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1

Health monitoring in landing gears

Skorupka Zbigniew, Tywoniuk Andrzej

Journal of KONES

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2019

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Vol. 26, No. 1

167--174

EN

Every mechanical construction loses its properties in time due to the usage wear that leads to malfunctions and, in the end, to failure. Widely used method of failure time prediction base on extended laboratory tests where a device is tested against fatigue and wear. This method is well established but is expensive, time-consuming, and costly. Another way of failure prediction is to calculate it using advanced algorithms what is faster and cheaper but less accurate than actual tests. Furthermore, both methods are not optimal due to the principle of operation based on simplified assumptions. In such cases, it is common to make the lifespan of the safety wise devices for example landing gears much less than real in case of fatal failure not covered by the predictions. This can lead to much higher price and maintenance costs of the landing gear. Nowadays the worldwide trend is to monitor the behaviour of the devices in real time and predict failure using actual state. There are several methods of health monitoring, most of them including sensors, acquisition systems and computer software for analysis. In this article, authors describe possible landing gears health monitoring methods based on authors’ laboratory experience in sensor appliance and test data analysis. The authors also present their idea of adding health monitoring to existing landing gears where no dedicated infrastructure was initially designed.

2

Strain gauge pin based force measurement

Skorupka Z., Sobieszek A.

Journal of KONES

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2018

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Vol. 25, No. 2

335--340

EN

In this article authors present force measurement method based on strain gauge measuring system installed inside pin, which is a part of light helicopter Main Landing Gear Shock Absorber. Strain gauges in full bridge configuration were installed inside the mounting pin (upper one – fuselage side). Placement and type of strain gauges were selected during the preliminary tests, which verified the validity and conditions of the force measurement. Preliminary tests allowed verification and selection of an optimal measurement system by testing two types of them. The impact on force according to the angle of force vector direction was also verified. Preliminary tests of the strain gauges equipped pin were performed using quasistatic tests stand – 40 T hydraulic press for applying force acting on shock absorber and pin. Whole measuring system is planned to be used in real time analysis of shock absorber force acting on fuselage mounting node. The strain gauges allows measurement of force in any place of the structure, the article presents the advantages of the system located inside pin. Additionally, the installation technologies of strain gauges in hard-to-reach places are presented. The article is summed up with an analysis of the problems, which arise during the installation and measurement process using strain gauges installed in such a specific place.

3

Adaptive landing gear control system assumptions

Skorupka Z.

Journal of KONES

|

2018

|

Vol. 25, No. 2

329--333

EN

In the present time, landing energy dissipation process in aviation shock absorber design is optimized for the most demanding, but still safe, landing scenario (reserve energy landing conditions). Most of the current solutions are based on a fixed hole (orifice) or a set of holes regulating hydraulic fluid flow in the shock absorber. This approach although safe provides no optimization of the forces acting on the fuselage in different (less energetic than limit energy) conditions. Due to the progress in hydraulic flow control, it is possible to design and control a proper system for extended optimization of the landing process energy dissipation. The complete system contains two parts, one of which is a direct flow executive electro-mechanical system and second of which is an electronic control system. The electronic control system directly manages executive system via a set of inputs, thus creating proper output signals for the optimal flow control. In this article, the author presents the idea of the computer control part of the adaptive hydraulic flow control system. The author describes a set of possible control input and output signals both external and internal, from the landing gear reference system, characterizing their role in the landing process. The author also defines possible control algorithms selected to fit the assumptions of the adaptive landing gear system. Finally, the author presents a proposal for the laboratory grade control system for future testing of the assumptions described in this article.

4

Laboratory investigations on landing gear ground reactions (load) measurement

Skorupka Z.

