scholarly journals EXPERIMENTAL STUDIES OF WEARING AND TEARING OF ASPHALT CONCRETE SURFACING UNDER THE ACTION OF WATER PRESSURE IN MICROPORES

2021 ◽  
pp. 83-92
Author(s):  
V. V. Volkov ◽  
V. A. Kozlov ◽  
V. N. Melkumov
Keyword(s):  
Experimental Data ◽  
Asphalt Concrete ◽  
Water Pressure ◽  
Fluid Pressure ◽  
Experimental Studies ◽  
Hydrodynamic Effect ◽  
Depth Of Penetration ◽  
Wear And Tear ◽  
The Impact ◽  
Whole Life Cycle

Statement of the problem. The goal of this study is to identify the effect of wet surfacing on its wear and tear. The mechanism of influence of transport loading in the presence of moisture and experimental methods of measurement of its influence on wear and tear of the top layer of asphalt concrete are discussed. Results. The contribution of the presence of moisture in the upper layer of the pavement to its wear and tear in the form of track formation was identified, and the hydrodynamic effect of water in the micropores of the pavement was investigated. Experimental data on the values of water pressure in the pores of the asphalt-concrete pavement in the moistened state under the action of the wheels of the moving traffic flow were obtained. Therefore it became possible to identify the maximum values of the pressure effect, the depth of penetration of the fluid pressure front and its effect on the destruction of the surfacing.Conclusions. The analysis of the data showed not only the presence of brittle fracture, but also the impact of moisture moving in the pores of asphalt concrete, exceeding its structural strength. Using experimental data, regression dependences of the wear and tear value on the standard flow parameters were obtained. For the operated surfacings regression dependence enables one to predict the size of wear and tear for the whole life cycle of the road.

Experimental Studies Of Wear and Tear of Asphalt Concrete Surfacing Under the Action of Water Pressure in the Micropores

2021 ◽  
pp. 83-91
Author(s):  
В. В. Волков ◽  
В. А. Козлов ◽  
В. Н. Мелькумов
Keyword(s):  
Experimental Data ◽  
Asphalt Concrete ◽  
Water Pressure ◽  
Experimental Studies ◽  
Hydrodynamic Effect ◽  
Depth Of Penetration ◽  
The Road ◽  
Flow Parameters ◽  
Wear And Tear ◽  
Asphalt Concrete Pavement

Постановка задачи. Целью исследования является выявление влияния увлажненного покрытия на его износ. Рассматривается механизм воздействия транспортной нагрузки в присутствии влаги и экспериментальные методы измерения ее воздействия на износ верхнего слоя асфальтобетона. Результаты. Определен вклад наличия влаги в верхнем слоя дорожного покрытия на его износ в виде образования колеи, исследовано гидродинамическое воздействие воды в микропорах покрытия. Получены экспериментальные данные величин давления воды в порах асфальтобетонного покрытия в увлажненном состоянии под действием колес движущегося транспортного потока. Это позволило определить максимальные величины барического воздействия, глубину проникновения фронта давления жидкости и влияние его на разрушение покрытия. Выводы. Анализ полученных данных показал не только наличие хрупкого разрушения, но и наличие ударного воздействия движущейся в порах асфальтобетона влаги, превышающего его структурную прочность. С использованием экспериментальных данных получены регрессионные зависимости величины износа от стандартных параметров потока. Для эксплуатируемых покрытий регрессионная зависимость позволяет прогнозировать величину износа на весь жизненный цикл дороги. Statement of the problem. The purpose of the study is to identify the effect of a wetted surfacing on its wear and tear. The mechanism of the effect of transport load in the presence of moisture and experimental methods of measuring its effect on the wear of the upper layer of asphalt concrete are discussed. Results. The contribution of the presence of moisture in the upper layer of the road surface to its wear and tear in the form of rutting is identified, and the hydrodynamic effect of water in the micropores of the surface is examined. Experimental data on the values of water pressure in the pores of an asphalt concrete pavement in a wet state under the action of the wheels of a moving traffic stream have been obtained. This made it possible to identify the maximum values of the pressure effect, the depth of penetration of the liquid pressure front and its influence on the destruction of a surfacing. Conclusions. Analysis of the obtained data showed not only the presence of brittle fracture, but also an impact effect of moisture moving in the pores of asphalt concrete exceeding its structural strength. Using the experimental data, regression dependences of the wear and tear value on the standard flow parameters were obtained. For the pavements in use, the regression dependence makes it possible to predict the amount of wear and tear for the entire life cycle of the road.

