scholarly journals Method for estimating the spectrum density of the resistance moment on the working body of a peat milling unit

2020 ◽  
Vol 241 ◽  
pp. 58
Author(s):  
K. Fomin
Keyword(s):  
Spectral Density ◽  
Operating Conditions ◽  
Design Stage ◽  
Strength Analysis ◽  
Operating Modes ◽  
Milling Machines ◽  
Resistance Moment ◽  
Spectrum Density ◽  
The Moment ◽  
Moment Of Resistance

The main source of dynamic loads in the drive elements and the design of the peat milling unit is the working body. The forces of external resistance arising in the process of performing a technological operation are sharply variable, random in nature. The article proposes a model of formation of the moment of resistance on the mill when interacting with peat. The case when there are several cutting planes with the same radius at the ends of the cutting elements is considered. When developing the model, it was taken into account that the operating conditions of the knives, determined by the type of cutting (blocked, semi-blocked, etc.), their width and type in each cutting plane can vary.Factors that determine the nature of loading, such as the frequency of interaction of the cutting elements with the fallow and the randomness of the operating conditions of the unit, lead to the presentation of the loads in the form of a sequence of pulses with random parameters. Expressions are obtained for determining the spectral density of the moment of resistance on the mill at the design stage, taking into account its design, operating modes, physico-mechanical properties of peat and their probabilistic characteristics.To illustrate the application of the developed approaches, a technique is presented for determining the spectral density of the moment on the working body of deep milling machines and in their drive elements based on a linear model. An example of calculation is given, and the obtained expressions are verified on the basis of experimental data.The probabilistic characteristics of the loads on the mill serve as initial information for the dynamic analysis of the drive system and the design of the unit, its strength analysis, the selection of optimal parameters and operating modes. 

scholarly journals Material Origins of Accelerated Operational Wear of RD-33 Engine Blades

2020 ◽  
Author(s):  
Adam Kozakiewicz ◽  
Stanislaw Jóźwiak ◽  
Przemysław Jóźwiak ◽  
Stanisław Kachel
Keyword(s):  
Chemical Composition ◽  
Construction Material ◽  
Operating Conditions ◽  
Design Stage ◽  
Strength Analysis ◽  
Jet Engine ◽  
Emergency Situations ◽  
Low Pressure Turbine ◽  
Propulsion Unit ◽  
Selection Of

The structural and strength analysis of the material used to construct such an important engine element as the turbine is of great significance, both at the design stage as well as during tests and expertises related to emergency situations. Bearing in mind the conditions above mentioned, the paper presents the results of research on the chemical composition, morphology and phased structure of the metallic construction material used to produce the blades of the high and low pressure turbine of the RD-33 jet engine, which is the propulsion unit of the MiG-29 aircraft. The data obtained as a result of the material tests of the blades allowed, on the basis of the analysis of chemical composition and phased structure, to determine the grade of the alloy used to construct the tested elements of the jet engine turbine. The structural stability of the material was found to be lower in comparison with engine operating conditions, which manifested itself as a clear decrease in the resistance properties of the blade material. The results obtained can be used as a basis for analyzing the life span of an object or a selection of material replacements, which enable to produce the analyzed engine element.

scholarly journals RESEARCH OF TECHNICAL CHARACTERISTICS OF NEW TYPES OF COUPLINGS

2020 ◽  
pp. 113-121
Author(s):  
Oleksii Tokarchuk ◽  
Yurii Polievoda
Keyword(s):  
Elastic Element ◽  
Rational Design ◽  
Experimental Studies ◽  
Bending Moment ◽  
Operational Reliability ◽  
Modern Technology ◽  
Operating Conditions ◽  
The Moment ◽  
Working Bodies ◽  
Moment Of Resistance