Journal of KONES

|

2017

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Vol. 24, No. 2

225--230

EN

Ground reaction measurement in landing gear laboratory tests is used in order to gain knowledge about loads transferred to the aircraft structure. Ground reaction level is defined during aircraft design phase and it is required not to exceed limit value in real construction. Load from landing affect directly strength of aircraft structure especially mounting points what translates both strength of aircraft structure especially mounting points what translates both on safety and weight of the final design. Meeting the safety requirements is crucial in aviation regulations conformity. Landing gear ground reactions evaluation is performed during laboratory tests in order to meet the compliance with the ground load requirements assumed in design phase. Proper test method is crucial to prove the actual load. One of the methods is landing gear dynamic drop test where landing forces are measured. Force measurement is made in several ways according to test stand construction and test object specifics. In this article, three methods are described due to author’s experience in landing gear tests. Proposed techniques cover two direct and one indirect force measurements. Direct approach is based on strain gauge measurement principle. One is a strain gauge plate fixed to the ground while the second one is based on strain gauges attached to landing gear mounting nodes. Indirect approach is based on the acceleration of the tested object, which by definition is correlated with the force applied to the structure. Obtained test results allow determining the kinetic energy absorbed by landing gear during drop test. In this article author also presented numerical integration of the time history data and compared them with simulation results in order to show equivalence of all three of the test methods and to prove correctness of the test initial conditions determination.

5

Effect of Fe Content on the Microstructure and Mechanical Properties of Ti-Al-Mo-V-Cr-Fe Alloys

Bae K.-C., Oak J.-J., Kim Y. H., Park Y. H.

Archives of Metallurgy and Materials

|

2017

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Vol. 62, iss. 2B

1105--1108

EN

To investigate the effect of Fe content on the correlation between the microstructure and mechanical properties in near-b titanium alloys, the Ti-5Al-5Mo-5V-1Cr-xFe alloy system has been characterized in this study. As the Fe content increased, the number of nucleation sites and the volume fraction of the α phase decreased. We observed a significant difference in the shape and size of the α phase in the matrix before and after Fe addition. In addition, these morphological deformations were accompanied by a change in the shape of the α phase, which became increasingly discontinuous, and changed into globular-type α phase in the matrix. These phenomena affected the microstructure and mechanical properties of Ti alloys. Specimen #2 exhibited a high ultimate tensile strength (1071 MPa), which decreased with further addition of Fe.

6

The selected problems of studies of aircraft landing gear

Rośkowicz M., Leszczyński P.

Prace Naukowe Instytutu Technicznego Wojsk Lotniczych

|

2016

|

nr 39

91--101

EN

The article portrays the results of experimental studies conducted in the field of static strength test of main landing gear of lightweight aircraft as well as in the area of establishing the pneumatic tyre characteristics of main landing gear. The studies were carried out in compliance with methodologies of performing studies for the purposes of solutions implemented in aviation structures. It was stated that static strength tests of landing gear should not be done with the use of shock absorbers, due to the fact that this element, distinguished by high viscoelastic properties, by being statically loaded, is subject to displacements that do not occur during normal operation of the aircraft. Excessive displacements of shock absorber result in the load distribution in other landing gear elements being incompatible with project assumptions, which in turn leads to this strength test being interrupted, bearing in mind significantly lower loads than anticipated. It was also concluded that in order to determine pneumatic tyre characteristics it is not necessary to carry out tests on the whole landing gear strut, because the results obtained in the compression test of the wheel itself with pneumatic tyre are identical as the results acquired during tests conducted in accordance with methodology. Test preparation process with the use of the wheel itself and its realization is less time-consuming, less expensive and does not entail the necessity to build complex test stands.

7

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

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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.

8

A design and numerical optimization of a landing gear for 1400 kg (AT-6) take-off mass aircraft

Tywoniuk A., Jakubowski R.

Journal of KONES

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2016

|

Vol. 23, No. 3

541--547

EN

One of the most important systems responsible for safe take-off and landing of aircraft is a landing gear system. Regardless of the configuration and the type of landing gear, its main function is to absorb energy from landing. The aim of this paper is to describe design and numerical optimization of modern tricycle-type, retractable landing gear system equipped with oleo-pneumatic amortization and mechanical emergency release. The landing gear was designed for a new prototype of 4 seats 1400 kg (AT-6) take-off mass aircraft in accordance with Certification Specifications for Normal, Utility, Aerobatic and Commuter Category Aeroplanes – CS-23. A complete design process from concept to final version was performed in Warsaw Institute of Aviation’s Landing Gear Laboratory. Proposed retractable landing gear concept substantially reduces aerodynamic drag of aircraft. Although application of one retraction system for the left and right gear make the system more complicated, this solution significantly reduces weight. The authors, because of the project complexity, focused on most important aspects of the main landing gear design and described numerical optimization of chosen components like composite leg with main and upper aluminium fittings. Engineers involved in the project used SolidEdge software for 3D modelling, kinematics optimization and 2D documentation preparation. Strength and stiffness analysis was carried out using hand and numerical calculation methods – FEMAP with NX Nastran and Hyperworks software.