Forced Response Sensitivity of a Mistuned Rotor From an Embedded Compressor Stage

2015 ◽  
Author(s):  
Fanny M. Besem ◽  
Robert E. Kielb ◽  
Nicole L. Key
Keyword(s):  
Experimental Data ◽  
Forced Response ◽  
Symmetric System ◽  
Response Analysis ◽  
Cfd Simulations ◽  
Forcing Function ◽  
Wear And Tear ◽  
The Individual ◽  
The Impact ◽  
Interblade Phase Angle

The frequency mistuning that occurs due to manufacturing variations and wear and tear of the blades can have a significant effect on the flutter and forced response behavior of a blade row. Similarly, asymmetries in the aerodynamic or excitation forces can tremendously affect the blade responses. When conducting CFD simulations, all blades are assumed to be tuned (i.e. to have the same natural frequency) and the aerodynamic forces are assumed to be the same on each blade except for a shift in interblade phase angle. The blades are thus predicted to vibrate at the same amplitude. However, when the system is mistuned or when asymmetries are present, some blades can vibrate with a much higher amplitude than the tuned, symmetric system. In this research, we first conduct a deterministic forced response analysis of a mistuned rotor and compare the results to experimental data from a compressor rig. It is shown that tuned CFD results cannot be compared directly with experimental data because of the impact of frequency mistuning on forced response predictions. Moreover, the individual impact of frequency, aerodynamic, and forcing function perturbations on the predictions is assessed, leading to the conclusion that a mistuned system has to be studied probabilistically. Finally, all perturbations are combined and Monte-Carlo simulations are conducted to obtain the range of blade response amplitudes that a designer could expect.

Investigation of Material Deformation by the High-Speed Water Slugs

2002 ◽  
Author(s):  
O. Petrenko ◽  
E. S. Geskin ◽  
G. A. Atanov ◽  
B. Goldenberg ◽  
A. Semko
Keyword(s):  
Shock Waves ◽  
Nozzle Exit ◽  
High Speed ◽  
Numerical Models ◽  
Water Pressure ◽  
Experimental Studies ◽  
Surface Cleaning ◽  
Water Velocity ◽  
Material Deformation ◽  
The Impact

Water constitutes an attractive manufacturing tool It is readily available and clean. The waterjets are conventionally used for surface cleaning, material removal, and surface modification. The intrinsic shortcomings of such an application are the need in the use of expensive and heavy pumping facilities and, what are more important, peculiarities of the waterjet-substrate interaction which limit material deformation by the incoming jet. These shortcomings are eliminated if the workpiece is impacted by the array of the water slugs, generated by the direct injection of high-intensity energy pulses into the water vessel (barrel) and ejection the portion of the water via the nozzle attached into the barrel. Such a device (barrel-nozzle combination) will constitute an effective and versatile manufacturing tool. Understanding of the phenomena that occur in the course of the energy injection into the water is necessary for the design of the desired device. The phenomena in question are determined by the ratio between the speed of the water in the barrel in the course of the energy injection and the speed of the shock waves in the water. If this ratio is much less than unity, the exit velocity is determined by the ratio between the cross section areas of the nozzle exit and the barrel. If the ratio in question approaches the unity, the water velocity at the nozzle exit is determined by the impact pressure. The device utilizing this principle is termed the water extruder. If however, the ratio is much more than unity the exit water velocity is determined by the superposition of shock waves developed in the fluid. This device termed the water cannon is able to accelerate the water slug to the speed far exceeding 1,000 m/sec. The numerical and experimental studies of water extruder were carried out. The numerical models were constructed and the variation of the water velocity and the water pressure in the barrel were investigated. Experimental setup for the study of the water extruder was constructed by the modification of Remington power tool. The experiments involved the piercing of metal strips. The effect of operational conditions on the maximal depth of the piecing was determined. Another series of experiments involved the study of the slug impact on plastic (lead) and brittle (concrete) materials. The effect of the stand off distance on the removal of both kinds of material was investigated. As the result the suggestions about the way of construction of the water extruders and their practical applications were made.

