scholarly journals Modeling and calculation of hydromechanical systems dynamics based on the volume rigidity theory

2018 ◽  
Vol 226 ◽  
pp. 01001 ◽  
Author(s):  
Alexander T. Rybak ◽  
Mikhail P. Shishkarev ◽  
Alexander A. Demyanov ◽  
Viktor P. Zharov
Keyword(s):  
Numerical Experiment ◽  
Hydraulic System ◽  
Shock Absorber ◽  
Rigidity Theory ◽  
Hydraulic Systems ◽  
Functional Parameters ◽  
Working Medium ◽  
Drive Systems ◽  
Volume Rigidity

A method for modeling hydraulic systems of hydromechanical devices based on the application of the volume rigidity theory - the property of the hydraulic system to keep its volume unchanged when the pressure of the working medium changes is proposed. The main analytical dependencies intended for modeling the hydraulic system are presented. An example of simulation and calculation of a hydromechanical shock absorber system which confirms the correctness and convenience of using the volume rigidity theory in modeling hydromechanical drive systems of complex machines is presented. The results of the numerical experiment make it possible to evaluate the functioning quality of the drive system under investigation to reveal the effect of the main design and system functional parameters on its operation. The graphs of the change in the main functional parameters of the shock absorber under investigation in real time are given, which make it possible to visually evaluate the results of a numerical experiment and draw conclusions about the need for modernization.

NUMERICAL EXPERIMENT ON SOLVING THE PROBLEM OF PARAMETRIC OPTIMIZATION TO ENSURE THE SAFETY OF THE HYDRAULIC SYSTEM

2016 ◽  
Vol 8 (4) ◽  
pp. 64-68
Author(s):  
Сазонова ◽  
Svetlana Sazonova
Keyword(s):  
Numerical Experiment ◽  
Economic Performance ◽  
Hydraulic System ◽  
Parametric Optimization ◽  
Computational Experiments ◽  
Research System ◽  
Hydraulic Systems ◽  
Residential District ◽  
The Impact ◽  
Gas Supply

The results of computational experiments to assess the impact of parametric optimization of hydraulic systems on economic performance. The object of the research system of low-pressure gas supply of a residential district was chosen. The purpose of research is to optimize the economic parameters for the number of backup sites, sufficient to provide the desired level of reliability and security in the operation of the systems studied.

Microbial water quality and diversity in hydraulic systems using tap water as a pressure medium

2000 ◽  
Vol 41 (12) ◽  
pp. 215-222 ◽  
Author(s):  
S. M. Soini ◽  
K. T. Koskinen ◽  
M. Vilenius ◽  
J. A. Puhakka
Keyword(s):  
Hydraulic System ◽  
Tap Water ◽  
Pilot Scale ◽  
Hydraulic Systems ◽  
Water Hydraulics ◽  
Pressure Medium ◽  
Viable Bacteria ◽  
Water Hydraulic ◽  
Cell Densities

Water hydraulics uses tap water or demineralised water as a pressure medium and has fewer environmental impacts than oil-using hydraulics. The applicability is restricted by the microbial quality of the medium. The objectives of this study were to determine whether microbes grow in the pressure medium of a water hydraulic system, biofilm is formed on the surfaces and to describe the diversity of bacteria that survive and grow in water hydraulic systems. A pilot-scale water hydraulic system was used in the experiments. The viable counts in the pressure medium increased in three days from 102 to 3 ×104 cfu/ml followed by a gradual decrease towards the steady-state concentration of 6× 1034 cfu/ml. The total cell numbers decreased from 3×105 to 2 ×104 cells/ml during the three weeks of operation indicating attachment onto the system surfaces as biofilms. The biofilm cell densities on collector slide surfaces varied between 7 ×103 and 1.2 ×104 cells/cm2 after 21 days of operation. The phosphatase activity in the pressure medium was in conformity with the numbers of viable bacteria. The enzymatic activities (α- and β- glucosidase, phosphatase, aminopeptidase) varied between 0.4 and 300 nmol/lh. The diversity of bacteria growing in the system was wide and differed from that of tap water.

