Skocz do pozycji: 1.

Tytuł:

A fatigue damage accumulation method in low - cycle fatigue zone

Autorzy:

Mroziński, S.

Powiązania:

https://bibliotekanauki.pl/articles/279495.pdf

Data publikacji:

2000

Wydawca:

Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej

Tematy:

fatigue life
fatigue damage accumulation
low-cycle fatigue

Opis:

A summation method of the fatigue damage in a low cycle fatigue zone is proposed in the paper. The method is based on a fatigue curve revolution, with the fatigue in the... co-ordinate system as a base line. The low-cycle properties and parameters of a loading program are necessary for fatigue life calculations. Experimental verification of the proposed hypothesis(one material, two types of loading: random and programed) showed a satisfactory agreement between the test and calculation results. A comparative analisys between the calculation results obtained using the linear damage rule (LDR) and those resulting from the method proposed, showed several advantages of the latter one. These are; e.g., the fact that the results obtained are located in the safe fatigue life area, simplicity of the method and sensitivity to the parameters of a loading program.
Hipoteza kumulacji uszkodzeń zmęczeniowych w obszarze niskicyklowego zmęczenia. W pracy przedstawiono propozycję metody sumowania uszkodzeń zmęczeniowych w obszarze niskocyklowego zmęczenia. Opisywana metoda jest oparta na koncepcji obrotu wykresu zmęczeniowego. Wykresem bazowym jest wykres trwałości zmęczeniowej w układzie współrzędnych ... . Niezbędne dane do obliczeń trwałości to własności niskocyklowe oraz parametry programu obciążenia. Weryfikacja doświadczalna proponowanej hipotezy (jeden materiał, dwa rodzaje obciążenia - losowe i programowane) wykazała zadowalającą zgodność wyników obliczeń i badań. Przeprowadzona analiza porównawcza wyników obliczeń uzyskanych przy wykorzystaniu hipotezy liniowej (LDR) oraz hipotezy przedstawionej w poniższej pracy wykazała szereg zalet tej ostatniej. Do zalet metody obliczeń zaliczono m. in. położenie uzyskanych wyników obliczeń w bezpiecznym obszarze trwałości, jej prostotę, oraz wrażliwość na parametry programu obciążenia.

Źródło:

Journal of Theoretical and Applied Mechanics; 2000, 38, 4; 767-780
1429-2955

Pojawia się w:

Journal of Theoretical and Applied Mechanics

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 2.

Tytuł:

Integral fatigue criteria evaluation for life estimation under uniaxial combined proportional and non-proportional loadings
Ocena zmęczeniowych kryteriów całkowych w zakresie szacowania trwałości w warunkach obciążeń jednoosiowych, złożonych proporcjonalnych i nieproporcjonalnych

Autorzy:

Skibicki, D.
Pejkowski, Ł.

Powiązania:

https://bibliotekanauki.pl/articles/281733.pdf

Data publikacji:

2012

Wydawca:

Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej

Tematy:

multiaxial fatigue
fatigue life
fatigue criteria
integral approach

Opis:

The paper presents a review and verification of integral fatigue criteria. The review signals the key assumptions and criteria structure elements. The verification has been developed drawing on the experimental data reported in literature containing fatigue life for uniaxial, combined proportional and non-proportional loads. The verification involves a comparison of computational fatigue life with the experimental one. To determine the quality of the results generated, statistical parameters were used. As a result of the analysis the best and the worst criteria were pointed to.
Celem niniejszej pracy jest ocena możliwości szacowania trwałości zmęczeniowej za pomocą całkowych kryteriów zmęczeniowych. Podejście całkowe bazuje na założeniu, że dla prawidłowej oceny zachowań zmęczeniowych konieczne jest zsumowanie (scałkowanie) wartości parametru zniszczenia na wszystkich płaszczyznach przechodzących przez rozpatrywany punkt materiału. Analizę przeprowadzono dla trzech najczęściej spotykanych kryteriów całkowych: kryterium Zennera i dwóch kryteriów Papadopoulosa. Uzyskane wyniki porównano z kryterium zmęczeniowym McDiarmida, bazującym na konkurencyjnym w stosunku do całkowego podejściu płaszczyzny krytycznej, oraz powszechnie stosowanym w wielu obszarach wytrzymałości materiałów kryterium Hubera-Misesa-Hencky’ego.

Źródło:

Journal of Theoretical and Applied Mechanics; 2012, 50, 4; 1073-1086
1429-2955

Pojawia się w:

Journal of Theoretical and Applied Mechanics

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 3.

Tytuł:

Aluminum and its alloys in the very high cycle fatigue regime

Autorzy:

Okechukwu, P. Nwachukwu
Gridasov, Alexander V.
Talskikh, Kristina Y.
Grishin, Anton V.
Nikiforov, Pavel A.
Sukhorada, Aleksey E.

Powiązania:

https://bibliotekanauki.pl/articles/1178317.pdf

Data publikacji:

2017

Wydawca:

Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN

Tematy:

Aluminum alloys
Crack initiation
Fatigue failure
Fatigue limit
Gigacycle fatigue

Opis:

This paper examines the very high cycle fatigue of aluminum alloys used in engineering applications. Specifically taken into consideration are findings of tests and experiments by some scientists and experts in the field of fatigue of structural materials. The examination of the most common material defects that initiate cracks and causes of fatigue failures in aluminum alloys in the very high cycle regime are reviewed. As aluminum alloys are among the most commonly used structural materials that do not exhibit a fatigue limit at 107 load cycles, it became very important to critically review the tests and experiments of experts in the field in order to ascertain the most causes of failures in these alloys. This paper concluded by suggesting the directions for future works in the very high cycle fatigue of aluminum alloys based on the theoretical review.

Źródło:

World Scientific News; 2017, 81, 2; 121-131
2392-2192

Pojawia się w:

World Scientific News

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 4.

Tytuł:

Application of two-parameter fatigue charactersitics in fatigue persistence calculations of structural components under conditions of a broad spectrum of loads

Autorzy:

Szala, G.

Powiązania:

https://bibliotekanauki.pl/articles/260285.pdf

Data publikacji:

2016

Wydawca:

Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa

Tematy:

fatigue persistence
linear hypothesis of fatigue damage summation
fatigue tests

Opis:

The paper presents an original method of calculation of the fatigue persistence based on the adoption of the load spectrum in the form of a correlation table, two-parameter fatigue characteristics and the linear hypothesis of fatigue damage summation. The calculation results by the proposed method were compared with the results of fatigue tests programmed for node-seal construction. On the basis of a comparative analysis of the test results and calculations conclusions regarding the usefulness of the proposed method to evaluate the fatigue persistence of components have been reached.

Źródło:

Polish Maritime Research; 2016, 4; 138-145
1233-2585

Pojawia się w:

Polish Maritime Research

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 5.

Tytuł:

A probabilistic method of determining fatigue life of a structural component using the paris formuła and the probability density function of time of exceeding the boundary condition - an outline

Autorzy:

Tomaszek, H.
Klimaszewski, S.
Zieja, M.

Powiązania:

https://bibliotekanauki.pl/articles/245569.pdf

Data publikacji:

2009

Wydawca:

Instytut Techniczny Wojsk Lotniczych

Tematy:

fatigue life
density function
fatigue cracking

Opis:

An attempt has been made to present a probabilistic method to determine fatigue life of an aeronautical structure's component by means of a density function of time a growing crack needs to reach the boundary condition. It has been assumed that in a component of a structure given consideration there is a small crack that grows due to fatigue load affecting it. After having reached the boundary value the component in question loses its usability. Time of the crack growth up to the boundary value is termed a fatigue life of the component. From the aspect of physics, the propagation of a crack within the component, if approached in a deterministic way, is described with the Paris 's relationship for m = 2. To model the fatigue crack growth a difference equation has been applied, from which the Fokker-Planck equation has been derived to be then followed with a density Junction of the growing crack. The in this way found density function of the crack length has been applied to find density Junction of time of reaching the boundary condition. This function has been used in the present paper to determine the randomly approached fatigue life of a component of a structure. The present paper has been prepared for the case there is coefficient m = 2 in the Paris formula. With the in the paper presented scheme, one can find fatigue life of the structure's component for the case m not equal to 2.

Źródło:

Journal of KONES; 2009, 16, 3; 431-438
1231-4005
2354-0133

Pojawia się w:

Journal of KONES

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 6.

Tytuł:

The Influence of The Degree of the Rivet Hole Sizing on the Fatigue Life

Autorzy:

Lipski, A.

Powiązania:

https://bibliotekanauki.pl/articles/97917.pdf

Data publikacji:

2012

Wydawca:

Sieć Badawcza Łukasiewicz - Instytut Lotnictwa

Tematy:

fatigue tests
rivets
holes
fatigue life

Opis:

The paper presents the results of fatigue tests of specimens with sized rivet holes. Samples for tests were made of 0.05'' (1.27 mm) thick non-clad plates of aluminium grade 2024-T3. Rivet holes were prepared assuming that they shall be used for 3 mm nominal diameter snap head rivets for aviation-related purposes. Different sizing degrees were achieved by drilling holes of different diameters in the samples followed by the sizing process using a sizing mandrel of the same diameter of 3.15 mm. Holes in the test samples were drilled using special device ensuring appropriate quality and repeatability of the holes. Five different sizing degrees were achieved be means of five drills of different diameters. Samples with holes of varying degrees of sizing were tested under constant amplitude sinusoidal loading conditions (cycle asymmetry coefficient R = 0) at the load frequency of 5 Hz. The study was conducted at three levels of maximum stress in the cycle. Fatigue life test results were presented in the form of fatigue diagrams (regression lines) determined in the bi-logarithmic coordinate system log N, log S_max. The results of the fatigue life tests received for the drilled as well as drilled and reamed holes were also presentedfor comparison. The results obtained lead to the conclusion that that the lowest fatigue life characterises samples with drilled holes and drilled and reamed holes. Fatigue life of specimens with holes for rivets improved (by 50% to 74%, depending on load level), even as a result of the hole surface polishing only (minimum sizing degree), whilst the two-fold growth of fatigue life was achieved for holes of a slight sizing degree. A further significant increase in fatigue life was achieved by the cold work of the hole's surface. Based on the location of the fatigue diagrams and the fatigue life tests results, it may be concluded that the higher a sizing degree, the higher the fatigue life growth. The growth is also proportional to the specimen load level: the lower the load level, the higher the fatigue life growth. Fatigue diagrams obtained from tests were divided into three groups: diagrams for drilled holes and drilled and reamed holes, diagrams for holes with a low degree of sizing and diagrams for holes with a high degree of sizing. This division was confirmed by statistical tests of regression lines parallelism by the “peer-to-peer” method.

