Author(s):  
R Whalley ◽  
M Ebrahimi ◽  
A A Abdul-Ameer
Keyword(s):  
Machine Tool ◽  
System Analysis ◽  
Block Diagram ◽  
Workpiece Surface ◽  
Lumped Parameter ◽  
Tool Axis ◽  
Screw Length ◽  
Axis Drive ◽  
Dynamic Signature ◽  
Tension Loading

The independent axis dynamics of machine tools that employ long slender lead screws, bearings, and workpiece saddles, mounted on supporting slides, will be considered. Distributed-lumped parameter techniques will be used for system analysis and in the model formulation procedures. Realizations that encompass combined torsional and tension loading will be incorporated. Specific, integrated, distributed-lumped machine tool configurations will be derived and described in block diagram form. Simulation studies illustrating the dynamic signature of a machine tool axis drive, when operated at various feed rates, together with the measured results will be presented. The effect of changes in the effective lead-screw length on the workpiece surface finish will be commented on.

Support for decision-making on the need to replace fire trucks in fire and rescue units

2021 ◽  
Vol 92 ◽  
pp. 106-115
Author(s):  
V. A. Aristarkhov ◽  
◽  
A. V. Rozhkov ◽  
Keyword(s):  
Mathematical Modeling ◽  
Service Life ◽  
System Analysis ◽  
Block Diagram ◽  
Operating Time ◽  
Technical Condition ◽  
Technical And Economic Analysis ◽  
Study Results ◽  
In Fire ◽  
Goals And Objectives

Introduction. A study of the fleet of fire trucks was conducted. The absence of a direct dependence of the operating time of a fire truck on its service life is confirmed on the basis of the analysis. A matrix of conditions for making a decision on the need to replace a fire truck is formed, taking into account the standard purpose of the fire truck, its service life, the actual technical condition described by the corresponding category of technical condition, as well as the date of termination of its release. A criterion for the need to replace a fire truck has been developed, as well as an algorithm for making a decision on the need to replace a fire truck in conditions of limited funding. Goals and objectives. The purpose of the article is to develop an algorithm for making a decision about the need to replace a fire truck. This goal allows us to solve the problem of justifying the need to replace the sample in the course of ensuring a given level of readiness of fire and rescue units. Methods. Methods of mathematical statistics, the theory of the importance of criteria, technical and economic analysis, mathematical modeling and system analysis were used to achieve the goal and solve the problems of the study. Results and discussion. A criterion for the need to replace a fire truck is developed, on the basis of which a block diagram of the algorithm for making a decision on the need to replace a sample is formed. Conclusion. The results obtained in the course of the work can be used in the development of programs (plans) for re-equipping fire and rescue units with modern fire trucks. Keywords: the criterion of the need for replacement, fire trucks, category by technical condition, service life

Recurrence Plot and Recurrence Quantification of the Dynamic Properties of Cross-Shaped Laminated Energy Harvester

2016 ◽  
Vol 849 ◽  
pp. 95-105 ◽  
Author(s):  
Peter Harris ◽  
Grzegorz Litak ◽  
Joanna Iwaniec ◽  
Chris R. Bowen
Keyword(s):  
Power Output ◽  
Dynamic Properties ◽  
Electrical Power ◽  
Mechanical Vibration ◽  
Recurrence Plot ◽  
Recurrence Quantification Analysis ◽  
Recurrence Plots ◽  
Recurrence Quantification ◽  
Time Histories ◽  
Quantification Analysis

The paper examines the dynamic properties of bistable cross-shaped laminate plates for broadband energy harvesting applications by converting mechanical vibration energy into the electrical power output. Bistable laminates plates coupled to piezoelectric transducers were excited by application of harmonic excitations and exhibited a range of vibration patterns. The vibration patterns included single-well oscillations and snap-through vibrations of both periodic and chaotic character; such vibration patterns led to a different power output. Classical spectral analysis of measured voltage, displacement and velocity time histories indicated the presence of a variety of nonlinear and chaotic phenomena. As a result, an analysis of the measured displacement and voltage time histories was carried out with the use of the Recurrence Plots and the Recurrence Quantification Analysis methods. The Recurrence Plots method was used for detection of qualitative changes in the dynamic behaviour of the non-linear harvesting system. In order to facilitate interpretation of piezoelectric voltage and laminate displacement, a detailed analysis using Recurrence Plots, Recurrence Quantification Analysis was employed.

scholarly journals Synchronous Generators Modeling and Control Using the Framework of Individual Channel Analysis and Design: Part 1

2007 ◽  
Vol 8 (5) ◽  
Author(s):  
Carlos Ernesto Ugalde Loo ◽  
Luigi Vanfretti ◽  
Eduardo Liceaga-Castro ◽  
Enrique Acha
Keyword(s):  
Control System ◽  
System Analysis ◽  
Block Diagram ◽  
Synchronous Generator ◽  
Careful Analysis ◽  
Operating Conditions ◽  
Synchronous Generators ◽  
Modeling And Control ◽  
Analysis And Design ◽  
Channel Analysis

In this paper a comprehensive dynamical assessment of a high order synchronous generator plant is carried out using the Individual Channel Analysis and Design (ICAD) framework –a multivariable control engineering tool that allows robustness and system performance evaluations. The great benefits of ICAD are elucidated and contrasted to those provided by the long-time honored block diagram representations. Several models used for the small signal stability analysis of synchronous generators are evaluated under the framework of ICAD. The study, which builds on pioneering work, reveals the great advantages of carrying out control system analysis and design with higher order generator models. Moreover, careful analysis of the ICAD's Multivariable Structure Function (MSF) helps to explain, formally, why some operating conditions of the control system are more critical than others. Furthermore, correct interpretations of MSFs are amenable to robust and stable control system designs. Two kinds of studies are considered in the paper; one assesses operation under various power factor conditions and the other under a varying tie-line reactance. The control system design and stability and structural robustness assessment of the system are presented in the second part of this paper. Moreover, results obtained under the ICAD framework are compared with those arising from conventional controllers.

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