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1

Montaż generatorów 1,25 MW, 0,4 kV w Ciechanowie oraz 2,3 MW, 15 kV w Bodaczowie wraz z systemem zabezpieczeń polskiego producenta

Horňáček Radek, Pospíšil Jaroslav, Krzęcio Michał

Wiadomości Elektrotechniczne

|

2024

|

R. 92, nr 3

30--36

PL

Przedmiotem artykułu są zagadnienia związane z uruchomieniem generatora o mocy 1,25 MW, 0,4 kV w Elektrowni Ciechanów oraz generatora o mocy 2,3 MW, 15 kV w Elektrowni Bodaczów. Omówiono projekt systemu zabezpieczeń generatora w Elektrowni Ciechanów, ich wykonanie i uruchomienie, zgodnie z Polskim Kodeksem RfG. W artykule przedstawiono projekt obwodów generatora w zakresie: obwodów pierwotnych i wtórnych, zabezpieczeń, elementów pomiarowych oraz wyłącznika generatora.

EN

The subject of the paper are issues related to starting a generator with a capacity of 1.25 MW, 0.4 kV in the Ciechanów Power Plant and a generator with a capacity of 2.3 MW, 15 kV in the Bodaczów Power Plant. The design of the generator protection system at the Ciechanów Power Plant, their implementation and commissioning, in accordance with the Polish RfG Code, were discussed. The paper presents the design of generator circuits in terms of: primary and secondary circuits, protections, measuring elements and generator switch.

2

Extended Identification-Based Predictive Control for adaptive impact mitigation

Graczykowski Cezary, Faraj Rami

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2023

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Vol. 71, nr 4

art. no. e145937

EN

The paper introduces Extended Identification-Based Predictive Control (EIPC), which is a novel control method developed for the problem of adaptive impact mitigation. The model-based approach utilizing the paradigm of Model Predictive Control is combined with sequential identification of selected system parameters and process disturbances. The elaborated method is implemented in the shock-absorber control system and tested under impact loading conditions. The presented numerical study proves the successful and efficient adaptation of the absorber to unknown excitation conditions as well as to unknown force and leakage disturbances appearing during the process. The EIPC is used for both semi-active and active control of the impact mitigation process, which are compared in detail. In addition, the influence of selected control parameters and disturbance identification on the efficiency of the impact absorption process is assessed. As a result, it can be concluded that an efficient and robust control method was developed and successfully applied to the problem of adaptive impact mitigation.

3

A Quick-and-Dirty Method for assessing the Risk of Negative Aeration Effects of Shock Absorbers equipped with Shim Sliding Base Valves

Czop Piotr, Gniłka Jacek

Computer Assisted Methods in Engineering and Science

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2022

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Vol. 29, no. 3

229--260

EN

This paper presents a quick-and-dirty method to assess the risk of negative aeration effects occurring in twin-tube hydraulic shock absorbers used in passenger cars at the early design stage. The method is intended to be implemented as an engineering calculation tool based on the computational fluid dynamics (CFD) two-dimensional (2D)/three-dimensional (3D) steady-state single-phase model. The CFD model was previously validated with the use of the particle image velocimetry (PIV) experiment. The negative aeration effect is a wellknown issue for automotive and railway shock absorbers manufacturers. It results in uncontrolled on-vehicle vibrations and the deteriorated shock absorber damping characteristic. The major aeration contributor in twin-tube hydraulic shock absorbers is the sliding shim intake valve, which requires design optimization to avoid a negative aeration effect. The method validation was conducted with the customized test rig equipped with a transparent cylinder where the specific sliding intake valve was assembled. The proposed method also requires a lumped-parameter model of a twin-tube shock absorber, which allows to simulate boundary conditions in assessing particular reservoirs of a shock absorber, i.e., pressures and flow balance. The method is implemented as a calculation routine that converts CFD pressure regions into a gas concentration indicator (GCI) using the pressure-density characteristic of an oil-gas emulsion of a shock absorber. GCI is calculated based on the sum of particular 2D/3D grid elements. The method application is to minimize the risk of occurrence of negative aeration effects by avoiding expensive and time-consuming experimental tests. This method can also be used for in-production shock absorbers projects as a part of a continuous improvement cycle or in the case of inefficient shock absorbers claimed by a vehicle manufacturer. The application scope of the method can be extended for arbitrary twin-tube designs of shock absorbers in the automotive and railway industries.