Źródło:

Fatigue of Aircraft Structures; 2012, 4; 64-69
2081-7738
2300-7591

Pojawia się w:

Fatigue of Aircraft Structures

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 7.

Tytuł:

Fatigue life of metallic material estimated according to selected models and load conditions

Autorzy:

Kluger, K.
Łagoda, T.

Powiązania:

https://bibliotekanauki.pl/articles/281337.pdf

Data publikacji:

2013

Wydawca:

Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej

Tematy:

uniaxial fatigue
multiaxial fatigue
mean stress

Opis:

The authors present results of a fatigue test for specimens made of the aluminium Allom 2017A-T4 and alloy steels S355J2WP and S355J2G3 subjected to constant-amplitude proportional combined bending with torsion including mean stress values and for the S355J2WP alloy steel under uniaxial constant-amplitude and random loading with both zero and non zero mean stress values. The test results were compared with the results of calculations according to the models proposed by Goodman, Gerber and Morrow as well as the stressstrain parameter. In the case of calculations based on the stresses, the multiaxial stress state was reduced to a uniaxial one using the Huber-Mises relationship. As for the method based on strain energy density, the multiaxial stress state was reduced to the uniaxial one with use of the stress-strain parameter. The plane in which the stress-strain parameter of shear loadings reaches its maximum value is assumed to be the critical plane.

Źródło:

Journal of Theoretical and Applied Mechanics; 2013, 51, 3; 581-592
1429-2955

Pojawia się w:

Journal of Theoretical and Applied Mechanics

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 8.

Tytuł:

Assessment of the fatigue life of machine components under service loading – a review of selected problems

Autorzy:

Będkowski, W.

Powiązania:

https://bibliotekanauki.pl/articles/279894.pdf

Data publikacji:

2014

Wydawca:

Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej

Tematy:

fatigue life prediction
multiaxial fatigue
service loading

Opis:

Based on a literature review, the author provides a historical outline of the fatigue analysis and describes the current trends aiming at comprehension of the fatigue life of engineering structures under service loading. Next, an algorithm for multiaxial fatigue life prediction is identified, describing steps of calculation. Classification criteria of fatigue failure and components of the stress state in multiaxial loading conditions are also presented, recognising the importance of the so-called Standarised Load Histories (SLH) used in the comparative analysis of fatigue life of finished products.

Źródło:

Journal of Theoretical and Applied Mechanics; 2014, 52, 2; 443-458
1429-2955

Pojawia się w:

Journal of Theoretical and Applied Mechanics

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 9.

Tytuł:

Wysokocyklowe badania zmęczeniowe z wykorzystaniem minipróbek
High cycle fatigue tests using mini specimen

Autorzy:

Tomaszewski, T.
Sempruch, J.
Piątkowski, T.

Powiązania:

https://bibliotekanauki.pl/articles/315934.pdf

Data publikacji:

2013

Wydawca:

Instytut Naukowo-Wydawniczy "SPATIUM"

Tematy:

trwałość zmęczeniowa
badania zmęczeniowe
fatigue life
fatigue tests

Opis:

Praca dotyczy oceny trwałości zmęczeniowej, traktowanej jako cecha niezawodności. Specyficznym obszarem zainteresowań autorów jest sytuacja, kiedy niemożliwe jest pobranie materiału do badań w ilości odpowiadającej próbkom normatywnym. Zaprezentowano metodykę badań z wykorzystaniem próbek o zmniejszonych wymiarach (tzw. minipróbek). W pracy wyznaczono efekt skali dla stopu aluminium EN AW-6063. Uzyskane wyniki pozwoliły określić zależność wytrzymałości na rozciąganie i wytrzymałości zmęczeniowej dla dwóch geometrii próbek. Otrzymano zbieżności wartości współczynnika wrażliwości materiału na zmianę rozmiaru przekroju wyznaczonego z prób monotonicznych i zmęczeniowych.
The paper concerns the assessment of the fatigue life, which is treated as a feature of reliability. A specific area of interest for the authors is situation, where taking test material is impossible in a quantity corresponding a normative specimens. The methodology of the tests using specimens with reduced dimensions (called mini specimen) were presented. The paper attempts to determine the size effect for the EN AW-6063 aluminum alloy. The results have made it possible to define the relationship of the ultimate tensile strength and fatigue strength for two geometry of the specimens. The values of the coefficient of material sensitivity to change in the cross-section for monotonic and fatigue tests are similar.

Źródło:

Autobusy : technika, eksploatacja, systemy transportowe; 2013, 14, 3; 875-882
1509-5878
2450-7725

Pojawia się w:

Autobusy : technika, eksploatacja, systemy transportowe

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 10.

Tytuł:

Some problems of slide bearing material fatigue evaluation

Autorzy:

Sikora, J.
Kłopocki, J.
Majewski, W.
Kurzych, K.

Powiązania:

https://bibliotekanauki.pl/articles/242756.pdf

Data publikacji:

2007

Wydawca:

Instytut Techniczny Wojsk Lotniczych

Tematy:

bearings
tribology
bearing testing
fatigue investigations
fatigue performance

Opis:

A slide bearing alloy resistance against fatigue failures have been investigated for three different lubricants, different heat loadings and different stress ratio K values. The research methods and data handling procedures for determination of particular parameter effects on fatigue strength have been described and analysed for experiments that were set and performed in laboratory tester SKMR-2. Main and interaction effects of lubricant and stress ratio factors on bearing material fatigue strength have been analysed. Design scheme of the SKMR-2 head unit, Standard tested half-bearing, fatigue failures on the surface of the specimen, cross-section through the damaged surface layer of the specimen, fatigue limit stress amplitude vs. temperature and kind of oil, main effect of stress ratio, main effects of temperature and oil are illustrated in the paper. Main conclusions are cover in statements that fatigue strength of the bearing material is affected, to the highest degree, by the mechanical stress value and stress ratio and resistance to the fatigue cracks is being reduced for higher tensional stress, increase in temperature is resulting in decreasing of the fatigue strength rating values, fatigue strength of the slide layer is considerably dependent on the type of the used lubricant interactions of the type of the lubricants, their temperatures, loading stress ratio have been noticed.

Źródło:

Journal of KONES; 2007, 14, 4; 427-432
1231-4005
2354-0133

Pojawia się w:

Journal of KONES

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 11.

Tytuł:

Comparing guidelines concerning construction of the S-N curve within limited fatigue life range

Autorzy:

Strzelecki, P.
Sempruch, J.
Nowicki, K.

Powiązania:

https://bibliotekanauki.pl/articles/260399.pdf

Data publikacji:

2015

Wydawca:

Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa

Tematy:

high-cycle fatigue
S-N curve
fatigue tests

Opis:

The article collates guidelines concerning experimental construction of the S-N fatigue curves within a limited fatigue life range. An attempt is made to compare these guidelines, based on experimental data recorded during rotating bending of a notched specimen made of 42CrMo4. The recorded differences in fatigue life values between the constructed curves reach the maximum of 12.2%. According to the above guidelines, the number of tests in particular test series varies from 6 to 28. Based on the performed analysis a conclusion was made that the increase in the number of tests leads to the increase of accuracy but, on the other hand, remarkably increases the time of the experiment and, consequently, its cost. In this context, it is the research worker who, taking into account a possible future use of the fatigue curve, should individually decide about its accuracy.

Źródło:

Polish Maritime Research; 2015, 3; 67-74
1233-2585

Pojawia się w:

Polish Maritime Research

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 12.

Tytuł:

Low-Cycle Fatigue Characteristics of Selected Titanium, Magnesium and Aluminium Alloys

Autorzy:

Junak, G.

Powiązania:

https://bibliotekanauki.pl/articles/351829.pdf

Data publikacji:

2018

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

fatigue life
low-cycle fatigue
light metal alloys

Opis:

In the paper, on the basis of the performed tests, low-cycle fatigue characteristics (LCF) of selected light metal alloys used among others in the automotive and aviation industries were developed. The material for the research consisted of hot-worked rods made of magnesium alloy EN-MAMgAl3Zn1, two-phase titanium alloy Ti6Al4V and aluminium alloy AlCu4MgSi(A). Alloys used in components of means of transport should have satisfactory fatigue, including low-cycle fatigue, characteristics. Low-cycle fatigue tests were performed on an MTS-810 machine at room temperature. Low-cycle fatigue tests were performed for three total strain ranges Δε_t = 0.8%, 1.0% and 1.2% with a cycle asymmetry coefficient R = –1. On the basis of the obtained results, characteristics of the fatigue life of materials, cyclic deformation σ_a = f(N) and cyclic deformation of the tested alloys were developed. The tests showed that titanium alloy Ti6Al4V was characterised by the highest fatigue life N_f , whereas the lowest fatigue life was found in the tests of the aluminium alloy AlCu4MgSi(A).

Źródło:

Archives of Metallurgy and Materials; 2018, 63, 4; 1949-1955
1733-3490

Pojawia się w:

Archives of Metallurgy and Materials

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 13.

