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Kazymyrovych, Vitaliy
Publications (10 of 13) Show all publications
Bergström, J., Kazymyrovych, V., Burman, C. & Ekengren, J. (2011). Test specimen geometry, stress calculation and mean stress in 20kHz testing in the very long fatigue life region. In: Christina Berger, Hans-Jurgen Christ (Ed.), VHCF5 5thInternational Conference on Very High Cycle Fatigue: . Paper presented at VHCF5 5thInternational Conference on Very High Cycle Fatigue (pp. 315-320). Berlin: Deutcher Verband fur Materialforschung und prufung
Open this publication in new window or tab >>Test specimen geometry, stress calculation and mean stress in 20kHz testing in the very long fatigue life region
2011 (English)In: VHCF5 5thInternational Conference on Very High Cycle Fatigue / [ed] Christina Berger, Hans-Jurgen Christ, Berlin: Deutcher Verband fur Materialforschung und prufung , 2011, p. 315-320Conference paper, Oral presentation only (Refereed)
Place, publisher, year, edition, pages
Berlin: Deutcher Verband fur Materialforschung und prufung, 2011
Keywords
very high cycle fatigue, steel, ultrasonic testing, notch effect, mean stress, damping
National Category
Materials Engineering
Research subject
Materials Engineering
Identifiers
urn:nbn:se:kau:diva-16131 (URN)978-3-9814516-0-3 (ISBN)
Conference
VHCF5 5thInternational Conference on Very High Cycle Fatigue
Available from: 2012-12-11 Created: 2012-12-11 Last updated: 2019-12-02Bibliographically approved
Kazymyrovych, V. & Bergström, J. (2010). Initial crack growth in very high cycle fatigue of a hot-work tool steel.
Open this publication in new window or tab >>Initial crack growth in very high cycle fatigue of a hot-work tool steel
2010 (English)Manuscript (preprint) (Other academic)
National Category
Materials Engineering
Research subject
Materials Engineering
Identifiers
urn:nbn:se:kau:diva-6244 (URN)
Available from: 2010-08-18 Created: 2010-08-18 Last updated: 2019-03-13Bibliographically approved
Kazymyrovych, V., Bergström, J. & Thuvander, F. (2010). Local stresses and material damping in very high cycle fatigue. International Journal of Fatigue, 32, 1669-1674
Open this publication in new window or tab >>Local stresses and material damping in very high cycle fatigue
2010 (English)In: International Journal of Fatigue, ISSN 0142-1123, E-ISSN 1879-3452, Vol. 32, p. 1669-1674Article in journal (Other academic) Published
National Category
Materials Engineering
Identifiers
urn:nbn:se:kau:diva-3363 (URN)10.1016/j.ijfatigue.2010.03.007 (DOI)000279622900014 ()
Note

At the time of the licentiate thesis from Vitaliy Kazymyrovych, this article was unpublished, and had a status as a manuscript.

Available from: 2009-01-23 Created: 2009-01-23 Last updated: 2017-12-14Bibliographically approved
Kazymyrovych, V., Bergström, J. & Ekengren, J. (2010). Stress verification and specimen design for ultrasonic fatigue testing.
Open this publication in new window or tab >>Stress verification and specimen design for ultrasonic fatigue testing
2010 (English)Manuscript (preprint) (Other academic)
National Category
Materials Engineering
Research subject
Materials Science
Identifiers
urn:nbn:se:kau:diva-6245 (URN)
Available from: 2010-08-18 Created: 2010-08-18 Last updated: 2019-03-13Bibliographically approved
Kazymyrovych, V., Bergström, J. & Burman, C. (2010). The Significance of Crack Initiation Stage in Very High Cycle Fatigue of Steels. Steel Research International, 81(4), 308-314
Open this publication in new window or tab >>The Significance of Crack Initiation Stage in Very High Cycle Fatigue of Steels
2010 (English)In: Steel Research International, ISSN 1869-344X, Vol. 81, no 4, p. 308-314Article in journal (Refereed) Published
National Category
Materials Engineering
Identifiers
urn:nbn:se:kau:diva-3362 (URN)10.1002/srin.200900139 (DOI)
Note
At the time of the licentiate thesis from Vitaliy Kazymyrovych, this article was unpublished, and had a status as a manuscript.Available from: 2009-01-23 Created: 2009-01-23 Last updated: 2019-07-10Bibliographically approved
Kazymyrovych, V. (2010). Very high cycle fatigue of tool steels. (Doctoral dissertation). Karlstad: Karlstad University
Open this publication in new window or tab >>Very high cycle fatigue of tool steels
2010 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