MOBILE PROCESSING OF ASSEMBLY ELEMENTS OF HIGHWAYS

2019 ◽  
pp. 40-44
Author(s):  
S. V. Safonov ◽  
V. P. Smolentsev ◽  
Ya. S. Smolentseva
Keyword(s):  
Current Source ◽  
Hydraulic Systems ◽  
Power Sources ◽  
Working Medium ◽  
Main Pipelines ◽  
Great Pressure ◽  
Service Environments ◽  
The Cost ◽  
Processing Techniques

The issues of preparation of connecting elements of pipelines during repair and restoration of highways in the field with a limited number of technological equipment are considered. It is shown that the replacement of traditional methods of processing on the combined types of preparation of the replaced sections of the highways for welding can improve the accuracy of the mating elements, eliminate the appearance of burrs at the junction of parts. This reduces the need for subsequent technological impacts, improves the quality of repair, provides tightness of highways, reduces the cost of operation and the period of restoration of the highways. Justified the field of rational use of combined processing techniques in the Assembly of parts after repair of main pipelines with account of operations in the field or during pre-flight tests on polygons. Here the greatest advantages are gained by the electrocontact method of separation of materials. Which does not require new power sources electric shock can be applied using as a working medium available technical water. Application of electrocontact processing method of connecting nodes on the proposed schemes ensures safe operation at low voltages the current source gives the possibility, without the complexity of mobile means of providing repairs quickly to restore the product to eliminate the causes of abnormal situations in the construction and operation of highways hydraulic systems of transport vehicles, especially in the case of use in service environments under great pressure.

scholarly journals Quality of service and reliability of railway vehicle autocoupling shock absorbers operating in randomly grouped freight trains.

2014 ◽  
Vol 2014 (2) ◽  
pp. 57-63 ◽  
Author(s):  
Татьяна Селенская ◽  
Tatyana Selenskaya ◽  
Евгений Селенский ◽  
Evgeniy Selenskiy
Keyword(s):  
Quality Of Service ◽  
Fatigue Damage ◽  
Shock Absorber ◽  
Railway Vehicle ◽  
Model Parameter ◽  
Functional Parameters ◽  
Shock Absorbers ◽  
Vehicle Load ◽  
Load Carrying

We formulate the problem of optimising the nominal values and tolerances of functional parameters of railway vehicle autocoupling shock absorber units. The model parameter optimisation is achieved with respect to a minimum of fatigue damage of the vehicle load-carrying structures such that strength reliability levels of these structures does not exceed known limits and all relevant conditions ensuring serviceability of the shock absorbers are satisfied.

Soft Switching Approach to Reducing Transition Losses in an On/Off Hydraulic Valve

2009 ◽  
Author(s):  
Michael B. Rannow ◽  
Perry Y. Li
Keyword(s):  
Hydraulic System ◽  
Check Valve ◽  
Fluid Flows ◽  
Soft Switching ◽  
Total System ◽  
System Efficiency ◽  
Hydraulic Systems ◽  
Controlled Systems ◽  
Flow Through ◽  
Hydraulic Valve

A method for significantly reducing the losses associated with an on/off controlled hydraulic system is proposed. There has been a growing interest in the use of on/off valves to control hydraulic systems as a means of improving system efficiency. While on/off valves are efficient when they are fully open or fully closed, a significant amount of energy can be lost in throttling as the valve transitions between the two states. A soft switching approach is proposed as a method of eliminating the majority of these transition losses. The operating principle of soft switching is that fluid can temporarily flow through a check valve or into a small chamber while valve orifices are partially closed. The fluid can then flow out of the chamber once the valve has fully transitioned. Thus, fluid flows through the valve only when it is in its most efficient fully open state. A model of the system is derived and simulated, with results indicating that the soft switching approach can reduce transition and compressibility losses by 79%, and total system losses by 66%. Design equations are also derived. The soft switching approach has the potential to improve the efficiency of on/off controlled systems and is particularly important as switching frequencies are increased. The soft switching approach will also facilitate the use of slower on/off valves for effective on/off control; in simulation, a valve with soft switching matched the efficiency an on/off valve that was 5 times faster.