scholarly journals Increasing the Durability of Asphalt Pavement - the Road to Road Safety

2021 ◽  
Vol 334 ◽  
pp. 01027
Author(s):  
Valentina Yadykina ◽  
Rashid Sharapov ◽  
Christina Pashkova ◽  
Anatoly Gridchin ◽  
Anna Trautvain
Keyword(s):  
Asphalt Concrete ◽  
Road Safety ◽  
Water Resistance ◽  
Experimental Studies ◽  
Softening Temperature ◽  
The Road ◽  
Fatigue Durability ◽  
The Impact ◽  
Positive Effect

Based on literature data, the paper analyzed the impact of transport operational indicators related to the quality of road surface coverage on road safety. It presented the results of experimental studies on the effect of the road adhesion cationic thermostable additive on the properties of bitumen and asphalt concrete. The authors identified that the introduction of this additive leads to an increase in the viscosity and softening temperature of bitumen, its adhesion to mineral materials, which has a positive effect on strength, water resistance, shear stability, crack resistance, fatigue durability of asphalt concrete. The conclusion was made about the regularity of improving road safety, related to the improvement of the quality of the pavement, arranged from asphalt concrete with the application of the tested additive.

scholarly journals The Effect of Cutting Speed on the Ploughing Forces

2021 ◽  
Author(s):  
Alexey Popov ◽  
Iuliia Krasnikova
Keyword(s):  
Stainless Steel ◽  
Cutting Tool ◽  
Experimental Studies ◽  
Cutting Speed ◽  
Comparison Method ◽  
Measurement Results ◽  
Wear And Tear ◽  
Flank Face ◽  
The Impact ◽  
Better Than

Abstract The ploughing forces (PFs) are one of the important parameters for calculating the tool life. They directly affect the stress on the tool flank face and are responsible for wear and tear conditions of the cutting tool as well. In this study we attempted to find the impact of cutting speed on PFs, that is, the relation between cutting speed and PFs. In this paper, the ploughing forces were estimated by a new comparison method in which forces at different point of contact areas are added (sum of forces) to get the PFs accurately. The accuracy of PFs estimated with this method will be better than previously used methods. This paper presents the measurement results of the PFs when turning stainless steel, structural steel and aluminum alloy materials. The results of experimental studies showed that an increase in cutting speed ranging from 50 to 200 m/min resulted in increase in PFs by 1.4–3.2 times when turning with different flank wears.

scholarly journals Processing and Generalization of Experimental Data on Thermal Diffusivity and Thermal Conductivity of Magnetic Fluids Depending on the Impact of the Magnetic Field

2021 ◽  
Vol 27 (2) ◽  
pp. 231-237
Author(s):  
D. S. Dzhuraev
Keyword(s):  
Magnetic Field ◽  
Experimental Data ◽  
Thermal Conductivity ◽  
Thermal Diffusivity ◽  
Iron Powder ◽  
Experimental Studies ◽  
Magnetic Fluids ◽  
Transformer Oil ◽  
The Impact ◽  
The Magnetic Field

The paper presents the results of experimental studies of the thermal diffusivity and thermal conductivity of magnetic fluids based on transformer oil, depending on the effect of a magnetic field in the range of B = 1.59...3.866 mT, and the addition of iron powder 0.1...0.3 g with an interval of 0.05 g. Equations were obtained for calculation with a certain fraction of error in thermal diffusivity and thermal conductivity of unexplored magnetic fluids.

