doc. Ing. Pavel Mazal, CSc.
E-mail:   Pavel.Mazal@vut.cz  Dept.:   Institute of Machine and Industrial Design Dept. of Condition Monitoring Position:   Associate Professor Room:   A3/705

Supervised courses:

• Engineering Drawing (2K)
• Engineering Drawing (2K-A)
• Engineering Drawing (2K-K)
• Nondestructive Evaluation and Quality Control (9NTK)

Publications:

• VLAŠIC, F.; VOLÁK, J.; NOHÁL, L.; MAZAL, P.; HORT, F.:
  Study of Initial Stages of Fatigue Process Using Non-destructive Testing Methods, Trans Tech Publications
  journal article in Web of Science
  akce: Materials Structure & Micromechanics of Fracture (MSMF-7), Brno, 01.07.2013-03.07.2013
• NOHÁL, L.; HORT, F.; DVOŘÁČEK, J.; MAZAL, P.:
  An Experimental Investigation of Rolling Contact Fatigue of Steels Using Acoustic Emission Method,
  INSIGHT, Vol.55, (2013), No.12, pp.665-669, ISSN 1354-2575, BINDT
  journal article - other
• MAZAL, P.; PAZDERA, L.; NOHÁL, L.; TOPOLÁŘ, L.:
  Netradiční aplikace metody akustické emise,
  ISBN 978-80-214-4629-8, (2012), VUT v Brně
  book
• MAZAL, P.; HORT, F.; VLAŠIC, F.:
  Acoustic Emission Diagnostics of Roller Bearings Damage,
  Nondestructive Testing of Materials and Structures, pp.411-418, ISBN 978-94-007-0722-1, (2012), Springer
  book chapter
  akce: Nondestructive Testing of Materials and Structures, Istanbul, 15.05.2011-18.05.2011
• MAZAL, P.; LIŠKUTÍN, P.; VLAŠIC, F.; HORT, F.:
  Usage of Acoustic Emission Signal and X-ray Diffraction Analysis for Detection of Microstructural Changes in Cyclically Loaded AlMg Alloys,
  Nondestructive Testing of Materials and Structures, pp.319-326, ISBN 978-94-007-0722-1, (2012), Springer
  book chapter
  akce: Nondestructive Testing of Materials and Structures, Istanbul, 15.05.2011-18.05.2011
• HORT, F.; MAZAL, P.; VLAŠIC, F.:
  Monitoring of Acoustic Emission Signal of Loaded Axial Bearings,
  Journal of Materials Science and Engineering A, Vol.2011, (2011), No.5A, pp.717-724, ISSN 1934-8959, David Publishing
  journal article - other
• MAZAL, P.; PAZDERA, L.; NOHÁL, L.; TOPOLÁŘ, L.; GRUM, J.:
  ACOUSTIC EMISSION IN QUALITY CONTROL OF MATERIALS AND PROCESSES MONITORING,
  ISBN 978-961-90610-8-4, (2011), University of Ljubljana
  book
• FIALA, J.; MAZAL, P.; KOLEGA, M.:
  Cycle induced microstructural changes,
  International Journal of Microstructure and Materials Properties, Vol.6, (2011), No.3/4, pp.259-272, ISSN 1741-8410, Inderscience
  journal article - other
• MAZAL, P.; PAZDERA, L.; DVOŘÁČEK, J.:
  Application of acoustic emission method in contact damage identification,
  INTERNATIONAL JOURNAL OF MATERIALS & PRODUCT TECHNOLOGY, Vol.41, (2011), No.1, pp.140-152, ISSN 0268-1900, Inderscience
  journal article - other

List of publications at Portal BUT

Abstracts of most important papers:

