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1

A new model for predicting the axial compression capacity of reinforced concrete cylinders strengthened with CFRP

Guo Guang, Zhou Li, Wang Bangkang

Archives of Civil Engineering

|

2024

|

Vol. 70, nr 1

389--404

EN

Numerous scholars have identified the shortcomings of imprecise terminology and substantial computational inaccuracies in the current models for predicting the axial compression capacity of CFRPstrengthened reinforced concrete (RC) cylinders. To improve the prediction accuracy of the axial compressive capacity model for CFRP-strengthened RC cylinders, the present axial compressive capacity model for CFRP-strengthened RC cylinders was scrutinized and evaluated. Drawing on Mander’s constraint theory and the concrete triaxial strength model, a novel axial compressive capacity model for CFRP-strengthened RC cylinders was proposed. This study collected 116 experimental data on the axial compression of CFRP-strengthened RC cylinders and analyzed the accuracy of various models using the data. The findings indicate that the model proposed in this study outperforms other models in predicting axial compression capacity and demonstrates high prediction accuracy. Furthermore, an analysis is conducted on the variation law of the model’s predicted value with respect to the design parameters. The proposed model in this study identifies concrete strength, stirrup spacing, and elastic modulus of CFRP as the primary factors that influence the axial compression capacity of CFRP-strengthened RC cylinders.

2

Slow flow of couple stress fluid past a cylinder embedded in a porous medium: slip effect

Sarkar Priya, Madasu Krishna Prasad

Engineering Transactions

|

2023

|

Vol. 71, iss. 4

537--551

EN

An analytical study for the creeping flow of a couple stress fluid past a cylinder embedded in a porous medium is presented using the slip condition. The uniform flow is considered far away from a cylinder. The boundary conditions used are zero couple stress and tangential slip conditions. The modified Bessel functions represent the stream function (the velocity). The drag exerted on a solid cylinder immersed in a porous medium is derived. The impacts of the couple stress, permeability, and slip parameters on the normalized drag force are presented graphically. The drag forces of well-known exceptional cases are reduced. The drag force is a decreasing function of the permeability and couple stress parameters and an increasing function of the slip parameter.

3

An experimental study of forced vibration on natural convection between closed ended concentric and eccentric annular of horizontal cylinder

Khudhair Baydaa K., Saleh Adel M., Ekaid Ali L.

Diagnostyka

|

2023

|

Vol. 24, No. 2

art. no. 20230212

EN

An experimental study has been done into the effects of vertical mechanical vibrating, vertical eccentricity, and the Rayleigh number on natural convection heat transferring out of a horizontally enclosed, ending cylindrical annulus with a radius rate of 2.6 and an aspect ratio of (2:1). The annulus produced between two concentric and vertically eccentric circular cylinders is positioned horizontally, and its internal wall is uniformly heated while isothermally cooling the external wall. The range of present conditions for Rayleigh number is 5×10^4 ≤ Ra≤ 6.48×10^6, and Pr = 0.703, the frequency of vibration is 0 ≤ f ≤ 20Hz; and the amplitude is b mm), with possible exclusion of the highest positive and negative eccentricities. Plots of the average Nusselt number variation against the Rayleigh number showed a significant increase in negative vertical eccentricity. It was found that the average Nusselt decreased as the internal cylinder changed its location vertically from negative to positive through the center, which is normally a desirable effect, but has no advantage over the concentric on the positive side. The Rayleigh number was found to be relatively sensitive to eccentricity. However, an increase of Rayleigh number leads to a nearly proportional increase in the average Nusselt number and a smaller yet still substantial increase in positive eccentricity. This study concluded that the vibration under the current experimental setup significantly affects the concentric position of the internal cylinder, whether the effect is positive or negative. The vibrational average Nusselt number increased in varying proportions, depending on the location of the heated inner cylinder.

4

Research on the wear of novel sets of piston rings in a diesel locomotive engine

Kaźmierczak Andrzej R.