Design and laboratory verification of a physical model of sloping capillary barrier

2004 ◽  
Vol 41 (5) ◽  
pp. 814-830 ◽  
Author(s):  
Denny Tami ◽  
Harianto Rahardjo ◽  
Eng-Choon Leong ◽  
Delwyn G Fredlund
Keyword(s):  
Experimental Data ◽  
Numerical Simulation ◽  
Numerical Analysis ◽  
Physical Model ◽  
Water Pressure ◽  
Experimental Studies ◽  
Silty Sand ◽  
Capillary Barrier ◽  
Simulation Results ◽  
Barrier Model

A physical model was designed and constructed to study the mechanisms associated with capillary barriers for slope stabilization purposes. Prior to construction of the model, various numerical analyses were conducted to determine the optimum dimensions and appropriate soil types for the materials of the capillary barrier model. This paper is divided into three sections: the first two sections are related to the design of the model and are to obtain the optimum dimensions of the model and to investigate the range of soil properties that are most suitable for experimental studies in the laboratory; and the last section is laboratory verification of the numerical analysis where the numerical simulation results are compared with the experimental data. Based on the numerical simulation results, the physical capillary barrier model was constructed using two different combinations of soils, namely silty sand over gravelly sand and fine sand over gravelly sand. From the comparison of the numerical results and experimental data, it was found that the numerical analysis was able to simulate the experiment on the physical capillary barrier model reasonably well.Key words: physical capillary barrier model, unsaturated water flow, numerical simulation, pore-water pressure, volumetric water content, slope stability, infiltration.

scholarly journals СРАВНИТЕЛЬНЫЙ АНАЛИЗ МЕТОДОВ РАСЧЁТА АМПЛИТУД КОЛЕБАНИЙ ДАВЛЕНИЯ, СОЗДАВАЕМЫХ КАВИТАЦИОННЫМ ГЕНЕРАТОРОМ

2018 ◽  
pp. 58-68
Author(s):  
Юрий Алексеевич Жулай ◽  
Юрий Александрович Кваша ◽  
Алексей Дмитриевич Николаев
Keyword(s):  
Experimental Data ◽  
Mathematical Model ◽  
Specific Energy Consumption ◽  
Fluid Pressure ◽  
Experimental Studies ◽  
Industrial Plant ◽  
Design Stage ◽  
Oscillatory Process ◽  
Pressure Oscillations ◽  
Element Discretization

One of the devices implementing energy-saving technologies is a Venturi tube of special geometry, called the cavitations generator of fluid pressure oscillation (hereinafter referred to as the generator). It converts the steady-state flow of process fluid into a discrete-impulse flow of increased power and has the simplicity of manufacturing that lacks moving parts, does not require additional energy sources and seamlessly fits into existing equipment. The practical use of the generator in engineering, metallurgy, the chemical industry and in mining, can reduce the specific energy consumption by up to 50%. The purpose of this paper is a comparative analysis of the existing methods for calculating the amplitudes of pressure oscillations generated by the generator and the choice of a method that makes it possible to determine the amplitudes with an acceptable accuracy. The technique is based on the determination by various computation methods of peak-to-peak values of the fluid pressure from the cavitations flow regime. The results are presented in the form of calculated dependences of the of peak-to-peak oscillation values of the fluid pressure on the value of the cavitations parameter and their comparison with the experimental data. Scientific novelty. It is established that the method using the finite-element discretization of the generator and outlet pipeline construction with fluid moving in it satisfactorily describes the parameters of the oscillatory process in various elements of the hydraulic system. However, the model requires some correction in the part of the description of the basic dependencies describing the dynamics of the cavitations flow in the generator, if it is necessary to more agreement with the experimental data. This model is convenient for carrying out multi-purpose research works, including experimental data correction, but its application for engineering calculations causes certain difficulties in the part of programming and the length of preparation for the calculations. The refined linear mathematical model of the generator makes it possible to obtain a quantitative agreement between the experimental and theoretical dependences of the amplitude of fluid pressure oscillations on the cavitations parameter by engineering methods. The practical significance of the results obtained is that the refined linear mathematical model of the generator makes it possible to establish at the design stage a rational regime of the hydroimpulse action of the generator (the peak-to-peakvalues of fluid pressure oscillations) at a certain pressure in the process pipeline of an industrial plant and does not require additional experimental studies