An increasing number of engineering components are expected to have fatigue life in the range of 107 - 1010 load cycles. Some examples of such components are found in airplanes, automobiles and high speed trains. For many materials fatigue failures have lately been reported to occur well after 107 load cycles, namely in the Very High Cycle Fatigue (VHCF) range. This finding contradicts the established concept of a fatigue limit, which postulates that having sustained around 107 load cycles the material is capable of enduring an infinite number of cycles provided that the service conditions are unchanged. With the development of modern ultrasonic fatigue testing equipment it became possible to experimentally establish VHCF behaviour of various materials. For many of them the existence of the fatigue limit at 107 load cycles has been proved wrong and their fatigue strength continues to decrease with increasing number of load cycles.

High performance steels is an important group of materials used for the components subjected to VHCF. This study explores the VHCF phenomenon using experimental data generated by ultrasonic fatigue testing of selected tool steels. The overall aim is to gain knowledge of VHCF behaviour of some common tool steel grades, while establishing a fundamental understanding of mechanisms for crack development in the very long life regime. The study demonstrates that VHCF cracks in tested steels initiate from microstructural defects like slag inclusions, large carbides or voids. It is established that VHCF life is almost exclusively spent during crack formation at below threshold stress intensity values which results in a unique for VHCF morphology on the fracture surface.

Significant attention is devoted in the thesis to the ultrasonic fatigue testing technique, i.e. the validity and applicability of its results. FEM is employed to give an additional perspective to the study. It was used to calculate local stresses at fatigue initiating defects; examine the effect of material damping on ultrasonic stresses; and to evaluate various specimen geometries with respect to resulting stress gradient and maximum stressed material volume.

Place, publisher, year, edition, pages
Karlstad: Karlstad University, 2010. p. 45
Series
Karlstad University Studies, ISSN 1403-8099 ; 2010:20
Keywords
fatigue, crack growth, ultrasonic testing, tool steels, inclusions
National Category
Materials Engineering
Research subject
Materials Engineering
Identifiers
urn:nbn:se:kau:diva-5877 (URN)978-91-7063-312-6 (ISBN)
Public defence
2010-09-10, 21A 244, Ljungberssalen, Karlstad University, 10:15 (English)
Opponent
Supervisors
Available from: 2010-08-20 Created: 2010-06-17 Last updated: 2011-10-27Bibliographically approved
Ekengren, J., Kazymyrovych, V. & Bergström, J. (2009). Assessment of strength and inclusions of Tool Steels in Very High Cycle Fatigue. In: P. Beiss, C. Broeckmann, S. Franke, B. Keysselitz (Ed.), Proceedings of the 8th International Tooling Conference, Vol 1. Verlag Mainz, Wissenschaftsverlag
Open this publication in new window or tab >>Assessment of strength and inclusions of Tool Steels in Very High Cycle Fatigue
2009 (English)In: Proceedings of the 8th International Tooling Conference, Vol 1 / [ed] P. Beiss, C. Broeckmann, S. Franke, B. Keysselitz, Verlag Mainz, Wissenschaftsverlag , 2009Conference paper, Published paper (Refereed)
Abstract [en]

Fatigue strength is an important material property for many tooling applications, particularly in high performance applications. The research in Very High Cycle Fatigue (VHCF) has demonstrated that the traditional fatigue limit may not be valid for many materials subjected to 107 or more load cycles. Presently, both materials data and mechanism knowledge is missing on VHCF applications, even though many components are run at these life lengths. The fatigue strength is commonly controlled by different defects initiating failure, as in well controlled laboratory experiments may be internal inclusions. In this paper VHCF experimental testing was accomplished by the use of ultrasonic fatigue testing run at 20 kHz allowing long life evaluation within reasonably short test time. Fatigue strength, failure mechanisms and inclusion content were accordingly assessed. Fatigue strength data on H13 tool steel are presented, as well as a statistical approach considering available defect distribution and load distribution in the critically stressed volume, important to both steel supplier and end-user.