Dynamic loads that occur during the operation of existing couplings cause significant shock loads, which leads to rapid wear of the surfaces of the couplings and shortens the service life. Modern technology faces the task of improving the operational reliability of the working bodies and drives of machines. One way to solve this problem is to develop and use high-precision and low-dynamic safety couplings. In this regard, the question of developing new designs of safety couplings that reduce impact loads and increase the reliability and durability of machinery is relevant. The synthesis of structural and kinematic schemes of ball, cam and planetary safety couplings, the method of their calculation in combination with the nature of the change in the moment of resistance on the working body of the equipment. The article conducts a set of theoretical and experimental studies to determine their rational design, kinematic and dynamic parameters that will satisfy the operating conditions of machines and mechanisms. A force analysis of the elastic element (ring spring) was performed. The scheme of loading of an elastic element by two forces and other settlement schemes are constructed, namely: equivalent system; force diagrams for determining the load torque; force schemes for determining the unit moment; schemes of total bending moment; force schemes to determine the total unit moment. During static experimental studies of the developed ball safety couplings, the nature of their operation was established, the maximum torque at the two stages of operation of the couplings was determined and a comparative analysis between the results of theoretical and experimental studies was performed. The positive results of experimental researches of the developed coupling and theoretical positions which can be applied to a substantiation and a choice of rational parameters of the developed designs of couplings and their engineering designing were confirmed.

scholarly journals Material Origins of the Accelerated Operational Wear of RD-33 Engine Blades

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 336
Author(s):  
Adam Kozakiewicz ◽  
Stanisław Jóźwiak ◽  
Przemysław Jóźwiak ◽  
Stanisław Kachel
Keyword(s):  
Chemical Composition ◽  
Construction Material ◽  
Operating Conditions ◽  
Design Stage ◽  
Strength Analysis ◽  
Jet Engine ◽  
Emergency Situations ◽  
Materials Used ◽  
Propulsion Unit ◽  
Selection Of

The structural and strength analysis of the materials used to construct an important engine element such as the turbine is of great significance, at both the design stage and during tests and training relating to emergency situations. This paper presents the results of a study on the chemical composition, morphology, and phased structure of the metallic construction material used to produce the blades of the high- and low-pressure turbines of the RD-33 jet engine, which is the propulsion unit of the MiG-29 aircraft. On the basis of an analysis of the chemical composition and phased structure, the data obtained from tests of the blade material allowed the grade of the alloy used to construct the tested elements of the jet engine turbine to be determined. The structural stability of the material was found to be lower in comparison with the engine operating conditions, which was shown by a clear decrease in the resistance properties of the blade material. The results obtained may be used as a basis for analyzing the life span of an object or a selection of material replacements, which may enable the production of the analyzed engine element.

scholarly journals Experimental Analysis of the Influence of the Application of TiN, TiAlN, CrN and DLC1 Coatings on the Friction Losses in an Aviation Internal Combustion Engine Intended for the Propulsion of Ultralight Aircraft

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 6839
Author(s):  
Piotr Wróblewski ◽  
Robert Rogólski
Keyword(s):  
Combustion Engine ◽  
Aircraft Engine ◽  
Internal Combustion ◽  
Operating Conditions ◽  
Maximum Pressure ◽  
Working Medium ◽  
The Moment ◽  
Main Components ◽  
Moment Of Resistance ◽  
Wear Coatings

Currently, there are many methods of reducing the friction losses of the main components of an internal combustion piston engine. The operating conditions of internal combustion piston engines intended for the propulsion of ultralight aircraft differ significantly from those prevailing in the case of using these engines for the propulsion of vehicles. There are many studies on the influence of selected anti-wear coatings on the friction coefficients when using various lubricants, measured via tribometers. Unfortunately, the conditions obtained in the laboratory significantly differ from those prevailing in an engine operating under external conditions. The study investigated the influence of a change in the tribological parameters of TiN, TiAlN, CrN and DLC1 anti-wear coatings on the moment of resistance to the piston movement of an aircraft engine. The operating parameters of a real engine working in an aircraft were simulated. The main focus was on the coating layers of the sliding surfaces of the piston rings and the cylinder running surface. The properties of the coatings affect the correlation of the scale of the adhesion and cohesion phenomena of the oil to the opposite planes, and this determines the nature of the changes in the moment of resistance to engine motion. As it is commonly known, with an increase in the value of the maximum pressure of the working medium in the combustion chamber, the share of mixed friction in liquid friction increases, similar to the high oil temperatures occurring in aircraft engines. Therefore, there is a justified need to supplement the research in the field of analyzing the characteristics of the torque of resistance to motion for these engines, in particular in the field of the usable rotational speeds of the crankshaft. Applicable anti-wear systems based on selected coatings can significantly improve operational safety and noticeably reduce fuel consumption.

