prof. Ing. Stanislav Věchet, CSc.
E-mail:   vechet@fme.vutbr.cz  Dept.:   Institute of Materials Science and Engineering Dept. of Mechanics and Design of Materials Position:   Professor Room:   A1/1334

Publications:

• KOHOUT, J.; VĚCHET, S.:
  Vývoj přístupů k regresi únavových křivek, ČSTN
  presentation
• KOHOUT, J.; VĚCHET, S.:
  Struktura a únavové vlastnosti litiny s kuličkovým grafitem, ČSTN
  lecture
• BUMBÁLEK, L.; NĚMEC, K.; VĚCHET, S.; HANZLÍKOVÁ, K.; PATA, V.; PERNIKÁŘ, J.; DOŇAR, B.:
  Kontrola a měření,
  Základní pojmy a metodiky měření pro studenty středních škol., pp.1-206, ISBN 978-80-7333-072-9, (2009), Informatorium, spol. s r.o.
  textbook
• ZAPLETAL, J.; VĚCHET, S.; KOHOUT, J.; LIŠKUTÍN, P.:
  FATIGUE LIFETIME OF 7075 ALUMINIUM ALLOY FROM ULTIMATE TENSILE STRENGTH TO PERMANENT FATIGUE LIMIT,
  Communications, Vol.2009, (2009), No.1, pp.17-21, ISSN 1335-4205
  journal article - other
• VĚCHET, S.; KOHOUT, J.; KLAKURKOVÁ, L.:
  Fatigue Properties of Austempered Ductile Iron,
  Materials Science, Vol.14, (2008), No.4, pp.324-327, ISSN 1392-1320, Technologia
  journal article - other
• KOHOUT, J.; VĚCHET, S.:
  Some Estimations of Tolerance Bands of S-N Curves,
  Materials Science, Vol.14, (2008), No.3, pp.202-205, ISSN 1392-1320, Technologia
  journal article - other

List of publications at Portal BUT

Abstracts of most important papers:

• KOHOUT, J.; VĚCHET, S.:
  Shift of S-N curves of ferritic nodular cast iron due to loading cycle asymmetry,
  ARABIAN JOURNAL FOR SCIENCE AND ENGINEERING, Vol.33, (2008), No.1B, pp.213-222, ISSN 1319-8025, KING FAGD UNIVERSITY OF TETROLEUM AND MINERALS, DGAGRAN 31261, SAUDI ARABIA
  journal article - other
  Increasing the mean stress of loading cycle causes a shift of fatigue (Wöhler s or S-N) curves towards higher values of fatigue strength if the curves are represented by the upper stress of loading cycle in dependence on the number of cycles to fracture. A successful quantitative description of the shift in gigh-cycle region was published by Walker. The aim of the present paper consists in deriving relations that describe the shift of fatigue curves in the whole cycle region from UTS to permanent fatigue limit. Their applicability is demonstrated by successful fit of the family of tfatigue curves loading cycle asymetries when the curves are described by the Stromeyer qquation as well as by the Kohout and Vechet qquation. Also the limitation of Walker s approach in the case of high mean stresses is discussed and a certain solution is proposed.
• VĚCHET, S.; KOHOUT, J.; HANZLÍKOVÁ, K.; HRUBÝ, V.:
  The influence of Mean Stress on Fatigue Properties of ADI,
  Materials Science Forum, Vol.567-568, (2008), No.5, pp.341-344, ISSN 0255-5476, Trans Tech Publications Ltd
  journal article - other
  The paper presents the results of research focused on assessment of the influence of loading cycle asymmetry on fatigue limit values. For tests two heats of unalloyed nodular cast iron were used. Test bars made of keel blocks were heat treated in salt bathes (austenitization at 900oC during 1 hour, isothermal transformation at 380 and 400oC) and loaded at symmetrical, repeating and pulsating loading cycles at room temperature. Evaluation of fatigue properties was based on the determination of S-N curves in high-cycle region including the fatigue limit assessment for 10*7 cycles to fracture. Fatigue and static tests were completed by metallographic and quantitative phase analysis. Most important result obtained from the presented study is that the dependence of stress amplitude on mean stress cannot be approached by the linear relation but by general power law with eyponent lower than 1 (i. e. the Haigh diagram has convex shape).
• VĚCHET, S.; KOHOUT, J.:
  Influence of Transformation Time on Fatigue Properties of Austempered Ductile Iron,
  Materials Science, Vol.12, (2006), No.1, pp.3-6, ISSN 1392-1320, Kaunas
  journal article - other
  Mechanical properties determined by tensile and fatigue tests of ADI transformed at the temperature of 400C during 11 various trnasformation dwells in the range from 2 min. to 25 hours are comfronted with obtained matrix structure.
• Věchet, S., Kohout, J., Hanzlíková K.:
  Influence of Isothermal Dwell on Tensile and Fatigue Properties of Austempered Ductile Iron.,
  Material Science Forum, pp.381-384, ISBN 0-87849-964-4, (2004), VUT Brno
  conference paper
  akce: Materials Structure & Micromechanics of Fracture (MSMF-4), Brno, 23.06.2004-25.06.2004
  Thanks to extraordinarily favourable both mechanical and technological properties, austempered ductile iron is ranked with very prospective structural materials. Its structure and consequently also mechanical properties can be substantially influenced by the conditions of isothermal transformation. The dependence between matrix composition and mechanical (static as well as fatigue) properties of unalloyed nodular cast iron, which was isothermally heat treated at transformation temperature of 380 °C, is studied in the present contribution.
• VĚCHET, S., ŠVEJCAR, J., KOHOUT, J.:
  High cycle fatigue properties of ductile cast iron.,
  Fatigue 99, pp.2077-2082, ISBN 1901537110, (1999), Higher education press
  conference paper
  Nodular shape of graphite in ductile cast iron causes that its fatigue characteristics are more substatially determined with the properties of matrix structure than the characteristics of cast iron with different shapes of graphite where the dominant role is played by notch effect of graphite where the dominant role is played by notch effect of graphite particles. Fatigue characteristics of ductile cast iron can then correlate not only with parametrers of graphite shape but above all with matrix structure.