scholarly journals Numerical and Analytical Evaluation of Service Life of the Details of Axial Piston Hydraulic Machines with Complicated Configuration under Cyclic Loading

2017 ◽  
Vol 176 ◽  
pp. 557-566 ◽  
Author(s):  
V. Zheglova ◽  
Yu. Khomiak ◽  
S. Medvedev ◽  
I. Nikolenko
Keyword(s):  
Cyclic Loading ◽  
Service Life ◽  
Analytical Evaluation ◽  
Hydraulic Machines ◽  
Axial Piston ◽  
Complicated Configuration

scholarly journals Quasi-Static Tests of Hybrid Adhesive Bonds Based on Biological Reinforcement in the Form of Eggshell Microparticles

Polymers ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1391 ◽  
Author(s):  
Viktor Kolář ◽  
Miroslav Müller ◽  
Rajesh Mishra ◽  
Anna Rudawska ◽  
Vladimír Šleger ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Cyclic Loading ◽  
Service Life ◽  
Adhesive Layer ◽  
Maximum Load ◽  
Adhesive Bonds ◽  
Static Tests ◽  
Static Test ◽  
The Matrix ◽  
Positive Effect

The paper is focused on the research of the cyclic loading of hybrid adhesive bonds based on eggshell microparticles in polymer composite. The aim of the research was to characterize the behavior of hybrid adhesive bonds with composite adhesive layer in quasi-static tests. An epoxy resin was used as the matrix and microparticles of eggshells were used as the filler. The adhesive bonds were exposed to cyclic loading and their service life and mechanical properties were evaluated. Testing was performed by 1000 cycles at 5–30% (165–989 N) and 5–70% (165–2307 N) of the maximum load of the filler-free bond in the static test. The results of the research show the importance of cyclic loading on the service life and mechanical properties of adhesive bonds. Quasi-static tests demonstrated significant differences between measured intervals of cyclic loading. All adhesive bonds resisted 1000 cycles of the quasi-static test with an interval loading 5–30%. The number of completed quasi-static tests with the interval loading 5–70% was significantly lower. The filler positively influenced the service life of adhesive bonds at a higher amount of quasi-static tests, i.e., the safety of adhesive bonds increased. The filler had a positive effect on adhesive bonds ABF2, where the strength significantly increased up to 20.26% at the loading of 5–30% against adhesive bonds ABF0. A viscoelasticity characteristic (creep) of the adhesive layer occurred at higher values of loading, i.e., between loading 5–70%. The viscoelasticity behavior did not occur at lower values of loading, i.e., between loading 5–30%.

scholarly journals Measuring system for monitoring the polydimensional deformation of superstructures of bridges and over-bridges improvement of volume hydraulic drive construction and road machines using flow shareholders

2021 ◽  
pp. 7
Author(s):  
Igor Pimonov
Keyword(s):  
Service Life ◽  
Hydraulic Drive ◽  
Road Construction ◽  
Measuring System ◽  
Working Fluid ◽  
Return Flow ◽  
Flow Divider ◽  
Working Volume ◽  
Hydraulic Machines ◽  
Hydraulic Motors