4

The influence of shock absorber characteristics’ nonlinearities on suspension Frequency Response Function estimation and possibilities of simplified characteristics modelling

Ślaski Grzegorz, Klockiewicz Zbyszko

Archiwum Motoryzacji

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2022

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Vol. 96, nr 2

77--95

EN

The paper shortly presents shock absorber design evolution and resulting achieved characteristics. The way in which suspension performance is evaluated is described giving information about models used for suspension parameter tuning during simulation testing of suspension transmissibility (FRF - Frequency Response Function) for most important suspension assessment criteria. More detailed information about models of shock absorber (damper) nonlinearities of characteristics allows for description of methods of linear and nonlinear suspension models FRF estimation. Testing linear suspension model is possible with the use of analytical transfer function formulas which were used to verify methods for estimation FRF using estimated power spectral density functions of excitation and response signals. Designing appropriate input signal allowing to get useful response signals was necessary to for the success of this research. Proposed FRF estimation method was used for linear estimation of nonlinear suspension for a given range of working condition. It was demonstrated that there is no single value of a damping coefficient which would make the linear model responses similar to the responses of the nonlinear one. Then the bilinear model was proposed, giving good damper static nonlinear characteristic.

5

Modelling the shock absorber piston valve using 2-way fluid-structure interaction

Buczkowski Daniel, Nowak Grzegorz

Transport Problems

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2021

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T. 16, z. 4

45--57

EN

The aim of this study is to examine the strongly coupled Fluid-Structure Interaction approach as a comprehensive method of predicting the performance of the shock absorber piston valve. For this purpose, numerical simulation sand experimental testing are carried out. The coupled CFD-FEA numerical model described in this article, contrary to the attempts made so far, takes into account the influence of contact between valve discs and the initial conditions of the disc stack preload. The model is based on the actual valve geometry used in the shock absorber design. As a result, the described approach is intended for use in industrial applications in development works, in particular, at the conceptual stage. To prove the reliability of the model, two valve compositions are chosen to be measured on a test bench and modelled in FSI simulations. For both of them, a satisfactory level of correlation is achieved, with the correlation error below 10% and well-predicted valve opening points. As a result, it is proved that the 2-way FSI approach has great potential to be successfully used to investigate the damper valve operation.

6

Effect of fail-safe mode on the damping characteristics of a bypass-controlled shock absorber

Konieczny Łukasz

Transport Problems

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2020

|

T. 15, z. 3

43--52

EN

The article provides and discusses results of tests of a bypass-controlled hydraulic shock absorber studied at a test stand (mechanical inductor), making it possible to plot work charts and determine velocity characteristics. Measurements of the shock absorber performance were conducted at different values of velocity and forced travel. The measurements were carried out for two statuses, i.e. for the emergency power failure condition and for normal setting. The results thus obtained can be used in simulation tests as input shock absorption characteristics for different technical conditions.

