Institute of Fundamental Technological Research
Polish Academy of Sciences

Staff

Tomasz Dębowski, MSc

Department of Experimental Mechanics (ZMD)
Division of Non-Destructive Testing (PBN)
position: Senior Specialist
telephone: (+48) 22 826 12 81 ext.: 163
room: 532
e-mail:

Recent publications
1.  Ranachowski Z., Wieczorek K., Ranachowski P., Dębowski T., Monitoring of Partial Discharges in Cable Insulation and Cable Head Using Acoustic Method, ARCHIVES OF ACOUSTICS, ISSN: 0137-5075, DOI: 10.24425/aoa.2022.141654, Vol.47, No.2, pp.259-265, 2022

Abstract:
The article presents the application of Acoustic Emission (AE) method for detection and registration of partial discharges (PD) generated in medium voltage (MV) cable isolation and MV cable head. The insulation of the high voltage cable is made of a flexible material whose properties are characterised by a high coefficient of attenuation of the acoustic signals. For this reason, the AE method has not been used so far to detect PD in energetic cables. The subjects of the research were the MV cable and the standard T-type cable head. The cable contained defects which were the source of partial discharges. In case of cable head the PD were provoked by thin grounded electrode which was introduced into connector opening. The results of AE measurements are presented in the form of spectrograms. Acoustic Emission was evoked when the applied voltage level reached the value of 7.5 kV for the cable and 4 kV for the cable head. The authors used the acoustic instrumentation of their own design intended for future field use. Obtaining successful results of partial discharges measurements using the acoustic method in the cable insulation makes an original contribution of the presented work.

Keywords:
partial discharges, medium voltage insulation, acoustic emission

Affiliations:
Ranachowski Z. - IPPT PAN
Wieczorek K. - Wroclaw University of Science and Technology (PL)
Ranachowski P. - IPPT PAN
Dębowski T. - IPPT PAN
2.  Ranachowski Z., Ranachowski P., Dębowski T., Brodecki A., Kopeć M., Roskosz M., Fryczowski K., Szymków M., Krawczyk E., Schabowicz K., Mechanical and non-destructive testing of plasterboards subjected to a hydration process, Materials, ISSN: 1996-1944, DOI: 10.3390/ma13102405, Vol.13, No.10, pp.2405-1-18, 2020

Abstract:
The aim of this study was to investigate the effect of plasterboards' humidity absorption on their performance. Specimens' hydration procedure consisted of consecutive immersing in water and subsequent drying at room temperature. Such a procedure was performed to increase the content of moisture within the material volume. The microstructural observations of five different plasterboard types were performed through optical and scanning electron microscopy. The deterioration of their properties was evaluated by using a three-point bending test and a subsequent ultrasonic (ultrasound testing (UT)) longitudinal wave velocity measurement. Depending on the material porosity, a loss of UT wave velocity from 6% to 35% and a considerable decrease in material strength from 70% to 80% were observed. Four types of approximated formulae were proposed to describe the dependence of UT wave velocity on board moisture content. It was found that the proposed UT method could be successfully used for the on-site monitoring of plasterboards' hydration processes.

Keywords:
plasterboards, moisture content, hydration processes, mechanical properties, ultrasound measurements

Affiliations:
Ranachowski Z. - IPPT PAN
Ranachowski P. - IPPT PAN
Dębowski T. - IPPT PAN
Brodecki A. - IPPT PAN
Kopeć M. - IPPT PAN
Roskosz M. - AGH University of Science and Technology (PL)
Fryczowski K. - Silesian University of Technology (PL)
Szymków M. - other affiliation
Krawczyk E. - other affiliation
Schabowicz K. - Wroclaw University of Science and Technology (PL)
3.  Ranachowski Z., Ranachowski P., Dębowski T., Gorzelańczyk T., Schabowicz K., Investigation of structural degradation of fiber cement boards due to thermal impact, Materials, ISSN: 1996-1944, DOI: 10.3390/ma12060944, Vol.12, No.6, pp.944-1-14, 2019