Combustion Engines

|

2023

|

R. 62, nr 4

56--62

EN

The paper describes the results of the wear test of innovative sets of piston rings intended, among others, to drive diesel locomotives operated in North America, including the USA. The main subject of research is an innovative set of piston rings, the first sealing ring containing a synthetic diamond embedded in a porous chrome coating. The developed multilayer coating is designed to reduce the wear of the piston rings and the combustion engine cylinder. This technology has been implemented at Piston Rings Manufactory "Prima" S.A. in Łódź. The tests were carried out using a two-stroke diesel engine of the EMD 645 type. This engine is manufactured by General Motors Corporation in the United States. The described research was carried out in the United States in San Antonio, Texas, at the Southwest Research Institute. The EMD 645 engine is widely used in power units of heavy diesel locomotives and inland waterway barges in the United States of America, India, and South Africa.

5

Osłony konwekcyjne maszyn z cylindrem Yankee – nowe rozwiązania

Reczulski Mariusz

Przegląd Papierniczy

|

2022

|

R. 78, nr 5

252--254

PL

Suszenie wstęgi papierniczej jest jedną z istotnych faz cyklu produkcyjnego papieru, ponieważ wpływa na jakość gotowego produktu i wydajność procesu. Ponadto sekcja susząca zużywa najwięcej energii cieplnej w maszynie papierniczej. Stosuje się wiele efektywnych sposobów obniżenia energochłonności procesu suszenia, m.in. poprzez jego intensyfikację, automatyzację oraz zmiany konstrukcyjne w maszynie. Wszystkie te czynniki determinują działania rozwojowe nowych rozwiązań energooszczędnych, ich instalacji w sekcji suszącej oraz wprowadzanie ulepszeń technicznych zwiększających wydajność maszyn papierniczych. Najczęściej w szybkobieżnych maszynach do produkcji bibułek higienicznych wykorzystuje się sekcję suszącą składającą się z osłony konwekcyjnej i cylindra Yankee. Osłona konwekcyjna posiada zwykle dwie części – „mokrą” i „suchą”. Każda część osłony zbudowana jest m.in. z komór rozprowadzających gorące powietrze, paneli nadmuchowych, komór wyciągowych/wylotowych, izolacji, zewnętrznej obudowy itp. Zazwyczaj w przemyśle stosuje się dwa rodzaje osłon wysokowydajnych – z urządzeniem grzewczym gazowym lub parowym.

6

Influence of hydraulic oil viscosity on the energy efficiency of hydrostatic drive

Skorek Grzegorz

Journal of KONBiN

|

2022

|

Vol. 52, iss. 1

11--30

EN

The article presents the influence of oil viscosity on the overall efficiency of the compared systems with proportional cylinder control. There are energy losses in the elements of the hydraulic system, which are, among other things, a function of the viscosity of the working fluid used, as well as energy losses which are practically independent of the viscosity. In order to assess the possibilities of saving energy during the operation of the hydrostatic drive system, it is necessary to understand and describe the losses occurring in the system. Determining the energy efficiency of the system can be performed simulation with the help of a computer program using an appropriate mathematical model. The efficiency determined in this way can be used in the process of designing and operating the system.

PL

W artykule przedstawiono wpływ lepkości oleju na sprawność całkowitą porównywanych układów ze sterowaniem proporcjonalnym siłownika. W elementach układu hydraulicznego występują straty energii będące m.in. funkcją lepkości zastosowanego płynu roboczego oraz straty energii praktycznie niezależne od lepkości. W celu oceny możliwości oszczędzania energii podczas pracy hydrostatycznego układu napędowego konieczne jest zrozumienie i opisanie strat występujących w układzie. Wyznaczenie sprawności energetycznej systemu można przeprowadzić symulacją za pomocą programu komputerowego z wykorzystaniem odpowiedniego modelu matematycznego. Tak wyznaczona sprawność może być wykorzystana w procesie projektowania i eksploatacji systemu.

7

Stress-strain state simulation of non-uniformly heated elements of components and assemblies of automotive

Hrevtsev O., Selivanova N., Popovych P., Poberezhny L., Brych V. Ya., Rudyak Yu., Shevchuk O., Bakulina N., Rozum R., Buriak M.