7

Influence of the Size and Distribution of Load on the Damping Coefficient of Shock Absorbers in Passenger Vehicles

Gonera Jarosław

Advances in Science and Technology. Research Journal

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2020

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Vol. 14, no 4

185--194

EN

This paper analyses the changes in the values of the damping coefficient of shock absorbers, depending on the size and distribution of loads in passenger vehicles. The tests were conducted in two stages. During the first stage, the influence of the size of a load in vehicles, and changes in the tyre pressure values on the damping coefficient of shock absorbers was defined. During the second stage, the influence of the changes of the damping coefficient of shock absorbers was researched, depending on the size and distribution of load in passenger vehicles with various suspension systems of front and rear axles, different kerb weights, lengths and wheel bases. Eight variants of load distribution in vehicles were tested. The evaluation of the damping coefficient of shock absorbers was conducted with the EUSAMA method. This paper identified the sizes and distribution of loads in the vehicles of varied structural parameters and tyre pressures on the damping coefficient values of shock absorbers. The test results indicate that when using a vehicle under varied load conditions, there are changes in the damping coefficient of shock absorbers. This may translate directly into the traction characteristics and stability of a vehicle while travelling, and this, in turn, is connected with the vehicle safety. This paper shows the considerable influence of the tyre pressure on the EUSAMA coefficient. The changes in the vehicle loads also influenced the values of the damping coefficient of shock absorbers. The changes in the damping coefficient of shock absorbers were also influenced by the size and distribution of loads in vehicles.

8

Evaluation of concrete barriers with novel shock absorbers subjected to impact loading

Kim WooSeok, Lee Ilkeun, Kim Kyeongjin, Jeong Yoseok, Lee Jaeha

Archives of Civil and Mechanical Engineering

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2019

|

Vol. 19, no. 3

657--671

EN

Vehicle speeds have increased due to improved road condition. However, this increased speed can result in high energy collisions. Recently, a vehicle occupant in South Korea was killed by a fragment ejected from a concrete median barrier that was struck by a vehicle. The current design impact level of a concrete median barrier (CMB) is SB5-B (270 kJ). However, the impact level of the mentioned accident was estimated as over SB7 (2300 kJ). In the present work, a series of numerical analyses was conducted to reduce the fragmentations of CMB due to impact. Field test were utilized to verify the newly developed model of CMB in impact events. The wire-mesh reinforcements and increment of the cross section were considered as design modifications. In particular, a special device to absorb a significant collision energy has been developed without a dramatic increase in construction cost. This device consists of an empty space around the dowel bars which fix the barrier to the foundation. The empty space allows the dowel bars to deform to absorb collision energy. The performance of the new concrete median barrier equipped with the shock absorbing devices was verified by using carefully designed field test data.

9

Braking efficiency determined using an accelerometer in the aspect of technical condition of shock absorber

Konieczny Ł., Burdzik R., Warczek J.

Transport Problems

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2018

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T. 13, z. 2

81--90

EN

This article presents results of tests of the effect exerted by technical condition of shock absorbers on the braking efficiency of an automotive vehicle. The tests were conducted using Fiat Seicento featuring front shock absorbers which enabled shock-absorbing fluid-level adjustment. The tests comprised measurements conducted on the shock absorbers in four states, i.e. the nominal state with the fluid level at 100%, with shock-absorbing fluid levels of 25%, 50% and 75% as well as with the fluid tank completely empty (0%). Road tests of braking efficiency were conducted on cobbled pavement by means of a decelerometer.

10

Wykorzystanie ciągłej transformaty falkowej w diagnostyce stanu technicznego amortyzatora zabudowanego w pojeździe samochodowym

Konieczny Ł., Burdzik R.

