Institute of Fundamental Technological Research
Polish Academy of Sciences

Staff

Tomasz Libura, MSc

Department of Experimental Mechanics (ZMD)
Division of Strength of Materials (PWM)
Laboratory for Testing of Materials and Structures
position: senior specialist
telephone: (+48) 22 826 12 81 ext.: 347
room: 029
e-mail:


Recent publications
1.  Frydrych K., Libura T., Kowalewski Z., Maj M., Kowalczyk-Gajewska K., On the role of slip, twinning and detwinning in magnesium alloy AZ31B sheet, MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING, ISSN: 0921-5093, DOI: 10.1016/j.msea.2021.141152, Vol.813, pp.141151-1-141151-14, 2021

Abstract:
The paper reports experimental and numerical study of different deformation mechanisms activated in the
AZ31B mag nesium alloy sheet subjected to cyclic in-plane tensile – compressive deformation. The influence ofslip, twinning and detwinning upon the mechanical response and texture evolution of the material is thoroughly investigated. The regime of twinning and detwinning activity is assessed based on the variation of hardening modulus in the course of the process. Velocity-based large strain crystal plasticity model accounting for twinning and detwinning is formulated. The crystal plasticity model parameters are identified using the implementation of the evolutionary algorithm. Predicted activity of deformation mechanisms is discussed with respect to the experimental data.

Keywords:
Twinning, Detwinning, Crystal plasticity, Magnesium alloys, AZ31B, Evolutionary algorithm

Affiliations:
Frydrych K. - IPPT PAN
Libura T. - IPPT PAN
Kowalewski Z. - IPPT PAN
Maj M. - IPPT PAN
Kowalczyk-Gajewska K. - IPPT PAN
2.  Wood P., Libura T., Kowalewski Z.L., Williams G., Serjouei A., Influences of horizontal and vertical build orientations and post-fabrication processes on the fatigue behavior of stainless steel 316L produced by selective laser melting, Materials, ISSN: 1996-1944, DOI: 10.3390/ma12244203, Vol.12, No.24, pp.4203-1-19, 2019

Abstract:
In this paper, the influences of build orientation and post-fabrication processes, including stress-relief, machining, and shot-peening, on the fatigue behavior of stainless steel (SS) 316L manufactured using selective laser melting (SLM) are studied. It was found that horizontally-built (XY) and machined (M) test pieces, which had not been previously studied in the literature, in both stress-relieved (SR) or non-stress-relieved (NSR) conditions show superior fatigue behavior compared to vertically-built (ZX) and conventionally-manufactured SS 316L. The XY, M, and SR (XY-M-SR) test pieces displayed fatigue behavior similar to the XY-M-NSR test pieces, implying that SR does not have a considerable effect on the fatigue behavior of XY and M test pieces. ZX-M-SR test pieces, due to their considerably lower ductility, exhibited significantly larger scatter and a lower fatigue strength compared to ZX-M-NSR samples. Shot-peening (SP) displayed a positive effect on improving the fatigue behavior of the ZX-NSR test pieces due to a compressive stress of 58 MPa induced on the surface of the test pieces. Fractography of the tensile and fatigue test pieces revealed a deeper understanding of the relationships between the process parameters, microstructure, and mechanical properties for SS 316L produced by laser systems. For example, fish-eye fracture pattern or spherical stair features were not previously observed or explained for cyclically-loaded SLM-printed parts in the literature. This study provides comprehensive insight into the anisotropy of the static and fatigue properties of SLM-printed parts, as well as the pre- and post-fabrication parameters that can be employed to improve the fatigue behavior of steel alloys manufactured using laser systems.