scholarly journals Method for calculating the spectral density of the moment resistance on the working body of the road mill machine

2020 ◽  
Vol 6 (4) ◽  
pp. 518-528
Author(s):  
K.V. Fomin ◽  
Keyword(s):  
Initial Data ◽  
Spectral Density ◽  
Design Stage ◽  
High Productivity ◽  
The Road ◽  
Reliability Indicators ◽  
Unit Structure ◽  
Characteristic Features ◽  
The Moment

Milling units are widely used in the construction and repair of roads. They guarantee high quality of work, have high productivity and make it possible to provide comprehensive mechanization of technological operations. During operation, significant dynamic loads occur in the drive elements and the design of the units, which leads to a deterioration in reliability indicators and a decrease in the technical and economic characteristics of their operation. Improving the reliability and efficiency of milling units is an problem, the solution of which is associated with the opportunity to predict the character and magnitude of the operating loads in the structural elements. The main source of these loads is the working body. At the same time, the forces of external resistance that arise during operation are sharply variable, random in nature. The article presents a method for calculating the spectral density and moment dispersion at the design stage. It takes into consideration the periodic character of the interaction of the cutters with the road surface, as well as random conditions and modes of operation of the milling unit. The article focuses on determining the initial data required for the calculation. The obtained expressions are analyzed and the main characteristic features of the mill loads are considered. The considered characteristics are the initial data for the dynamic analysis of the drive elements and the unit structure, as well as for strength calculations.

scholarly journals Long-term stability of the final slopes of the mining waste dumps from Oltenia

2021 ◽  
Vol 342 ◽  
pp. 03005
Author(s):  
Maria Lazar ◽  
Florin Faur ◽  
Izabela-Maria Apostu ◽  
Constantin Rada
Keyword(s):  
Operating Conditions ◽  
Strength Characteristics ◽  
Design Stage ◽  
Term Stability ◽  
Long Term Stability ◽  
Influence Area ◽  
Waste Dumps ◽  
The Stability ◽  
The Moment

The waste dumps resulted from the lignite exploitation activities from Oltenia are constructions that reach, in most cases, impressive dimensions and store large volumes of sterile rocks. Usually, the dumps are arranged and ecologically restored, but between the moment of their release from technological tasks and the beginning of the arrangement works, periods of time, measured even in years, can pass. The calculations regarding the geometry of the waste dumps are performed in the design stage, taking into account the mechanical strength characteristics of the mixture of sterile material that forms them, so as to ensure a sufficient stability reserve during the construction period and when the projected storage capacity is achieved. If the arrangement and ecological restoration works do not start immediately after the depositing activity is stopped, the exposure of loose and disaggregated material to the influence of external factors (especially erosion and rainfall infiltration) can lead to landslides with disastrous consequences on natural and anthropogenic objectives located in the influence area. This paper analyzes the stability elements of waste dumps under normal operating conditions, the modification of the strength characteristics over time and the geometry required in the final phase so as to ensure their long-term stability.

scholarly journals Dynamics of the hydraulic fluid power of rotation of the hose concrete pump

2021 ◽  
Vol 1 (92) ◽  
pp. 135
Author(s):  
Grygoriy Avrunin ◽  
Igor Kyrychenko ◽  
Vladimir Shatokhin ◽  
Dmitriy Shevchenko ◽  
Irene Moroz
Keyword(s):  
Fluid Power ◽  
Graphical Form ◽  
Working Fluid ◽  
Hydraulic Fluid ◽  
Schematic Diagram ◽  
Hydraulic Motor ◽  
Resistance Moment ◽  
The Moment ◽  
Moment Of Resistance ◽  
Concrete Pump

