Wyniki wyszukiwania - Biblioteka Nauki

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Use of the finite element method to design the properties of shaped joints made of composite materials

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Dylewski A. , Łogin W.

Advances in Science and Technology. Research Journal

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2018

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tom Vol. 12, no 2

59--64

EN

Polskie Zaklady Lotnicze in Mielec within the framework of the BloStEr project implemented in the sectoral program INNOLOT develops technology whose main idea is to be able to connect parts into structures through the use of specially designed shaped joins. The article presents the results of numerical analyzes of the selected shape joint made of long fiber composite and verification of analyzes on real object. The second part of the paper presents the results of performed numerical analyzes, which investigated the influence of the change of the layer system on the properties of the joint, in particular the opening force and deformation phenomena of the working elements.

2

Analysis of wear of tools made of 1.2344 steel and MP159 alloy in the process of friction stir welding (FSW) of 7075 T6 aluminium alloy sheet metal

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Więckowski W. , Burek R. , Lacki P. , Łogin W.

Eksploatacja i Niezawodność

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2019

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tom Vol. 21, no. 1

54--59

EN

The study presents an analysis of wear of tools made of 1.2344 steel and MP159 alloy for the process of obtaining an overlap joint in 1.0 mm and 0.8 mm sheet metal made of 7075 T6 aluminum alloy using friction stir welding (FSW) technology. Tool geometry was designed at the Czestochowa University of Technology. Evaluation of tool wear was conducted based on the measurements of geometry of working area of tools by means of a multisensory meter system and based on the assessment of the working area by means of a stereoscope after individual stages of wear tests. Furthermore, based on the results of a static tensile strength test and metallographic examinations of the specimens sampled from the joints obtained during tool wear tests, the effect of the degree of tool wear on joint quality was also evaluated. Analysis of the results revealed that both the tool made of 1.2344 steel and that made of MP159 alloy were substantially worn, increasing the risk of further use of the tools for the joint material (7075-T6) after obtaining the joint with length of 200m, which suggests their low durability. Furthermore, modification of tool geometry caused by wear led to insignificant improvements in joint strength. Therefore, the results of wear measurement set directions for further modification of tool geometry, also due to the fact that despite a substantial wear, the tools continued to yield high-quality joints without defects. As demonstrated in the study, the type of tool material does not only impact on tool life but also, as it was the case in their geometry, has a significant effect on the quality of obtained joints. Although the tool made of MP159 alloy was worn more than the tool made of 1.2344 steel, it allowed for obtaining the joints with substantially better strength parameters.

PL

W pracy przedstawiono analizę procesu zużycia narzędzi wykonanych ze stali 1.2344 oraz stopu MP159 w procesie wykonywania złączy zakładkowych z blach ze stopu aluminium 7075 T6 o grubości 1,0mm i 0,8mm technologią zgrzewania tarciowego z przemieszaniem materiału (FSW). Geometrię narzędzi użytych do badań opracowano na Politechnice Częstochowskiej. Ocenę zużycia narzędzi przeprowadzono w oparciu o pomiary geometrii części roboczej narzędzi na maszynie multisensorycznej oraz na podstawie oględzin powierzchni roboczej przy użyciu stereoskopu po kolejnych etapach badań zużycia narzędzia. Dodatkowo, w oparciu o wyniki statycznej próby rozciągania oraz badania metalograficzne próbek pobranych ze złączy wykonywanych w trakcie badań zużycia narzędzi, przeprowadzono ocenę wpływu stopnia zużycia narzędzi na jakość wykonanych złączy. Na podstawie analizy wyników można stwierdzić, że zarówno narzędzie wykonane ze stali 1.2344 oraz ze stopu MP159 ulegają intensywnemu, zagrażającemu ich dalszej eksploatacji zużyciu, we współpracy z materiałem zgrzeiny (7075-T6) już po wykonaniu złącza o długości 200m, co świadczy o ich niskiej trwałości. Przy czym zmiany geometrii narzędzia spowodowane zużyciem pozwoliły na nieznaczną poprawę wytrzymałości złączy. Uzyskane wyniki pomiarów zużycia wyznaczają zatem kierunek w procesie dalszej modyfikacji geometrii badanych narzędzi, również z uwagi na fakt, iż pomimo znaczącego zużycia badanych narzędzi, pozwalały one w dalszym ciągu uzyskać dobre jakościowo złącza pozbawione wad. Jak wykazały badania, rodzaj materiału narzędzia wpływa nie tylko na trwałość narzędzi ale również, jak ma to miejsce w przypadku ich geometrii, ma on istotny wpływ na jakość uzyskanych połączeń. Pomimo tego, że narzędzie wykonane ze stopu MP159 uległo większemu zużyciu w porównaniu z narzędziem ze stali 1.2344, to pozwoliło ono uzyskać złącza o znacznie lepszych parametrach wytrzymałościowych.

3

State of residual stresses after the process of milling selected aluminium alloys

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Kuczmaszewski J. , Łogin W. , Pieśko P. , Zagórski I.

Advances in Science and Technology. Research Journal

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2018

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tom Vol. 12, no 1

63--73

EN

The purpose of this paper was to analyse the structure and the state of residual stresses in the samples made of rolled AW-2024 and AW-7075 aluminium alloy plates, prior to machine cutting and after the process of milling under various machining conditions. The state of stresses was evaluated on the basis of measurements by means of sin2vF X-ray diffractometry and layer removal method. Furthermore, top layer microstructures were compared in half-finished product, machined product, and core material samples.

4

The Influence of Modification of the Front Surface Geometry of the RFSSW Tool Sleeve on the Plasticization Effect and Stirring Materials During Joining Sheets Made of Aluminum Alloy 2024

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Łogin W. , Śliwa R. E. , Ostrowski R.

Archives of Metallurgy and Materials

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2022

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tom Vol. 67, iss. 4

1435--1442

EN

The paper presents the results of research and analysis of the effect of joining by the RFSSW method of alclad sheets made of Al2024 with an anodic oxide coating, with the using the tool with modified geometry of the front surface of inner sleeve. The different effects of the modifications made on the phenomenon of plasticization and stirring of materials in the process of creating a weld, microstructure of welds and mechanical strength of lap joints were shown. The tests were carried out on 1.27 mm thick sheets, with the use of an unmodified tool and modified tools with three variants of the geometry. The welds and the joints samples were subjected to metallographic and strength tests. It has been shown that the use of a properly selected modified geometry has a beneficial effect on the transport of materials to be joined in the joint zone (flow pattern of plasticized layers and the stirring effect) during the welding, which translates into the strength of the joints and the nature of the weld failure.