scholarly journals Investigation of oscillatory displacement of the hydraulic presses moving parts during their braking in the upper initial position

2020 ◽  
Vol 99 (3) ◽  
pp. 66-74
Author(s):  
O. Korchak
Keyword(s):  
Mathematical Model ◽  
Numerical Analysis ◽  
Oscillatory System ◽  
Initial Position ◽  
Point Of View ◽  
Servo Drive ◽  
Inlet Valve ◽  
Starting Position ◽  
Damped Oscillations ◽  
The Mathematical Model

The investigations revealed that, despite the usage of individual servo drive of the inlet valve of return cylinders, ram overrun upwards after its being shut down which is accompanied by intensive oscillatory phenomena is inevitable. By analyzing the experimental diagrams it is stated that the existing mechanism of ram braking in upper starting position is unacceptable from the point of view of fast and non-impact process realization, as well as the accuracy of stoppage. The mathematical model of ram damped oscillations in the upper position after the inlet valve of return cylinders shut down, which takes into account the parameters of oscillatory system consisting of ram and fluid masses in power and return cylinders, is developed. A numerical analysis of the developed mathematical model established that when using counterbalance cylinders in press design, the period of oscillations increases with decreasing the amplitude. Besides, the complete damping of the oscillations occurs earlier than in the case of counterbalance cylinders absence.

Mathematical Model of the Servo Drive with Friction Wheals. Simulations and Real Object Examination Results

2013 ◽  
Vol 198 ◽  
pp. 15-20 ◽  
Author(s):  
Lukasz Fracczak
Keyword(s):  
Mathematical Model ◽  
Cardiac Surgery ◽  
Control System ◽  
Simulation Model ◽  
Degrees Of Freedom ◽  
Point Of View ◽  
Real Object ◽  
Servo Drive ◽  
Two Degrees Of Freedom ◽  
The Mathematical Model

In this paper the servo drive with friction wheels is presented. The servo drive is designed to move the automatic laparoscope tool or laparoscope camera (thereinafter laparoscope sleeve or sleeve) in two Degrees of Freedom (DOF). The description of the drive mechanism, operating principle and mathematical model of this drive is presented. Based on this model, the Control System (CS) has been created, and used to the construction of a simulation model. The simulation illustrates the proper functionality of the mathematical model of the servo drive with the described CS. This paper also presents the servo drive test stand and the most important examination results from the point of view of using them in the cardiac surgery Robin Heart robot.

scholarly journals On using the rotor acceleration mode to increase the accuracy of a two-stage gyrocompass

2020 ◽  
pp. 5-13
Author(s):  
Volodymyr Fedorov ◽  
Vladislav Kikot ◽  
Nataliya Shtefan
Keyword(s):  
Mathematical Model ◽  
Initial Position ◽  
Effect Of Temperature ◽  
Two Stage ◽  
Best Estimate ◽  
Torsion Suspension ◽  
Measured Angle ◽  
State Position ◽  
Acceleration Mode ◽  
The Mathematical Model

The article considers a two-stage gyrocompass with a rigid torsion suspension of the moving part. The principle of its action is based on balancing the elastic moment of the torsion bars with the gyroscopic moment. When this condition is met, the azimuth of the steady-state position of the rotor axis is calculated from the known kinetic moment , latitude and angular rigidity of the torsion bars, and the measured angle of rotation of the moving part of the gyroscope relative to its initial position. The “aging of the material” of the torsion bars, the effect of temperature on them, etc., leads to an uncontrolled change in the angular stiffness of the torsion bars, which, in turn, leads to an error in determining the position of the meridian. A method is proposed for determining the position of the meridian under conditions when the angular stiffness of the torsion is unknown. The method involves observing the motion of the gyroscope in a mode where the kinetic momentum changes linearly (the rotor accelerates). This movement is associated with the movement of the mathematical model of a two-stage gyrocompass in the same mode in the form of a differential equation of motion or in the form of its solution. As a result of minimizing the discrepancy between the real movement of the gyrocompass and the movement of its mathematical model, the “best estimate” of the parameter characterizing the position of the meridian and the “best estimate” of the angular stiffness of the torsion bars in this dimension are found. The results of modeling the corresponding information processing algorithms are considered. The advantages of the proposed method compared with traditional methods are indicated .

The Properties of Two-Way Cartridge Valve in Water Hydraulic through Matlab/Simulink

2012 ◽  
Vol 271-272 ◽  
pp. 1073-1076
Author(s):  
Zhen Hua Duan ◽  
Zhang Yong Wu ◽  
Qing Hui Wang ◽  
Xi Wu ◽  
Cheng Zhuo Wen
Keyword(s):  
Mathematical Model ◽  
Simulation Analysis ◽  
Point Of View ◽  
Matlab Simulink ◽  
Practical Point ◽  
Structure Characteristics ◽  
Water Hydraulic ◽  
The Mathematical Model

According to the requirements of hydraulic transmission to two-way cartridge valve, and from the practical point of view a water hydraulic two-way cartridge valve was designed. Then its structure characteristics was introduced and the mathematical model was established. The simulation analysis of the water hydraulic two-way cartridge valve has been carried out through Matlab/Simulink proving that its structure was reasonable and it had good performances.

