Wyniki wyszukiwania - BazTech

1

Control of the parameters of the surface layer of steel parts during their processing applying the material homogeneity criterion

Kusyi Yaroslav, Stupnytskyy Vadym, Kostiuk Olha, Onysko Oleh, Dragašius Egidijus, Baskutis Saulius, Chatys Rafał

Eksploatacja i Niezawodność

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2024

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Vol. 26, no. 3

art. no. 187794

EN

The main goal of the presented research is to assess the technological damageability of the material and use this as a criterion for analyzing the technological route of product machining in the "blank-workpiece-final part" technological chain. This technological chain is examined in detail in the most important stages of the life cycles of mechanical engineering products aiming to take into account the principles of technological inheritability of their characteristics and quality parameters. The technological inheritability of the properties of the surface layers of the made of steel parts of machines and mechanisms during their machining evaluates and predicts the transformation of the structurally heterogeneous material obtained after the production of blanks into the structurally homogeneous material of the final parts. The procedure for evaluating the homogeneity of the processed material for each technological step by the LM hardness method is presented according to the calculated values of the Weibull homogeneity coefficient, material constant, variation coefficient, technological damageability along with corresponding intensity of the expansion. The developed methodology was implemented and proven at the manufacturing process of the conveyor belt drive drum shaft.

2

Influence of the Curing Process on the Fatigue Strength and Residual Strength of a Fiber Composite Estimation Using the Theory of Markov Chains

Chatys Rafał, Kłonica Mariusz

Advances in Science and Technology. Research Journal

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2023

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Vol. 17, no 2

53--62

EN

The paper deals with the influence of quality failure of matrix post-curing on the strength of such complex and difficult "new generation" materials as fiber composites, especially those with polymer matrix. The performed statistical analysis of the components determined the complexity of the layered composite structure. And the developed model of the weakest micro-volume presented in this paper has helped to describe not only the pre-dictable strength of the laminate, but also the nature of failure, taking into account the fiber stresses and/or the distribution of end strains in the structure of the composite under consideration. The strength of fibre composi-te structures based on Markov chain theory takes into account technological aspects during the curing process. The presented model was verified on the basis of literature examples and experimental data obtained during the testing process. Numerical results show good agreement with literature examples and measured data. The pre-sented model may represent a novel method that provides further insight into the curing process of epoxy re-sins.

3

Using adverse event pyramids to assess probabilities in airline safety management

Bitinš Aleksandrs, Maklakovs Juris, Bogdane Ruta, Chatys Rafał, Shestakov Vladimir

Transactions on Aerospace Research

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2021

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Nr 2 (263)

71--83

EN

This article reviews the methods of safety management using Heinrich’s and Bird’s pyramids. The presence of a causal relationship between pyramid levels, as a result of inconsistencies in the activities of an organization and personnel, lead to incidents, and incidents in turn lead to accidents. The existence of such a relationship makes it possible to predict the risk of “top-level” events by reducing risks at the middle and lower levels. A mathematical description of the development process of an undesired aviation event is presented, which makes it possible to evaluate the probability of the successful (or unsuccessful) completion of a transportation task. Also given is an analysis of the development of an aviation accident, based on the example of the crash of a Lufthansa A-320 aircraft on 14 September 1993 at the airport of Warsaw (Poland) while landing in adverse weather conditions.

PL

W artykule dokonano przeglądu metod zarządzania bezpieczeństwem z wykorzystaniem tzw. piramid Heinricha i Birda. Zachodzenie związku przyczynowo-skutkowego pomiędzy poziomami piramidy, w wyniku niespójności w działaniach organizacji i personelu, prowadzi do incydentów, a incydenty z kolei prowadzą do wypadków. Istnienie takiego związku pozwala na przewidywanie ryzyka zdarzeń “najwyższego poziomu” poprzez ograniczanie ryzyka na poziomach średnim i niższym. Przedstawiono matematyczny opis procesu rozwoju niepożądanego zdarzenia lotniczego, który pozwala na ocenę prawdopodobieństwa pomyślnego (lub niepomyślnego) zakończenia zadania transportowego. Przedstawiono również analizę sposobu rozwoju wypadku lotniczego na przykładzie katastrofy samolotu A-320 linii Lufthansa w dniu 14 września 1993 r. na lotnisku w Warszawie podczas lądowania w niekorzystnych warunkach atmosferycznych.

4

Influence of speed of resin injection under pressure into mould on strength properties of polymer composite

Chatys Rafał, Piernik Krzysztof

Composites Theory and Practice

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2021

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R. 21, nr 1-2

40--45

EN

The paper presents a part of research aimed at determining the impact of the speed of resin injection under pressure into the mould on the quality of a laminate. In addition, technological defects such as inaccurate material placement, uneven resin injection into the mould, microvoids and microcracks during gelation are taken into account. For this purpose, the velocity and viscosity of the injected resin (via the Hagen-Poiseuille equation) were analysed analytically, and the gelation temperaturę of the resin was analysed numerically and compared with the experimental results. Strength tests were carried out on samples of two different lengths made using the RTM method. In the specimens cut with a different measuring base, significant scatter was found resulting from the superposition of effects and phenomena (delamination, voids or scale effect) related to the quality of the produced laminate.

PL

Przedstawiono fragment badań mających na celu określenie wpływu prędkości wtrysku żywicy pod ciśnieniem do formy na jakość laminatu. Dodatkowo uwzględniono wady technologiczne, takie jak niedokładne ułożenie materiału, nierównomierne wtryskiwanie żywicy do formy, mikropustki i mikropęknięcia podczas żelowania. W tym celu przeprowadzono analizę analityczną prędkości i lepkości wtryskiwanej żywicy (poprzez zależność Hagen-Poiseuille'a) oraz analizę numeryczną temperatury żelowania żywicy i porównano ją z wynikami doświadczalnymi. Badania wytrzymałościowe przeprowadzono na próbkach o dwóch różnych długościach, wykonanych metodą RTM. W próbkach wyciętych z różną podstawą pomiarową stwierdzono znaczny rozrzut wynikający z nałożenia się efektów i zjawisk (delaminacji, pustek czy efektu skali) związanych z jakością wytworzonego laminatu

5

Application of the Markov Chain Theory in Estimating the Strength of Fiber-Layered Composite Structures with Regard to Manufacturing Aspects

Chatys Rafał

Advances in Science and Technology. Research Journal

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2020

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Vol. 14, no 4

148--155

EN

The following work describes the application of a mathematical model based on Markov chain theory (MM) to estimate the fiber composite strength parameters, taking into account the laminate forming aspects using the vacuum bag method. This provides, from a unified position, a tool for a coordinated description of static strength and fatigue life. It was shown that the MM model gives relatively good results.