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1

Crystallization of the Structural Components of Multiple Remelted AlSi9Cu3 Alloy

Matejka M., Bolibruchova D., Kuriš M.

Archives of Foundry Engineering

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2021

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Vol. 21, iss. 2

41--45

EN

At present, Al-Si-Cu based alloys (with a typical representative AlSi9Cu3 alloy) represent more than half of the castings used in various industries (automotive, aerospace and electrical engineering). These are most often sub-eutectic (exceptionally eutectic) alloys with a content of 6 to 13 wt. % Si and 1 to 5 wt. % Cu. The aim of the paper is to point out the importance of the evaluation of input raw materials that determines the overall properties of the casting and the costs invested in its production. A negative impact on performance can be expected when using an alloy made up of a high proportion of recycled material, despite its economic benefits. Experimental alloys were evaluated based on the results of crystallization process and a combination of scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), and deep etching. The effect of remelting and increasing the remelted returnable material in the batch was manifested especially in the crystallization of iron-rich phases. The negative effect of remelting on the structural components was manifested after the fourth remelting. Gradual increase of remelted returnable material in the batch causes harmful changes in the crystallization process.

2

Risks and Implications for Decision-Making Processes Associated with Existing Design Codes or Their Non-Existence

Błachut J., Sala D.

Decision Making in Manufacturing and Services

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2018

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Vol. 12, no. 1-2

5--15

EN

The buckling phenomenon is a perplexing and unresolved issue in many safety critical structures; as a result, it has been heavily regulated. The existence of regulations would normally benefit modern decision-making tools. But there are various obstacles coming from real-life situations. In order to illustrate the above and draw awareness to the problem, the paper chooses the buckling of shells and discusses (i) the case of an internally pressurized dome found in a plane’s fuselage that failed during a routine flight, (ii) a case where advances in structural mechanics challenge the existing design codes (i.e., metallic domes in pressure vessels), and (iii) a case of extracting rich seabed resources where efficient buoyancy units are required. In the last-mentioned case, the paper points towards the use of advanced Carbon Fiber Plastics (CFRPs) and illustrates this by a failed CFRP dome manufactured from a woven fabric (a topic still within the research sphere of activities). Cases of several other industrial failures caused by buckling are also provided. Finally, the paper highlights the risks to the decision-making processes due to the growing tendencies of eliminating the records of disastrous events from public domains through confidentiality arrangements and the erosion of the existing human know-how.

3

The concept of creation and use of the polycriterial diagnostics systems of enterprise activity

Kuzmin O. Ye., Melnyk O. H., Shpak N. O., Muk O. V.

ECONTECHMOD : An International Quarterly Journal on Economics of Technology and Modelling Processes

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2012

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Vol. 1, No 4

23-28

EN

The objective reason for the development of the tendencies causing transition from monocriterial to polycriterial approach in the diagnostics of enterprises’ functioning and the need for a systematic approach in this area is grounded. The concept of formation and use of the systems of polycriterial diagnostics of enterprises on the basis of selection and specification of the key structural elements of such systems is developed.

4

Probabilistic Fatigue Design of Structural Components

Jakubczak H.

Zeszyty Naukowe. Mechanika / Politechnika Opolska

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2005

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z. 79

85-104

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Ocena pewności działania konstrukcji nośnych narażonych na pękanie zmęczeniowe

Jakubczak H.

Diagnostyka

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2005

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Vol. 34

79--84

PL

Konstrukcje nośne maszyn wymiarowane w zakresie odporności na pękanie zmęczeniowe muszą wykazywać znaczny nadmiar wytrzymałości zmęczeniowej ze względu na obserwowany rozrzut ich trwałości oraz konieczność zapewnienia bezpiecznej pracy maszyn. Takie przewymiarowanie konstrukcji nośnych prowadzi w efekcie do pewnych kosztów, które mogą przejawiać się w różnej postaci. W referacie przedstawiono analizę pewności działania wybranej konstrukcji nośnej, wykazując jak poziom tej pewności wpływa na możliwy sposób jej uzyskania w zależności od przeznaczenia analizowanej konstrukcji.

EN

Structural and mechanical components designed against fatigue failure have to be over dimensioned due to scatter in the fatigue life and the necessity of safe operation of machines. Such an over dimensioning results in additional manufacturing costs. An example of reliability analysis of a structural component is presented in the paper which shows how the required reliability can be achieved depending on component destination.

6

Properties of electron beam welded 300M steel

Dudek S., Karliński W., Poznańska A., Śnieżek M.

Prace Instytutu Lotnictwa

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2003

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z. 1-2 (172-173)

55-58

EN

Electron beam welding technology of ultrahigh-strength steel of 300M grade was worked up. The steel would replace 30HGSNA steel for such aircraft structural components as landing gear units and wing spars. The weld strength properties meet requirements of AMS 614 E standard for nonwelded specimens and are much higher than of 30HGSNA steel, both welded and parent metal. The welds show good homogeneity and dispersion of properties.

PL

Opracowano technologię spawania wiązką elektronów stali 300M, przeznaczonej do zastąpienia stali 30HGSNA w wykonawstwie wysokoobciążonych elementów konstrukcyjnychkonstrukcyjnych płatowców, takich jak: podwozia i dźwigary. Uzyskano złącza o właściwościach wytrzymałościowych spełniających wymagania normy amerykańskiej AMS6414H dla materiału niespawanego. Złącza odznaczają sie dużą jednorodnością i małym rozrzutem właściwości, które są znacznie wyższe od stali 30HGSNA, spawanej i niespawanej.