9

Mi-2 na płozach - "prywatna" modyfikacja polskiego śmigłowca

Choiński A.

Prace Instytutu Lotnictwa

|

2015

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Nr 4 (241)

33--41

PL

W artykule przedstawiono propozycję modyfikacji śmigłowca Mi-2, polegającą na zastosowaniu podwozia płozowego oraz znacznym zmniejszeniu masy własnej śmigłowca. Zaprezentowano kolejne fazy zmian struktury kadłuba, modernizacje dotyczące osprzętu oraz konstrukcję podwozia płozowego. Zaproponowano także sposoby uzyskania formalnego dopuszczenia do lotu wykonanej już konstrukcji mogącej cieszyć się istotnym zainteresowaniem potencjalnych użytkowników cywilnych.

EN

The modification of Mi-2 helicopter is presented which includes applying of the new skid landing gear and significant reduction of the helicopter mass. The subsequent phases of helicopter structure change, modernization of avionics and construction of the skid landing gear are shown. The proposition of the procedure to receive the formal airworthiness certification for modified helicopter is discussed.

10

Zagadnienia pomiarów prędkości liniowej w spadku swobodnym

Paprzycki I.

Logistyka

|

2015

|

nr 3

3750--3757, CD 1

PL

Przemysłowe rozwiązania pomiarów prędkości liniowej zazwyczaj opierają się o pośrednie obliczenie wartości z pomiaru prędkości obrotowej. Podczas badań dynamicznych podwozi lotniczych standardowe metody nie znajdują zastosowania. Konieczne zatem stało się poszukiwanie innych metod. W artykule przedstawiono przegląd rozwiązań, opis metodyki pomiarów oraz zaproponowane dwie metody wyznaczania prędkości liniowej opadania (lądowania) podczas badań zrzutu swobodnego podwozia. Autor zaproponował dwie metody numeryczne różniczkowania sygnału pomiarowego z czujnika przemieszczeń w celu wyznaczenia poszukiwanego parametru. Pomimo szerokich możliwości stosowania algorytmów numerycznych, bardzo ważne jest zebranie danych pomiarowych jak najniższym zaszumieniu. Przedstawione wyniki potwierdzają prawidłowość wyboru metodyki i algorytmu numerycznego przez co udowodniono uzyskiwanie podczas prób dynamicznych wymaganych parametrów próby.

EN

Industrial solutions of linear velocity measurement are usually based on the indirect method of rotational speed measurement calculations. During the landing gear drop test the chassis moves down in a free fall. Differences between industrial and laboratory measurement method makes it inappropriate to adopt the indirect linear speed measurement methods in the dynamic landing gear tests. It was necessary to seek for other methods. This article presents an overview of solutions, description of measurement methods and two proposed methods for calculating the descent linear velocity. The author shows two numerical methods of linear displacement sensor measured signal derivation. Despite the wide applicability of numerical algorithms, it is important to collect as low noisy as it is possible. The results confirm the correct choice of the measurement methodology and numerical derivation technic. It was proved that proper dynamic test parameters are obtained during the drop tests.

11

Wstępna detekcja wad i uszkodzeń kompozytowego podwozia samolotu lekkiego z wykorzystaniem termografii aktywnej w podczerwieni

Pawluczy-Majka J., Sibilski K.