Abstract:
The aim of the present study was to investigate the degradation of the microstructure and mechanical properties of fiber cement board (FCB), which was exposed to environmental hazards, resulting in thermal impact on the microstructure of the board. The process of structural degradation was conducted under laboratory conditions by storing the FCB specimens in a dry, electric oven for 3 h at a temperature of 230 °C. Five sets of specimens, that differed in cement and fiber content, were tested. Due to the applied heating procedure, the process of carbonization and resulting embrittlement of the fibers was observed. The fiber reinforcement morphology and the mechanical properties of the investigated compositions were identified both before, and after, their carbonization. Visual light and scanning electron microscopy, X-ray micro tomography, flexural strength, and work of flexural test Wf measurements were used. A dedicated instrumentation set was prepared to determine the ultrasound testing (UT) longitudinal wave velocity cL in all tested sets of specimens. The UT wave velocity cL loss was observed in all cases of thermal treatment; however, that loss varied from 2% to 20%, depending on the FCB composition. The results obtained suggest a possible application of the UT method for an on-site assessment of the degradation processes occurring in fiber cement boards.

Keywords:
cement-based composites, fiber cement boards, durability, ultrasound measurements

Affiliations:
Ranachowski Z. - IPPT PAN
Ranachowski P. - IPPT PAN
Dębowski T. - IPPT PAN
Gorzelańczyk T. - Wroclaw University of Science and Technology (PL)
Schabowicz K. - Wroclaw University of Science and Technology (PL)
4.  Dębowski T., Lewandowski M., Mackiewicz S., Ranachowski Z., Schabowicz K., Badania ultradźwiękowe płyt włóknisto-cementowych, PRZEGLĄD SPAWALNICTWA, ISSN: 0033-2364, Vol.88, No.10, pp.69-71, 2016

Abstract:
W artykule przedstawiona została możliwość lokalizacji delaminacji w płycie włóknisto-cementowej za pomocą specjalnie do tego celu skonstruowanego urządzenia wykorzystującego metodę ultradźwiękową i fale podłużne. Przeprowadzono badania na trzech rodzajach płyt. Stwierdzono, że proponowana metoda diagnostyczna umożliwia wykrywanie lokalnych nieciągłości, np. obszarów o obniżonej zwartości, czy delaminacji w płytach włóknisto-cementowych na obszarze średnicy wiązki metodą estymacji prędkości fali ultradźwiękowej. Zaletami metody są niewielkie wymiary urządzenia i krótki czas badania

Keywords:
płyty włóknisto-cementowe, badania nieniszczące, ultradźwięki

Affiliations:
Dębowski T. - IPPT PAN
Lewandowski M. - IPPT PAN
Mackiewicz S. - IPPT PAN
Ranachowski Z. - IPPT PAN
Schabowicz K. - Wroclaw University of Science and Technology (PL)
5.  Ranachowski Z., Jóźwiak-Niedźwiedzka D., Brandt A.M., Dębowski T., Application of Acoustic Emission Method to Determine Critical Stress in Fibre Reinforced Mortar Beams, ARCHIVES OF ACOUSTICS, ISSN: 0137-5075, Vol.37, No.3, pp.261-268, 2012

Abstract:
The objective of this investigation was to test the effectiveness of the Acoustic Emission (AE) measurements in determining the critical stresses during four-point bending of mortar beams. Within the measuring procedure the parameter σcr/σ300 was calculated and analysed. Additionally, the influence of cement replacement by high calcium fly ash (HCFA) on the process of crack healing was discussed. Mortar beams with different content of HCFA and reinforced by steel microfibres were prepared for tests. After curing in standard conditions the beams were subjected to four-point bending test in order to introduce the pre-cracking. Thereafter the beams were cured in the lime water and loaded after 56 and 112 days in the same way as for the first time. Additionally the microstructure of mortars was studied in a stereo optical microscope as well in an electron scanning microscope including the Energy Dispersive X-ray analysis (EDX). The results of microstructural characterization of mortar containing HCFA from lignite combustion are presented. The applied load level slightly exceeded the critical stress, producing intense crack growth processes however did not significant affected the load capacity of the beams. During the consecutive loading the decreasing tendency of σcr/σ300 ratio was noted. The obtained results confirm that the latter parameter can be applied as a measure of the composite degradation level for the elements carrying the repeated loads of amplitude close to the critical stress of the structure and also that the cement replacement with HCFA influences the process of crack healing.