Tytuł:

On the Estimation of Fatigue Crack Initiation Life of H62 Brass

Autorzy:

Zheng, M.
Zhang, S.
Peng, Xiao Jian
Wang, Yi

Powiązania:

https://bibliotekanauki.pl/articles/2048866.pdf

Data publikacji:

2022

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

strain energy density
fatigue damage strain
theoretical strain fatigue limit
fatigue crack initiation
life prediction

Opis:

In the present paper, the excavation of the energetic approach that estimates the fatigue crack initiation life of metal is conducted for H62 brass. The benefit of the energetic approach is the division of the actual applied strain range Δε into two parts, that is, a damage strain range Δεd that induces fatigue damage within the metal, and an undamaged strain range Δεc, which does not produce fatigue damage of the metal and corresponds to theoretical strain fatigue limit. The brightness of this approach is that the undamaged strain range Δεc can be estimated by the fundamental conventional parameters of metal in tensile test. The result indicated that the fatigue crack initiation life of H62 brass can be estimated by this approach successfully.

Źródło:

Archives of Metallurgy and Materials; 2022, 67, 1; 31-35
1733-3490

Pojawia się w:

Archives of Metallurgy and Materials

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 14.

Tytuł:

Fatigue life of compacted wire ropes for applications in deep mining

Autorzy:

Kubiś, Bogusław
Olszyna, Grzegorz
Szade, Piotr
Tytko, Andrzej

Powiązania:

https://bibliotekanauki.pl/articles/27315587.pdf

Data publikacji:

2023

Wydawca:

STE GROUP

Tematy:

steel wire rope
fatigue tests
compacted ropes
fatigue durability

Opis:

Recent months have highlighted the progressing energy crisis across Europe in connection with the severe sanctions imposed on the import of hydrocarbons and coal from Russia. This is particularly visible in Poland, where over 40% of electricity is generated from coal, while in individual households it is the primary source of heat. This situation puts the already enigmatic plans of shutting down coal mining in Poland into question. Therefore, work aimed at increasing the extraction capacity of existing shafts while maintaining the highest level of operational safety is still valid. This article concerns the issues of the fatigue life of compacted ropes used as hoist ropes in mine shafts. The discussion regarding the use of these ropes among shaft hoist users has been going on for several years. This paper presents the unique results of compacted rope fatigue tests carried out at the Central Mining Institute in Katowice. In the authors’ view, these results and their interpretation should serve to clarify several important aspects that arouse the interest of users.

Źródło:

Management Systems in Production Engineering; 2023, 1 (31); 95--101
2299-0461

Pojawia się w:

Management Systems in Production Engineering

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 15.

Tytuł:

Analysis of axle shaft fatigue failure and anti-fatigue system design

Autorzy:

İrsel, G.

Powiązania:

https://bibliotekanauki.pl/articles/102537.pdf

Data publikacji:

2017

Wydawca:

Stowarzyszenie Inżynierów i Techników Mechaników Polskich

Tematy:

CATIA
ANSYS
fatigue analysis
redesign
shaft fatigue
product development

Opis:

In this study, an axle shaft subjected to static deformation and fatigue damage was considered by using computer-aided engineering. This shaft system was modeled with CATIA and subjected to dynamic fatigue analyses with Ansys workbench. The damaged fracture surfaces of the shaft have been examined. Thus, the fatigue and damage was revealed in greater detail. For the present system, a design with a minimum cost, short production process, minimum weight was sought together with methodical construction principles. By means of CATIA and ANSYS, the product development design with reasonable tension and deformation values was formed for endless life fatigue. A design was produced in a short space of time with the help of 2D CATIA drawings and field tests were carried out. The design was used through 560.000 cycles and damage was not observed.

Źródło:

Advances in Science and Technology. Research Journal; 2017, 11, 3; 150-163
2299-8624

Pojawia się w:

Advances in Science and Technology. Research Journal

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 16.

Tytuł:

The influence of loading program on the course of fatigue damage cumulation
Wpływ programu obciążenia na przebieg kumulacji uszkodzeń zmęczeniowych

Autorzy:

Mroziński, S.

Powiązania:

https://bibliotekanauki.pl/articles/280948.pdf

Data publikacji:

2011

Wydawca:

Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej

Tematy:

fatigue life
low-cycle fatigue
damage accumulation
programmed loading

Opis:

In the paper, results of a comparative analysis of cyclic properties of specimens made of 30HGSA steel under constant-amplitude and programmed loading were presented. The analysis was carried out with the use of parameters of the characteristic hysteresis loop in function of the degree of fatigue damage. The analysis showed that courses of cyclic properties changes for chosen strain levels are very similar and do not depend on the loading program. It was shown that during damage cumulation it is possible to take into account the changes of cyclic properties.
W pracy przedstawiono wyniki analizy porównawczej właściwości cyklicznych próbek ze stali 30 HGSA w warunkach obciążenia stałoamplitudowego i programowanego. Analizę prowadzono z wykorzystaniem charakterystycznych parametrów pętli histerezy w funkcji stopnia uszkodzenia zmęczeniowego. Przeprowadzona analiza wykazała, że przebiegi zmian właściwości cyklicznych na wybranych poziomach odkształcenia są bardzo podobne i nie zależą od programu obciążenia. W pracy wykazano, że podczas sumowania uszkodzeń istnieje możliwość uwzględniania zmian własności cyklicznych.

Źródło:

Journal of Theoretical and Applied Mechanics; 2011, 49, 1; 83-95
1429-2955

Pojawia się w:

Journal of Theoretical and Applied Mechanics

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 17.

Tytuł:

Fatigue strength determination of ship structural joints. Part I. Analytical methods for determining fatigue strength of ship structures

Autorzy:

Kozak, J.
Górski, Z.

Powiązania:

https://bibliotekanauki.pl/articles/258582.pdf

Data publikacji:

2011

Wydawca:

Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa

Tematy:

fatigue of ship structure
cumulative damage
fatigue life analysis

Opis:

Spectacular accidents at sea which have happened for a few last years show that hull structures of contemporary sea-going ships are not perfect and must be systematically improved. Fatigue strength is one of the groups of strength problems which affect design of contemporary ship’s structures and greatly contribute in their improvement process. In this paper several approaches to estimation of fatigue life of hull structural elements are presented. In practice the some approaches based on nominal stresses, „hot spot” stresses or notch stresses which constitute the basis for fatigue life determination by using ó-N design curves are applied. In this paper the existing proposals have been critically analyzed and their drawbacks (often hidden) presented.

Źródło:

Polish Maritime Research; 2011, 2; 28-36
1233-2585

Pojawia się w:

Polish Maritime Research

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 18.

Tytuł:

Fatigue Life Predicting for Nitrided Steel - Finite Element Analysis

Autorzy:

Sawicki, J.
Siedlaczek, P.
Staszczyk, A.

Powiązania:

https://bibliotekanauki.pl/articles/355788.pdf

Data publikacji:

2018

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

numerical simulation
nitriding
fatigue life
fatigue analysis
finite element

Opis:

Thermo-chemical treatments are known to increase the fatigue life of industrial parts. Due to the imprecise consideration of residual stresses in predicting the durability of components subjected to cyclic loading and their effect on the fatigue life, the authors developed a numerical model combining the influence of residual stresses with stresses caused by bending. The authors performed the numerical simulation with the use of Finite Element Method to analyse material behaviour during cyclic loading. The residual stress state developed during nitriding was introduced onto cross-section of the numerical specimen. The goal of this work was better understanding of the real conditions of the nitride steel fatigue processes and improving the knowledge about numerical predicting of the fatigue life for parts with residual stresses. The results of simulation were compared with plane bending fatigue tests. The presented method indicates the possibility of increasing the accuracy of the fatigue analysis of elements after surface treatment, increasing its certainty and the ability to perform better optimization of service life.

Źródło:

Archives of Metallurgy and Materials; 2018, 63, 2; 921-927
1733-3490

Pojawia się w:

Archives of Metallurgy and Materials

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 19.

Tytuł:

Introduction of Fatigue Markers in Full Scale Fatigue Test of an Aircraft Structure

Autorzy:

Leski, A.
Kłysz, S.
Lisiecki, J.
Gmurczyk, G.
Reymer, P.
Bochenek, D.
Zasada, D.

Powiązania:

https://bibliotekanauki.pl/articles/97777.pdf

Data publikacji:

2012

Wydawca:

Sieć Badawcza Łukasiewicz - Instytut Lotnictwa

Tematy:

full scale fatigue test
fatigue markers
load block rearrangement

Opis:

Air Force Institute of Technology participates in the service life assessment programme SEWST. The aim of this programme, funded by the Polish Ministry of Defense, is to modify the operation system of PZL-130 "Orlik" TC-II turbo propelled trainer aircraft. The structural part of the programme is focused on the Full Scale Fatigue Test of the whole airframe to be conducted at the VZLU in the Czech Republic. The load spectrum for the test was developed by the AFIT based on the flight test results. The basic load block represents 200 simulated flight hours and consists of 194 flights showing different levels of severity. At the end of the Full Scale Fatigue Test a teardown inspection is planned during which it would be most beneficial to be able to determine crack propagation rate by means of a crack surface inspection. Markers are usually visible on most fatigue crack surfaces, however they occur randomly therefore it is almost impossible to conclude anything about the crack history. Since the preliminary load block consisted of separate flights (flight loads together with landing and taxing loads) showing significantly different levels of severity, the easiest way to modify the load block was to change the order of flights within the block. Hence a pilot programme was started at the AFIT which was focused on the determination of the influence of flight sequence on crack appearance. Several load blocks were determined using various techniques of rearranging the order of flights within the preliminary load spectrum. This approach ensured the preservation of the initial severity of the load block and simultaneously enabled a significant increase in the probability of the markers occurrence introducing neither artificial underloads nor overloads that would most probably affect the crack propagation rate. Fatigue crack surfaces were inspected using Scanning Electron Microscope. As a result of the investigations a series of images were obtained showing the specimen microstructure with visible markers arranged in the desired sequences. Based on the obtained pictures the most promising load block arrangements were chosen for the Full Scale Fatigue Test.

Źródło:

Fatigue of Aircraft Structures; 2012, 4; 29-37
2081-7738
2300-7591

Pojawia się w:

Fatigue of Aircraft Structures

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 20.

Tytuł:

Nonlinear Fatigue Damage Accumulation

Autorzy:

Dębski, D. K.