Place, publisher, year, edition, pages
Verlag Mainz, Wissenschaftsverlag, 2009
Keywords
very high cycle fatigue, tool steel, inclusion distribution
National Category
Metallurgy and Metallic Materials
Identifiers
urn:nbn:se:kau:diva-8225 (URN)9783810793058 (ISBN)
Available from: 2011-09-12 Created: 2011-09-12 Last updated: 2017-12-06Bibliographically approved
Kazymyrovych, V. (2009). Very high cycle fatigue of engineering materials: A literature review. Karlstad: Karlstad University
Open this publication in new window or tab >>Very high cycle fatigue of engineering materials: A literature review
2009 (English)Report (Other (popular science, discussion, etc.))
Abstract [en]

Many engineering components reach a finite fatigue life well above 109 load cycles. Some examples of such components are found in airplanes, automobiles or high speed trains. For some materials the fatigue failures have lately been found to occur well after 107 load cycles, namely in the Very High Cycle Fatigue (VHCF) range. This finding contradicted the established concept of fatigue limit for these materials, which postulates that having sustained 107 load cycles the material is capable of enduring an infinite number of cycles provided that the service conditions are unchanged.

With the development of modern ultrasonic fatigue testing equipment it became possible to experimentally establish VHCF behaviour of various materials. For most of them the existence of the fatigue limit at 107 load cycles has been proved wrong and their fatigue strength continues to decrease with increasing number of load cycles. This report describes very long life fatigue properties of most commonly used engineering materials including aluminium, titanium, nickel alloys and various types of steel.

Place, publisher, year, edition, pages
Karlstad: Karlstad University, 2009. p. 33
Series
Karlstad University Studies, ISSN 1403-8099 ; 2009:22
National Category
Materials Engineering
Research subject
Materials Engineering
Identifiers
urn:nbn:se:kau:diva-3933 (URN)978-91-7063-246-4 (ISBN)
Available from: 2009-06-02 Created: 2009-04-03 Last updated: 2011-10-27Bibliographically approved
Kazymyrovych, V. (2008). Very high cycle fatigue of high performance steels. (Licentiate dissertation). Karlstad university studies
Open this publication in new window or tab >>Very high cycle fatigue of high performance steels
2008 (English)Licentiate thesis, monograph (Other academic)
Place, publisher, year, edition, pages
Karlstad university studies, 2008
Identifiers
urn:nbn:se:kau:diva-25514 (URN)9789170632143 (ISBN)
Available from: 2013-01-22 Created: 2013-01-22 Last updated: 2013-01-22
Kazymyrovych, V. (2008). Very high cycle fatigue of high performance steels. (Licentiate dissertation). Karlstad: Karlstad University
Open this publication in new window or tab >>Very high cycle fatigue of high performance steels
2008 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

Many engineering components reach a finite fatigue life well above 109 load cycles. Some examples of such components are found in airplanes, automobiles or high speed trains. For some materials the fatigue failures have lately been found to occur well after 107 load cycles, namely in the Very High Cycle Fatigue (VHCF) range. This finding contradicted the established concept of fatigue limit for these materials, which postulates that having sustained 107 load cycles the material is capable of enduring an infinite number of cycles provided that the service conditions are unchanged. With the development of modern ultrasonic fatigue testing equipment it became possible to experimentally establish VHCF behaviour of various materials. For most of them the existence of the fatigue limit at 107 load cycles has been proved wrong and their fatigue strength continues to decrease with increasing number of load cycles.

 

One important group of materials used for the production of high performance components subjected to the VHCF is tool steels. This study explores the VHCF phenomenon using experimental data of ultrasonic fatigue testing of some tool steel grades. The causes and mechanisms of VHCF failures are investigated by means of high resolution scanning electron microscopy, and in relation to the existing theories of fatigue crack initiation and growth. The main type of VHCF origins in steels are slag inclusions.

However, other microstructural defects may also initiate fatigue failure. A particular attention is paid to the fatigue crack initiation, as it has been shown that in the VHCF range crack formation consumes the majority of the total fatigue life. Understanding the driving forces for the fatigue crack initiation is a key to improve properties of components used for very long service lives. Finite element modelling of VHCF testing was added as an additional perspective to the study by enabling calculation of local stresses at the fatigue initiating defects.

 

 

Place, publisher, year, edition, pages
Karlstad: Karlstad University, 2008. p. 14
Series
Karlstad University Studies, ISSN 1403-8099 ; 2008:56
Keywords
fatigue, tool steels, ultrasonic testing, fatigue life, crack growth rate, fatigue mechanisms
National Category
Materials Engineering
Research subject
Materials Engineering
Identifiers
urn:nbn:se:kau:diva-3066 (URN)978-91-7063-214-3 (ISBN)
Presentation
(English)
Available from: 2009-01-23 Created: 2008-11-24 Last updated: 2011-11-28Bibliographically approved
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