Wyniki wyszukiwania - BazTech

1

Insight Into Vibration Sources in Turbines

Moneta Grzegorz, Jachimowicz Jerzy, Pietrzakowski Marek, Doligalski Adam, Szwedowicz Jarosław

Fatigue of Aircraft Structures

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2021

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Iss. 13

40--53

EN

Despite of nearly 100 years of turbine engine development and design, blade vibrations remain a great engineering challenge. The rotating turbine blades’ vibrations lead to cyclic oscillations, which result in alternating stress and strain in harsh environments of high temperature and pressure. In modern aeroengines, high hot flow velocities might generate erosion and corrosion pitting on the metal surfaces, that leverage remarkably mean stresses. The combination of both mean and alternating stresses can lead to unexpected engine failures, especially under resonance conditions. Then, alternating stress amplitudes can exceed the safety endurance limit, what accelerates the high cyclic fatigue leading quickly to catastrophic failure of the blade. Concerning the existing state-of-the-art and new market demands, this paper revises forced vibrations with respect to excitation mechanisms related to three design levels: (i) a component like the blade design, (ii) turbine stage design consisting of vanes and blades and (iii) a system design of a combustor and turbine. This work reviews the best practices for preventing the crotating turbine and compressor blades from High Cyclic Fatigue in the design process. Finally, an engine commissioning is briefly weighed up all the pros and cons to the experimental validations and needed measuring equipment.

2

Rosnący apetyt na technologie przyrostowe w ceramice

Bonter-Jędrzejewska Renata

Szkło i Ceramika

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2020

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R. 71, nr 3

19--23

3

Assessment of mechanical properties of PA 3200 GF polyamide models made by SLS

Kundera C., Kozior T.

Technical Transactions

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2018

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Vol. 115, iss. 11

181--186

EN

The paper presents the results of mechanical properties research of samples made in the Selective Laser Sintering technology. Polyamide powder PA 3200 GF reinforced with glass fiber was the material used to build the model. Samples subjected to a uniaxial tensile test were made in accordance with ASTM D638 – V standard. The printing direction was the technological parameter of the study. The analysis of the results showed that the addition of fiberglass significantly influenced the improvement of mechanical properties, especially the isotropic of mechanical properties with respect to the printing direction.

PL

W artykule przedstawiono wyniki badań mechanicznych próbek wykonanych w technologii Selektywnego Spiekania Laserowego. Materiałem wykorzystanym do budowy modeli był poliamid PA 3200 GF wzmacniany włóknem szklanym. Próbki poddane jednoosiowej próbie rozciągania wykonane zostały zgodnie z norma ASTM D638-V. Parametrem technologicznym uwzględnionym podczas badań był kierunek budowy modeli. Analiza wyników badań wykazała, iż dodatek włókna szklanego w znaczny sposób wpływa na poprawę własności mechanicznych, przede wszystkim na izotropię własności mechanicznych w odniesieniu kierunku budowania modeli.

4

The effect of shot peening on the corrosion behaviour of Ti-6Al-4V alloy made by DMLS

Żebrowski R., Walczak M.

Advances in Materials Science

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2018

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Vol. 18, nr 3(57)

43--54

EN

Additive Manufacturing processes are being used increasingly in the scope of medicine and dentistry. As indicated by literature data, the durability and quality of medical implants is decisively influenced by surface modification. Insufficient quality of surface finishing leads, among others, to reduced service life of applied implants and to increased number of necessary revision surgeries. Furthermore, various types of finishing processes e.g. cleaning, shot peening or abrasive techniques are suggested by the manufacturers of products made by means of DMLS processes. Due to this fact, the analysis of proper formation of the surface layer of titanium products made by means of the method consisting in the direct laser sintering of metal powders (DMLS) was the subject matter of our research. Therefore, Ti-6Al-4V titanium alloy has been used for tests. The samples have been produced by means of EOSINT M280 system dedicated for laser sintering of metal powders. The surfaces of prepared samples have been subjected to shot peening process at three different values of working pressure (0.2, 0.3 and 0.4 MPa) by means of three different working media i.e. CrNi steel shot, crushed nut shells and ceramic balls. The characteristics of the materials used for shot peening process have been determined by means of Zeiss Ultra Plus scanning electron microscope. The samples have been subjected to profilometric measurements on Bruker Contour GT optical profilometer and the corrosion behaviour of Ti-6Al-4V titanium alloy in Ringer solution has been determined in electrode impedance spectroscopy (EIS) measurements by means of Atlas 0531 set dedicated for corrosion testing. The overall results of all tests indicate to favourable influence of the shot peening process on the corrosion behaviour of titanium alloy.

5

Influence of printing parameters on the mechanical properties of polyamide in SLS technology

Kundera C., Kozior T.

Czasopismo Techniczne. Mechanika

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2016

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Y. 113, iss. 3-M

31--37

EN

This paper presents the research results of the influence of selected process parameters on the tensile strength samples obtained according to the ISO 527 standard. Bio-capable polyamide powder PA 2200 was the material used in the process. The research included such parameters as energy density transmitted to the sintered layer, laser power and speed, printing direction and the number of scanning. A computer program based on artificial neural network was used to analyze the research results. The program allowed us to assess the influence of printing parameters on the tensile strength, based on previously made research without the need to prepare samples according to the experimental plane.

PL

W artykule przedstawiono wyniki badań wpływu wybranych parametrów procesu technologii Selektywnego Spiekania Laserowego na wytrzymałość na rozciąganie próbek wykonanych zgodnie z normą ISO 527 z użyciem poliamidowego proszku PA 2200. Uwzględniono parametry takie jak: gęstość energii, prędkość i moc lasera, kierunek wydruku oraz liczbę naświetleń. Do analizy uzyskanych wyników badań wykorzystano program działający w oparciu o modele sztucznych sieci neuronowych, pozwalający na oszacowanie wpływu opisanych czynników na wytrzymałość uprzednio wykonanych próbek.

6

Wpływ nowych technik wytwarzania na konstrukcję samolotu

Adamski W.

Mechanik

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2015

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R. 88, nr 12CD3

1--5

PL

W pracy podano jak przy wykorzystaniu nowo powstałych technologii i strategii obróbki części w przemyśle lotniczym można obniżyć koszty wytwarzania. Podano przykłady wdrożeń w przemyśle lotniczym. Zastosowanie HSM w lotnictwie wymusiło zmianę w konstrukcji dzisiejszych samolotów. Opisano strategię obróbki cienkich ścianek i wręg struktury samolotu. Zwrócono uwagę na nowe technologie jak technologia przyrostowa i odprężanie wibracyjne.

EN

The paper describes how the use of modern technologies and parts machining strategies can reduce manufacturing costs in the aerospace industry. Sample implementations in the aerospace industry have been presented. The use of HSM in aviation forced a change in today's aircraft designs. Machining strategy for thin walls and aircraft structure framers have been described. Modern technologies of manufacturing like Additive Manufacturing and Vibratory Stress Relief have been presented.