• VLAŠIC, F.; VOLÁK, J.; NOHÁL, L.; MAZAL, P.; HORT, F.:
  Study of Initial Stages of Fatigue Process Using Non-destructive Testing Methods, Trans Tech Publications
  journal article in Web of Science
  akce: Materials Structure & Micromechanics of Fracture (MSMF-7), Brno, 01.07.2013-03.07.2013
  This paper deals with the basic research of cyclic damage during the initial stages of fatigue process using the non-destructive testing methods. The acoustic emission method was used for monitoring of the microstructure changes during fatigue loading. The electrical potential measurements of specimen and microscopic observation were used mainly to detect the first short cracks and their propagation. The fatigue tests at room temperature were conducted on titanium alloy and creep-resistant steel specimens under bending and tension loading. The aim of the study was to compare the acoustic emission signal at different types of loading until fracture and to analyze in detail the signal changes in initial stages of fatigue process. This analysis was primarily based on the waveform similarity and division into classes. The results show the high sensitivity of the acoustic emission technology in the transition from the stage of surface relief evolution to the stage of crack nucleation and propagation.
• NOHÁL, L.; HORT, F.; DVOŘÁČEK, J.; MAZAL, P.:
  An Experimental Investigation of Rolling Contact Fatigue of Steels Using Acoustic Emission Method,
  INSIGHT, Vol.55, (2013), No.12, pp.665-669, ISSN 1354-2575, BINDT
  journal article - other
  Rolling-element bearings are widely used machine components and their failure can result in damage to the whole machine. A bearing failure can be caused by many factors such as improper lubrication, presence of abrasive particles, overloading, moisture, corrosive environment, improper mounting, electrical discharges and material defects. These causes can be eliminated by observance of correct operating conditions, except rolling contact fatigue (RCF). For this reason, the full-scale bearing life tests or material tests for RCF resistance are performed. Various methods of condition monitoring are used to detect damage of these components or specimens in the industry or during testing in laboratories. An analysis of vibrations from tested bearings/specimens is the most widely used method for damage detection and is based on vibration acceleration measurement and its analysis in the time or frequency domain. A more sensitive method for surface damage or subsurface crack detection is the acoustic emission (AE) method. Over the past three decades, the AE based monitoring has developed as a potential tool for rolling bearing diagnostics. This paper is aimed on detection and monitoring of onset and propagation of natural defects of steel specimens using the AE technology. The experiments were carried out under various loading conditions on specimens of case-hardening steel 16MnCr5. The AE signal parameters such as count rate, cumulative count rate and RMS were compared with vibration levels and temperature. In conclusion, the results of this study suggest that the AE monitoring method can be employed as an evaluation tool for rolling contact fatigue testing of material specimens.
• MAZAL, P.; PAZDERA, L.; NOHÁL, L.; TOPOLÁŘ, L.:
  Netradiční aplikace metody akustické emise,
  ISBN 978-80-214-4629-8, (2012), VUT v Brně
  book
  The monography describes the contemporary methods of application options in the area of acoustic emission diagnosis of rotating machinery parts, the quality control in the field of welding, construction and selected areas of the biological sciences.
• MAZAL, P.; NOHÁL, L.; ČERNÝ, M.; ČERMÁK, J.:
  Measurements of Acoustic Emission in Evaluating of Sap Flow in Trees, INT SOC HORTICULTURAL SCIENCE
  journal article in Web of Science
  This article deals with measurement techniques of water conducting system in the trees. Water conducting system (including xylem and phloem) indicates its importance for related physiological processes. However, there are still problems how to measure its functioning (which variables and how), especially in the open field (e. g., forests and orchards) in order to get maximum information about it. In this study we focused on a general description of acoustic events measurable in a wide range of their spectrum (acoustic emission method). The first aim was to detect such signals and the second to learn them and gradually analyze in order to better understand the associated processes causing their occurrence and their relations to plant life.
• HORT, F.; MAZAL, P.; VLAŠIC, F.:
  Monitoring of Acoustic Emission Signal of Loaded Axial Bearings,
  Journal of Materials Science and Engineering A, Vol.2011, (2011), No.5A, pp.717-724, ISSN 1934-8959, David Publishing
  journal article - other
  The disclosure of initial stadium of contact fatigue of rotating machines is very difficult. At present, some methods which are suitable for diagnosis exist, such as vibration method, shock pulse method, acoustic emission and others. The article describes laboratory tests with axial bearings which are monitored by acoustic emission method. In the article, experimental stands, measuring devices and chosen types of axial bearings are presented. The exploitation of acoustic emission signal for the lifetime evaluation of selected bearings is shown with the characteristics as number of counts, rise time, maximal amplitude or duration of event. The bearing lifetime is separated to three stages and a representative sample in its time and frequency domain for each of them is chosen. Final failures of the bearings are shown too. The paper is focused also on examples of results obtained with continuous AE signal sensing.