Dynamic balance analysis of contamination control for hydraulic systems based on dynamic filtration ratio

2016 ◽  
Vol 68 (1) ◽  
pp. 45-51
Author(s):  
Guangying Ma ◽  
Shurong Ning ◽  
Yunlong Hu ◽  
jun Gao
Keyword(s):  
Hydraulic System ◽  
Dynamic Balance ◽  
Contamination Level ◽  
Hydraulic Systems ◽  
Level Control ◽  
Content Type ◽  
Contamination Control ◽  
Precise Control ◽  
Dynamic Filtration ◽  
The Relationship

Purpose – The aim of this study is to establish a dynamic model of the filtration ratio. For the problem that the measured value of the filtration ratio is far less than the theoretical value in the actual hydraulic filtering system, the paper aims to find the relationship between the filtration ratio and the parameters of the hydraulic systems, such as the contamination level and the dirt-holding quantity of the filter. Design/methodology/approach – The paper opted for the method of experimental analysis and simulation to determine the relationship between the filtration ratio and the parameters of the hydraulic system, and established a dynamic filtration ratio model. Findings – The paper provides a preliminary model of dynamic filtration ratio, and the model shows that the filtration ratio is exponentially related to the contamination level and the dirt-holding quantity. Different filters have different influence coefficients. The filtering capacity for a certain particle size and the contamination level control of the filter for different hydraulic systems can be judged according to the dynamic balance equation of hydraulic systems. Originality/value – The paper is useful in the selection of filters and in the precise control of the contamination level of the hydraulic system.

ENSURING QUALITATIVE-ACCURACY CHARACTERISTICS DURING RESTORING OF VEHICLE PARTS

2021 ◽  
Vol 3 (144) ◽  
pp. 116-121
Author(s):  
Nikita A. Pen’kov ◽  
◽  
Oleg A. Sidorkin ◽  
Sergey Yu. Zhachkin ◽  
Anatoliy I. Zavrazhnov ◽  
...  
Keyword(s):  
Wear Resistance ◽  
Current Density ◽  
Hydraulic Drive ◽  
Research Purpose ◽  
Working Fluid ◽  
Agricultural Machinery ◽  
Servo Valve ◽  
Contact Points ◽  
Drive Systems

One of the most common reasons for the failure of hydraulic drive systems for agricultural machinery is the working fluid leak in the contact points of the rubbing surfaces of hydraulic blocks. The application of composite coatings based on chromium on the contacting surfaces allows you to restore the defect in the shape of the part caused by wear, as well as reduce the friction coefficient at the contact points, which positively affects the wear resistance of the part. (Research purpose) The research purpose is in developing technologies for restoring parts of agricultural machinery with predetermined operational properties. (Materials and methods) A servo valve, widely used in various hydraulic drive systems, was used as an experimental sample. Its working surface was restored with a composite coating applied by electroplating to increase the wear resistance of the servo valve. (Results and discussion) Authors conducted a series of direct measurements under the same conditions. The article presents the de-pendence of the microhardness on the parameters of the electrolysis mode and the thickness of the applied coating using the method of least squares. The nature of changes in microhardness and residual stresses was evaluated to determine the quality of the coatings. The article presents the dependences of these indicators on various control parameters (current density, temperature, tool pressure). The equations of the regression of the main qualitative and accuracy characteristics of the parts were deter-mined using the apparatus of the theory of experimental planning. (Conclusions) The article presents the method for predicting coatings of a given quality, taking into ac-count the influence of the current density and the temperature of the electrolyte during electrolysis on the nature of the precipitation obtained. The influence of the tool pressure on the depth of deformation of the formed layers was estimated. This approach allows us to evaluate the nature of the stress distribution in the formed coating and the quality of the restored parts.