Prace Naukowe Politechniki Warszawskiej. Transport

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2018

|

z. 121

171--179

PL

Diagnozowanie stanu technicznego amortyzatorów zabudowanych w zawierzeniach samochodowych jest zagadnieniem trudnym ze względu na to, iż stanowią one elementy złożonego układu mechanicznego zawierającego elementy sprężyste i tłumiące o nieliniowych charakterystykach, które w czasie eksploatacji ulegają degradacji. W referacie przedstawiono wynik badań samochodu z amortyzatorami z zaprogramowanymi usterkami na stanowisku harmonicznym. Obiektem badań był samochód osobowy marki Fiat Seicento. Eksperyment badawczy polegał na pobudzeniu pojazdu do drgań wymuszonych mas nieresorowanych i resorowanych i rejestracji przyśpieszeń drgań tych mas. Badaniom poddano amortyzatory o zaprogramowanych usterkach w postaci ubytku płynu amortyzatorowego od 100% do 35% dla amortyzatorów przednich. Przyspieszenie płyt, wahacza (mas nieresorowanych) i nadwozia (mas resorowanych) rejestrowano za pomocą czujników przyspieszenia. Uzyskane w ten sposób wyniki badań poddano analizie falkowej z wykorzystaniem falki Morleta w środowisku MatLab i w oparciu o te przekształcenia wyznaczono wartości maksymalne amplitud drgań w zależności od stopnia ubytku płynu amortyzatorowego.

EN

Diagnosing the technical condition of shock absorbers installed in automotive suspensions is a difficult issue due to the fact that they are elements of a complex mechanical system containing elastic and damping elements with nonlinear characteristics that degrade during operation. The paper presents the result of testing car with shock absorbers with programmed faults on the harmonic stand. The test object was a Fiat Seicento passenger car. The research experiment consisted in stimulating the vehicle to vibrations of forced masses, unsprung and sprung, and registration of vibration accelerations of these masses. The tests were subjected to shock absorbers with programmed faults in the form of loss of shock absorber fluid from 100% to 35% for rear shock absorbers. The acceleration of plates, swingarm (unsprung masses) and bodywork (sprung masses) were recorded by acceleration sensors. The results obtained in this way were subjected to wavelet analysis using the Morlet wavelet in the MatLab environment and based on these transformations the maximum of vibration amplitudes were determined depending on the degree of loss of the shock absorber fluid.

11

Wpływ wybranych parametrów eksploatacyjnych na ocenę stanu technicznego amortyzatorów na stanowisku EUSAMA

Konieczny Ł., Niedziela Z., Łukowski J., Stańczyk M.

Prace Naukowe Politechniki Warszawskiej. Transport

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2018

|

z. 123

55--61

PL

W artykule przedstawiono wyniki badan stanu technicznego amortyzatorów na stanowisku z harmonicznym wymuszeniem kinematycznym typu Eusama stosowanym na stacjach kontroli pojazdów. Jako parametr eksploatacyjny przyjęto ciśnienie w ogumieniu (założono obniżoną wartość w stosunku do zalecanej wartości nominalnej) oraz określono wpływ tego parametru na wartości uzyskane podczas testów na stanowisku badawczym. Pomiary powtarzano kilkukrotnie zadanych parametrów. Wyniki pomiarów zestawiono tabelarycznie i w formie wykresu i na ich podstawie sformułowano wnioski końcowe.

EN

The article presents the results of the technical state of shock absorbers on the stand with harmonic Eusam type kinematic forcing applied at vehicle inspection stations. As operating parameter, the pressure in the tires was assumed (assumed a reduced value in relation to the recommended nominal value) and the impact of this parameter on the values obtained during testing on the test bench was determined. The measurements were carried out several times. The results are summarized in tabular form and in the form of a graph and based on them final conclusions were formulated.

12

Nonlinear modeling and analysis of a shock absorber with a bypass

Ferdek U., Łuczko J.

Journal of Theoretical and Applied Mechanics

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2018

|

Vol. 56 nr 3

615—629

EN

The model of a mono-tube shock absorber with a bypass is proposed in this paper. It is shown that the application of an additional ﬂow passage (bypass) causes changes to the damping force characteristics when the excitation amplitudes are large. In such cases, the damping force values increase, thereby improving safety of the ride. For small excitation amplitudes, the shock absorber behaves in a similar fashion as shock absorbers without a bypass, ensuring a high comfort level of the ride on roads with smooth surfaces.