Keywords:
critical stress, Acoustic Emission, microcracking, self-healing, concrete microstructure, fly ash

Affiliations:
Ranachowski Z. - IPPT PAN
Jóźwiak-Niedźwiedzka D. - IPPT PAN
Brandt A.M. - other affiliation
Dębowski T. - IPPT PAN
6.  Dyniewicz B., Sekuła K., Dębowski T., Pomiary wielkości dynamicznych w transporcie kolejowym z wykorzystaniem czujników piezoelektrycznych, DROGI I MOSTY, ISSN: 1643-1618, Vol.1, pp.31-44, 2010

Abstract:
Prawidłowe funkcjonowanie sieci kolejowej wymaga poznania stanu wyeksploatowanego toru oraz podtorza. Diagnozowanie sieci kolejowej wymaga m. in. Budowy poprawnego modelu numerycznego, symulującego możliwie wiernie badany układ, zachowując przy tym rozsądny czas obliczeń. W pracy przedstawiono wyniki eksperymentów zrealizowanych na doświadczalnym stanowisku polowym. W pomiarach wykorzystano czujniki piezoelektryczne wykonane w formie płytek o prostokątnym kształcie. Otrzymane wyniki porównano z rezultatami obliczeń numerycznych wykonanych metodą elementów czasoprzestrzennych. Wykazano skuteczność symulacji komputerowych w opisie dynamiki rzeczywistych torów kolejowych.

Affiliations:
Dyniewicz B. - IPPT PAN
Sekuła K. - other affiliation
Dębowski T. - IPPT PAN
7.  Sekuła K., Konowrocki R., Dębowski T., Badania nowego typu systemu ważenia pojazdów drogowych w ruchu, DROGI I MOSTY, ISSN: 1643-1618, Vol.8, No.3, pp.69-88, 2009

Abstract:
W pracy zaprezentowano wstępną ocenę nowej metodologii stosowanej do identyfikacji obciążeń wywieranych przez przejeżdżające pojazdy na nawierzchnię drogi. Proponowane rozwiązanie opiera się na pomiarze lokalnych odkształceń powstałych na powierzchni detektora nacisku. Celem jest rozwój koncepcji oraz sprawdzenie nowego typu dynamicznej wagi drogowej oraz algorytmu rozwiązania zagadnienia odwrotnego. Przyjętą koncepcję wstępnie sprawdzono wykorzystując metodę elementów skończonych. Przeprowadzono też testy laboratoryjne proponowanego urządzenia. Uzyskano dzięki temu wstępne dane do kalibracji urządzenia. Ważnym zagadnieniem było sprawdzenie czynników wpływających na identyfikację obciążeń. Skuteczność rozwiązania sprawdzono w badaniach doświadczalnych wstępnej wersji urządzenia w warunkach drogowych.

Keywords:
ważenie pojazdów w ruchu, identyfikacja obciążeń, czujniki piezoelektryczne, badania eksperymentalne

Affiliations:
Sekuła K. - IPPT PAN
Konowrocki R. - IPPT PAN
Dębowski T. - IPPT PAN
8.  Pawełek A., Kuśnierz J., Bogucka J., Jasieński Z., Ranachowski Z., Ranachowski P., Rejmund F., Dębowski T., Acoustic emission and the Portevin-Le Chatelier effect in tensile tested Al processed by ARB technique, ARCHIVES OF ACOUSTICS, ISSN: 0137-5075, Vol.32, No.4, pp.955-962, 2007

Abstract:
The paper presents the investigations of the relation between the acoustic emission (AE) and the Porte vin-Le Chatelier (PL) phenomena occurring in tensile tested two kinds of aluminium alloys: not-predeformed and predeformed earlier using the technique of accumulative rolling banding (ARB). There have been found essential correlations between AE and PL effects in ARB not-predeformed alloys. The tensile tests for ARB predeformed alloys were performed on a series of samples of various degree of work hardening and it has been observed that the correlations between the AE and PL effects are not so pronounced as in the case of ARB not-predeformed alloys. The results of AE measurements obtained using a new software allowed additionally to carry out the spectral analysis of AE signals and, in consequence, to determine the acoustic maps (acoustograms) and the spectral characteristics which are very useful in the discussion of the relations between the non-homogeneous strain mechanisms of the PL effect and the mechanisms of AE events generation. The results are discussed in the context of the existing dislocation models of the PL effect and the theoretical concepts of AE sources