Calculation of a closed hydraulic volumetric system

2021 ◽  
pp. 27-30
Author(s):  
Keyword(s):  
Power Plant ◽  
Wind Power ◽  
Hydraulic System ◽  
Working Fluid ◽  
Wind Power Plant ◽  
Hydraulic Systems ◽  
Hydraulic Motor ◽  
Hydraulic Pump ◽  
Oil Pump ◽  
Selection Of

An algorithm is proposed for calculating a closed volumetric hydraulic pump-hydraulic motor system using the example of the hydraulic system of a wind power plant, based on the calculation of the hydraulic systems of mobile machines. The main characteristics of the system components, the selection of initial data for the calculation, working fluid and diameters of hydraulic lines are analyzed. Keywords: hydraulic system, energy, fluid, oil, pump, motor, renewable energy source, wind power plant, machine. [email protected]

Synchronous Control Characteristics Analysis of Shield Propulsion Hydraulic System Based on Tracking Differentiator and Self-Adaptive Nonlinear PID

2021 ◽  
Author(s):  
Sen Li ◽  
XiaoHua Cao
Keyword(s):  
Pid Control ◽  
Hydraulic System ◽  
Control Method ◽  
Hydraulic Systems ◽  
Fuzzy Pid Control ◽  
Synchronous Control ◽  
Tracking Differentiator ◽  
Characteristics Analysis ◽  
Servo Tracking ◽  
Self Adaptive

Aiming at the low precision problem of multi-cylinder cooperative propulsion control in different regions of shield propulsion hydraulic systems under conditions of large load changes, this paper proposes a tracking differentiator and self-adaptive nonlinear PID (TD-NPID) control method to improve the synchronous control characteristics of shield propulsion hydraulic systems. First, the working principles of shield propulsion hydraulic systems were analyzed, and a mathematical model and TD-NPID controller were developed. Then, a simulation model was developed in AMESim-MATLAB environment, and the synchronous dynamic performances of fuzzy PID control, conventional PID control, and TD-NPID control were compared and analyzed. The results demonstrated that the shield propulsion hydraulic system with TD-NPID control had better servo tracking ability and steady-state performance than the systems with fuzzy or conventional PID control, which verified the feasibility of the application of TD-NPID control for the synchronous control of shield propulsion hydraulic systems.

scholarly journals The Influence of Valve-Pump Weight Ratios on the Dynamic Response of Leaking Valve-Pump Parallel Control Hydraulic Systems

2018 ◽  
Vol 8 (7) ◽  
pp. 1201 ◽  
Author(s):  
Haigang Ding ◽  
Jiyun Zhao ◽  
Gang Cheng ◽  
Steve Wright ◽  
Yufeng Yao
Keyword(s):  
Dynamic Response ◽  
Hydraulic System ◽  
Weight Ratio ◽  
Open Loop ◽  
Hydraulic Systems ◽  
Variable Speed ◽  
Weight Factors ◽  
Wide Range ◽  
Parallel Control ◽  
Valve Control

A new leaking valve-pump parallel control (LVPC) oil hydraulic system is proposed to improve the performance of dynamic response of present variable speed pump control (VSPC) system, which is an oil hydraulic control system with saving energy. In the LVPC, a control valve is operating at leaking status, together with a variable speed pump, to regulate the system flow of hydraulic oil simultaneously. Therefore, the degree of valve control and pump control can be adjusted by regulating the valve-pump weight ratio. The LVPC system design, mathematical model development, system parameter and control performance analysis are carried out systematically followed by an experimental for validation process. Results have shown that after introducing the valve control, the total leakage coefficient increases significantly over a wide range with the operating point and this further increases damping ratios and reduces the velocity stiffness. As the valve-pump weight ratio determines the flow distribution between the valve and the pump and the weight factors of the valve and/or the pump controls determines the response speed of the LVPC system, thus if the weight factors are constrained properly, the LVPC system will eventually have a large synthetic open-loop gain and it will respond faster than the VSPC system. The LVPC will enrich the control schemes of oil hydraulic system and has potential value in application requiring of fast response.

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