13

Badanie skuteczności działania amortyzatorów w świetle obowiązujących przepisów prawnych w Polsce i na Słowacji

Gorzelańczyk P., Wachowiak P., Kalina T.

Autobusy : technika, eksploatacja, systemy transportowe

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2018

|

R. 19, nr 6

764--770, CD

PL

Budowa amortyzatorów z biegiem lat bardzo się zmieniała. Wraz z rozwojem technologicznym samochodów pojawiały się coraz nowsze ich modele. Technologie stosowane w amortyzatorach były ulepszane wraz z ich rozwojem, aby sprostać wymogom producentów samochodów. Głównym celem stosowania amortyzatorów w samochodzie jest zapewnienie utrzymania ciągłego kontaktu kół z nawierzchnią drogi poprzez przechwycenie i rozproszenie nadmiaru energii w układzie mechanicznym. W dzisiejszych czasach używanych jest wiele różnych rodzajów amortyzatorów, do których możemy zaliczyć m.in. amortyzatory mechaniczne, hydrauliczne, hydrauliczno-pneumatyczne, magnetyczne, elektromagnetyczne, cierne, powietrzne, elastomerowe, sprężynowe oraz gumowe, których przeznaczenie oraz budowa pozwala na pracę w różnych warunkach atmosferycznych na całym świecie. W pracy dokonano na stacji kontroli pojazdów, badania stanu technicznego amortyzatorów w 30 samochodach poruszających się po polskich drogach. Następnie sprawdzono te wyniki z przepisami prawnymi obowiązującymi w Polsce i na Słowacji.

EN

The construction of shock absorbers has changed over the years. With the technological development of cars, newer and newer models appeared. The technologies used in shock absorbers have been improved along with their development to meet the requirements of car manufacturers. The main purpose of using shock absorbers in the car is to ensure continuous contact of the wheels with the road surface and the comfort of driving by appropriate damping of vibrations captured from the body. Nowadays, many different types of shock absorbers are used, i.e. mechanical, hydraulic and hydraulic-pneumatic and many others which purpose and construction allows them to work in various atmospheric conditions all over the world. For this reason the shock absorbers of 30 cars traveling on Polish roads were examined at the vehicle inspection station. After the trails these results were contrasted with the legal provisions in force in Poland and Slovakia.

14

Comparison of computing efficiency of different hydraulic vehicle damper models

Maniowski M., Para S.

Technical Transactions

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2017

|

Vol. 8(114)

207--214

EN

This paper deals with comparisons of computing efficiency of 20 damper models with functional and hybrid approaches, which can be used to solve typical problems in vehicle dynamics. Efficiency is evaluated based on model accuracy and computing time. The computed results of different damper models are compared to measurements of an actual car damper. Its damping characteristics were measured on a hydraulic damper test rig with three different excitations.

PL

W artykule porównano efektywność dwudziestu modeli amortyzatorów, funkcjonalnych i hybrydowych, które można stosować przy rozwiązywaniu podstawowych problemów dynamiki pojazdów. Efektywność jest oceniana przez dokładność odwzorowania i czas obliczeń. Odpowiedzi kolejnych modeli amortyzatora porównywano z wynikami badań rzeczywistego amortyzatora samochodowego na stanowisku ze wzbudnikiem.

15

Quarter car model to evaluate behaviour under road and body excitation

Niculescu A. I., Jankowski A., Kowalski M., Sireteanu T.

