scholarly journals Simulation model of a chair vibration protective mechanism with a part of quasi-zero-stiffness for the operator of a road-building machine

2020 ◽  
Vol 6 (4) ◽  
pp. 486-496
Author(s):  
M.S. Korytov ◽  
◽  
V.S. Sherbakov ◽  
I.E. Pochekueva ◽  
◽  
...  
Keyword(s):  
Mathematical Model ◽  
Vibration Isolation ◽  
Degree Of Freedom ◽  
Protection System ◽  
Production Factor ◽  
Protective Mechanism ◽  
Static Force ◽  
Vertical Movements ◽  
Vibration Protection ◽  
Protection Systems

Vibrations of construction and road machinery components that occur during their operation are a harmful production factor for machine operators, therefore, their reduction can be considered a very urgent task. The main route of vibration transmission is through vibration isolation systems for the operator’s seat and cab. The easiest and most cost-effective way to isolate the operator from vibration is through his seat by reducing vibration. The simplest and most reliable vibration protection systems with one degree of freedom limited by vertical movements of the chair can be used for the chairs. Vibration protection mechanisms and systems with quasi-zero rigidity are considered promising. They provide constant static force over a certain range of movement of the object. The task of developing mathematical models describing vibration protection systems with quasi-zero rigidity is urgent. In the Matlab software package using the Simscape library for modeling physical elements, a simulation mathematical model of the vibration protection system of a chair with one degree of freedom has been developed. The base of the chair in the developed model performs harmonic sinusoidal movements. The output parameters of the developed mathematical model are the time dependences of the chair coordinates and accelerations. The blocks used in the model are described, the static force characteristics are given, given using the Hermite spline. The model includes a block of hard movement restrictions. An example of using the developed simulation mathematical model of the chair is given. The developed model makes it possible to specify both the dimensions of the quasi-zero stiffness section and the shape of the curves of the force static characteristics of the vibration protection system. It can be integrated into higher level models.

Mathematical models for evaluating the effectiveness of shock-absorbing fasteners of vibro-active mechanisms of marine objects by vibrational power

2021 ◽  
pp. 13-20
Author(s):  
В.А. Пятакович ◽  
В.Ф. Рычкова ◽  
А.П. Пурденко
Keyword(s):  
Mathematical Models ◽  
Rational Design ◽  
Vibration Isolation ◽  
Vibrational Energy ◽  
Technical Problem ◽  
Vibration Protection ◽  
Protection Systems ◽  
Neural Network System ◽  
Theoretical Mechanics ◽  
Theoretical Developments

Для создания виброакустической защиты судового оборудования необходимо учитывать потоки колебательной энергии, распространяющиеся от источников как через опорные и неопорные связи, так и в виде воздушного шума. В работе представлены математические модели оценки эффективности амортизирующих креплений виброактивных механизмов морских объектов по колебательной мощности, учитываемые при обучении разрабатываемой нейросетевой системы классификации морских целей. Теоретические разработки в области виброзащиты и виброизоляции во многом имеют междисциплинарный характер и опираются на методы теории механизмов и машин, теоретической механики, теории колебаний, теории управления, используются методы инфорьт мационные технологии для оценки, поиска и выбора рациональных проектно-конструкторских решений. Создание амортизирующих устройств, способных защитить объекты от вибраций и ударов и, вместе с тем, обладающих ограниченными размерами, является сложной технической проблемой. В связи с этим первостепенное значение приобретают вопросы теории и расчета адаптивных виброзащитных систем. To create vibro-acoustic protection of ship equipment, it is necessary to take into account the flows of vibrational energy propagating from sources both through support and non-support connections, and in the form of air noise. The paper presents mathematical models for evaluating the effectiveness of shock-absorbing fasteners of vibro-active mechanisms of marine objects by vibrational power, which are taken into account when training the developed neural network system for classifying marine targets. Theoretical developments in the field of vibration protection and vibration isolation are largely interdisciplinary in nature and are based on the methods of the theory of mechanisms and machines, theoretical mechanics, vibration theory, control theory, information technology methods are used to evaluate, search and select rational design solutions. The creation of shock-absorbing devices that can protect objects from vibrations and shocks and, at the same time, have limited dimensions is a complex technical problem. In this regard, the issues of the theory and calculation of adaptive vibration protection systems are of paramount importance.

