Temat: fatigue strength - Prolib Integro

Skocz do pozycji: 1.

Tytuł:: The influence of treating welded joints edges on the strength and fatigue of S640Q steel
Autorzy:: Cicholska, M.
Tematy:: weldability
high strength weldable steel
thermomechanical treatment
increasing fatigue strength
fatigue strength; Pokaż więcej
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Powiązania:: https://bibliotekanauki.pl/articles/246584.pdf Link otwiera się w nowym oknie
Opis:: Weldable steels of high strength were discussed. The factors influencing the achievement of low grain structure that ensures high strength of these steels was explained. Traditional and modern methods of producing high strength steel were shown. The scheme of production line was shown, the line which is used to manufacture steel of high strength in thermomechanical way. The methods of achieving strength to fatigue used for welded joints were presented. The factors influencing the increase of strength to fatigue of welded joints were elaborated. The thermally hardened steel sheets of high strength weldable S640Q steel underwent research. Basic mechanical properties of this steel were indicated. The results of static tensile test and technological bend test were given. Then the sheets were welded by semiautomatic MAG method. The examinations of welds quality were conducted and their usefulness for further tests was stated. Mechanical properties of welded joints were determined. The mechanical properties of native material and welded joints were compared. The microstructure of welded joints in the weld axis, in heat influence zone as well as in native material was examined. Fatigue tests in a non-symmetrical cycle of lengthening – compressing for the welded joints were carried out. The computational strength to fatigue was determined and compared with fatigue strength of welded joints. Tests results were elaborated by the statistical analysis of linear regression. After conducting fatigue tests, the Wöhler diagrams were made. Afterwards, the joints welded with TIG method, were penetrated without adding filler metal. The results were presented for the fatigue tests as well as the Wohler graph for welded joints after penetration of the joints edges with TIG method without adding filler metal. The results were compared.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: The influence of the shape of weld nobs on the fatigue strength of S540Q steel
Autorzy:: Cicholska, M.
Tematy:: weldability
high strength weldable steel
fatigue strength; Pokaż więcej
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Powiązania:: https://bibliotekanauki.pl/articles/242857.pdf Link otwiera się w nowym oknie
Opis:: The development of weldable steels was discussed together with the methods of obtaining them. The influence of these methods on steel properties was explained. Research was performed on quenched weldable S540Q steel of high strength. Basic mechanical properties of this steel were determined. The results of a static tensile test and technological bending test were given. Next, steel sheets were welded by semi-automatic MAG method. The welds quality was examined and their future suitability was stated. Mechanical properties of the joints welded of this steel were determined. Mechanical properties of native material and welded joints were compared. Joints microstructure was examined in the weld axis, in the heat influence zone and in the native material. Fatigue tests were conducted in the cycle of nonsymmetrical tension – compression of welded joints. The analytical fatigue strength was obtained and it was compared with fatigue strength of welded joints. Tests results were elaborated with the static analysis of linear regression. Wohler diagrams were made after conducting fatigue tests. Finally, weldable joints were melted by TIG method without adding filler metal. The angle and radius of welds nobs entrance into the native material was measured. The increase of fatigue strength is related to the decrease of geometric notch on the edges of weld nobs.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Carbon - epoxy composite fatigue strength - experiment and fem numerical estimation
Autorzy:: Derewońko, A.
Gieleta, R.
Tematy:: fatigue strength
carbon-epoxy composite
FEM; Pokaż więcej
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Powiązania:: https://bibliotekanauki.pl/articles/246504.pdf Link otwiera się w nowym oknie
Opis:: The development of composite materials characterized by the constant amelioration of their mechanical properties (stiffness and strength) has widened their application for structural elements, mainly in aeronautical, naval and automobile industries. The possibility of tailoring the composite’s properties appropriately to the applied load (by changing the direction of the fibre alignment and applying a corresponding matrix) results in the growing importance of the design process. The paper presents a numerical technique of determining the fatigue strength of the laminated carbon–epoxy composite. The experimental investigations were carried out to determine the complete set of the stiffness characteristics Eij, Gij, ..ij, the strength characteristics ..i,n, ..i,n. and the S-N fatigue curves. The static and fatigue numerical calculations were carried out for the material anisotropic model of the particular composite layers. Eight-node 3D finite elements with the composite’s properties were used to develop the specimen’s numerical model. The contact problem between the composite layers enabling the reflection of a mutual interaction was taken into account. The numerical investigation also included the state of effort analysis and the fatigue life assessment of the composite. The assessment of the composite’s fatigue life was performed using the MSC.Fatigue code. The verification of models and numerical analysis was carried out for composite specimens made of the CE 8201-245- 45/120 prepreg. The experimental verification confirmed that the places of the lowest fatigue life, found out in numerical analysis, are located in the area of the gauge part.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Fatigue strength of screw joints at loading variable
Autorzy:: Nieoczym, A.
