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Anna Kulesa, Andrzej Kurek, Tadeusz Łagoda, Henryk Achtelik and Krzysztof Kluger

Abstract

The paper presents a comparison of the fatigue life curves based on test of 15Mo3 steel under cyclic, pendulum bending and tension-compression. These studies were analyzed in terms of a large and small number of cycles where strain amplitude is dependent on the fatigue life. It has been shown that commonly used Manson-Coffin-Basquin model cannot be used for tests under cyclic bending due to the impossibility of separating elastic and plastic strains. For this purpose, some well-known models of Langer and Kandil and one new model of authors, where strain amplitude is dependent on the number of cycles, were proposed. Comparing the results of bending with tension-compression it was shown that for smaller strain amplitudes the fatigue life for both test methods were similar, for higher strain amplitudes fatigue life for bending tests was greater than for tension-compression.

Open access

Adam Niesłony, Michał Böhm, Tadeusz Łagoda and Filippo Cianetti

REFERENCES 1. Banvillet A., Łagoda T., Macha E., Niesłony A., Palin-Luc T., Vittori J.-F. (2004), Fatigue life under non-Gaussian random loading from various Models, International Journal of Fatigue , 26, 349–363. 2. Benasciutti D., Cristofori A., Tovo R. (2013) Analogies between spectral methods and multiaxial criteria in fatigue damage evaluation, Probabilistic Engineering Mechanics , 31, 39–45. 3. Benasciutti D., Tovo R. (2005), Spectral methods for lifetime prediction under wide-band stationary random processes, International

Open access

Józef Błachnio and Iwona Zabrocka

Abstract

This paper outlines a non-destructive method that is suitable for evaluation of condition demonstrated by gas turbine blades and is based on digital processing of images acquired from the blade surface in visible light. To enable high clearness of these images the particular attention is paid to the problem of how to provide optimum conditions for investigations and mitigate geometrical distortions of images acquired from maintenance operations. The paper demonstrates that there are relationships between operation lifetime of blades and discoloration of their surfaces due to overheating of the blade material. These relationships are revealed by digital analysis of images acquired for the blade surfaces and expressed as statistical parameter of the first and second order. To improve unambiguity of the analysis results a low-pass filter was applied. It was demonstrated that these relationships are suitable for evaluation how much the status of the blade material microstructure is altered

Open access

Sylwia M. Wojda

Abstract

Wear of dental materials used for permanent dental fillings has a significant impact on their lifetime. Wear products generated during chewing process involving direct tribological contact between a composite and tooth enamel can cause damage not only to enamel itself but also to the entire tooth structure thus affecting the patient’s the health. It is essential therefore to assess the process of wear rates as well as the usefulness and effectiveness of the method used to measure these values. As there are a number of different methods used to quantify the loss of dental materials subjected to friction, eg.: scanning digital 3D models of dental casts, confocal microscope scanning or profilographometer measurements, the authors chose to analyze two selected research methods using confocal microscopy and profilographometer to assess their effectiveness. Two commercially available composite dental materials, i.e. ES and FFE previously subjected to friction tests in contact with human dental enamel, were used for the analysis.

Open access

Jerzy Jaroszewicz, Krzysztof Łukaszewicz and Vladimir Antonyuk

Abstract

Heavy-duty, oil-cooled brake discs (MMOTs) are often used in heavy-duty brake systems manufactured by companies such as Caterpilar, Clark, Komatsu and Liebherr. These discs are usually made of special steels, and in most cases, the flatness of the working surfaces should not exceed 0.15–0.30 mm. Although the technological processes of friction disc production include several stages of heat treatment and grinding, the required accuracy is not achieved in some cases. In addition, the remaining residual stresses lead to the deformation of the discs during their lifetime. In production practice, three methods are used to reduce residual stresses: thermo-fixing, dynamic stabilisation and vibratory stabilisation consisting in bringing discs to transverse resonance vibrations and maintaining resonance until significant stress reduction. The article proposes a method of stabilising the discs using the resonance phenomenon at the first few frequencies. In this article, Cauchy’s function method and characteristic series method are used to develop solution value problem for clamped circular plates with discrete inclusions as concentrated masses and springs. Calculation methods for quick estimation of the own frequency of discs with additional ring mass enabling the use of low power vibration inductors are presented. The use of a special membrane and a pneumatic cushion in the construction of the stand allows to induce vibrations of higher frequencies.