Powiązania:

https://bibliotekanauki.pl/articles/97967.pdf

Data publikacji:

2015

Wydawca:

Sieć Badawcza Łukasiewicz - Instytut Lotnictwa

Tematy:

cumulative fatigue damage
fatigue damage accumulation
cumulative damage rules
load interaction effects
fatigue life prediction

Opis:

One important element of any computational fatigue analysis is the adoption of a hypothesis of fatigue damage accumulation. The most commonly used is the hypothesis of linear accumulation of fatigue damage called the Palmgren-Miner hypothesis. This linear hypothesis does not take into account a factor of great importance: the mutual influence of consecutive fatigue load sequences on each other. In the presented paper, only two consecutive load sequences linked by mutual relations have been analyzed and the results of the analysis have been shown. A more complex form which takes into account the full load history would create complex formula difficult to use. Perhaps, we should go in this direction, especially that today we have enormous computing power at our disposal.

Źródło:

Fatigue of Aircraft Structures; 2015, 7; 18-23
2081-7738
2300-7591

Pojawia się w:

Fatigue of Aircraft Structures

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 21.

Tytuł:

Kryterium zmęczeniowe dla złożonych obciążeń sinusoidalnych z przesunięciem fazowym
Fatigue criterion for out-of-phase loads

Autorzy:

Pejkowski, Ł.
Skibicki, D.

Powiązania:

https://bibliotekanauki.pl/articles/95532.pdf

Data publikacji:

2014

Wydawca:

Politechnika Bydgoska im. Jana i Jędrzeja Śniadeckich. Wydawnictwo PB

Tematy:

zmęczenie materiałów
zmęczenie wieloosiowe
trwałość zmęczeniowa
obciążenia nieproporcjonalne
kryterium zmęczeniowe
fatigue of materials
multiaxial fatigue
fatigue life
non-proportional loads
fatigue criterion

Opis:

W pracy przedstawiono propozycję nowego kryterium zmęczeniowego dla obciążeń nieproporcjonalnych, uwzględniającego wpływ wartości kąta przesunięcia fazowego δ i stosunku amplitud naprężenia stycznego i normalnego λ na trwałość zmęczeniową.
In hereby work a proposal of new fatigue criterion for non-proportional loads, which includes influence of value of phase shift angle δ and shear to normal stress ratio λ, onto fatigue life.

Źródło:

Postępy w Inżynierii Mechanicznej; 2014, 4(2); 13-22
2300-3383

Pojawia się w:

Postępy w Inżynierii Mechanicznej

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 22.

Tytuł:

Comparison of some selected multiaxial fatigue failure criteria dedicated for spectral method
Porównanie kilku wybranych kryteriów wieloosiowego zniszczenia zmęczeniowego dedykowanych metodzie spektralnej

Autorzy:

Niesłony, A.

Powiązania:

https://bibliotekanauki.pl/articles/280078.pdf

Data publikacji:

2010

Wydawca:

Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej

Tematy:

spectral method
multiaxial fatigue
high cycle fatigue
random loading

Opis:

The paper presents the procedure of estimation of fatigue life in the high- cycle fatigue regime under a multiaxial random loading using the spectral method. The procedure consists of application of the power spectral density function of the equivalent stress in the fatigue life assessment together with the known spectral method developed for the uniaxial stress state. The model proposed by Miles and Dirlik was presented as an example. Two groups of multiaxial fatigue failure criteria have been distinguished: the criteria based on the critical plane approach and the criteria using invariants of the stress state. Two sets of experimental data were used in order to compare the calculated and experimental fatigue lives. It has been shown that under the multiaxial random loading the results of fatigue life calculated according to the considered method are well correlated with the results of experiments if the multiaxial fatigue failure criterion is properly selected for mechanical parameters of the tested material.
Wpracy przedstawiono metodologię wyznaczania trwałości zmęczeniowej w zakresie dużej liczby cykli przy obciążeniu losowym z wykorzystaniem metody spektralnej. Metodologia ta wykorzystuje funkcję gęstości widmowej mocy naprężenia ekwiwalentnego przy wyznaczaniu trwałości zmęczeniowej wraz ze znanymi jednoosiowymi modelami spektralnymi. Jako przykład przedstawiono modele proponowane przez Milesa i Dirlika. Wyróżniono dwie grupy kryteriów wieloosiowego zmęczenia: kryteria opierające się na pojęciu płaszczyzny krytycznej i kryteria wykorzystujące niezmienniki stanu naprężenia. W celu porównania obliczeniowej i eksperymentalnej trwałości zmęczeniowej wykorzystano dwa zestawy danych otrzymanych przy kombinacji zginania ze skręcaniem. Wykazano, że przy wieloosiowym obciążeniu losowym trwałości obliczeniowe korelują dobrze z otrzymanymi podczas eksperymentu, jeżeli zostanie zastosowane odpowiednie do właściwości mechanicznych materiału kryterium wieloosiowego zniszczenia zmęczeniowego.

Źródło:

Journal of Theoretical and Applied Mechanics; 2010, 48, 1; 233-254
1429-2955

Pojawia się w:

Journal of Theoretical and Applied Mechanics

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 23.

Tytuł:

Fatigue life tests of steel laser-welded sandwich structures

Autorzy:

Boroński, D.
Szala, J.

Powiązania:

https://bibliotekanauki.pl/articles/260496.pdf

Data publikacji:

2006

Wydawca:

Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa

Tematy:

fatigue
laser welding
fatigue life diagrams
steel panel structures

Opis:

This paper presents results of the fatigue life tests of elements of steel laser-welded sandwich structure, performed at the Department of Machine Design, University of Technology and Agriculture, Bydgoszcz, in cooperation with the Department of Ship and Offshore Structures Technology, Gdańsk University of Technology, within the frame of ASPIS EUREKA E!3074 project titled : „Application of steel sandwich panels into ship structural design”. The obtained information on fatigue features of various specimens, the so called elementary structures of sandwich panels, can make it possible to formulate design and manufacturing recommendations for application of such structures in shipbuilding. An important result of the performed tests is the extended range of fatigue strength data for laser-welded joints.

Źródło:

Polish Maritime Research; 2006, S 1; 27-30
1233-2585

Pojawia się w:

Polish Maritime Research

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 24.

Tytuł:

Fatigue development mechanisms during increased intensity exertion

Autorzy:

Klich, Sebastian

Powiązania:

https://bibliotekanauki.pl/articles/1054635.pdf

Data publikacji:

2013

Wydawca:

Uniwersytet Szczeciński. Wydawnictwo Naukowe Uniwersytetu Szczecińskiego

Tematy:

central fatigue
free tryptophan
peripheral fatigue
physical exertion
serotonin

Opis:

During motor preparation, the attention is paid more and more frequently to the complex significance of fatigue in the case of the achieved sport outcome. The complexity of this process has not been utterly explained so far. It is important to acquire the profound knowledge about the central and peripheral fatigue while explaining this mechanism, because they remain in the background of the human body malfunction. It needs to be emphasized that both fatigue mechanisms should not be analyzed separately, because they are subordinated to one another. The changes mechanism in central nervous system (CNS) influenced by physical exertion leads to reticular formation impairment. This in turn results in analytic and decision making process malfunction. The proper functioning of these centers depends on appropriate neurotransmitters concentration. The short tryptophan to serotonin metabolic pathway plays a significant role in the central fatigue development. The concentration increase of this hormone leads to CNS malfunction, which causes the above mentioned changes. The purpose of this paper was to show, based on the current literature data, the predisposing mechanisms and factors in the development of fatigue.

Źródło:

Central European Journal of Sport Sciences and Medicine; 2013, 1, 1; 39-45
2300-9705
2353-2807

Pojawia się w:

Central European Journal of Sport Sciences and Medicine

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 25.

Tytuł:

Fatigue life testing of the round link mining chains

Autorzy:

Kandzia, Ryszard
Szot, Mariusz

Powiązania:

https://bibliotekanauki.pl/articles/27315586.pdf

Data publikacji:

2023

Wydawca:

STE GROUP

Tematy:

chain
fatigue
safety

Opis:

The material fatigue phenomenon consists of progressive material damage through the appearance and development of fractures under the influence of variable, periodically recurring stresses. Engineers designing machinery and structures to be fatigue resistant can gain useful insights about design and material properties by reviewing the literature. In this way, we can avoid costly research, but in the case of complex loading phenomena and the interaction of components, we must carry out such research. Fatigue strength calculations are less accurate than simple static calculations. The wear of link chains is concentrated in three areas, depending on the installation location and function of the individual links, namely: in the joints (the points of contact between two links), on the outer surfaces of the arches and on the outer surfaces of the straight sections of the links. During operation, chains are particularly vulnerable to wear through abrasion, corrosion and fatigue. These ageing factors, which act with varying intensity depending on the properties of the deposit, determine the service life of the chain, unless other unforeseen damage occurs, e.g. "hard" blockage of the chain. In many cases, users are guided by their own subjective criteria for assessing the technical condition of chains, which does not always lead to fully rational decisions regarding the continued use of used chains. To date, there have been no attempts to transfer the results of chain fatigue tests to behaviour of real objects. This paper presents issues related to mining chain fatigue testing. The test results presented are for both new and used chains. The experimental tests conducted at GIG made it possible to solve the problem of applying fatigue test results in industrial practice.

Źródło:

Management Systems in Production Engineering; 2023, 1 (31); 78--85
2299-0461

Pojawia się w:

Management Systems in Production Engineering

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 26.

Tytuł:

Review of aeronautical fatigue investigations in Poland during the period May 2009 to March 2011

Autorzy:

Niepokólczycki, A.

Powiązania:

https://bibliotekanauki.pl/articles/213894.pdf

Data publikacji:

2011

Wydawca:

Sieć Badawcza Łukasiewicz - Instytut Lotnictwa

Tematy:

aeronautical fatigue investigations

Opis:

This review gives the summary of work performed in Poland in the area of aeronautical fatigue during the period from May 2009 to march 2011. The various contributions to this come from the following sources: Air Force Institute of Technology, Warsaw; Warsaw University of Technology, Warsaw; Military University of Technology, Warsaw; Rzeszow University of tTchnology, Rzeszow; Institute of Aviation, Warsaw. The names of the principal investigators and their affiliations are presented in brackets at the end of each chapter.