Journal of KONES

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2017

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Vol. 24, No. 1

265--273

EN

The paper presents a quarter car model two degrees of freedom (wheel and body), with vertical guiding system, the model being equipped with suspension stroke limiters and with excitation by wheel and/ or by body. The model reproduces elastic and damping characteristics of wheel and of rebound and compression stopper bumpers, the spring elastic characteristic and the shock absorber damping characteristic on rebound and compression, function piston speed. The road profile is generated with simple or summation of harmonic functions, or by reproducing real roads. The forces acting on full vehicle body e.g. aerodynamic and inertial forces are reproduced in the proposed quarter model by vertical forces reduced to the analysed quarter part. Thus, the model can be used for evaluation the vertical and horizontal stability at acceleration, deceleration, pitch and roll, at aerial forces, the body ground clearance and the comfort. The model can evaluate the influence of the damping and elastic characteristics of suspension and wheel, of the static position, of the vehicle load state, of the road profile and of the external forces, to the vehicle behaviour

16

Development and verification of a shock absorber and its shim valve model based on the force method principles

Skačkauskas P., Žuraulis V., Vadluga V., Nagurnas S.

Eksploatacja i Niezawodność

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2017

|

Vol. 19, no. 1

126--133

PL

W danej publikacji został opisany model matematyczny zaworu talerzowego jednorurowego amortyzatora, wyprowadzenia którego zastosowano metodę sił. Metoda ta wyraża związki pomiędzy przemieszczeniami i siłami działającymi na elementy amortyzatora. Stosowanie metody sił w praktycznej sferze modyfikacji amortyzatorów samochodowych pozwala efektywnie analizować wpływ różnych parametrów, w tym ilość, wzajemne położenie i właściwości materiałów talerzy zaworu, na generowaną amortyzatorem wielkość siły tłumienia. Tłumienie, które generuje amortyzator, wywiera znaczący wpływ na komfort jazdy samochodem oraz jego dynamikę. W publikacji również został stworzony kompletny model jednorurowego amortyzatora. Walidacja modelu matematycznego oraz możliwość zastosowania jego w praktyce zostały ocenione na podstawie eksperymentalnych pomiarów charakterystyk amortyzatorów na specjalnym stanowisku.

EN

In this paper, a mathematical model of a monotube shock absorber’s shim valve, which is developed by applying the force (flexibility) method, is described. This method expresses the relationship between displacements and the forces existing in the shock absorber structure. An application of the force method in the field of practical modification of vehicle shock absorbers enables to effectively analyse the influence of a wide range of parameters, including the number of shims in the valve, their disposition and the properties of the material on the level of the damping force. The damping of the shock absorber considerably impacts comfort and road holding characteristics of the vehicle. In addition, a whole model of a monotube shock absorber is designed in this paper. The validation and practical application of the mathematical model were evaluated by carrying out experimental measuring of the characteristics of the shock absorber using a special stand.

17

Free vibration method for technical condition assessment of automotive shock absorbers

Konieczny Ł., Warczek J., Młynczak J., Zawisza M.

Diagnostyka

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2017

|

Vol. 18, No. 3

47--53

EN

The article provides a discussion on oscillatory methods used for technical condition assessment of shock absorbers in automotive vehicles, focusing primarily on free vibration methods. It comments on results of simulation studies of a simple two-mass model conducted by application of a pulse input function. Results of experimental tests have also been provided in the paper. The foregoing tests consisted in recording of accelerations of the body of an automotive vehicle equipped with a shock absorber enabling simulation of shock absorbing liquid leakage. The follow-up analyses were conducted to establish the decrement of damping as well as the damping coefficient.

PL

W artykule opisano metody drganiowe stosowane w ocenie stanu technicznego zawieszenia pojazdu samochodowego ze szczególnym uwzględnieniem metody drgań swobodnych. Przedstawiono wyniki badań symulacyjnych dla prostego modelu dwumasowego przy wykorzystaniu wymuszenia impulsowego. Zaprezentowano również wyniki badań eksperymentalnych. Badania te polegały na rejestracji przyśpieszeń drgań nadwozia pojazdu samochodowego wyposażonego w amortyzator umożliwiający zasymulowanie wycieku płynu amortyzatorowego. W ramach analiz wyznaczono dekrement tłumienia oraz współczynnik tłumienia.

18

Role of magnetorheological fluids and elastomers in today’s world

Skalski A., Kalita K.