Keywords:
selective laser melting, stainless steel 316L, fatigue, defect, fracture

Affiliations:
Wood P. - University of Derby (GB)
Libura T. - IPPT PAN
Kowalewski Z.L. - IPPT PAN
Williams G. - University of Derby (GB)
Serjouei A. - University of Derby (GB)

Conference papers
1.  Libura T., Kowalewski Z.L., Szymczak T., Wpływ cyklicznego obciążenia na odporność na uderzenia laminatu z żywicy termoplastycznej wzmocnionej tkaniną z włókna szklanego, XIII NKRM 2019, XIII Konferencja Nowe Kierunki Rozwoju Mechaniki, 2019-03-20/03-23, Będlewo (PL), pp.41-42, 2019

Keywords:
kompozyty, żywice termoplastyczne, badania zmęczeniowe, udarność

Affiliations:
Libura T. - IPPT PAN
Kowalewski Z.L. - IPPT PAN
Szymczak T. - Motor Transport Institute (PL)
2.  Libura T., Kowalewski Z.L., Dietrich L., Socha G., Anti-buckling system for flat specimens investigations under cyclic tension-compression, Materials Today: Proceedings, ISSN: 2214-7853, DOI: 10.1016/j.matpr.2016.03.045, No.3, pp.1045-1050, 2016

Abstract:
Modern automobile and airplane structures made of sheet metals or composites require usage of thinner and stronger materials. On the other hand, manufacturers are trying to reduce production costs by shortening the fabrication processes and by application of computed simulation for forming operation. Therefore, it is necessary to better understand and more accurately investigate deformation behaviour of sheet alloys. Testing of flat specimens under compression and cyclic tension-compression within large deformation procures a lot of problems. One of them is the buckling phenomenon. A new version of the device mounted in a standard testing machine was developed and geometry of the specimen for validation of the device was proposed. Specimens of DP690 steel with nominal thickness equal to 1.6 mm were investigated at ambient temperature. Tension-compression cyclic tests within a strain range ± 0.04 were executed starting in tension direction. It is shown that the results are repeatable.

Keywords:
Buckling, cyclic loading, fixture, thin sheets

Affiliations:
Libura T. - IPPT PAN
Kowalewski Z.L. - IPPT PAN
Dietrich L. - IPPT PAN
Socha G. - other affiliation

Conference abstracts
1.  Kowalewski Z.L., Szczęsny G., Libura T., Brodecki A., Destabilization of the comminuted clavicle shaft fracture due to breakage of the titanium locking plate - mechanical analysis, DAS 2019, 36th DANUBIA-ADRIA Symposium on Advances in Experimental Mechanics, 2019-09-24/09-27, Pilzno (CZ), pp.1-2, 2019
2.  Kowalewski Z.L., Nowak Z., Pęcherski R.B., Libura T., Identification of effects associated to dynamic testing using shpb or dict- experiment and numerical analysis, DynaMAT, The 13th WORKSHOP on DYNAMIC BEHAVIOR OF MATERIALS AND ITS APPLICATIONS IN INDUSTRIAL PROCESSES, 2019-04-17/04-19, Nicosia (CY), pp.1-2, 2019
3.  Libura T., Kowalewski Z.L., Matadi Boumbimba R., Rusinek A., Gerard P., Behaviour of glass woven reinforced thermoplastic laminates under uniaxial cyclic loading, DynaMAT, The 13th WORKSHOP on DYNAMIC BEHAVIOR OF MATERIALS AND ITS APPLICATIONS IN INDUSTRIAL PROCESSES, 2019-04-17/04-19, Nicosia (CY), pp.1-2, 2019
4.  Kowalewski Z.L., Libura T., Experimental characterization of magnesium alloy thin sheets using anti-buckling fixture, LMM 2019, International Conference on Lightweight Materials and Manufacture, 2019-10-09/10-12, Changsha (CN), pp.1-1, 2019
5.  Libura T., Brodecki A., Kowalewski Z.L., Behaviour of glass woven reinforced thermoplastic laminates under uniaxial cyclic loading, PCM-CMM, 4th Polish Congress of Mechanics, 23rd International Conference on Computer Methods in Mechanics, 2019-09-08/09-12, Kraków (PL), pp.1-1, 2019