Logistyka

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2015

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nr 3

3841--3847, CD 1

PL

Prezentowany artykuł przedstawia rezultaty użycia nowoczesnej metody badań nieniszczących termografii w podczerwieni w badaniach technicznych kompozytowej struktury podwozia samolotu lekkiego. Wraz ze zwiększonym wykorzystaniem kompozytów w przemyśle lotniczym, pojawia się konieczność opracowania metody pozwalającej na identyfikację wad technologicznych i uszkodzeń powstałych w procesie eksploatacji statków powietrznych. Wraz ze wzrostem oczekiwań wobec konstrukcji lotniczych - ich efektywności i obniżenia kosztów eksploatacji, rozwojowi podlegają również metody diagnostyczne oraz procedury kwalifikacji do lotu. Cel obniżenia kosztów dotyczy zarówno procesu produkcji poszczególnych elementów jak też skrócenia czasu przestojów samolotów podczas przeglądów eksploatacyjnych. Niniejszy artykuł przedstawia wyniki badań eksperymentalnych kompozytowego podwozia samolotu lekkiego skorelowanych z pracą naziemnej obsługi technicznej.

EN

The article presents the effects of using active IR Thermography technique for the tests of composite aircraft With the growing use of composites in the aviation industry a necessity appears to work out a method allowing early identification of technological defects and damages appeared in the process of the aircraft operation. It could be the active thermography techniques used for the thin walled elements tests, such as wing and fuselage skin, with the focus on fractures and delamination. The obtained research results bring closer the problem of selection of the well-fitted non-destructive testing method depending on the kind of the diagnosed construction.

12

Metody pomiarów prędkości obrotowej wykorzystywanych w dynamicznych badaniach podwozi lotniczych

Paprzycki I.

Logistyka

|

2015

|

nr 3

3728--3735, CD 1

PL

W artykule przedstawiono przegląd rozwiązań oraz opis metodyki pomiarów prędkości obrotowej koła samolotu. Autor opisuje dostępne rozwiązania techniczne czujników i przetworników pomiarowych. Wybrana optyczna metoda pomiarowa cechuje się wysoką dokładnością oraz odpornością na zakłócenia elektromagnetyczne. Miniaturowa konstrukcja głowicy czujnika oraz możliwość poprowadzenia światłowodów pomiarowych w dowolnym dostępnym miejscu zadecydowało o wyborze wspomnianego rozwiązania. Dodatkową zaletą rozwiązania jest brak konieczności stosowania dodatkowych elementów referencyjnych, takich jak metalowa tarcza zębata. Artykuł zawiera również wyniki wzorcowania toru pomiarowego prędkości obrotowej wykorzystanego do badań dynamicznych podwozia lotniczego przeprowadzonych w Laboratorium Badań Podwozi Lotniczych Instytutu Lotnictwa. W wyniku prac udało się uzyskać wymagane przepisami lotniczymi parametry prób i przeprowadzić certyfikację podwozia do lekkiego samolotu o masie startowej nie przekraczającej 1400kg.

EN

This article presents an overview of market solutions and description of the aircraft wheel speed measurements methodology. The author describes well-known and available on the market sensors and transducers. The selected optical measuring method characterizes high accuracy and resistance to electromagnetic interferences. The miniature sensor head and the ability to route freely the optical fibers resulted in this solution selection. An additional advantage is no need to use any reference elements such as metal gear disk. The article contains the results of the measurement chain calibration used for dynamic tests performed in Institute of Aviation Landing Gear Laboratory. As a result the required by aviation regulations test parameters have been achieved. Certification tests performed for light aircraft (of maximum 1400kg take-off mass ) landing gear were completed successfully.

13

Wykorzystanie optycznych metod badawczych do analizy pracy podwozia lotniczego

Parafiniak M.

Logistyka

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2014

|

nr 6

8373--8382

PL

W opracowaniu omówiono wykorzystanie autorskiego optycznego systemu pomiarowo-rejestrującego SORIA do analizy zachowania się podwozia lotniczego w zakresie deformacji i drgań, w trakcie badań procesu lądowania i przyziemienia. Omówiono kompletację systemu optycznego, niezbędne parametry oraz przedstawiono podstawowe funkcje, sposób realizacji pomiarów i sposób prezentacji wyników. Opisano zalety i zakres zastosowania systemu optycznego SORIA oraz na przykładzie prób podwozia wiatrakowca I-28 przedstawiono na wykresach wybrane rezultaty analiz badań belki sprężystej podwozia. Przedstawienie wyników uzyskanych optycznymi metodami eksperymentalnymi, poprzedzono prezentacją metod numerycznych i wybranych wyników analizy numerycznej w postaci wykresów symulacji opartej na przyjętym modelu matematycznym oraz dokonanej przy użyciu metod MES. We wnioskach podsumowano efekty prac analitycznych i pomiarowych jako propozycję metodyki analizy podwozi, zestawiając wybrane wyniki uzyskane obiema metodami: metodą optyczną i przy użyciu analizy numerycznej.