Źródło:

Prace Instytutu Lotnictwa; 2011, 1 (210); 6-34
0509-6669
2300-5408

Pojawia się w:

Prace Instytutu Lotnictwa

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 27.

Tytuł:

Influence of the Fatigue Load Level and the Hole Diameter on the Laminate Structure’s Fatigue Performance

Autorzy:

Zalewska, M.

Powiązania:

https://bibliotekanauki.pl/articles/97951.pdf

Data publikacji:

2018

Wydawca:

Sieć Badawcza Łukasiewicz - Instytut Lotnictwa

Tematy:

composite
fatigue
damage

Opis:

Damage tolerance of composite aircraft structure is one of the main areas of research, important when a new product is being developed. There are a number of variables, such as damage characteristics (dent depth, delamination area) and loading parameters (load type, amplitude of cyclic loading, load sequence) that need to be investigated experimentally [1]. These tests of composite materials are usually performed at an element level and are carried out in order to validate the analytical model, developed to predict the full-scale component’s behaviour. The paper presents the results of compression testing of the [36/55/9] carbon fibre/epoxy laminate, manufactured with the Automated Fibre Placement technology (AFP) and subjected to static and fatigue loads. The laminate compression loading mode was achieved through sandwich 4-point flexure. At the stage of fatigue testing, two parameters were investigated: the damage size, simulated by the hole diameter and the fatigue load level. Based on the test results, the laminate fatigue load limit equal to 75% of the OHC failure load was evaluated. By collating the static and fatigue tests results, the damage tolerance characteristic of the considered laminate was created.

Źródło:

Fatigue of Aircraft Structures; 2018, 10; 21-30
2081-7738
2300-7591

Pojawia się w:

Fatigue of Aircraft Structures

Dostawca treści:

Biblioteka Nauki

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Skocz do pozycji: 28.

Tytuł:

Carbon Fibre Reinforced Polymer Fatigue Strengthening of Old Steel Material

Autorzy:

Kowal, Maciej
Pietras, Daniel

Powiązania:

https://bibliotekanauki.pl/articles/2201890.pdf

Data publikacji:

2023

Wydawca:

Stowarzyszenie Inżynierów i Techników Mechaników Polskich

Tematy:

puddled steel
mild steel
CFRP laminate
CFRP
fatigue test
steel reinforcement
fatigue strength testing
fatigue strengthening

Opis:

This paper reports the experimental results of a study investigating the effect of CFRP strengthening of metallic structures for increasing fatigue life. In the study, samples made form puddled steel and mild S235 grade steel strengthened with CFRP strips were examined. Samples were subjected to tensile fatigue loading with a stress ratio R of 0.115 and 0.130 (mild steel samples) and 0.13/1.25/0.15/1.07 (puddled steel samples). A total of 9 samples with CFRP/steel single overlap joints and 20 reference specimens were tested to determine their fatigue life and failure modes. Normal modulus CFRP strips with one cross section (20 x 1.4 mm) were used in this study. Laboratory test results showed that CFRP strengthening has visible effect on the fatigue life of the steel. The application of adhesively bonded CFRP laminates significantly prolongs fatigue life of the specimens. The increase in fatigue life of the steel samples strengthened with CFRP strips was 2 to 16 times (for mild steel) and 11.6 to 34.8 times (for puddled steel).

Źródło:

Advances in Science and Technology. Research Journal; 2023, 17, 1; 197--209
2299-8624

Pojawia się w:

Advances in Science and Technology. Research Journal

Dostawca treści:

Biblioteka Nauki

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Skocz do pozycji: 29.

Tytuł:

Verification of analytical models of the S-N curve within limited fatigue life

Autorzy:

Strzelecki, P.
Sempruch, J.

Powiązania:

https://bibliotekanauki.pl/articles/279631.pdf

Data publikacji:

2016

Wydawca:

Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej

Tematy:

fatigue design
S-N curve
high-cycle fatigue
accelerated method

Opis:

This paper presents analytical methods for determination of the curve for a high-cycle fatigue. It has been found based on qualitative and quantitative verification that the error introduced by these methods can be as large as 3-fold length of the experimental life. In addition, the wrong result can lay on either the safe or the unsafe side with equal probability. Therefore, an analytical-and-experimental (hybrid) method has been proposed. Verification of computed characteristics vs. experimental data demonstrated that the “proprietary” proposal reduced the error. In addition, an approximate error depending on the number of experiments has been determined based on the computations.

Źródło:

Journal of Theoretical and Applied Mechanics; 2016, 54, 1; 63-73
1429-2955

Pojawia się w:

Journal of Theoretical and Applied Mechanics

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 30.

Tytuł:

Estimation of high temperature fatigue lifetime of SUS304 steel with an energy parameter in the critical plane
Ocena wysokotemperaturowej trwałości zmęczeniowej stali SUS304 za pomocą parametru energetycznego w płaszczyźnie krytycznej

Autorzy:

Łagoda, T.
Macha, E.
Sakane, M.

Powiązania:

https://bibliotekanauki.pl/articles/281113.pdf

Data publikacji:

2003

Wydawca:

Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej

Tematy:

low-cycle fatigue
multiaxial fatigue
energy approach
lifetime
high temperature

Opis:

The paper studies the application of the energy parameter, a sum of elastic and plastic strain energy densities in the critical plane, for the correlation of two series of proportional biaxial low-cycle lives using SUS304 stainless steel at elevated temperature. The first data used thin-walled cylinder specimens subjected to 7 proportional strain paths of combined tension-torsion and the other used cruciform specimens subjected to 5 proportional strain paths of biaxial tension-compression. These tests were done at the temperature of 923 K. The normal total strain energy density in the plane with the maximum damage was a suitable parameter for describing the test results.
Praca dotyczy zastosowania parametru energetycznego, sumy gęstości energii sprężystej i plastycznej odkształcenia w płaszczyźnie krytycznej do korelacji dwóch serii proporcjonalnych, dwuosiowych, niskocyklowych trwałości zmęczeniowych stali nierdzewnej SUS303 w podwyższonej temperaturze.Badano cienkościenne próbki cylindryczne poddane siedmiu proporcjonalnym torom odkształcenia w warunkach kombinacji rozciągania-skręcania oraz próbki krzyżowe poddane pięciu proporcjonalnym torom odkształcenia w warunkach dwuosiowego rozciągania-ściskania. Badania prowadzono w temperaturze 923 K. Gęstość energii całkowitego odkształcenia normalnego w płaszczyźnie maksymalnego uszkodzenia była odpowiednim parametrem do opisania wyników badań.

Źródło:

Journal of Theoretical and Applied Mechanics; 2003, 41, 1; 55-73
1429-2955

Pojawia się w:

Journal of Theoretical and Applied Mechanics

Dostawca treści:

Biblioteka Nauki

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Skocz do pozycji: 31.

Tytuł:

Comments on linear summation hypothesis of fatigue failures

Autorzy:

Szala, G.

Powiązania:

https://bibliotekanauki.pl/articles/259846.pdf

Data publikacji:

2014

Wydawca:

Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa

Tematy:

fatigue life calculations
summation hypothesis of fatigue failures
variable load

Opis:

This paper presents a comparative analysis of results of fatigue life calculations with the use of the linear summation hypothesis of fatigue failures (LHSUZ), confronted with experimental test results. The calculations and fatigue tests were performed for variable amplitude(VA), two-step and ten-step loading conditions , both in the low-cycle fatigue (LCF) and high-cycle fatigue ( HCF) range, for the case of C45 steel as an example. Experimental verification of the hypothesis LHSUZ did not revealed any significant influence of load level and form of load spectrum on conformity of results of the calculation by using the LHSUZ, to results of fatigue tests on C45 steel. However, it enabled to assess magnitude of a correction factor which appears in the considered linear hypothesis.

Źródło:

Polish Maritime Research; 2014, 3; 77-85
1233-2585

Pojawia się w:

Polish Maritime Research

Dostawca treści:

Biblioteka Nauki

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Skocz do pozycji: 32.

Tytuł:

Physical fatigue measured by functional MRI

Autorzy:

Truszkiewicz, Adrian
Aebisher, David
Ożog, Łukasz
Bartusik-Aebisher, Dorota

Powiązania:

https://bibliotekanauki.pl/articles/454820.pdf

Data publikacji:

2018

Wydawca:

Uniwersytet Rzeszowski. Wydawnictwo Uniwersytetu Rzeszowskiego

Tematy:

functional MRI
physical fatigue
physiological condition
temporary and chronic fatigue

Opis:

Introduction. Physical fatigue is a physiological condition that can be measured by functional Magnetic Resonance Imaging (fMRI). Aim. Therefore, this work aims to present the research results currently reported in the scientific literature between the years 2014 and 2018 in the field of chronic fatigue syndrome using the functional MRI method. Material and methods. Analysis of literature. Results. We reviewed here the differences between temporary and chronic fatigue.

Źródło:

European Journal of Clinical and Experimental Medicine; 2018, 3; 239-244
2544-2406
2544-1361

Pojawia się w:

European Journal of Clinical and Experimental Medicine

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 33.