Deregulation of p53-dependent microRNAs: the results of mathematical modeling

2017 ◽  
Vol 12 (1) ◽  
pp. 151-175 ◽  
Author(s):  
О.Ф. Воропаева ◽  
O.F. Voropaeva
Keyword(s):  
Mathematical Modeling ◽  
Mathematical Model ◽  
Numerical Analysis ◽  
Neurodegenerative Disease ◽  
Numerical Investigation ◽  
Tumor Markers ◽  
Critical Properties ◽  
Laboratory Studies ◽  
The Mathematical Model ◽  
Good Agreement

The mathematical model of the dynamics of the tumor markers network p53–Mdm2–microRNA for microRNA class with a direct positive connection with p53 was formulated. Numerical investigation of the microRNA functioning in conditions of the deregulation of p53 and p53–Mdm2-network was carried out. The deregulation of microRNA in detail was studied. The situations in which p53, its inhibitor Mdm2 and microRNAs exhibit critical properties for the patient's status and can be identified as diagnostic markers of cancer and neurodegenerative disease were studied. The results of numerical analysis are in good agreement with the data of clinical and laboratory studies of known microRNAs.

An Application for Analysis of Temperature during Cold Rolling

2013 ◽  
Vol 199 ◽  
pp. 131-136
Author(s):  
Olena Yevtushenko
Keyword(s):  
Mathematical Model ◽  
Plastic Deformation ◽  
Temperature Field ◽  
Numerical Analysis ◽  
Cold Rolling ◽  
Partition Ratio ◽  
Transient Temperature ◽  
Heat Partition ◽  
Transient Temperature Field ◽  
The Mathematical Model

The problem of software creation for the analysis of transient temperature field in cold rolling of metals is under consideration. Firstly, the mathematical model of the process of heating the strip and rolls at cold rolling it is proposed. This model assumes that the generation of heat during the rolling takes place due to friction on the contact surface of the rolls and the strip as well as plastic deformation of the strip material. Next, some fragments of created application for the purpose of an overall numerical analysis of heat partition ratio between the rolls and a strip as well as the temperature in any point of these elements are presented.

scholarly journals Modeling of additive height and numerical analysis of cooling parameters for aero blade remanufacturing

2021 ◽  
Vol 12 (2) ◽  
pp. 803-818
Author(s):  
Miao Gong ◽  
Shijie Dai ◽  
Tao Wang ◽  
Liwen Wang
Keyword(s):  
Heat Transfer ◽  
Mathematical Model ◽  
Numerical Analysis ◽  
Cooling Effect ◽  
Transfer Model ◽  
Factors Affecting ◽  
Coupled Heat Transfer ◽  
Blade Repair ◽  
Geometric Morphology ◽  
The Mathematical Model

Abstract. Additive remanufacturing height and matching cooling parameters are the key factors affecting blade repair quality. First, the mathematical model of the single additive remanufacturing repair height and wire-feeding speed was established, the solution method was proposed and the numerical solution was obtained, and the validity of the model was verified by experiments. Then, based on the calculation results of a single additive remanufacturing repair, the geometric morphology of the cross section under double additive remanufacturing repair was analyzed, and the mathematical model was established. Second, based on the optimal parameters obtained by numerical analysis and the mathematical model, the fluid structure coupling heat transfer model of “blade fixture” for base channel cooling was established. The cooling effect of the typical section under different initial temperatures and different flow rates was calculated, and the coupled heat transfer in the process of blade remanufacturing was explained by the mechanism. Third, through the comparative analysis of the cooling effect, optimal cooling parameters of double additive remanufacturing repair were obtained, and the model of coupled heat flow was verified by experiment. The results showed that the mathematical model of additive remanufacturing height is effective for studying the thermal cycle and cooling effect of welding, and the cooling parameters obtained by numerical analysis can effectively guarantee the quality of double additive remanufacturing of blade repair.