EN

In the paper author presents application of optical system SORIA to analyze behavior of landing gear, during landing tests. Through optical measurements and implemented methodology, analysis of design and verification of landing gear parameters can be performed quickly and in safe way. Analysis software, based on LabVIEW Machine Vision and Image Processing, can calculate motion (trajectory, displacement and deformation) and vibration of structure or selected points. Autogiro is the aircraft requiring specific functionality from the landing gear, which will need to take advantage of optical measurements during tests. Landing gear of I-28 gyroplane, designed and tested in Institute of Aviation, is an example of that kind. Author describe set of instrumentation and parameters necessary to perform measurements, general functions of the software then presents advantages and disadvantages of such system, and area of implementation. Some results of numerical analysis and simulations and measurements with optical system during experiment, are pointed and presented on charts. In summary, results of measurements and numerical analysis are compared and discussed, as a methodology of analysis of main element of spring landing gear – leaf spring beam.

14

Automatyzacja procesu badań piasty lotniczej

Paprzycki I.

Logistyka

|

2014

|

nr 6

8339--8345

PL

Konstruktor piasty lotniczej jest odpowiedzialny za obliczenie maksymalnych obciążeń statycznych i dynamicznych,które muszą być mniejsze niż wartości eksploatacyjne. Dowodem poprawności procesu projektowania i wykonania są badania laboratoryjne na wykonanym prototypie. Laboratorium Badań Podwozi Lotniczych Instytutu Lotnictwa w Warszawie przeprowadza badania zarówno kompletnych podwozi jak i poszczególnych elementów. W artykule przedstawiono efekty modernizacji stanowiska na którym przeprowadza się badania wytrzymałości piasty podczas długotrwałej próby toczenia. Rezultatem przeprowadzonych modernizacji i implementacji algorytmu sterowania automatycznego jest podniesienie bezpieczeństwa personelu, badanych obiektów i wyposażenia laboratoryjnego. Autor opisuje ogólna metodykę przeprowadzania prób dynamicznych prototypowej piastyoraz rezultat modernizacji stanowiska laboratoryjnego na potrzeby badań.

EN

Aircraft wheel manufacturer is responsible for calculating the maximum static and dynamic loads on the wheels, which must be less than the rated loads.The laboratory tests on the prototype made are the only proof of the proper design and manufacturing process. The Instytut Lotnictwa Landing Gear Department Laboratory performs both the complete landing gears as well as individual components tests. The article presents the results of the laboratory test stand modernization on which the rolling tests are performed. The aim of the modernization was personnel, tested objects and laboratory equipment safety improvement. Author describes the methodology of the dynamic aviation wheel tests and the result of the test rig automation for that purpose.

15

Analiza geometryczna procesu mechanicznej kompensacji odkształceń temperaturowych elementów podwozia samolotu typu STRUCTURAL POST

Boś P., Budzik G., Cygnar M., Rokicki P., Rybak M.

Logistyka

|

2014

|

nr 6

2247--2253

PL

Dokładność i jakość wykonania elementów podwozia lotniczego ma bezpośredni wpływ na bezpieczeństwo ludzi podróżujących tym środkiem transportu. Szczególnie należy zwrócić uwagę na problemy z jakimi borykają się konstruktorzy i technolodzy podwozi związanymi z wymaganiami dotyczącymi zapewnieniu gwarantowanego poziomu niezawodności poszczególnych elementów. Oczywiście należy przy tym pamiętać o ergonomiczności i ekonomiczności procesu produkcyjnego. Obecnie najpopularniejsze z uwagi na niewątpliwe zalety jest rozwiązanie podwozia wielośladowe (trójkołowe) z przednim punktem podparcia. Zasadnicze obciążenie w tym podwoziu przejmują dwa główne koła umieszczone za środkiem ciężkości samolotu. Jego główne elementy tzw. STRUCTURAL POST mają szczególne zadania jeśli chodzi o bezpieczeństwo przewożonych ludzi. Stąd wysokie wymagania dotyczące jakości procesu produkcyjnego a w nim szczególnie newralgicznych jego operacji związanych z obróbką cieplną oraz prostowaniem przygotowującym do dalszej obróbki wykańczającej. W artykule zwrócono uwagę na towarzyszące procesowi bezpośredniego wytwarzania pomiary stanowiskowe, na podstawie których podejmowane są decyzje dotyczące kolejnych operacji.