scholarly journals Application of the parallelogram mechanism with the effect of quasi-zero stiffness in the vibration protection systems of the operator’s chair of a road construction machine

2021 ◽  
Vol 7 (2) ◽  
pp. 132-140
Author(s):  
M.S. Korytov ◽  
◽  
V.S. Sherbakov ◽  
I.E. Pochekueva ◽  
◽  
...  
Keyword(s):  
Vibration Isolation ◽  
Tensile Force ◽  
Road Construction ◽  
Negative Stiffness ◽  
Force Characteristic ◽  
Straight Line Passing ◽  
Tension Spring ◽  
Vibration Protection ◽  
Protection Systems ◽  
Isolation Systems

For vibration protection of operators of construction and road machines, a promising direction is the use of passive vibration protection systems based on mechanisms with quasi-zero rigidity. Passive vibration isolation systems, being less complex than active ones, require less frequent maintenance, are cheaper to manufacture and more reliable than active ones. The problem of selecting the optimal, most reliable and simple design of the mechanism with the effect of quasi-zero rigidity remains urgent. In this case, the most widespread use of elements that create negative stiffness. This requires elements with positive stiffness in the mechanism, which complicates the design. More promising structures of mechanisms, where elements with negative stiffness are not separated into a separate structure. In mechanisms such as the parallelogram, studied in this work, a section with quasi-zero stiffness can be provided with just one tension spring, which simplifies the design and reduces the cost of the entire vibration protection system. By the method of direct analytical inference for the presented diagram of a parallelogram mechanism with one spring, analytical expressions are obtained for the tensile force of the spring necessary to compensate for the force of gravity of the chair with the operator on the height of the chair and the length of the spring. As an example, the graphical dependences of the spring tensile force on the chair lift and on the spring’s own length are given as an example. It was found that the static force characteristic of the spring is a straight line passing through the origin. That is, the zero force corresponds to the zero spring length, which is not technically feasible. It is proposed to use a mechanism that replaces the tension spring, which will provide a given power characteristic.

ACTIVE VIBRATION PROTECTION BASED ON THE MECHATRONIC SYSTEM

2020 ◽  
Vol 3 ◽  
pp. 76-82
Author(s):  
R.N. POLYAKOV ◽  
A.V. GORIN ◽  
R.K. ZARETSKIY ◽  
N.V. TOKMAKOV
Keyword(s):  
Protection System ◽  
Mechatronic System ◽  
Vibration Protection ◽  
Protection Systems ◽  
Piezoelectric Elements ◽  
Active Vibration

The article examined and analyzed various types of vibration protection systems. Based on the results of the analysis, it was concluded that the known methods for providing vibration protection do not fully satisfy the requirements for them. Therefore, the possibility of using an active vibration protection system based on piezoelectric elements is considered. The design was developed and general ideas about the structure of the active vibration protection system, the principle of its operation were formulated.

scholarly journals Mathematical Model of the Dynamics in a One Nonholonomic Vibration Protection System

2018 ◽  
Vol 10 (10) ◽  
pp. 20-26
Author(s):  
Viktor Legeza ◽  
◽  
Ivan Dychka ◽  
Ruslan Hadyniak ◽  
Lіubov Oleshchenko
Keyword(s):  
Mathematical Model ◽  
Protection System ◽  
Vibration Protection

scholarly journals Solving current problems in engineering system dynamics

2021 ◽  
Vol 2021 (2) ◽  
pp. 3-19
Author(s):  
O.V. Pylypenko ◽  
Keyword(s):  
Mathematical Model ◽  
System Dynamics ◽  
Gas Turbine ◽  
Launch Vehicle ◽  
Gas Turbine Engine ◽  
Protection System ◽  
Liquid Propellant ◽  
Turbine Engine ◽  
Vibration Protection ◽  
Engine Components