Due to its advantages, the hydraulic drive is widely used in road construction machines. Depending on its design, the share of the hydraulic drive, which is the most expensive unit of a road construction machine, accounts for thirty to eighty percent of all failures. Reliable hydraulic drive, provides, to a large extent, the reliability of the whole machine and the efficiency of the construction organization as a whole. The efficiency of the hydraulic drive of construction machines, and, as a consequence, the machines themselves, is ensured by a set of measures, among which the most important is the quality design, manufacture and operation, combined into a single structural system. Depending on the quality of cleaning of the working fluid, the service life of hydraulic machines can be increased or decreased several times. Accumulation of pollutants in the hydraulic drive, the hardness of which is significantly higher than the hardness of metals, causes rapid wear of the surfaces of hydraulic units and the service life is rapidly reduced. Cavitation in the pump is accompanied by a pulsation of fluid pressure and noise. These pulsations are due to the return flow of fluid from the discharge cavity of the pump, which is accompanied by hydraulic shocks and as a result of alternating shocks, a pressure pulsation in the discharge line of the pump. The amplitude of these pulsations can, under known conditions, reach a value that causes the destruction of the pump. The possibility of cavitation can be reduced by rational choice of modes of operation of the hydraulic system and the correct design of its units, but this phenomenon can be completely eliminated only by using auxiliary pumping pumps, as well as increasing the pressure in the suction line of the pump. On the basis of the analysis of perspective directions of improvement of the hydraulic drive of the excavator the following improved scheme of it is developed. Usually only high-flow hydraulic motors can be used in flow dividers. But in our case it is necessary that the device had, first of all, small mechanical losses and small cost, and accuracy of division of working liquid which follows on filters can be small. In the volume flow divider, hydraulic motors are used: gear, piston, vane, screw, roller. The simplest dividers of volume type are paired (connected by shafts) hydraulic motors of lamellar (vane) and roller types. Hydraulic motors in this scheme are flow measuring devices (dispensers), which supply for one revolution the volume of liquid, equal without taking into account the leaks in the hydraulic motor, its working volume. The use of a flow divider as a source of hydraulic energy makes it possible to improve the hydraulic drive by combining in a single system the purification of the working fluid and the ejector feed of the pump. The most promising, in terms of cost, are flow dividers based on vane and rotary hydraulic motors..

scholarly journals Increasing service life of chuck unit of tank during cyclic loading

2018 ◽  
Vol 1118 ◽  
pp. 012040 ◽  
Author(s):  
K. Verzhbitskiy ◽  
G. Samigullin ◽  
A. Schipachev
Keyword(s):  
Cyclic Loading ◽  
Service Life

Testing of an Ultrahigh-performance Concrete Overlay Developed Using Local Materials

2019 ◽  
Author(s):  
Mark P. Manning ◽  
Brad D. Weldon ◽  
Craig M. Newtson
Keyword(s):  
Cyclic Loading ◽  
Service Life ◽  
High Performance ◽  
High Performance Concrete ◽  
Flexural Behavior ◽  
Flexural Testing ◽  
Channel Beam ◽  
And Behavior ◽  
Beam Bridge ◽  
Local Materials

<p>The superior mechanical and durability properties of ultrahigh-performance concrete (UHPC) offer significant potential advantages when used as an overlay material—a common method for extending the service life of concrete bridge decks. Providing high compressive strength, improved environmental resistance, and increased service-life expectancy compared to conventional concretes, UHPC mixture proportions can be adapted using local materials. Flexural testing of a high-performance concrete (HPC; 66 MPa) prestressed channel beam bridge girder was conducted to investigate the use of nonproprietary UHPC (120 MPa) developed using materials primarily local to New Mexico, USA, for bridge deck overlays. The girder was first subjected to cyclic loading (minimum 1000 load-unload cycles to deflection-based service load conditions) to establish baseline performance and behavior. The girder surface was then textured, and a 25 mm nonproprietary UHPC overlay was cast. Cyclic loading was repeated for the girder-overlay system before loading the system to failure to investigate post-cracking flexural behavior. The UHPC overlay developed satisfactory bond with the HPC substrate without a bonding agent and exhibited no visible signs of distress or debonding after cyclic loading. Comparative analyses indicated increased stiffness and capacity for the girder- overlay system.</p>

Scientific and technical reserves for increasing service life of side frames of two-axle three-element freight cars

2020 ◽  
pp. 45-49
Author(s):  
Alexander Olegovich Belskiy ◽  
◽  
Alexander Vasilyevich Smolyaninov ◽  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Service Life ◽  
Numerical Calculations ◽  
Analytical Evaluation ◽  
Main Criterion ◽  
Operational Characteristics ◽  
Element Method

The paper considers the existing problem associated with the operation of side frames of two-axle three-element bogies of freight cars. The main criterion for increasing the service life is the reduction of stresses in the side frame elements. The authors have proposed variants of side frames that increase the operational characteristics. The authors have also carried out numerical calculations of the proposed variants with the use of finite element method. As a result, the paper present the comparative analytical evaluation of the proposed side frames compared to the typical one.