Journal of Achievements in Materials and Manufacturing Engineering

|

2022

|

Vol. 115, nr 1

26--32

EN

Purpose: Develop a method for determining and evaluating the stress-strain state, particularly the distribution of thermomechanical stresses in the materials of individual rotating parts of vehicles. Design/methodology/approach: The proposed method is based on the principle of gradual approximations of the solution when the boundary conditions are satisfied on the curvilinear limiting surfaces of the disk body. Findings: The proposed method of determining and estimating the distribution of thermomechanical stresses in the disk material makes it possible to take into account the variable geometry: thickness and presence of a hole in the central part of the disk, also correctly determine stress-strain state at any point of unevenly heated rotating axial body. Research limitations/implications: The work uses generally accepted assumptions and limitations for thermomechanical calculations. Originality/value: It is proved that in real disks, the stress-strain state is spatial, and the well - known method based on the hypotheses of the plane-stress state does not provide the possibility of calculating the values of stresses in the thickness of the disk. The obtained results can be used to improve the methodology of auto technical examination of road accidents. In addition, they can be taken into account by bus drivers on urban routes when choosing a safe distance in heavy traffic, as well as design engineers of car brake systems.

8

Influence of form defect on the mechanical behavior and stress intensity factor of shrink-fitted thick-walled cylinders

Boutoutaou Hamid, Chebbab Brahim, Belmessous Abdelmounaime

International Journal of Applied Mechanics and Engineering

|

2022

|

Vol. 27, no. 4

40--51

EN

In this research work, the finite element software, ABAQUS is used to study by simulations the influence of form defect on mechanical behavior of a shrink-fitted assembly presenting internal radial cracks. Under the action of contact pressure induced by the tightening between two cylinders, these cracks resulting from incorrect assembly operations or materials elaboration defect, can be harmful to the assembly. Various simulations were carried out in two modeling cases, taking into account the geometric parameters of defect (amplitude Df), of cylinders (thickness t) and of cracks (length a, ratio a/t). Another important parameter such as the tightening was also considered in the modeling. The first modeling relates to the case with defect, external cylinder presents an oval (elliptical) form defect and internal radial cracks. The other concerns the perfect equivalent case (without form defect). The comparison of results obtained by two models shows that form defect modifies the uniformity of equivalent stresses distribution in cylinders and increases the value of stress intensity factor (SIF) KI in cracks. Defect amplitude and tightening significantly influence the value of equivalent stress and that of stress intensity factor (SIF) KI.

9

Wpływ popiołu lotnego i popiołu z wytłoczyn z trzciny cukrowej na właściwości mechaniczne betonu lekkiego

Gunasekaran M., Palanisamy T.

Cement Wapno Beton

|

2022

|

R. 27, nr 2

72--101

PL

Beton lekki jest ważną częścią technologii betonu. Zastosowanie dodatków mineralnych zastępujących kruszywa drobne, takich jak popiół lotny i popiół z wytłoczyny z trzciny cukrowej, pozwala na zmniejszenie zawartości cementu. Prezentowane badania miały na celu uzyskanie lekkiego betonu dzięki dodatkowi popiołu lotnego i popiołu z wytłoczyn z trzciny cukrowej, jako drobnego kruszywa. Wytrzymałość na ściskanie kostek, i walców oraz wytrzymałość na rozciąganie przy rozłupywaniu były badane po różnych okresach, aby znaleźć optymalny poziom wspomnianych dodatków mineralnych w betonie. Porównano wytrzymałość i ustalono optymalny dodatek popiołu lotnego i popiołu z wytłoczyn z trzciny cukrowej. Wytrzymałość na ściskanie walca i wytrzymałość na rozciąganie przy rozłupywaniu betonu lekkiego, uzyskano przy tych samych poziomach zastąpienia dodatków mineralnych po 28 dniach. Zaproponowano równania matematyczne pozwalające na obliczenie wytrzymałości na ściskanie i rozciąganie kostki oraz walca oraz te same właściwości, w zakresie typowej wytrzymałości.