This paper overviews the main results obtained over the past few years at the Department of Hydromechanical Systems Dynamics and Vibration Protection Systems, Institute of Technical Mechanics of the National Academy of Sciences of Ukraine and the State Space Agency of Ukraine, in the solution of current problems in the dynamics of liquid-propellant rocket engines (LPREs), liquid-propellant launch vehicle pogo stability, vibration protection system dynamics, the gas dynamics of aircraft gas turbine engine components, and the dynamics of hydraulic systems with cavitating elements. These results are as follows. A mathematical model of LPRE pump dynamics was developed. The model complements a hydrodynamic model of LPRE cavitating pumps by allowing a mathematical simulation of choking regimes. An approach was developed to the construction of a nonlinear mathematical model of LPRE hydraulic line filling. The approach allows one to automatically change, if necessary, the finite element partitioning scheme of a hydraulic line in the process of its filling during LPRE startup calculations. An investigation was conducted into the startup dynamics of a multiengine liquid-propellant propulsion system that consists of four staged-combustion oxidizer-rich LPRDs with account for the possibility of their nonsimultaneous startup. The maximum values of oxidizer and fuel pressure surges and undershoots at the liquid-propellant jet system (LPJS) inlet at an engine spartup and shutdown were determined and used in determining the LPJS operability at the startup and shutdown of the RD861K sustainer engine. The pogo stability of the Cyclone-4M launch vehicle was analyzed analytically using Nyquist’s criterion. A numerical approach was developed to characterizing acoustic oscillations of the combustion products in annular rocket combustion chambers with account for the configuration features of the fire space and the variation of the physical properties of the gaseous medium with the axial length of the chamber. A prototype vibration protection system was developed and made, and its dynamic tests confirmed its high efficiency in damping impact and harmonic disturbances. Approaches were developed to the aerodynamic improvement of aircraft gas turbine engine components. Topical problems in solids grinding in a liquid medium with the use a cavitation pulse technology were solved.

Cloud-Based Multimedia Content Protection System

2020 ◽  
pp. 164-169
Author(s):  
B. Aparna ◽  
S. Madhavi ◽  
G. Mounika ◽  
P. Avinash ◽  
S. Chakravarthi
Keyword(s):  
Large Scale ◽  
Protection System ◽  
Multimedia Content ◽  
Computationally Efficient ◽  
Content Protection ◽  
Protection Systems ◽  
Multimedia Content Protection ◽  
High Scalability ◽  
Cloud Infrastructures ◽  
Rapid Deployment

We propose a new design for large-scale multimedia content protection systems. Our design leverages cloud infrastructures to provide cost efficiency, rapid deployment, scalability, and elasticity to accommodate varying workloads. The proposed system can be used to protect different multimedia content types, including videos, images, audio clips, songs, and music clips. The system can be deployed on private and/or public clouds. Our system has two novel components: (i) method to create signatures of videos, and (ii) distributed matching engine for multimedia objects. The signature method creates robust and representative signatures of videos that capture the depth signals in these videos and it is computationally efficient to compute and compare as well as it requires small storage. The distributed matching engine achieves high scalability and it is designed to support different multimedia objects. We implemented the proposed system and deployed it on two clouds: Amazon cloud and our private cloud. Our experiments with more than 11,000 videos and 1 million images show the high accuracy and scalability of the proposed system. In addition, we compared our system to the protection system used by YouTube and our results show that the YouTube protection system fails to detect most copies of videos, while our system detects more than 98% of them.