Tytuł:

A confirmatory factor analysis for an adapted and validated Polish version of the Chalder Fatigue Questionnaire

Autorzy:

Zdun-Ryżewska, Agata
Basiński, Krzysztof
Michalik, Anna

Powiązania:

https://bibliotekanauki.pl/articles/2116721.pdf

Data publikacji:

2020-01-17

Wydawca:

Instytut Medycyny Pracy im. prof. dra Jerzego Nofera w Łodzi

Tematy:

Chalder Fatigue Questionnaire
fatigue
validation
factor structure
confirmatory analysis
adaptation

Opis:

ObjectivesThe Chalder Fatigue Questionnaire (CFQ) was developed to measure fatigue in 2 dimensions: physical and mental. The aim of the study was to translate, adapt and evaluate the psychometric properties of the Polish version of the CFQ (CFQ-PL).Material and MethodsThe process of translation was conducted using a forward and backward translation procedure. After cultural adaptation, the psychometric properties of the CFQ-PL were evaluated. Participants of the study were healthy individuals: medical students (N = 304) and pregnant women (pregnancy without complications, N = 925). The reliability and validity were estimated using fatigue numerical rating scales, the Beck Depression Inventory and the State-Trait Anxiety Inventory. To examine the factor structure of the CFQ-PL, a confirmatory factor analysis was conducted.ResultsThe internal consistency of the CFQ-PL was similar to the original version (Cronbach’s α 0.85–0.91). Statistically significant correlations between the CFQ-PL and the current fatigue level, average fatigue and the sleepiness level (measured using numerical rating scales), as well as the intensity of depression and anxiety symptoms, all confirming the validity of the adapted scale. Using a confirmatory factor analysis, it was determined that a 1-factor model did not fit the data well. A 2-factor model with a correlation between mental and physical factors fitted better than the 1-factor model, yet fit indices revealed a poor fit. Using a 2-factor model with added covariance between items – 1 (problems with fatigue), 2 (resting more), 9 (slips of the tongue), 10 (finding the correct word) – resulted in acceptable fit indices in both groups of participants.ConclusionsAfter the process of translation, adaptation and validation of the CFQ-PL, it is now available for use under Polish conditions. This study provided evidence for structural validity of the 2-factor model of the 11-item version.

Źródło:

International Journal of Occupational Medicine and Environmental Health; 2020, 33, 1; 67-76
1232-1087
1896-494X

Pojawia się w:

International Journal of Occupational Medicine and Environmental Health

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 34.

Tytuł:

Prognozowanie trwałości zmęczeniowej elementów z karbami
The fatigue life prediction of notched elements

Autorzy:

Łukaszewicz, K.
Osipiuk, W.

Powiązania:

https://bibliotekanauki.pl/articles/386390.pdf

Data publikacji:

2011

Wydawca:

Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej

Tematy:

trwałość zmęczeniowa
karb
naprężenie
fatigue life
fatigue strength
notch
tension

Opis:

W pracy zaproponowano wyznaczanie efektywnego współczynnika działania karbu przez określenie lokalnych naprężeń w pewnej odległości d od dna karbu, właściwej dla danego materiału. Przedstawiono w sposób graficzny zmiany wartości współczynnika działania karbu, w zależności od liczby cykli dla trzech badanych promieni dna karbu. W celach porównawczych dokonano także obliczeń współczynnika ßk przy wykorzystaniu dwóch ogólnie znanych zależności Neubera oraz Petersona.
The paper presents five methods of signal generation which can be applied for simulation of service loadings at fatigue test stands. They are: the method of block programs of cyclic loadings, the matrix method for generation of random loading extrema, the congruence method for generation of random loading and formation of their probabilistic characteristics with use of digital filters, the method of generation of random signals as a sum of harmonic histories according to the given spectral power density function, the method of random signal generation with the inverse Fourier transform according to the given spectral power density function.

Źródło:

Acta Mechanica et Automatica; 2011, 5, 1; 53-58
1898-4088
2300-5319

Pojawia się w:

Acta Mechanica et Automatica

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 35.

Tytuł:

Evolution of tensile properties of the TiAl6V4 alloy due to the prior cyclic loading history

Autorzy:

Moćko, W.
Kowalewski, Z. L.

Powiązania:

https://bibliotekanauki.pl/articles/281363.pdf

Data publikacji:

2014

Wydawca:

Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej

Tematy:

fatigue
metals and alloys
deformation and fracture
cumulative fatigue damage

Opis:

The influence of the initial fatigue loading on tensile characteristics of the TiAl6V4 titanium alloy is presented in this work. For cumulative fatigue damage equal to 0.75, a decrease in the pre-fatigue amplitude leads to a lowering in the elongation. Moreover, independent of the amplitude, the loading induces an increase in the yield stress by approximately 100MPa. An increase in the number of pre-fatigue cycles at a constant amplitude results in a decrease in the elongation. Such mechanical behaviour is related to the cyclic hardening effect and the development of fatigue damage, which clearly affects the tensile characteristics of the alloy.

Źródło:

Journal of Theoretical and Applied Mechanics; 2014, 52, 3; 847-851
1429-2955

Pojawia się w:

Journal of Theoretical and Applied Mechanics

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 36.

Tytuł:

Effect of Laser Preheating AISI 4140 Specimens for Micro-Forging

Autorzy:

Jung, C.
Lee, M. G.
Jeon, Y.

Powiązania:

https://bibliotekanauki.pl/articles/351766.pdf

Data publikacji:

2017

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

laser preheating
micro-forging
fatigue strength
ultrasonic fatigue test
hardness

Opis:

Many high performance and permanent service parts require suitable material characteristics-high fatigue strength is one of the most important characteristics. For this reason, surface treatment processes are essential to increase the material performance and avoid the use of costly ineffective material. There exist various surface treatment processes for various applications. Each process has advantages and disadvantages and hybridization can solve various problems. The micro-forging process delivers a controlled and uniform surface hardness, but the depth of the forged surface is limited. On the other hand, laser heat treatment can increase the hardness drastically, but the surface may become brittle, which reduces the fatigue life. Laser-assisted micro-forging is a novel hybrid process of laser heat treatment and micro-forging that has the potential to increase the forging depth and relax the stress caused by the high temperature of the forging process. This study examines the effect of laser preheating in the micro-forging of AISI 4140. The processes were varied as follows: no treatment, micro-forging only, and laser-assisted micro-forging. The fatigue strength of the specimens was examined by means of an ultrasonic fatigue tester and then compared. The microstructural changes were investigated with respect to the processes by using scanning electron microscopy. In conclusion, it was confirmed that the laser preheating auxiliary forging affects the fatigue life. It was confirmed that the fatigue life was the mostly increased in 550°C temperature laser preheating micro forging process and the temperature was identified as the most important factor.

Źródło:

Archives of Metallurgy and Materials; 2017, 62, 2B; 1209-1213
1733-3490

Pojawia się w:

Archives of Metallurgy and Materials

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 37.

Tytuł:

Test stand for the examination of steel cyclic properties under the condition of temperature changes
Stanowisko do badań właściwości cyklicznych stali w warunkach zmian temperatury

Autorzy:

Mroziński, S.
Marciniak, B.

Powiązania:

https://bibliotekanauki.pl/articles/258286.pdf

Data publikacji:

2014

Wydawca:

Sieć Badawcza Łukasiewicz - Instytut Technologii Eksploatacji - Państwowy Instytut Badawczy

Tematy:

mechanical fatigue
thermal fatigue
service load
control
fatigue specimen
zmęczenie mechaniczne
zmęczenie cieplne
obciążenie eksploatacyjne
sterowanie
próba zmęczeniowa

Opis:

In this study, a stand for tests of technical objects under the conditions of thermal and mechanical fatigue is presented. Temperature and load changes and the interrelations between them cause difficulties in controlling and recording basic parameters of fatigue tests in laboratory conditions. The article presents the design and creation of a system for temperature change control and adjustment during fatigue tests under the conditions of thermal loading. The test stand was built through the modernization of a standard strength-testing machine.
W pracy przedstawiono stanowisko do badań w warunkach zmęczenia cieplnego oraz mechanicznego. Zmiany temperatury i obciążenia oraz występujące pomiędzy nimi interakcje powodują, że w warunkach laboratoryjnych występują trudności w zakresie sterowania i rejestracji podstawowych parametrów prób zmęczeniowych. W artykule opisano projekt i wykonanie układu sterowania oraz kontroli zmian temperatury podczas badań zmęczeniowych w warunkach obciążeń cieplnych. Stanowisko badawcze zostało stworzone poprzez modernizację standardowej maszyny wytrzymałościowej.

Źródło:

Problemy Eksploatacji; 2014, 3; 5-16
1232-9312

Pojawia się w:

Problemy Eksploatacji

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 38.

Tytuł:

Badania doświadczalne trwałości zmęczeniowej elementów wykonanych ze stopu aluminium D16CzATW w obecności karbu geometrycznego
Experimental research of fatigue life in D16CzATW aluminium alloy specimen with a geometrical notch

Autorzy:

Mierzyński, J.

Powiązania:

https://bibliotekanauki.pl/articles/210846.pdf

Data publikacji:

2012

Wydawca:

Wojskowa Akademia Techniczna im. Jarosława Dąbrowskiego

Tematy:

mechanika pękania
mikromechanizmy pękania
propagacja pęknięć zmęczeniowych
trwałość zmęczeniowa
fracture mechanics
fatigue micromechanism
fatigue crack propagation
fatigue life

Opis:

Wyznaczono trwałość zmęczeniową próbek wykonanych ze stopu aluminium D16CzATW. Badaniom poddano próbki z karbem geometrycznym w postaci otworu walcowego uzyskanego w wyniku wiercenia i rozwiercania, a także w postaci otworu walcowego poddanego kalibracji. Uzyskane wyniki porównano z trwałością zmęczeniową próbek bez karbu geometrycznego. Trwałość zmęczeniową określono zarówno dla próbek obustronnie platerowanych jak i dla próbek pozbawionych takiej ochronnej warstwy. Analizie poddano wpływ wybranych procedur badawczych stosowanych w pomiarach propagacji pęknięć zmęczeniowych na trwałość zmęczeniową. Badania przeprowadzono w warunkach stałoamplitudowego zginania przy współczynniku asymetrii cyklu R = -1. Uzyskano zaskakująco duże różnice trwałości zmęczeniowej w zależności od zastosowanego wariantu badań. Te różnice starano się wyjaśnić zmianą stanu naprężenia wokół otworu poddanego kalibracji oraz negatywnym wpływem kruchej warstwy plateru na inicjację pęknięć zmęczeniowych. Zaobserwowano skomplikowany przebieg mechanizmu niszczenia, w którym mikromechanizmy pękania kruchego i plastycznego występują na różnych etapach propagacji pęknięć zmęczeniowych.
There was examined fatigue life in D16CzATW aluminium alloy clad specimens. The research was carried out under the conditions of constant-amplitude bending at the stress ratio R = -1. Fatigue life diagrams were plotted for full specimens, specimens with drilled holes each and specimens with holes that were strengthened in a calibration process. As a result of the research, it was concluded that fatigue lives of specimens with calibrated holes were longer by 15% to 35% (depending on applied loads) in relation to specimens with common holes. The aforementioned increase was explained by a change in the state of stress around the hole. Significantly bigger differences were observed in comparative tests conducted on similar specimens, clad layers of which had been removed. It should be emphasized that fatigue lives of calibrated specimens prepared in that way were longer even in relation to clad specimens without geometric notches. An unfavourable effect of plate layers on fatigue failure processes was observed. A plate layer is the source of numerous surface micro-cracks and its effect on fatigue life is comparable to the effect of the presence of a strong concentrator in components. A microfractographic analysis of fracture surfaces made it possible to observe that in the parent material, there were present numerous marks of brittle and quasi-brittle cracking and, at the same time, an insignificant presence of plastic deformations. Increase in cracking depth was accompanied by intensification of plastic deformations, formation of multidirectionally oriented systems of fatigue striations as well as numerous fracture-originating cracks. In the residual zone, there was observed plastic cracking in the form of a homogenous slice structure.