EN

Light weight concrete is an important part in the concrete technology. The use of mineral additives in light-weight concrete, to replace fine aggregate with fly ash and bagasse ash, helps to reduce the cement content. The present investigation aims to meet the performance of light weight concrete, by adding fly ash and bagasse ash, as fine aggregate replacement additives. The strength properties such as cube compressive strength, cylinder compressive strength and split tensile strength were investigated after different ages, to find the optimum addition of mineral additives such as fly ash and bagasse ash, in concrete. The strengths were compared and the optimal replacement level of cement with fly ash and bagasse ash was found. The cylinder compressive strength and split tensile strength of light weight concrete were measured, at the same replacement levels of mineral additives, at the age of 28 days curing. The mathematical equations were proposed to achieve cube compressive and tensile strengths, cylinder compressive and tensile strength and cube compressive and cylinder compressive strengths, concerning typical strength.

10

Design Sensitivity Studies on a Hydroacoustic Projector Using an Experimentally Validated Easy-to-Build Model

Sreejith Vattaparambil Sreedharan, Tiwari Nachiketa

Archives of Acoustics

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2022

|

Vol. 47, No. 1

113--124

EN

Hydroacoustic projectors are useful for generating low frequency sounds in water. Existing works on hydroacoustic projectors require two significant enhancements, especially for designers. First, we need to understand the influence of important projector design parameters on its performance. Such insights can be very useful in developing a compact and efficient projector. Second, there is a need for an integrated model of the projector based on easily available and user-friendly numerical tools which do not require development of complex customised mathematical analogs of projector components. The present work addresses both such needs. Towards these goals, an experimentally validated, easy-to-build projector model was developed and used to conduct design sensitivity studies. We show that reductions in pipe compliance and air content in oil, and an increase in orifice discharge coefficient can yield remarkable improvements in projector’s SPL. We also show that reductions in pipe length and cylinder diameter cause moderate improvements in performance in mass and stiffness controlled regions, respectively. In contrast, the projector performance is insensitive to changes in pistonic mass, cylinder length, and diaphragm stiffness. Finally, we report that while pipe compliance and air content in oil can sharply alter system resonance, the effects of changes in pipe length and pistonic mass on it are moderate in nature.

11

Thermal stresses due to non-uniform internal heat generation in functionally graded hollow cylinder

Rani P., Singh K., Muwal R.

International Journal of Applied Mechanics and Engineering

|

2021

|

Vol. 26, no. 2

186--200

EN

Thermal stresses of a functionally graded hollow thick cylinder due to non-uniform internal heat generation are studied in this paper. Analytical solutions are obtained with radially varying properties by using the theory of elasticity. Thermal stresses distribution for different values of the powers of the module of elasticity and varying power law index of heat generation are studied. The results have been computed numerically and illustrated graphically.

12

Effects of pressure work over a semi-infinite vertical oscillating cylinder

Sarojini A., Palani G.

International Journal of Applied Mechanics and Engineering

|

2021

|

Vol. 26, no. 1

215--225

EN

An arithmetical methodology is used to study natural convection with properties of pressure work over a semi-infinite vertical oscillating cylinder. The governing partial differential equations are set up and the resulting equations are changed into a non-dimensional form using the proper non-dimensional quantities. The set of non-dimensional partial differential equations is solved arithmetically using a well-organized method known as the Crank-Nicolson method. The velocity, as well as temperature profiles for different values of parameters are studied with the assistance of graphs.

13

Analysis of hydraulic system for adjustable ground clearance mechanism

Chada Jithendra Sai Raja, Sandeep Venkat G., Chollangi Rajesh

Journal of Mechanical and Energy Engineering

|

2020

|

Vol. 4, No 3

203--208

EN

The stability of a vehicle depends on many parameters. The Centre of Gravity is one of the most important in them. If the height of center of gravity from the ground decreases the stability of the vehicle increases. But when the ground clearance is too low it has a chance of collision vehicle and the ground while going on an uneven road or with speed brakes. So, to avoid the collision of a vehicle to ground and increase the stability a mechanism to adjust the ground clearance is to be attached. Also, the lift and drag forces can also be altered using this adjustable ground clearance mechanism. The designers usually fix ground clearance and they try to acquire this by the suspension system. The suspension system has tires, tire air, springs, shock absorber, and other parts to connect the vehicle with the wheels. The present paper describes the significance of using hydraulic oil as a working fluid in an adjustable ground clearance mechanism. Also describes the design and analysis of piston and cylinder rod.