Keywords:
cyclic loading, damage evolution, laminate composites

Affiliations:
Libura T. - IPPT PAN
Brodecki A. - IPPT PAN
Kowalewski Z.L. - IPPT PAN
6.  Libura T., Nowak Z., Kowalewski Z.L., Widłaszewski J., Behaviour of inconel 718 aerospace alloy thin sheets under in-plane tension-compression, SME, XXVIII Symposium On Experimental Mechanics of Solids in memory of prof. Jacek Stupnicki, 2018-10-17/10-20, Jachranka (PL), pp.42-42, 2018
7.  Taras W., Pyrzanowski P., Gadomski J., Kowalewski Z.L., Libura T., An influence of fiber orientation and load direction on behaviour of thin composite samples, SME, XXVIII Symposium On Experimental Mechanics of Solids in memory of prof. Jacek Stupnicki, 2018-10-17/10-20, Jachranka (PL), pp.1, 2018
8.  Libura T., Kowalewski Z.L., Kowalczyk-Gajewska K., The Bauschinger Effect in thin sheet magnesium alloy using anti-buckling fixture, DAS 2017, 34th Danubia-Adria Symposium on Advances in Experimental Mechanics, 2017-09-19/09-22, Trieste (IT), pp.1-2, 2017
9.  Libura T., Kowalewski Z.L., Kowalczyk-Gajewska K., Dietrich L., Strain-hardening effect in thin-sheet magnesium alloy AZ31B under low cyclic loading, XII Konferencja „Nowe Kierunki Rozwoju Mechaniki”, 2017-03-22/03-25, Białystok - Supraśl (PL), pp.1-2, 2017

Abstract:
Optimization of sheet metal forming processes requires a very good knowledge of material forming ability. During the forming of industrial parts, very complex strain paths are usually observed and can affect the formability of the sheet. Therefore, it is necessary to better understand and more accurately investigate deformation behaviour of sheet alloys. It should be noted that material testing of flat specimens under compression within a large deformation range procures many difficulties, and the buckling phenomenon seems to be the most im-portant. This paper shows the results of tension-compression tests carried out on specimens made of ultralight magnesium alloys AZ31B with nominal thickness equal to 1 mm using the anti-buckling fixture to avoid buckling problem.

Keywords:
Bauschinger effect, cyclic loading, buckling, fixture, thin sheet

Affiliations:
Libura T. - IPPT PAN
Kowalewski Z.L. - IPPT PAN
Kowalczyk-Gajewska K. - IPPT PAN
Dietrich L. - IPPT PAN
10.  Libura T., Kowalewski Z.L., Kowalczyk-Gajewska K., Dietrich L., Low cycle fatigue of a rolled magnesium alloy using anti-buckling fixture, DYMAT, 10th Workshop, 2016-08-24/08-26, Poznań (PL), pp.59-61, 2016
11.  Kowalewski Z.L., Socha G., Dietrich L., Libura T., Thin sheet of brass testing under cyclic tension - compression using novel anti-buckling fixture, DAS 2015, 32nd Danubia-Adria-Symposium on Advances in Experimental Mechanics, 2015-09-22/09-25, Smokovec (SK), Vol.1, pp.128-129, 2015
12.  Libura T., Moćko W., Kowalewski Z.L., A new version of Hopkinson bar testing stand for determination of dynamic tensile characteristics, SolMech 2014, 39th Solid Mechanics Conference, 2014-09-01/09-05, Zakopane (PL), pp.311-312, 2014

Patents
Filing No./Date
Filing Publication
Autors
Title
Protection Area, Applicant Name
Patent Number
Date of Grant
pdf
429504
2019-04-03
BUP 21/2020
2020-10-05
Libura T., Rusinek A., Kowalewski Z.L., Bouslikhane S.
Stanowisko do badań perforacji płyt z materiałów konstrukcyjnych, zwłaszcza płyt cienkich
PL, Instytut Podstawowych Problemów Techniki PAN
-
-
-
41383
2017-10-31
-
2017-10-31
Rusinek A., Libura T., Klósak M., Kowalewski Z.L.
Chambre thermique - sarcophage pour essais de perforation a chaud
MA, Instytut Podstawowych Problemów Techniki PAN, Universiapolis (Agadir)
MA 41383 A1
-
2019-05-31



420748
2017-03-06
BUP 19/2018
2018-09-10
Libura T., Kowalewski Z.L., Moćko W.
Urządzenie do dynamicznych badań materiałów konstrukcyjnych przy rozciąganiu w zakresie dużych wartości prędkości odkształcenia
PL, Instytut Podstawowych Problemów Techniki PAN
234759
WUP 03/2020
2020-03-31

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