Purpose. Search for ways to improve the technical level of the hydraulic fluid power of a hose concrete pump by analyzing the hydraulic schematic diagram and dynamic characteristics depending on the moment of resistance, moment of inertia and properties of the working fluid. Method. The construction of a mathematical model of the dynamics of a hydraulic fluid power is based on Newton's laws of mechanics, Pascal's law and the continuity equation for fluids. The dynamics study was implemented using the VisSim package. The results of studies of the influence of variable parameters on the rotor speed and pressure in the discharge line of the hydraulic motor are presented in graphical form. Results. It was found that in a volumetric hydraulic fluid power of a concrete pump with rotor rotation from a gerotor hydraulic motor, there are significant fluctuations in pressure and speed, due to the kinematics of the pump, temporary factors of the increase in the moment of resistance and supply of the working fluid to the hydraulic motor with the throttle method of its regulation. The ratio of the maximum and steady-state pressure values is 1,9 times obtained for hydraulic motors of different displacement. The possibilities of reducing the dynamic loading of the hydraulic fluid power by improving its hydraulic schematic diagram and control algorithm are shown. Conclusion. Recommendations have been developed for reducing dynamic loads in a hydraulic fluid power by modernizing the hydraulic circuit diagram by introducing electrohydroautomatics devices and changing the algorithm for starting and stopping the pump.

Distributed Modeling Of Building Systems Through Cyber-Physical Integration

2019 ◽  
pp. 12-17
Keyword(s):  
Data Structure ◽  
Operating Conditions ◽  
Physical Models ◽  
Distributed Model ◽  
Physical Processes ◽  
Distributed Modeling ◽  
Distributed Models ◽  
Operating Modes ◽  
Building Systems ◽  
Important Practical Application

This article describes the proposed approaches to creating distributed models that can, with given accuracy under given restrictions, replace classical physical models for construction objects. The ability to implement the proposed approaches is a consequence of the cyber-physical integration of building systems. The principles of forming the data structure of designed objects and distributed models, which make it possible to uniquely identify the elements and increase the level of detail of such a model, are presented. The data structure diagram of distributed modeling includes, among other things, the level of formation and transmission of signals about physical processes inside cyber-physical building systems. An enlarged algorithm for creating the structure of the distributed model which describes the process of developing a data structure, formalizing requirements for the parameters of a design object and its operating modes (including normal operating conditions and extreme conditions, including natural disasters) and selecting objects for a complete group that provides distributed modeling is presented. The article formulates the main approaches to the implementation of an important practical application of the cyber-physical integration of building systems - the possibility of forming distributed physical models of designed construction objects and the directions of further research are outlined.

scholarly journals Managing energy performance in buildings from design to operation using modelling and calibration

2021 ◽  
pp. 014362442110083
Author(s):  
Nishesh Jain ◽  
Esfand Burman ◽  
Dejan Mumovic ◽  
Mike Davies
Keyword(s):  
Best Practice ◽  
Good Practice ◽  
Energy Performance ◽  
Operating Conditions ◽  
Design Stage ◽  
Performance Gap ◽  
Actual Performance ◽  
Simulation Tools ◽  
Calibration Protocol ◽  
Covering Design

To manage the concerns regarding the energy performance gap in buildings, a structured and longitudinal performance assessment of buildings, covering design through to operation, is necessary. Modelling can form an integral part of this process by ensuring that a good practice design stage modelling is followed by an ongoing evaluation of operational stage performance using a robust calibration protocol. In this paper, we demonstrate, via a case study of an office building, how a good practice design stage model can be fine-tuned for operational stage using a new framework that helps validate the causes for deviations of actual performance from design intents. This paper maps the modelling based process of tracking building performance from design to operation, identifying the various types of performance gaps. Further, during the operational stage, the framework provides a systematic way to separate the effect of (i) operating conditions that are driven by the building’s actual function and occupancy as compared with the design assumptions, and (ii) the effect of potential technical issues that cause underperformance. As the identification of issues is based on energy modelling, the process requires use of advanced and well-documented simulation tools. The paper concludes with providing an outline of the software platform requirements needed to generate robust design models and their calibration for operational performance assessments. Practical application The paper’s findings are a useful guide for building industry professionals to manage the performance gap with appropriate accuracy through a robust methodology in an easy to use workflow. The methodological framework to analyse building energy performance in-use links best practice design stage modelling guidance with a robust operational stage investigation. It helps designers, contractors, building managers and other stakeholders with an understanding of procedures to follow to undertake an effective measurement and verification exercise.

Sign in / Sign up

Export Citation Format

Share Document