14

The numerical calculation module for piston rings & cylinder and research with analysis of the results of the internal combustion engine locomotive during the 85-hour endurance test

Kaźmierczak Andrzej, Borkowska Joanna, Tkaczyk Marcin

Pojazdy Szynowe

|

2019

|

Nr 3

24--34

EN

The piston with piston rings and bearing surface is a self-contained and highly complex tribological system. One of the most widespread global friction pairs traversed by reciprocating a pair of piston rings - cylinder internal combustion engine. Group PRC combustion engine is the solution generating considerable friction. Various researchers estimate the share of friction losses, per node piston rings - cylinder liner, at 19 to 60% of the total friction losses in the combustion engine. This paper describes part of a larger program to reduce wear the set working parts (piston, piston ring and bearing surface). The project is implemented through the development of new designs of piston rings with anti-wear coating that contains synthetic diamond in the form of loose embedded in a coating of chromium (PRC). The aim of the author was to present the methodology used to compute characterized by a particular procedure. In practical use FEM software is used and the FVM. Developed and implemented Piston Rings Calculation Module is compatible with the idea of numerical computational methods is to say: functionally consists in carrying out a calculation of the desire to achieve the exact solution (the nearest is real) by conducting and receiving intermediate solutions (the next).

PL

Tłok wraz z pierścieniami oraz powierzchnią cylindra jest bardzo złożonym zamkniętym systemem trybologicznym. Pierścienie tłoka – cylinder jest jedną z najbardziej globalnie rozpowszechnionych par tarcia silników spalinowych. Para tarcia TPC jest rozwiązaniem wytwarzającym znaczące tarcie w silnikach spalinowych. Różne źródła naukowe określają straty na jeden węzeł spowodowane tarciem pary pierścień-ściana cylindra jako 19 do 60% wartości wszystkich strat tarcia w silniku spalinowym. W tym artykule omówiono część większego programu badawczego mającego na celu zmniejszenie zużycia pracujących elementów (tłok, pierścienie tłoka, powierzchnia cylindra). Projekt ten jest wdrażany w ramach rozwoju nowych konstrukcji pierścieni tłokowych z powłoką zapobiegającą zużyciu, zawierającą syntetyczny diament luźno zatopiony w powłoce chromu (TPC). Celem Autorów było przedstawienie metodologii stosowanej do obliczeń charakteryzującej się określoną procedurą. W praktyce wykorzystuje się oprogramowanie MES oraz MOS. Opracowany i wdrożony moduł obliczeniowy pierścieni tłokowych jest zgodny z ideą numerycznych metod obliczeniowych, to znaczy: funkcjonalnie polega na przeprowadzeniu obliczenia zamiaru uzyskania dokładnego wyniku (najbardziej zbliżonego rzeczywistości) poprzez uzyskanie i wykorzystanie wartości pośrednich.

15

Collapse of the single layered cylinder shell with model experimental study

Nie Gui-bo, Zhang Chen-xiao, Zhi Xu-dong, Dai Jun-wu

Archives of Civil and Mechanical Engineering

|

2019

|

Vol. 19, no. 3

883--897

EN

With the rapid development of the large-span space structure, it has been widely used in the public buildings such as gymnasiums, exhibition hall, airplane terminal, etc. in China recently. The large-span latticed shell buildings are usually the landmark buildings in a city, so its collapse will cause serious economic and personal loss, which will affect national security and social stability. The shaking table test was conducted on the single layered cylinder shell model in this paper, and the dynamic amplification effects of the lower support frame and the dynamic responses of the whole model were obtained under different seismic motion inputs. The seismic performance of the single layered cylinder shell was evaluated under different ground motion inputs and input principal directions, and the collapse mode was obtained. The results show that the input principal direction has great effect on the dynamic characteristics of the model, and the dynamic amplification effect of the lower support frame increases with the magnitude increase of the ground motion inputs. There is no obvious impact effect and the dynamic strain responses behave elastic during the collapse process, and the whole shell collapse because of local instability. It concludes that the single layered cylinder shell has the risk of progressive collapse under the seismic motions, so the collapse resistance of single layered cylinder shell should be enhanced or it should be optimum designed to prevent the progressive collapse. This experimental study will provide references to the seismic design and engineering practices.

