Innowacyjne podejście do kształtowania trwałości maszyn pod względem bezpieczeństwa i niezawodności / Mateusz Wygoda, Bogdan Szybiński // W: Innowacyjność jako narzędzie kreowania jakości = ... więcej

Innowacyjne podejście do kształtowania trwałości maszyn pod względem bezpieczeństwa i niezawodności / Mateusz Wygoda, Bogdan Szybiński // W: Innowacyjność jako narzędzie kreowania jakości = Innovation as a tool for creating quality / red. nauk. Agnieszka Cholewa-Wójcik, Agnieszka Kawecka. – Radom : Sieć Badawcza Łukasiewicz - Instytut Technologii Eksploatacji, 2019. – (Towaroznawstwo w Badaniach i Praktyce = Commodity Science in Research and Practice). – S. 74-86 : fot., schem., tab., wykr. – Bibliogr. s. 86, Streszcz. ang. – Mat. konf.: Towaroznawstwo w badaniach i praktyce : Nauki o jakości wobec wyzwań innowacyjnej gospodarki i zrównoważonego rozwoju, Kraków, 6-8.11.2019. – ISBN 978-83-7789-596-2

Designing and construction of contemporary structures, machines usually undergo the strict design rules or codes published by the respective state institutions. This is because of the safety reasons, probable ... więcej

Designing and construction of contemporary structures, machines usually undergo the strict design rules or codes published by the respective state institutions. This is because of the safety reasons, probable exposition to life threat, economics consequences and others factors. Among many different scenarios of damage the fatigue failure or cracking are the most important. This kind of failure is the essential one for structures loaded by loads, which are varied in time. The proper assessment of the possible failure mechanism and time of safe exploitation of constructional elements attracts researchers since many years. On the base of the results of many experiments several rules for safe designing have been worked out so far. However, the investigations in this area are still in progress, due to the introduction of new materials or more and more complex and sophisticated designs. In case of using typical constructional steels the certain characteristic behavior under cyclic loads was observed several years before by Woehler and the so called Woehler (S-N) still remains the source of information about the fatigue strength of the constructional elements. In this curve the dependency between the external loads (stress) and the number of cycles to failure is plotted. Such curves may be produced for samples prepared according to the standards or for real constructional elements. The common constructional elements usually have more complex shape, including openings, holes, undercuts, etc. The presence of them strongly influences the fatigue endurance and time of safe exploitation of the structures due to the local increase of the stress, which is called the notch or stress concentration effect.This effect was the reason for several catastrophic failures of airplanes, ships and other machines observed in the past. In the proposed paper the influence of the rectangular hole cut in flat constructional element subjected to axial cyclic loading is studied. The investigated sample with notch (hole) possesses the rounded corners and the proper choice of their radii becomes the crucial point in designing. The detailed experimental tests were made for mild steel, which appears to be less sensitive for the presence of notches. The experimental results were compared with the results of numerical simulations.