EN

The accuracy and quality of the chassis components of aircraft has a direct impact on the safety of people traveling in this means of transport. Especially pay attention to the problems with faced by engineers and technologists chassis associated with the requirements for ensuring a guaranteed level of reliability of the individual elements. Currently, the most popular due to the undoubted advantages has chassis tricycle with the front fulcrum. The principal load the chassis takes over the two main wheels positioned behind the center of gravity of the airplane. The main elements of the so-called POST STRUCTURAL, have the specific tasks when it comes to the safety of the people. Hence the high quality requirements of the production process associated with the heat treatment and straightening to the further finishing. The article focuses on accompanying in the manufacturing process of direct determine the measurements of bench based on which subsequent operations are undertaken.

16

Influence of ABS system use on aviation brake temperature

Paprzycki I.

Journal of KONES

|

2014

|

Vol. 21, No. 4

381--388

EN

The main functions of an aviation brake system are to slow the speed of the vehicle, to perform stable deceleration, and to hold the vehicle stationary after it stopped. They must perform safely under a variety of operating conditions such as slippery, wet and dry runways, full or light load of the vehicle, new or worn brake linings, novice or experienced pilot, etc. The experimental tests show that about 95% of friction energy is converted into thermal energy by plastic deformation of brake linings surface layers and other deformations. The friction materials temperature growth is caused by this energy transformation. The influence of braking temperature is very important to the tribology characteristics, durability and reliability of friction brakes. Landing Gear Department Laboratory performed many experimental tests on full-scale brakes and also on friction material samples. It was performed on the special laboratory test rigs. During the Anti Lock Braking system test, the Landing Gear Department Laboratory workers performed the brake linings temperature measurements. Author observed a positive influence of ABS system use on temperature curve. The aim of this article is to compare the test results of braking with ABS system applied to braking without ABS.

17

Analysis of links positions in landing gear mechanism

Brewczyński D., Tora G.

International Journal of Applied Mechanics and Engineering

|

2014

|

Vol. 19, no. 3

503--512

EN

This article contains a kinematic analysis of an aircraft chassis mechanism in a range of positions. The mechanism of the chassis is made up of several smaller subsystems with different functions. The first mechanism is used to eject the chassis before landing (touchdown) and fold it to hatchway after the lift off. The second mechanism is designed to perform rotation of the crossover with the wheel, in order to adjust the position of the wheel to fit it in the limited space in the hold. The third mechanism allows movement of the chassis resulting from the change in length of the damper. To determine the position of the following links of the mechanism calculus of vectors was applied in which unit vectors were used to represent the angular position of the links. The aim of the analysis is to determine the angle of convergence and the angle of heel wheels as a function of the variable length of hydraulic cylinder, length of the shock absorber, length of the regulations rods.

18

Drop Test Simulation for An Aircraft Landing Gear Via Multi-Body Approach

Leo R, Fenza A, Barile M, Lecce L.

Archive of Mechanical Engineering

|

2014

|

Vol. LXI, nr 2

287--304

EN

This work deals with the effectiveness of a multi-body approach for the study of the dynamic behavior of a fixed landing gear, especially the research project concerns the drop tests of the AP.68 TP-300 aircraft. First, the Digital Mock-up of the of landing gear system in a C.A.D. software has been created, then the experimental structural stiffness of the leaf spring has been validated using the FEM tools MSC. Patran/Nastran. Finally, the entire model has been imported in MSC.ADAMS environment and, according to the certifying regulations, several multi-body simulations have been performed varying the heights of fall and the weights of the system. The results have shown a good correlation between numerical and experimental tests, thus demonstrating the potential of a multi-body approach. Future development of the present activity will probably be an application of the methodology, herein validated, to other cases for a more extensive validation of its predictive power and development of virtual certification procedures.