Open access

Krzysztof Nowak

lifetime for CAFE creep damage model, Computer Methods in Materials Science, 11, 315-323. 16. Raabe D. (2002), Cellular Automata in Materials Science with Particular Reference to Recrystallization Simulation, Ann. Review of Materials Research, 32, 53-76. 17. Weibull W. (1939), The Phenomenon of Rupture in Solids, Proceedings of Royal Swedish Institute for Engineering Research, 153, 5-55. 18. Yatomi M., Nikbin K.M., O'Dowd N.P. (2003), Creep crack growth prediction using a damage based approach, International Journal of

Open access

Jerzy Narojczyk and Dmitrij Morozow

-870. 13. Musil J . (2012), Hard nanocomposite coatings: Thermal stability, oxidation resistance and toughness, Surface & Coatings Technology , 207, 50-65. 14. Narojczyk J., Werner Z., Piekoszewski J., Szymczyk W. (2005), Effects of nitrogen implantation on lifetime of cutting tools made of SK5M tool steel, Vacuum , 78, 229-233. 15. Perez F.J., Cristobal M.J., Hierro M.P., Pedraza F . (1999), The influence of implanted silicon on the cyclic oxidation behaviour of two different stainless steels, Surface and Coatings Technology , 120-121, 442

Open access

Mariusz Banaszkiewicz and Waldemar Dudda

REFERENCES 1. Armstrong P., Frederick C. (1966), A mathematical representation of the multiaxial Bauschinger effect, CEGB Report No. RD/B/N 731 . 2. Banaszkiewicz M. (2015), Multilevel approach to lifetime assessment of steam turbines, International Journal of Fatigue , 73, 39–47. 3. Banaszkiewicz M. (2016), Online monitoring and control of thermal stresses in steam turbine rotors, Applied Thermal Engineering , 94, 763–776. 4. Banaszkiewicz M. (2018), The low-cycle fatigue life assessment method for online monitoring of steam

Open access

Tetiana Cherepova, Galyna Dmitrieva, Oleksandr Tisov, Oleksandr Dukhota and Myroslav Kindrachuk

TiC self-healing coatings on the cyclic oxidation resistance and lifetime of thermal barrier coatings, Journal of Alloys and Compounds , 656, 992–1003 22. Sakamoto T., Kurishita H., Matsuo S., Arakawa H, Takahashi S, Tsuchida M., Kobayashi S., Nakai K,. Terasawa M., Yamasaki T., Kawai M. (2015) Development of nanostructured SUS316L-2%TiC with superior tensile properties, Journal of Nuclear Materials , 466, 468–476. 23. Shuster L.S., Mamleyev R.F., Kamaletdinova R.R., Chertovskikh S.V., Kireev R.M. (2016). Wear of friction pairs made of titanium

Open access

Michał Petaś, Krzysztof Mróz and Krzysztof Doliński

International Conference on Fracture (ICF 5), Cannes, Vol. 3, Pergamon Press, Oxford, 1381-1393. 15. Chaboche J. L. (1982), Lifetime predictions and cumulative damage under high-temperature conditioned, In Low-cycle Fatigue and Life Prediction, ASTM STP 770, eds. C, Amzallag, B. N, Leis and P.Rabbe, American Society for Testing and Materials, Philadelphia, PA, 81-103. 16. Chaboche J. L., Lesne P. M. (1988), A non-linear continuous fatigue damage model, Fatigue and Fracture of Engineering Materials and Structures, 11, 1, 1-7. 17