Acta Mechanica et Automatica

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2017

|

Vol. 11, no. 4

267--274

EN

This paper explains the role of magnetorheological fluids and elastomers in today’s world. A review of applications of magnetorheological fluids and elastomers in devices and machines is presented. Magnetorheological fluids and elastomers belong to the smart materials family. Properties of magnetorheological fluids and elastomers can be controlled by a magnetic field. Compared with magnetorheological fluids, magnetorheological elastomers overcome the problems accompanying applications of MR fluids, such as sedimentation, sealing issues and environmental contamination. Magnetorheological fluids and elastomers, due to their ability of dampening vibrations in the presence of a controlled magnetic field, have great potential present and future applications in transport. Magnetorheological fluids are used e.g. dampers, shock absorbers, clutches and brakes. Magnetorheological dampers and magnetorheological shock absorbers are applied e.g. in damping control, in the operation of buildings and bridges, as well as in damping of high-tension wires. In the automotive industry, new solutions involving magnetorheological elastomer are increasingly patented e.g. adaptive system of energy absorption, system of magnetically dissociable [hooks/detents/grips], an vibration reduction system of the car’s drive shaft. The application of magnetorheological elastomer in the aviation structure is presented as well.

19

An energy absorption dynamic test of landing gear for 1400 kg general aviation aircraft

Jakubowski R., Tywoniuk A.

Journal of KONES

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2016

|

Vol. 23, No. 4

159--165

EN

Landing gear as one of the most crucial systems ensuring safe take-off and landing must be rigorously tested before first flight of each newborn aeroplane. In the static and dynamic tests strength, functionality and energy absorption capability of landing gear components (wheel, brake, shock absorber, support structure and retraction system) are verified. One of the most important is an energy absorption dynamic test. During drop, test campaign a landing gear damping system is not only verified but also optimized by changing parameters like: damping orifice diameter, geometry of gas and oil chambers and shock absorber and tire inflation pressures. This process often takes substantial amount of time because of influence of the mentioned parameters on landing gear energy absorption efficiency. Other factors like landing configuration spin up and spring back effects generated during wheel contact with the ground [1] also have to be considered in the energy absorption optimization process. The paper describes the landing gear drop test campaign and main challenges, which have to be overcome to achieve optimal dynamic characteristics of the system. The tested object was the main landing gear of the 1400 kg General Aviation aircraft certified in accordance with EASA CS-23 regulations. The drop test campaign was carried out in Warsaw Institute of Aviation Landing Gear Laboratory.

20

Advantages conferred by shock absorbers with cylindrical actuator application to landing gear

Niculescu A. I., Jankowski A., Kowalski M., Sireteanu T.

Journal of KONES

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2016

|

Vol. 23, No. 1

255--262

EN

Shock absorber with cylindrical actuator is a new concept of integrated damper with floating device, in international patent application PCT/EP2016/061515, with wide application in road, rail and aerial vehicles. Comparative to the known solution with rubber sleeves or bellows, the new one is capable to work at more increased pressure being more compact and due to metallic cylinder is more reliable. The other important advantage consists of it applicability at any kind of shock absorber without any special preparation, the solution consisting of replacing the dust shield with a pneumatic cylinder sealed against rod with a gasket and sliding closed in the lower part by sealing element/s fitted in trough/troughs practiced in an annular body fastened against the outer cylinder. For a better behaviour the patent application contains and solutions with double sliding sealing working at high pressure and thus assuring enough floating forces to sustain the vehicle without standard metallic spring so it can be utilized successfully in aerial vehicles landing gear. By using displacement and pressure transducers and equipment of control and command, it becomes an active suspension. The paper presents the double sliding sealing solution and demonstrates, by simulation the advantages confer by this new solution of shock absorber with cylindrical actuator in landing gear. This purpose was realized a virtual suspension model on which simulated hard landing for vehicle load and unload states, for different pneumatic spring preloaded forces.