Gardyński, L.
Krzysiak, Z.
Bartnik, G.
Samociuk, W.
Beer-Lech, K.
Tematy:: screw joints
fatigue strength
heat treatment; Pokaż więcej
Wydawca:: Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Powiązania:: https://bibliotekanauki.pl/articles/1396459.pdf Link otwiera się w nowym oknie
Opis:: In the article was described an influence of the construction of screw joint on the strength at loading variable. Relation of the type of material of the bolt was described to strength from the technology of making thread. Presented findings of cracking of double – nutted bolts at low – cycles loading.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: The fatigue strength evaluation of S540Q steel and its welded joints
Autorzy:: Cicholska, M.
Tematy:: weldability
fatigue strength
weldable steels of high strength; Pokaż więcej
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Powiązania:: https://bibliotekanauki.pl/articles/245662.pdf Link otwiera się w nowym oknie
Opis:: The research deals with the examination of thermally hardened sheets of weldable S540Q steel of high strength, obtained by thermo mechanical treatment. Conventional rolling and controlled rolling with rapid cooling processes were compared. Example of technological process of high strength sheets production was presented. The basic mechanical properties of this steel were determined (static tensile tests results as well as technological bend tests results were given). Then the steel sheets were welded by a semi-automatic MAG method. The research on the quality of welded joints was performed and their suitability for further research was worked out. Mechanical properties of S540Q steel welded joints were elaborated. The mechanical properties of native material were compared to the properties of welded joints. Joints microstructure was examined in the joints axis, in heat-affected zone and in native material. Fatigue tests were conducted in the non-symmetric tension - compression cycle for the welded joints. The computational fatigue strength was determined and then compared to fatigue strength of the welded joints. The tests results were elaborated statistically by the analysis of linear regression. Wöhler charts were made after conducting fatigue tests. The analysis of increasing the fatigue strength of S540Q steel welded joints was also performed.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Numerical investigation of production-related characteristics regarding their influence on the fatigue strength of additively manufactured components
Autorzy:: Zeißig, Michaela
Jablonski, Frank
Tematy:: additive manufacturing
fatigue strength
Weibull distribution
FEM; Pokaż więcej
Wydawca:: Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
Powiązania:: https://bibliotekanauki.pl/articles/2204622.pdf Link otwiera się w nowym oknie
Opis:: In order to further enhance the application of additive manufacturing (AM) processes, such as the laser powder bed fusion (L-PBF) process, reliable material data are required. However, the resulting specimen properties are significantly influenced by the process parameters and may also vary depending on the material used. Therefore, the prediction of the final properties is difficult. In the following, the effect of residual stresses on the fatigue strength of 316L steel, a commonly used steel in AM, is investigated using a Weibull distribution. The underlying residual stress distributions as a result of the building process are approximated for two building directions using finite element (FE) models. These imply significantly different distributions of tensile and compressive residual stresses within the component. Apart from the residual stresses, the impact of the mean stress sensitivity is discussed as this also influences the predicted fatigue strength values.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Prognozowanie trwałości zmęczeniowej elementów z karbami
The fatigue life prediction of notched elements
Autorzy:: Łukaszewicz, K.
Osipiuk, W.
Tematy:: trwałość zmęczeniowa
karb
naprężenie
fatigue life
fatigue strength
notch
tension; Pokaż więcej
Wydawca:: Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
Powiązania:: https://bibliotekanauki.pl/articles/386390.pdf Link otwiera się w nowym oknie
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.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: Effect of Laser Preheating AISI 4140 Specimens for Micro-Forging
Autorzy:: Jung, C.
Lee, M. G.
Jeon, Y.
