Wyniki wyszukiwania - Biblioteka Nauki

1

Verification of selected models of the size effect based on high-cycle fatigue testing on mini specimens made of EN AW-6063 aluminum alloy

100%

Tomaszewski T. , Sempruch J. , Piątkowski T.

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tom Vol. 52 nr 4

883--894

EN

The study presents several cases where use of specimens with reduced overall dimensions, i.e. mini specimens in the course of fatigue tests is advantageous. The high-cycle fatigue tests based on a developed method have been performed on mini specimens and normative specimens (comparative tests). The tests have been conducted on EN AW-6063 aluminum alloy specimens. A correction coefficient determined as a result of monotonic tests and selected models of the size effect have been critically assessed based on the test results. A statistical Weibull’s weakest link model and a monofractal approach based on a fractal dimension have been verified.

2

Stress-life curve for high and low cycle fatigue

100%

Kurek A. , Kurek M. , Łagoda T.

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tom Vol. 57 nr 3

677--684

EN

The paper contains a proposal of a new model for the stress-life curve. The new model reflects the nature of the stress curve occurring under current conditions, which means its shape of an inclined letter S. It can be used for both low and high cycle fatigue. Verification of the proposed model was performed on experimental results of ten various materials from three main types that are low-alloy, high-alloy and non-alloy steels.

3

Investigating the size effect for the small-dimension specimens made from the EN AW-6063 aluminium alloy

100%

Tomaszewski T. , Sempruch J. , Piątkowski T.

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tom Vol. 7, no 3

339-346

EN

The paper concerns the size effect on fatigue life and fatigue strength. As for the mini specimens, smaller than the normative specimens, they show an increase in fatigue life with a decrease in the object cross-section area. Theoretically the calculational models assume a lack of sensitivity of the aluminum alloys to changes in the crosssection size, which is contrary to the experimental tests. The paper has been an attempt at determining the size effect for EN AW-6063 aluminum alloy mini specimens. Monotonic and fatigue tests were made. There were observed correlations of the results for the coefficient of material sensitivity to change in the cross-section. The results have made it possible to define the relationship of the ultimate tensile strength and fatigue strength for the specimens of various size.

4

Investigation of low- and high-cycle fatigue in Al 2024-T4 alloy

75%

Kłysz S.

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tom nr 23(4)

309--321

EN

The article presents the results of low- (LCF) and high-cycle fatigue (HCF) analyses of 2024-T4 aluminum alloy which is used in aircraft construction, mainly for highly loaded structural components, including for plating, fuselage frames and rotor blade girders in helicopters. The alloy is used in structures where a high strength-to-weight ratio and high fatigue resistance are required. However, the alloy is poorly weldable and has low corrosion resistance. The tests were performed on hourglass and cylindrical samples with parallel and perpendicular orientation relative to the rolling direction. Samples for analysis were obtained from the production line of PZL-130 Orlik TC-II trainer aircraft. The results of the analysis were described by Manson- -Coffin and Morrow equations.

5

Trwałość wysokocyklowa stopów metali lekkich

51%

Cieśla M. , Marek A.

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tom Vol. 82, nr 8

546--548

PL

Praca dotyczy badań zmęczenia wysokocyklowego przerabianych plastycznie stopów metali lekkich, mających zastosowanie między innymi w technice lotniczej. Przydatność stopów metali lekkich na elementy konstrukcyjne urządzeń determinowana jest, oprócz ich niskiej gęstości, także szeregiem korzystnych właściwości mechanicznych, a w przypadku zastosowań na elementy środków transportu dodatkowo dobrą wytrzymałością zmęczeniową. Materiał do badań stanowiły pręty po przeróbce plastycznej na gorąco ze stopów magnezu AZ31 i AZ61, dwufazowego stopu tytanu Ti-6Al-4V oraz stopu aluminium 2017A (T451). Do badań zmęczenia wysokocyklowego w warunkach zginania obrotowego przy współczynniku asymetrii cyklu R= −1 wykonano próbki walcowe o średnicy d0=8 mm. Przeprowadzono próby w zakresie ograniczonej wytrzymałości zmęczeniowej. Na podstawie uzyskanych wyników opracowano charakterystyki trwałości zmęczeniowej badanych materiałów. W badaniach zmęczenia wysokocyklowego największą trwałość wykazał stopu tytanu Ti-6Al-4V.

EN

The paper refers to the research on high-cycle fatigue of wrought light metal alloys, applied, inter alia, in the aviation technology. Usefulness of the light metal alloys for various structural components is determined, apart from their low density, by a number of favourable mechanical properties and in the case of their use for components of transport means - additionally by good fatigue strength. The material for the research consisted of hot-worked rods made of AZ31 and AZ61 magnesium alloys, Ti-6Al-4V two-phase titanium alloy and 2017A (T451) aluminium alloy. Cylindrical specimens with a diameter of d0 = 8 mm were made for the fatigue test under high-cycle rotary bending conditions with the cycle asymmetry coefficient R = −1. The tests were carried out for a limited fatigue strength range. Based on the obtained results, fatigue life characteristics of the tested materials were drawn up. It was found that the Ti-6Al-4V alloy has the longest fatigue life.