Determining Cyclic Durability of Piezoceramic Structures Using Probabilistic-Structural Approach

2016 ◽  
Vol 713 ◽  
pp. 216-219 ◽  
Author(s):  
Dmytro Babich ◽  
Tatiana Dorodnykh
Keyword(s):  
Cyclic Loading ◽  
Service Life ◽  
Structural Approach ◽  
Estimation Methods ◽  
Structural Members ◽  
Piezoelectric Transformer ◽  
Idle Mode ◽  
Microcrack Density ◽  
Cyclic Durability

The present paper addresses the new probabilistic-structural approach to determining the service life of piezoceramic structural members under multiple static or cyclic loading. The cyclical service life of structures is related to the intensity with which a microcrack density increases with the cycles of loading. To illustrate the approach the problem of durability of piezoelectric transformer plate for idle mode is considered. Two estimation methods of the durability of this type transformer are proposed.

scholarly journals Analysis of the characteristics of axial-piston hydraulic machines for drives for maintenance of airfields and planes

2021 ◽  
pp. 15
Author(s):  
Grygoriy Avrunin ◽  
Valery Shevchenko ◽  
Dmitriy Shevchenko ◽  
Oleg Shcherbak ◽  
Igor Pimonov ◽  
...  
Keyword(s):  
Energy Saving ◽  
Three Dimensional ◽  
Technological Equipment ◽  
Standard Size ◽  
Axial Piston Pumps ◽  
Goal Development ◽  
Domestic Enterprise ◽  
Working Volume ◽  
Hydraulic Machines ◽  
Axial Piston

Is an integral part of the development of the concept of forming a standard range of transport and technological hydrophilic modular means for maintenance of airfields and aircraft. Goal. Development of scientifically sound recommendations for determining the rational parameters of the hydraulic system with automation of control and energy saving during operation of modular vehicles for maintenance of airfields and aircraft, taking into account the potential of domestic engineering and critical imports of units. Methodology. Analysis of the development of axial-piston pumps and  motors according to the manufacturers' catalogs taking into account the needs of modular vehicles for maintenance of airfields and aircraft, in particular, taking into account the creation of modern hydraulic machines by  enterprise «Hydrosila»  by increasing pressure, speed and development new  regulators. Results. It is established that the domestic nomenclature of modern pumps and  motors of axial piston type allows to create three-dimensional hydraulic drives with power to 110 kW for transmissions with machine stepless remote electrohydraulic regulation of speed of rotation of wheels of modular vehicles and to  85 kW throttle drives of technological equipment with energy saving systems by using pumps with automatic regulators of change of working volume. It has been established that in the pumps for  of transmissions the ratio of mass to power is reduced three times.Originality.  Graphic dependences of power, supply and torque of standard size series on the working volume of axial-piston pumps and hydraulic motors of the domestic enterprise "Hydrosila" for volumetric hydraulic transmissions and technological equipment of aerodrome and aircraft maintenance facilities are constructed. Practical value. The possibility of a rational selection of axial-piston domestic hydraulic machines for the development of hydraulic drives for airfields and aircraft.

scholarly journals Hydrodynamic processes in the piston and cylinder unit of axial-piston hydraulic machines

2017 ◽  
pp. 86-90
Author(s):  
A. O. Kuz'min ◽  
V. V. Popov ◽  
S. M. Stazhkov
Keyword(s):  
Reynolds Equation ◽  
Pressure Field ◽  
Fluid Layer ◽  
Working Fluid ◽  
Sweep Method ◽  
Pressure Fields ◽  
Hydraulic Machines ◽  
Piston Mechanism ◽  
Hydrodynamic Processes ◽  
Axial Piston

The purpose of the research was to analyze the kinematics of the piston mechanism of an axial-piston hydraulic machine with an adjustable-angle cam plate. The kinematic analysis resulted in establishing various types of relative motion of the piston in the guide bushing, writing and solving Reynolds equation with respect to velocities. A sweep method was used to construct a pressure field in the working fluid layer between the piston and the guide bushing. Pressure fields are constructed for several cases of kinematics of the piston mechanism.

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