Źródło:

Biuletyn Wojskowej Akademii Technicznej; 2012, 61, 1; 65-82
1234-5865

Pojawia się w:

Biuletyn Wojskowej Akademii Technicznej

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 39.

Tytuł:

Accuracy of determined S-N curve by selected models

Autorzy:

Strzelecki, Przemysław

Powiązania:

https://bibliotekanauki.pl/articles/279431.pdf

Data publikacji:

2019

Wydawca:

Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej

Tematy:

S-N curve
high-cycle fatigue
steel
fatigue design
data analysis

Opis:

The study shows models defining the relationship between the fatigue life and the stress amplitude. The first models have been developed at the beginning of the 20th century; however, new models are still being developed. The author decided to compare the most commonly used model, i.e. a linear regression model and the two models discussed in ISO-12107. The comparison also included some recently developed models, i.e. Strohmeyer, Basenaire, Castillo et al., Kohout and Vechet, Leonetti et al., and Pasual and Meeker model, including its modified version. The fatigue data for S355J2+C and AISI 1045 steel were used for the comparison. The best estimate of the fatigue life was obtained by using the modified Pasual and Meeker model.

Źródło:

Journal of Theoretical and Applied Mechanics; 2019, 57, 4; 859-868
1429-2955

Pojawia się w:

Journal of Theoretical and Applied Mechanics

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 40.

Tytuł:

Problems of equivalent load amplitude in fatigue life calculations

Autorzy:

Ligaj, B.
Sołtysiak, R.

Powiązania:

https://bibliotekanauki.pl/articles/258812.pdf

Data publikacji:

2016

Wydawca:

Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa

Tematy:

operational load
equivalent load amplitude
two-parameter fatigue characteristics
fatigue life

Opis:

This paper presents issues of fatigue life calculations in operational load conditions. The assumed runs were so processed as to get a set of sinusoidal cycles by using the following methods: full cycles counting method and rainflow counting method. On the basis of such sets of cycles of the varying parameters Sm i and Sa i were prepared block load spectra of equivalent amplitudes Saz , obtained with the use of an original method of these authors, in which two-parameter fatigue characteristics were applied. The work resulted in comparison of fatigue life results for load spectra determined by using the assumed cycles counting methods and the assumed two-parameter fatigue characteristics: the model IM, model II, model III and model IV, respectively.

Źródło:

Polish Maritime Research; 2016, 1; 85-92
1233-2585

Pojawia się w:

Polish Maritime Research

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 41.

Tytuł:

Experimental method for plotting S-N curve with a small number of specimens

Autorzy:

Strzelecki, P.
Sempruch, J.

Powiązania:

https://bibliotekanauki.pl/articles/260334.pdf

Data publikacji:

2016

Wydawca:

Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa

Tematy:

high-cycles fatigue
S-N curve
fatigue tests
number of specimens

Opis:

The study presents two approaches to plotting an S-N curve based on the experimental results. The first approach is commonly used by researchers and presented in detail in many studies and standard documents. The model uses a linear regression whose parameters are estimated by using the least squares method. A staircase method is used for an unlimited fatigue life criterion. The second model combines the S-N curve defined as a straight line and the record of random occurrence of the fatigue limit. A maximum likelihood method is used to estimate the S-N curve parameters. Fatigue data for C45+C steel obtained in the torsional bending test were used to compare the estimated S-N curves. For pseudo-random numbers generated by using the Mersenne Twister algorithm, the estimated S-N curve for 10 experimental results plotted by using the second model, estimates the fatigue life in the scatter band of the factor 3. The result gives good approximation, especially regarding the time required to plot the S-N curve.

Źródło:

Polish Maritime Research; 2016, 4; 129-137
1233-2585

Pojawia się w:

Polish Maritime Research

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 42.

Tytuł:

The Attempt of the Low-Cycle Fatigue Life Description of Chosen Creep-Resistant Steels Under Mechanical and Thermal Interactions

Autorzy:

Okrajni, J.
Marek, A.

Powiązania:

https://bibliotekanauki.pl/articles/354016.pdf

Data publikacji:

2017

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

low-cycle fatigue
high temperatures
fatigue life prediction
creep-resistant steels

Opis:

The study focuses on the problem of determination of low-cycle fatigue properties for the chosen group of creep-resistant steels used in the power and chemical industries. It tries to find the parameter which would describe well the fatigue life and take into account mechanical loads and temperature. The results of LCF tests have been presented in the paper. New parameter P has been introduced. This parameter joins a plastic strain range, a stress range and temperature. The fatigue life has been predicted versus parameter P. The comparison of the predicted and observed values of fatigue life shows the agreement between these values. The method of fatigue life prediction formulated in this way is expected to describe the behavior of materials under thermo-mechanical fatigue.

Źródło:

Archives of Metallurgy and Materials; 2017, 62, 4; 2349-2353
1733-3490

Pojawia się w:

Archives of Metallurgy and Materials

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 43.

Tytuł:

Zastosowanie minipróbek w ocenie stanu uszkodzenia zmęczeniowego elementów konstrukcyjnych
Application of minispecimens in assessment of fatigue damage of structural parts

Autorzy:

Suszek, J.
Boroński, D.

Powiązania:

https://bibliotekanauki.pl/articles/327936.pdf

Data publikacji:

2005

Wydawca:

Polska Akademia Nauk. Polskie Towarzystwo Diagnostyki Technicznej PAN

Tematy:

trwałość zmęczeniowa
zmęczenie konstrukcji
diagnostyka
fatigue life
fatigue of structures
diagnostics

Opis:

Eksploatacja obiektów technicznych w warunkach obciążeń zmiennych w czasie niesie ze sobą zagrożenia związane ze zmęczeniowym pękaniem elementów konstrukcyjnych. Cyklicznie zmienne obciążenie może prowadzić do stopniowej degradacji struktury, aż do inicjacji i rozwoju pęknięcia zmęczeniowego. W referacie przedstawiono wyniki wstępnych badań mających na celu zastosowanie w ocenie stanu zmęczenia elementów konstrukcyjnych w fazie do inicjacji pęknięcia zmęczeniowego minipróbek materiałowych poddawanych obciążeniom odwzorowującym odkształcenia w węźle konstrukcyjnym.
The exploitation of technical objects in the variable loading conditions carries a menace connected with the fatigue cracking of the structural parts. The cyclically changing loading may lead to gradual degradation of structure, up to fatigue crack initiation. In the paper, results of preliminary verification of a new method of the fatigue damage assessment of structural parts analysis in the crack initiation period are presented. In the method the local strains existing in a structural parts, are applied to simple material minispecimen according to the local approach assumptions used in the fatigue design methods.

Źródło:

Diagnostyka; 2005, 36; 73-78
1641-6414
2449-5220

Pojawia się w:

Diagnostyka

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 44.

Tytuł:

Numerical simulation of fatigue delamination growth under mode I loading conditions

Autorzy:

Bajurko, P.
Czajkowska, K.
Czarnocki, P.
Szeląg, D.

Powiązania:

https://bibliotekanauki.pl/articles/247320.pdf

Data publikacji:

2012

Wydawca:

Instytut Techniczny Wojsk Lotniczych

Tematy:

polymeric composite
fatigue delamination
numerical simulation
fatigue test
Paris-Erdogen relationship

Opis:

Delaminations are common defects that deteriorate strength of laminates. Delaminations can arise in the course of manufacturing due to faulty fabrication process or can result from low energy impacts, (e.g. FOD), that can take place in service. Once a delamination has been detected, a question will arise whether the defective component can still stay in service or should be immediately repaired or replaced. Before the decision is made, one of the factors that must be considered is a possible delamination growth rate under the expected service cyclic loading. One of the most effective tools that help to answer this question is a numerical simulation of delamination growth. Relatively easy way to simulate fatigue delamination growth under Mode I loading conditions is presented. The a=f(n) relationship was simulated. The simulation was performed with the help of FEM. The delamination extension resulted from gradual reduction in the stiffness of cohesive elements of length t that were located along the expected delamination path. It was assumed that the delamination would extend by delta a=t if the cohesive element stiffness dropped to 0. The applied degradation procedure of the initial mechanical properties of the cohesive elements was based on Paris low. For each delamination, extension increment the degradation process was limited to the cohesive element adjacent to the delamination front. In case of laminates, so far, there is no standard procedure available to determine Paris low and the one used to determine it for the purpose of the simulation performed is presented, as well. The simulation was ended when the number of cycles simulated exceeded 1000 000. The numerical results were verified against the experimental ones resulting from the four specimens tested and a satisfactory agreement was found. The difference between the a=f(n) relationship obtained by the simulation and the one being the average of the four tests was smaller than the scatter of the tests results.