16

Study of losses and energy efficiency of hydrostatic drives with hydraulic cylinder

Skorek G.

Polish Maritime Research

|

2018

|

nr 4

114--129

EN

Energy efficiency of hydrostatic transmissions, and especially efficiencies of drives with motor speed controlled by throttle, as well as efficiency of hydraulic servomechanisms can in fact be higher than the efficiency values most frequently given by the respective literature in this field. With the progress achieved in recent years in the development of hydraulic systems it is becoming necessary to develop methods for precise energy efficiency calculation of such systems. It is difficult to imagine that more and more, better and better machines and control elements could be used without the possibility of a mathematical tool at our disposal to enable an accurate analysis and assessment of behavior of the system in which such machines and control elements have been applied. The paper discusses energy savings using mathematical model of losses in elements, the energy efficiency of the system. There are possibilities to reduce energy losses in proportional control systems (in the pump, in the throttle control unit, especially in the cylinder), and thus to improve the energy efficiency of the throttling manifold. The considerations allow for comparison of the loss power resulting from the applied hydraulic control structure of the hydraulic cylinder and the power consumed by the pump from the electric motor that drives it, the power necessary to provide pump-driven hydraulic cylinder. The article shows the impact on the output (useful) power consumed in the considered systems, and the impact on the power consumed of the loss power in the individual elements. The paper presents also formulas of loss power, formulas of energy efficiency connected with investigated hydrostatic drives, two schematic diagrams of hydraulic systems, their principle of operation and problems of studying losses in elements and energy efficiency characteristics of systems consisting of a feed assembly, control set and cylinder. It also includes a subject matter connected with an energy loss power of hydrostatic systems with hydraulic cylinder controlled by proportional directional control valve. Diagrams of loss power of two hydraulic systems worked at the same parameters of speed and load of a cylinder, which were different due to structure and ability of energy saving, were presented and compared.

17

Makroskopowy model gładzenia cylindrów silników spalinowych jako narzędzie optymalizujące wysokość osełek gładzarskich w technologii napraw

Michalski J., Domański J.

Autobusy : technika, eksploatacja, systemy transportowe

|

2018

|

R. 19, nr 6

600--608, CD

PL

W artykule przedstawiono założenia makroskopowego modelu matematycznego gładzenia uwzględniające zarówno kinematykę narzędzia jak również charakterystyczny dla tego procesu rozkład nacisków jednostkowych występujących w oddziaływaniu osełek gładzących na powierzchnię obrabianego cylindra. Na bazie opisanych złożeń został opracowany działający i przetestowany program komputerowy, który w sposób numeryczny modeluje ten proces technologiczny. W pamięci komputera są tworzone cyfrowe mapy jakościowe dotyczące powierzchni zarówno cylindra i osełek gładzących. Mapy te można oceniać analitycznie jak również poddać wizualizacji. W artykule zamieszczono wyniki obliczeń optymalizujących wysokość osełek gładzarskich dla procesu gładzenia konkretnej tulei cylindrowej wraz z analizą otrzymanych wyników. Opisany program komputerowy umożliwia oszczędność czasu oraz środków finansowych w czasie dedykowanych badań optymalizujących parametry tego procesu.

EN

The paper presents the assumptions of the macroscopic mathematical model of honing, taking into account both the kinematics of the tool and the characteristic for this process the distribution of unit pressures occurring in the interaction of sharpening stones on the surface of the honing stones on the surface of the workpiece are characteristic for this process. On the basis of these assemblies an active and tested computer program has been developed, which numerically model this technological process. In the computer memory are created digital quality maps of the surface of the machined cylinder. On the basis of the described assemblies, a working and tested computer program has been developed that numerically models this technological process. Digital quality maps are created in the computer's memory regarding the surface of both the cylinder and the smoothing stones. These maps can be assessed analytically as well as subjected to visualization. The article presents the results of calculations that optimize the height of smooth ground for the process of honing a specific cylinder liner with the analysis of the results obtained. The described computer program saves time and funds during dedicated research that optimizes the parameters of this process.