Keywords:
acoustic emission (AE), Portevin-Le Chatelier (PL) effect, tensile test, dislocations, strain mechanism, nanocrystalline and/or ultra fine-grained structure, accumulative rollbonding (ARB)

Affiliations:
Pawełek A. - other affiliation
Kuśnierz J. - other affiliation
Bogucka J. - other affiliation
Jasieński Z. - Institute of Metallurgy and Materials Science, Polish Academy of Sciences (PL)
Ranachowski Z. - IPPT PAN
Ranachowski P. - IPPT PAN
Rejmund F. - IPPT PAN
Dębowski T. - IPPT PAN

List of chapters in recent monographs
1. 
Ranachowski Z., Jóźwiak-Niedźwiedzka D., Dąbrowski M., Wołowicz J., Sobczak M., Dębowski T., Glinicki M.A., Proc. Int. Symp. Brittle Matrix Composites, BMC-10, October 15-17, Warsaw, rozdział: Microhardness testing procedure applied to blended cement based matrix, IFTR and Woodhead Publ., Warsaw, pp.209-222, 2012

Conference papers
1.  Ranachowski Z., Schabowicz K., Gorzelańczyk T., Lewandowski M., Cacko D., Katz T., Dębowski T., Investigation of Acoustic Properties of Fibre-Cement Boards, IEEE 2018, IEEE Joint Conference - Acoustics, 2018-09-11/09-14, Ustka (PL), DOI: 10.1109/ACOUSTICS.2018.8502341, pp.275-279, 2018

Abstract:
The paper describes two different techniques of ultrasound measurements performed in fibre cement boards, the material widely applied in building technology. An in-house device dedicated for fibre-cement board testing is also presented. To overcome the difficulty of determining the arrival time of the waveform of a longitudinal wave travelling across a thin and inhomogeneous body, a cross-correlation method of signal processing was proposed and applied

Keywords:
ultrasound, fibre-cement board, waveform cross correlation coefficient

Affiliations:
Ranachowski Z. - IPPT PAN
Schabowicz K. - Wroclaw University of Science and Technology (PL)
Gorzelańczyk T. - Wroclaw University of Science and Technology (PL)
Lewandowski M. - IPPT PAN
Cacko D. - IPPT PAN
Katz T. - IPPT PAN
Dębowski T. - IPPT PAN

Patents
Filing No./Date
Filing Publication
Autors
Title
Protection Area, Applicant Name
Patent Number
Date of Grant
pdf
435320
2020-09-16
BUP 12/2022
2022-03-21
Schabowicz K., Ranachowski Z., Dębowski T., Szymków M., Krawczyk E.
Device for determining gypsum hydration in plaster-boards
PL, Politechnika Wrocławska, Instytut Podstawowych Problemów Techniki PAN
241120
WUP 31/2022
2022-08-01



431047
2019-09-04
BUP 05/2021
2021-03-08
Szelążek J., Ranachowski Z., Mackiewicz S., Katz T., Dębowski T.
Ultrasound head in the form of a waveguide for measuring the acoustic birefringence coefficient with a semi-transparent acoustic mirror
PL, Instytut Podstawowych Problemów Techniki PAN
240246
WUP 10/2022
2022-03-07



417777
2016-06-30
BUP 02/2017
2017-01-16
Dębowski T., Lewandowski M., Mackiewicz S., Ranachowski Z., Hoła J., Schabowicz K.
Method for detecting delamination in fibre cement tiles and the device for detecting delamination in fibre cement tiles
PL, Politechnika Wrocławska, Instytut Podstawowych Problemów Techniki PAN
227043
WUP 10/2017
2017-10-31



399026
2012-04-27
BUP 22/2013
2013-10-28
Ranachowski Z., Glinicki M.A., Knor G., Dębowski T., Ossowski A.
Three-day measuring method for heat hardening of concrete and a device for measuring the three-day heat hardening of concrete
PL, Instytut Podstawowych Problemów Techniki PAN
220335
WUP 10/2015
2015-10-30



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