Diagnostics of metal samples using the results of experimental and theoretical study of positively charged microparticles formed upon sample destruction

2018 ◽  
Vol 84 (10) ◽  
pp. 23-28
Author(s):  
D. A. Golentsov ◽  
A. G. Gulin ◽  
Vladimir A. Likhter ◽  
K. E. Ulybyshev
Keyword(s):  
Experimental Data ◽  
Early Stage ◽  
Experimental Studies ◽  
Material Model ◽  
Total Charge ◽  
Cross Sectional ◽  
Practical Applications ◽  
Mechanical And Electrical Properties ◽  
Order Of Magnitude ◽  
Using Data

Destruction of bodies is accompanied by formation of both large and microscopic fragments. Numerous experiments on the rupture of different samples show that those fragments carry a positive electric charge. his phenomenon is of interest from the viewpoint of its potential application to contactless diagnostics of the early stage of destruction of the elements in various technical devices. However, the lack of understanding the nature of this phenomenon restricts the possibility of its practical applications. Experimental studies were carried out using an apparatus that allowed direct measurements of the total charge of the microparticles formed upon sample rupture and determination of their size and quantity. The results of rupture tests of duralumin and electrical steel showed that the size of microparticles is several tens of microns, the particle charge per particle is on the order of 10–14 C, and their amount can be estimated as the ratio of the cross-sectional area of the sample at the point of discontinuity to the square of the microparticle size. A model of charge formation on the microparticles is developed proceeding from the experimental data and current concept of the electron gas in metals. The model makes it possible to determine the charge of the microparticle using data on the particle size and mechanical and electrical properties of the material. Model estimates of the total charge of particles show order-of-magnitude agreement with the experimental data.

Воздействиеультразвуковогополянадинамическуювязкостьводы

2019 ◽  
pp. 27-29
Author(s):  
P. Vikulin ◽  
K. Khlopov ◽  
M. Cherkashin
Keyword(s):  
Dynamic Viscosity ◽  
Experimental Studies ◽  
Ultrasonic Field ◽  
Maximum Effect ◽  
Ultrasonic Frequency ◽  
Ultrasonic Vibrations ◽  
Wastewater Disposal ◽  
Laboratory Setup ◽  
Sonic Treatment ◽  
The Impact

Enhancing water purification processes is provided by various methods including physical ones, in particular, exposure to ultrasonic vibrations. The change in the dynamic viscosity of water affects the rate of deposition of particles in the aquatic environment which can be used in natural and wastewater treatment. At the Department Water Supply and Wastewater Disposal of the National Research Moscow State University of Civil Engineering experimental studies were conducted under laboratory conditions to study the effect of ultrasound on the change in the dynamic viscosity of water. A laboratory setup has been designed consisting of an ultrasonic frequency generator of the relative intensity, a transducer (concentrator) that transmits ultrasonic vibrations to the source water, and sonic treatment tanks. Experimental studies on the impact of the ultrasonic field in the cavitation mode on the dynamic viscosity of the aqueous medium were carried out the exposure time was obtained to achieve the maximum effect.Интенсификация процессов очистки воды осуществляется с помощью различных методов, в том числе и физических, в частности воздействием ультразвуковых колебаний. Изменение динамической вязкости воды влияет на скорость осаждения частиц в водной среде, что может быть использовано в процессах очистки природных и сточных вод. На кафедре Водоснабжение и водоотведение Национального исследовательского Московского государственного строительного университета в лабораторных условиях проведены экспериментальные исследования по изучению влияния ультразвука на изменение динамической вязкости воды. Разработана схема лабораторной установки, состоящая из генератора ультразвуковых частот с соответствующей интенсивностью, преобразователя (концентратора), передающего ультразвуковые колебания в исходную воду, и емкости для озвучивания. Выполнены экспериментальные исследования по влиянию ультразвукового поля в режиме кавитации на динамическую вязкость водной среды, получено время экспозиции для достижения максимального эффекта.

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