NUMERICAL AND PROGRAM IMPLEMENTATION OF A ONE-DIMENSIONAL MATHEMATICAL MODEL OF HYDRAULIC FRACTURING

2021 ◽  
Vol 7 (1) ◽  
pp. 126-145
Author(s):  
Alexey S. SHLYAPKIN ◽  
Alexey V. TATOSOV
Keyword(s):  
Mathematical Model ◽  
Hydraulic Fracturing ◽  
Program Implementation ◽  
Software Package ◽  
Import Substitution ◽  
Point Of View ◽  
Growth Potential ◽  
Design Problems ◽  
Software Market ◽  
The Mathematical Model

At present, an active policy of import substitution is being pursued, dictated by the imposed international sanctions, which creates a need for finding optimal engineering solutions, in particular, in the field of creating Russian software. In the study and design of hydraulic fracturing, they often rely on the results of modeling in specialized simulators. The appearance of the Russian products on the software market, surely, sets the correct vector of development; however, some aspects are not implemented in the existing mathematical models. The authors of this article present a model that allows considering in detail the process of movement of proppant particles in a hydraulic fracture. The chosen direction is important from the point of view of calculating the fracture cavity and refining its productivity, since the behavior of the particles has a significant effect on both the growth potential of the crack and its shape. The research methodology includes a theoretical justification of the mathematical model presented by the authors in their previous works; a description of the basic principles of selecting and constructing a numerical calculation scheme and creating a software package. The main methods of research are the methods of mathematical modeling, formed from practical problems on the estimation of geometric parameters of the crack, including the areas of continuum mechanics and fracture of solids, underground hydrodynamics. The proposed and implemented numerically mathematical model forms the basis of the authors’ software package, which allows solving the main design problems when performing hydraulic fracturing operations.

scholarly journals Optimisation of a clam bunk skidder from the emission production point of view

2012 ◽  
Vol 58 (No. 4) ◽  
pp. 136-141
Author(s):  
A. Janeček ◽  
R. Adamovský
Keyword(s):  
Mathematical Model ◽  
Production System ◽  
Operating Performance ◽  
Point Of View ◽  
Optimal Rate ◽  
Simple Mathematical Model ◽  
Operation Performance ◽  
The Mathematical Model

This article presents a proposal of a simple mathematical model for minimisation of the production of extraneous substances as a function of the rate of operation performance of a production system. The model is then verified by operation tests of the Terri 2040 clam bunk skidder and by determining the system&rsquo;s optimal rate of performance from the point of view of production of SO<sub>2</sub>, HC and NO<sub>x </sub>emissions. The operation tests conducted to verify the mathematical model have confirmed that conditions can be determined for the production system at which it produces minimum emissions. Min. values of SO<sub>2</sub>, and HC were achieved at approximately the same rate of performance of the clam bunk skidder. Minimum values of NO<sub>x </sub>were achieved at significantly higher rate of performance of the equipment. At the calculated optimal rate of operating performance of the Terri 2040 clam bunk skidder, the values of the produced emissions were determined per m<sup>3</sup> of timber: SO<sub>2</sub> = 1.00035 g/m<sup>3</sup>, HC = 7.796 g/m<sup>3</sup> and NO<sub>x</sub> = 0.277 g/m<sup>3</sup>.

Selection of Method for Underwater Robot Control

2010 ◽  
Vol 164 ◽  
pp. 149-154 ◽  
Author(s):  
Piotr Szymak
Keyword(s):  
Mathematical Model ◽  
Control System ◽  
Numerical Analysis ◽  
Automatic Control ◽  
Robot Control ◽  
Underwater Vehicle ◽  
Underwater Robot ◽  
Underwater Robots ◽  
The Mathematical Model ◽  
Selection Of

Automatic control of motion of underwater robots, particularly along desired trajectory, requires application of proper controllers taking into account dynamics of the underwater robot and features of the marine environment. In the paper the mathematical model of an underwater vehicle [2] and the architecture of designed control system [4] have been presented. Moreover, selected results of numerical analysis in the form of comparison of different course controllers have been provided.

Simulation Model of the Thermodynamic Cycle of a Three-Cylinder Double-Acting Steam Engine

2008 ◽  
Vol 3 (1) ◽  
Author(s):  
Evzen Thoendel
Keyword(s):  
Mathematical Model ◽  
Thermodynamic Cycle ◽  
Steam Pressure ◽  
Heat Energy ◽  
Point Of View ◽  
Steam Engine ◽  
Pressure Reduction ◽  
Software Environment ◽  
The Mathematical Model ◽  
Pressure Reduction Station

Today, steam engines are used for special purposes only, for example to reduce steam pressure in pressure reduction stations, where they replace the traditional and inefficient throttling process. Throttling is the most used way to control the pressure in steam reduction stations. This way is unsatisfactory from the economical point of view, because the exergy is lost uselessly. It is a part of heat energy that can perform a work. The better way of a pressure reduction is an expansion in a backpressure turbine or in a steam engine by simultaneous transformation of the heat energy into electricity (cogeneration). This article describes the design and implementation of the mathematical model of a steam engine used as pressure regulator in a pressure reduction station. The present model is a part of a comprehensive mathematical model of a cogeneration unit and also a part of the author's doctoral thesis. The model assumes detailed mathematical description of physical processes in a steam engine and implementation in an MATLAB-SIMULINK software environment.

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