The Impact of Plant Protection Systems on the Productivity of Soybean Varieties under Irrigated Conditions

2019 ◽  
pp. 109-117
Keyword(s):  
Plant Protection ◽  
Crop Protection ◽  
Production Costs ◽  
Protection System ◽  
Average Weight ◽  
The South ◽  
Biological Origin ◽  
Chemical Protection ◽  
Protection Systems ◽  
The Impact

The application of preparations of biological origin in the protection system of soybean grown under conditions of intensive irrigated crop rotations conforms to the modern tendencies of science and production development. The use of them contributes to solving ecological, production and social-economic problems. The study presents the three-year research on the efficiency of systems protecting soybean from pests and diseases based on biological and chemical preparations. The research was conducted in typical soil and climate conditions of the South of Ukraine. Zonal agricultural methods and generally accepted research methodology were used. The purpose of the research was to create a soybean protection system based on preparations of biological origin, ensuring high productivity of high-quality products reducing a negative impact of the crop production on the environment. The study emphasizes that, under irrigated conditions of the South of Ukraine, the application of biological preparations has a positive impact on the indexes of growth, development and formation of the elements of soybean yield structure. There was an increase in the crop biological weight by 13.8 % and 22.1 % and the number of seeds per plant rose by 11.6 and 14.6 % as a consequence of eliminating harmful organisms with the plant protection systems. The larger ground mass was formed by medium-ripe varieties Danai and Svyatogor, on which the increase from protection measures was higher. Weight 1000 pcs. the seeds did not undergo significant changes. It is established that the larger seeds were formed by Danaya and Svyatogor varieties, in which the average weight is 1000 pcs. seeds were 142 and 136 g, respectively, while in the variety Diona this figure was 133 g. There was an increase in the height of the lowest pod when the total plant height rose. For medium-ripe varieties was characterized by a higher attachment of beans, where the highest values of this indicator acquired in the variety Svyatogor. The medium maturing soybean variety Danaia formed the maximum yield of 3.23 and 3.35 t/ha respectively, when biological and chemical protection systems were applied. The research establishes that the application of the bio-fungicide Psevdobakterin 2 (2.0 l/ha) in the crop protection system at the beginning of soybean flowering and the bio-fungicide Baktofit (2.5 l/ha) with the bio-insecticide Lepidotsid-BTU (10.0 l/ha) at the beginning of pod formation does not reduce the productivity of the soybean varieties under study considerably, when compared to the application of chemical preparations. The research determines that the soybean protection system under study ensures a decrease in the coefficient of soybean water uptake by 7.2-13.0 %, increasing the total water intake to an inconsiderable degree. Biologization of the soybean crop protection system leads to a reduction in production costs compared to the chemical protection system. Taking into account the needs for the collection of additional products, costs increase by an average of 1 thousand UAH/ha, while for chemical protection systems by 1.8 thousand UAH/ha. At the same time, the cost is reduced by 220-360 UAH/t and the profitability of growing crops is increased by 3.8-7.8 %. There has been a reduction in the burden of pesticides on the environment and the production of cleaner products. This indicates the prospect of using the biofungicides Pseudobacterin 2 and Bactophyte and the bioinsecticide Lepidocid-BTU on soybeans to protect plants from pests.

scholarly journals Trustworthiness of Flexible Rockfall Protection Systems

Geosciences ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 197
Author(s):  
Axel Volkwein ◽  
Marcel Fulde ◽  
Ingvar Krieger Hauksson
Keyword(s):  
Energy Levels ◽  
Protection System ◽  
Protection Systems ◽  
The World ◽  
Rockfall Protection

Flexible rockfall protection systems are an effective and efficient remedy against rockfalls with energy levels between 100 and up to 10,000 kJ. Although they are heavily in use all around the world, the backgrounds that guarantee a reliable barrier are not well known by most of intervening agents and users. This contribution gives some insights on how to judge the capability, reliability, and trustworthiness of a rockfall protection system. The paper focuses on three strategies to build up confidence and trustworthiness regarding the barrier’s correct or expected functioning: testing, certification, and how to assess adaptions of standard barrier systems.

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