Źródło:

Journal of KONES; 2012, 19, 2; 17-24
1231-4005
2354-0133

Pojawia się w:

Journal of KONES

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 45.

Tytuł:

Shoulder girdle muscle activity and fatigue in traditional and improved design carpet weaving workstations

Autorzy:

Allahyari, Teimour
Mortazavi, Narges
Khalkhali, Hamid Reza
Sanjari, Mohammad Ali

Powiązania:

https://bibliotekanauki.pl/articles/2177075.pdf

Data publikacji:

2015-10-21

Wydawca:

Instytut Medycyny Pracy im. prof. dra Jerzego Nofera w Łodzi

Tematy:

muscle activity
surface electromyography
muscle fatigue
carpet weaving
workstation
perceived fatigue

Opis:

Objectives Work-related musculoskeletal disorders in the neck and shoulder regions are common among carpet weavers. Working for prolonged hours in a static and awkward posture could result in an increased muscle activity and may lead to musculoskeletal disorders. Ergonomic workstation improvements can reduce muscle fatigue and the risk of musculoskeletal disorders. Material and Methods The aim of this study is to assess and to compare upper trapezius and middle deltoid muscle activity in 2 traditional and improved design carpet weaving workstations. These 2 workstations were simulated in a laboratory and 12 women carpet weavers worked for 3 h. Electromyography (EMG) signals were recorded during work in bilateral upper trapezius and bilateral middle deltoid. The root mean square (RMS) and median frequency (MF) values were calculated and used to assess muscle load and fatigue. Repeated measure ANOVA was performed to assess the effect of independent variables on muscular activity and fatigue. The participants were asked to report shoulder region fatigue on the Borg’s Category-Ratio scale (Borg CR-10). Results Root mean square values in workstation A are significantly higher than in workstation B. Furthermore, EMG amplitude was higher in bilateral trapezius than in bilateral deltoid. However, muscle fatigue was not observed in any of the workstations. Conclusions The results of the study revealed that muscle load in a traditional workstation was high, but fatigue was not observed. Further studies investigating other muscles involved in carpet weaving tasks are recommended.

Źródło:

International Journal of Occupational Medicine and Environmental Health; 2016, 29, 2; 345-354
1232-1087
1896-494X

Pojawia się w:

International Journal of Occupational Medicine and Environmental Health

Dostawca treści:

Biblioteka Nauki

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Skocz do pozycji: 46.

Tytuł:

Badanie połączeń o wybranych złączach obciążanych zmęczeniowo
Issledovanie soedinenijj s vybrannymi ustalostno nagruzhennymi vjazkami
Investigations of connections of selected fatigue-burdened joints

Autorzy:

Dziegielewski, S.

Powiązania:

https://bibliotekanauki.pl/articles/799074.pdf

Data publikacji:

1990

Wydawca:

Szkoła Główna Gospodarstwa Wiejskiego w Warszawie. Wydawnictwo Szkoły Głównej Gospodarstwa Wiejskiego w Warszawie

Tematy:

badania
polaczenia
zlacza obciazeniowe
zmeczenie
connection
fatigue-burdened joint
material fatigue

Opis:

Соответствущие исследования были направлены на определение механических свойств мебельных соединений с выбранными вязками. Особое внимание уделяли статической прочности, деформациям под влиянием статических нагрузок и вопросам усталостной прочности, а также зависимости между статической и усталостной прочностью. Исследования охватывали группу 4 видов вязок: шиповых, нахлесточных, с открытым сквозным типом и с плоским шипом. Все вязки склеивали двумя видами клеев: глютиновым и полиуксусновиниловым. Для всех групп вязок определяли максимальное напряжение возникающее при статической нагрузке. Определяли также графическим способом зависимость деформации вязки от нагрузки в статической пробе. Целью указанных исследований была разработка основной проблемы, какой являлось определение зависимости между статической и усталостной прочностью. Эта зависимость была определена путем дисперсионного анализа для каждого вида вязки и для всей их группы с помощью общего уравнения: n=e⁻ax₁+b, где а и Ь коэффициенты с различным значением для разных вязок.
The aim of the investigations was to determine mechanical properties of furniture connections of selected joints. The main attention was concentrated upon the static strength, deformation occurring under the effect of static loads and upon the problem of fatigue strength and relations between the static and fatigue strength. The investigations comprised a group of 4 joint kinds: tenon, halved, forked and dowel joints. All joints were glued with two glue kinds: glutine and poly- acetovinyl glue. Maximum tensions occurring at the static load were determined for all joint groups. Also the dependences of connection deformation on the load in a static test were determined in the graphical way. The above investigations were aimed at solution of the main problem, i.e. determination of the relationship between static and fatigue strength. This relationship was determined by means of the analysis of variance for each joint kind and for the whole group of joints by the general equation: n=e⁻ax₁+b, where a and b - coefficients of different values for particular joint kinds.

Źródło:

Zeszyty Problemowe Postępów Nauk Rolniczych; 1990, 379
0084-5477

Pojawia się w:

Zeszyty Problemowe Postępów Nauk Rolniczych

Dostawca treści:

Biblioteka Nauki

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Skocz do pozycji: 47.

Tytuł:

Understanding the Effect of Speed of Exertion on Isokinetic Strength Using a Multiaxial Dynamometer

Autorzy:

Nimbarte, A. D.
Aghazadeh, F.
Bogolu, S. C. R.
Rajulu, S. L.

Powiązania:

https://bibliotekanauki.pl/articles/90640.pdf

Data publikacji:

2009

Wydawca:

Centralny Instytut Ochrony Pracy

Tematy:

isokinetic strength
fatigue
repetitions

Opis:

In this study a multiaxial isokinetic dynamometer was used to measure strength during various upper-body isokinetic exertions. Ten male participants performed 7 different upper-body isokinetic exertions. In addition, to evaluate the effect of speed on strength, each participant performed sitting pull exertions at the speed of 0.026, 0.130, and 0.260 m/s. Average isokinetic strength increased from 236.6 ± 39.1 to 291.8 ± 65.8 N with the initial increase in speed from 0.026 to 0.130 m/s. The average isokinetic strength decreased to 276.7 ± 87.2 N with a further increase in speed to 0.260 m/s. The curve between isokinetic strength and speed followed a bell-shaped curve (fitted with the Gaussian function, R2 = .9). The results of this study could be useful in deciding on the work pace of various manual material handling tasks requiring maximal and/or near maximal exertions.

Źródło:

International Journal of Occupational Safety and Ergonomics; 2009, 15, 3; 255-263
1080-3548

Pojawia się w:

International Journal of Occupational Safety and Ergonomics

Dostawca treści:

Biblioteka Nauki

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Skocz do pozycji: 48.

Tytuł:

HEALTHY LIFE STYLE AS AN ELEMENT OF SAFETY CULTURE

Autorzy:

Dorota, Szczeblowska,
Iwon, Grys,
Mariusz, Sokołowski,

Powiązania:

https://bibliotekanauki.pl/articles/891856.pdf

Data publikacji:

2018-08-21

Wydawca:

Wyższa Szkoła Bezpieczeństwa Publicznego i Indywidualnego Apeiron w Krakowie

Tematy:

safety
health
fatigue
prevention

Opis:

Due to WHO – health is a physical, psychical and social welfare. The collapse of health is serious threats of safety. Only healthy man may be liable to education, will participate in organizational processes, actively and creatively incorporate processes aimed at improving safety culture and defense, which serves harmonious development of certain entities and achieving safety in its broad sense. Meanwhile fatigue, caused by unhealthy lifestyle or physico-somatic changes, reduces feeling of welfare which is equivalent of safety. Taking adequate measures to minimize subjective feeling of lack of welfare might contribute to increasing our effectiveness and creativity and, at the same time, to improve conditions to our safety.

Źródło:

Kultura Bezpieczeństwa. Nauka – Praktyka – Refleksje; 2014, 16; 474-479
2299-4033

Pojawia się w:

Kultura Bezpieczeństwa. Nauka – Praktyka – Refleksje

Dostawca treści:

Biblioteka Nauki

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Skocz do pozycji: 49.

Tytuł:

Pomiar zmęczenia – przegląd narzędzi
Measurement of fatigue – a review of fatigue scales

Autorzy:

Kulik, Agnieszka

Powiązania:

https://bibliotekanauki.pl/articles/1178404.pdf

Data publikacji:

2013

Wydawca:

Uniwersytet Kazimierza Wielkiego w Bydgoszczy

Tematy:

adults
children
fatigue
scales

Opis:

Chronic fatigue is a common symptom but a small investigated. Scientific interests of this problem increased significantly during the last two decades. The same a large number of instruments have been developed to measure chronic fatigue. The aim of this article is to present a review of fatigue measures. These are divided in three groups: scales for healthy people, scales for people with chronic fatigue syndrome, scales for patients with other chronic diseases. Each scale is described in followed aspects: structure, way of answering, interpretation, utility, modification and psychometric properties.

Źródło:

Polskie Forum Psychologiczne; 2013, XVIII, 4; 419-440
1642-1043

Pojawia się w:

Polskie Forum Psychologiczne

Dostawca treści:

Biblioteka Nauki

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Skocz do pozycji: 50.

Tytuł:

Review of Aeronautical Fatigue Investigations in Poland (2013-2014)

Autorzy:

Niepokólczycki, A.
Leski, A.
Dragan, K.

Powiązania:

https://bibliotekanauki.pl/articles/97803.pdf

Data publikacji:

2016

Wydawca:

Sieć Badawcza Łukasiewicz - Instytut Lotnictwa

Tematy:

fatigue of aircraft structures

Opis:

This review was presented on the 34 Conference of the International Committee on Aeronautical Fatigue and Structural Integrity, Helsinki, Finland, June 1-2, 2015. It contains description of main works and investigations in fatigue of aircraft structures performed in Poland during the years 2013 and 2014.

Źródło:

Fatigue of Aircraft Structures; 2016, 8; 5-48
2081-7738
2300-7591

Pojawia się w:

Fatigue of Aircraft Structures

Dostawca treści:

Biblioteka Nauki

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