18

Characteristics of loss power in compared hydraulic systems

Skorek G.

Journal of KONES

|

2017

|

Vol. 24, No. 2

217--223

EN

In this article, two hydrostatic systems with a throttling steering fed by a constant capacity pump were compared. It also includes a subject matter connected with an energy loss power of hydrostatic systems with hydraulic cylinder controlled by proportional directional control valve. Diagrams of loss power of two hydraulic systems worked at the same parameters of a speed and a load of hydraulic cylinder, which were different due to structure and ability of an energy saving, were presented and were compared. There are possibilities to reduce energy losses in proportional control systems (in the pump, in the throttle control unit, especially in the cylinder), and thus to improve the energy efficiency of the throttling manifold. The considerations allow for comparison of the loss power resulting from the applied hydraulic control structure of the hydraulic cylinder and the power consumed by the pump from the electric motor that drives it, the power necessary to provide the required unchanged usable pump-driven hydraulic cylinder. Presents the impact on the output (useful) power of the power consumed in the considered systems, and the impact on the power consumed of the loss power in the individual elements. Instantaneous useful power of the cylinder, which is determined by the product of force and speed of the cylinder rod, is independent of all losses. There are mechanical loss power occurs in the cylinder, the loss power in the conduits, the structural volume and pressure loss power that are associated with the throttling control and loss power in the pump: pressure, volumetric and mechanical which have to be added to the useful power. As a result, the sum of the effective useful power and the loss power of all system is the instantaneous value of the power consumed by the pump from the electric motor that drives it.

19

Оптимизация формы поперечного сечения штока гидроцилиндра

Kobzov D. U., Eresko S. P., Rajczyk J., Zenkov S. A.

Zeszyty Naukowe Politechniki Częstochowskiej. Budownictwo

|

2016

|

Z. 22 (172)

135-141

RU

В статье предложены формулы моделирования и оптимизации форм поперечного сечения штока гидроцилиндра. Их применение позволит существенно увеличить единичные мощности не только машин с гидроцилиндрами двухстороннего действия с односторонним штоком, но других технических объектов (ободья, маховики, брусья, прокладки и др.).

EN

The article suggests formulas modeling and optimization of cross-sectional shapes of the hydraulic cylinder rod. Their use will significantly increase the capacity of the unit is not only machines with double-acting hydraulic cylinders with single-rod, but other technical facilities (rims, flywheels, boards, pads, etc.).

20

Research and analysis of the results of the internal combustion engine locomotive during the 85-hour endurance test

Borkowska J., Kaźmierczak A.

Journal of KONES

|

2016

|

Vol. 23, No. 2

53--59

EN

Piston – ring – cylinder assembly of combustion engine has many friction pairs examples, also one of them which decide about fastness to wear, it means first sealing ring – cylinder, called further very simply ring – cylinder unit. During work of this unit, we can observe wear of piston, precisely – of coating which is deposited on ring to prolong service life. Objective of this work was to realize a test of set durability of railway engine EMD645 with power about 1300 kW. Within the framework of this test were investigated a prototyped piston’s rings with diamond embankment. Piston rings are made of diamond coating technology with a porous chromium coating, where in pores is deposited on said diamond powder with a grain size about 1 micron. The work will be carried out of an analysis of collaboration piston – rings – cylinder unit in internal combustion engine and an analysis of the use of hard materials in friction pairs, including powders. Will be performed research of material and description of diamond powder, which will be applied to the piston rings. After stability, testing in the locomotive engine EMD645 on the basis of the collected results will be developed conclusions of the wearing intensity on piston ring and relating them to the requirements for coatings. The work aims to show the possibilities and benefits of the application of new protective coatings on structural elements of the internal combustion engine in order to reduce their wearing, which is consistent with the observed trend of technology development.