Tematy:: laser preheating
micro-forging
fatigue strength
ultrasonic fatigue test
hardness; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/351766.pdf Link otwiera się w nowym oknie
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.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: The Influence of the High Speed Multipass Drawing Process on the Fatigue Strength of High Carbon Steel Wires
Wpływ wielostopniowego procesu ciągnienia z dużymi prędkościami na wytrzymałość zmęczeniową drutów ze stali wysokowęglowej
Autorzy:: Suliga, M.
Tematy:: drawing speed
fatigue strength
rope wires
wire roughness; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/356211.pdf Link otwiera się w nowym oknie
Opis:: In this work the influence of the drawing speed on fatigue strength of high carbon steel wires has been assessed. The drawing process of φ5.5 mm wires to the final wire of φ1.6 mm was conducted in 11 passes, in industrial conditions, by means of a modern Koch multi-die drawing machine. The drawing speeds in the last passes were: 5, 10, 15 and 20 m/s. For φ1.6 mm wires the investigation of fatigue strength has been carried out. In order to explain the effect of drawing speed on fatigue strength of rope wires, the roughness of drawn wires have been also determined. In addition, the numerical analysis of the drawing process on the base of Drawing 2D in which distribution of redundant strain, has been shown. The data of investigations prove the favourable effect of high drawing speed on fatigue strength of drawn wires. It was found that the better fatigue strength of wires drawn at the speed of 20 m/s compared to the wires drawn at the speeds of 5-15 m/s is associated with a better geometric structure of the surface of those wires. In addition to the high fatigue strength of the wires drawn with high speed is related to theirs higher redundant strain. The obtained data investigation can be applied in wire industry while implementing the new technologies of high speed drawing process of high carbon steel wires.
W pracy określono wpływ dużej prędkości ciągnienia na wytrzymałość zmęczeniowa drutów ze stali wysokowęglowej. Proces ciągnienia drutów o średnicy 5,5 mm na średnice końcowa 1,60 mm zrealizowano w 11 ciągach, w warunkach przemysłowych, na nowoczesnej ciągarce wielostopniowej Kocha. Prędkości ciągnienia na ostatnim ciągu wynosiły odpowiednio: 5, 10, 15 i 20 m/s. Badania wytrzymałości zmęczeniowej przeprowadzono dla drutów końcowych φ1,60 mm. Dla pełniejszej oceny wpływu wielkości prędkości ciągnienia na wytrzymałość zmęczeniowa drutów liniarskich przeprowadzono także badania chropowatości powierzchni. Dodatkowo w pracy, w oparciu o program Drawing 2d, przeprowadzono analizę numeryczną procesu ciągnienia, w której określono odkształcenia postaciowe w drutach po procesie ciągnienia. Uzyskane wyniki badan świadczą o korzystnym wpływie dużej prędkości ciągnienia na wytrzymałość zmęczeniowa drutów. Stwierdzono, ze lepsza wytrzymałość zmęczeniowa drutów ciągnionych z prędkością 20 m/s, w stosunku do drutów ciągnionych z prędkościami 5-15 m/s, związana jest z ich lepsza struktura geometryczna powierzchni oraz większymi odkształceniami postaciowymi. Uzyskane wyniki badan mogą być wykorzystane w przemyśle ciągarskim przy wdrażaniu nowych technologii szybkościowego ciągnienia drutów ze stali wysokowęglowych.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: The Effect of Non-Metallic Inclusions Formed as a Result of Deoxidation on the Fatigue Strength of 15CrNi6 and 16MnCr5 Steel
Autorzy:: Lipa, S.
Sawicki, J.
Dybowski, K.
Pietrasik, R.
Januszewicz, B.
Tematy:: fatigue strength
non-metallic inclusions
thermo-chemical treatment; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/353324.pdf Link otwiera się w nowym oknie
Opis:: This paper presents the findings of fatigue strength tests of 15CrNi6 steel following low-pressure carburizing and oil quenching, subjected to cycles of one-sided three-point bending. The fatigue fractures were compared with the results of fatigue strength studies of 16MnCr5 steel following low-pressure carburizing and nitrogen quenching. The fatigue tests for 16MnCr5 steel were conducted as part of a high-cycle resonance test, with a pendular bending load. The study also involved an analysis of the effects on non-metallic inclusions in the structure on the mechanism of fatigue destruction. The inclusions were found to initiate fatigue cracks. In both cases, a similar method of a fatigue fissure initiation was observed, independent of the study method or specimen material.
Dostawca treści:: Biblioteka Nauki

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