PL

Praca dotyczy efektywności analizy dynamicznej stałego podwozia samolotu wykonanej przy pomocy oprogramowania dla układu wieloczłonowego. Przedstawiono dowód zgodności między symulacją numeryczną a wynikami eksperymentalnych testów spadowych dla samolotu AP.68 TP-300. Po wykonaniu makiet cyfrowych głównych części składowych podwozia w oprogramowaniu C.A.D. 3D, importowano je do środowiska ADAMS i zmontowano wirtualnie by odtworzyć rzeczywiste więzy. W środowisku ADAMS zrealizowano także model obiektu testowego. Kadłub samolotu i podstawowe części podwozia zostały zamodelowane jako ciało sztywne. Jedynie resor piórowy i opona były symulowane jako ciała elastyczne. W symulacji wykorzystano model opony ze środowiska ADAMS dodając informację o podłożu z pliku danych drogowych. Opracowano symulacje mające odtworzyć przebieg doświadczalnego testu spadowego, scharakteryzowany przez określoną masę i wysokość spadku. Wyniki wykazały dobrą korelację między symulacją cyfrową i testem doświadczalnym, co stanowi wstępny dowód możliwości przyszłej redukcji kosztów dzięki wirtualnej certyfikacji nowych opracowań podwozi samolotowych. Przyszły rozwój prowadzonych obecnie badań będzie prawdopodobnie iść w kierunku zastosowania tej metodologii do innych przypadków, co pozwoli na szerszą walidację mocy predykcyjnej metody. Będzie także opracowana wirtualna procedura certyfikacji.

19

The analysis of chosen technological parameters in the process of manufacturing components of landing gear of structural post aircraft

Boś P., Hakim M., Budzik G., Rybak M.

Journal of KONES

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2013

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Vol. 20, No. 1

23--28

EN

High quality of components used in constructions of Landing Gears forces the manufacturers to choose appropriate technologies in order to manufacture and control dimensions of particular details. It is especially difficult to predict how the elements of huge dimensions will act during heat treat and chemical processing. The changes in size and. shape of the elements of suspension of STRUCTURAL POST aircraft are connected with hardening stresses. This requires accurate determining of allowance of final machining. The analysis of processing parameters and manufacturing of a precise component is possible with the use of high-tech coordinate measuring techniques based on touch and untouched measurements . The highest quality of machines used in manufacturing and measuring as well as innovative technologies used during the process of manufacturing STRUCTURAL POST components result in effects assumed by the designing engineer. The aim of this article is to present issues connected with technological process of manufacturing STRUCTURAL POST components as well as the analysis of particular parameters of manufacturing process which have an impact on the accuracy of dimensions and shape of the final product. These parameters are also responsible for functionality, operational reliability and safety of the Landing Gear.

20

Analysis of electric - drive applicability in mechanical brake for the commuter class airplane

Grygorcewicz P.

Journal of KONES

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2013

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Vol. 20, No. 2

143--148

EN

This article presents selected issues related to the design methodology of the electric brakes during the construction process as well as other factors which are important in the design process. It is a very important issue due to affect on the airplane and automotive brake design. Nowadays when new solution of brakes is being designed there is a need to take into account various factors influencing the design such as: weight, compatibility and flexibility of use in various aircraft, reliability and durability, ease of installation and maintenance, low-cost operation and low cost components, braking efficiency, short braking distance. All of these factors are taken into account when designing a prototype of the electric brake as well as economical factor of the design. It is also necessary to verify the design during its creation using experimental and laboratory test data from other similar designs. The aim of the paper is to discuss design process from the very beginning (i.e. by comparing features of the electric brakes with other types of brakes in order to show advantages and disadvantages of chosen solution) to the creation of a working demonstrator in future. Author of the paper in his electric brake design bases on the experience of the Warsaw’s Institute of Aviation Landing Gear Department.