Instytut Podstawowych Problemów Techniki
Polskiej Akademii Nauk

Pracownicy

Leszek Urbański

Zakład Mechaniki Materiałów (ZMM)
Laboratorium Termoplastyczności (LT)
stanowisko: starszy technik dokumentalista
telefon: (+48) 22 826 12 81 wewn.: 405
pokój: 217
e-mail:
ORCID: 0000-0002-9113-0657

Ostatnie publikacje
1.  Musiał S., Maj M., Urbański L., Nowak M., Field analysis of energy conversion during plastic deformation of 310S stainless steel, INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES, ISSN: 0020-7683, DOI: 10.1016/j.ijsolstr.2021.111411, Vol.238, pp.111411-1-20, 2022

Streszczenie:
The paper concerns the experimental analysis of the energy conversion process during uniaxial tension of 310S austenitic steel. The plastic work distributions were obtained taking into account the influence of strain rate and plastic anisotropy based on the displacement gradient determined experimentally using Digital Image Correlation (DIC) method. On the other hand, the energy dissipated as heat was obtained by the calculation of heat sources from the transient heat conduction equation basing on both the evolution of the temperature field determined by Infrared Thermography and mechanical field provided by DIC. It was shown that the proportions between the terms of the heat conduction equation and between the particular components of the energy dissipated as heat are significantly different for various process durations. As a measure of energy conversion the energy storage rate was used. At the beginning of the plastic deformation, the values are in the range from 0.4 to 0.6 depending on the strain rate and then decrease monotonically up to the level of around 0.15 with the increasing strain. Moreover, just before the end of the process the values decrease significantly and become close to 0 or even negative, which means that the material loses its ability to store the energy.

Słowa kluczowe:
digital image correlation, infrared thermography, energy conversion, transient heatconduction equation, heat sources, energy storage rate

Afiliacje autorów:
Musiał S. - IPPT PAN
Maj M. - IPPT PAN
Urbański L. - IPPT PAN
Nowak M. - IPPT PAN
140p.
2.  Staszczak M., Nabavian Kalat M., Golasiński K.M., Urbański L., Takeda K., Matsui R., Pieczyska E.A., Characterization of Polyurethane Shape Memory Polymer and Determination of Shape Fixity and Shape Recovery in Subsequent Thermomechanical Cycles, Polymers, ISSN: 2073-4360, DOI: 10.3390/polym14214775, Vol.14, No.4775, pp.1-19, 2022

Streszczenie:
Multifunctional polyurethane shape memory polymers (PU-SMPs) have been of increasing interest in various applications. Here we report structure characterization, detailed methodology, and obtained results on the identification of functional properties of a thermoset PU-SMP (MP4510) with glass transition temperature of 45 C. The stable, chemically crosslinked network of this thermoset PU-SMP results in excellent shape memory behavior. Moreover, the proximity of the activation temperature range of this smart polymer to room and body temperature enables the PU-SMP to be used in more critical industrial applications, namely fast-response actuators. The thermomechanical behavior of a shape memory polymer determines the engineering applications of the material. Therefore, investigation of the shape memory behavior of this class of commercial PU-SMP is of particular importance. The conducted structural characterization confirms its shape memory properties. The shape fixity and shape recovery properties were determined by a modified experimental approach, considering the polymer’s sensitivity to external conditions, i.e., the temperature and humidity variations. Three thermomechanical cycles were considered and the methodology used is described in detail. The obtained shape fixity ratio of the PU-SMP was approximately 98% and did not change significantly in the subsequent cycles of the thermomechanical loading due to the stability of chemical crosslinks in the thermoset materials structure. The shape recovery was found to be approximately 90% in the first cycle and reached a value higher than 99% in the third cycle. The results confirm the effect of the thermomechanical training on the improvement of the PU-SMP shape recovery after the first thermomechanical cycle as well as the effect of thermoset material stability on the repeatability of the shape memory parameters quantities.

Słowa kluczowe:
polyurethane shape memory polymer, thermomechanical loading program, shape fixity, shape recovery

Afiliacje autorów:
Staszczak M. - IPPT PAN
Nabavian Kalat M. - IPPT PAN
Golasiński K.M. - IPPT PAN
Urbański L. - IPPT PAN
Takeda K. - Aichi Institute of Technology (JP)
Matsui R. - Aichi Institute of Technology (JP)
Pieczyska E.A. - IPPT PAN
100p.
3.  Grodzki W., Oliferuk W., Doroszko M., Szusta J., Urbański L., Prediction of crack initiation based on energy storage rate during low-cycle fatigue of austenitic stainless steel, Materials, ISSN: 1996-1944, DOI: 10.3390/ma14195526, Vol.14, No.19, pp.5526-1-13, 2021

Streszczenie:
The low-cycle deformation of 304L austenitic stainless steel was examined in terms of energy conversion. Specimens were subjected to cyclic loading at the frequency of 2 Hz. The loading process was carried out in a hybrid strain–stress manner. In each cycle, the increase in elongation of the gauge part of the specimen was constant. During experimental procedures, infrared and visible-range images of strain and temperature fields were recorded simultaneously using infrared thermography (IR) and digital image correlation (DIC) systems. On the basis of the obtained test results, the energy storage rate, defined as the ratio of the stored energy increment to the plastic work increment, was calculated and expressed in reference to selected sections of the specimen. It was shown that, before the specimen fracture in a specific area, the energy storage rate is equal to zero (the material loses the ability to store energy), and the energy stored during the deformation process is released and dissipated as heat. Negative and close-to-zero values of the energy storage rate can be used as a plastic instability criterion on the macroscale. Thus, the loss of energy storage ability by a deformed material can be treated as an indicator of fatigue crack initiation.

Słowa kluczowe:
low-cycle fatigue, infrared thermography, plastic strain localization, digital image correlation, energy storage rate, plastic instability criterion

Afiliacje autorów:
Grodzki W. - Bialystok University of Technology (PL)
Oliferuk W. - IPPT PAN
Doroszko M. - Bialystok University of Technology (PL)
Szusta J. - Bialystok University of Technology (PL)
Urbański L. - IPPT PAN
140p.
4.  Frydrych K., Maj M., Urbański L., Kowalczyk-Gajewska K., Twinning-induced anisotropy of mechanical response of AZ31B extruded rods, MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING, ISSN: 0921-5093, DOI: 10.1016/j.msea.2019.138610, Vol.771, pp.138610-1-14, 2020

Streszczenie:
Texture and twinning-induced anisotropy of the yield stress and hardening of AZ31B extruded rods is investigated. The multidirectional compression tests involving strain path changes are performed in order to: i. assess which slip and twinning systems are active in the polycrystalline sample with a strong texture, ii. analyze the influence of the preliminary deformation upon twin formation, iii. observe the resulting change of the mechanical response. In order to fulfil these goals mechanical testing is supplemented by microstructure analysis. Experimental observations are used to validate the proposed crystal plasticity framework when it is combined with the viscoplastic self-consistent scheme. On the other hand, the results of numerical simulations are used to confirm an advocated interpretation of experimental findings. Finally, the experimental and numerical results are discussed with respect to the theoretical study of slip and twinning activity on the basis of the generalized Schmid criterion. It is concluded that twinning activity influences the mechanical response predominantly by the texture change and to lesser extent by modification of strain hardening due to slip-twin interactions.

Słowa kluczowe:
crystal plasticity, anisotropy, plastic deformation, twinning, hcp

Afiliacje autorów:
Frydrych K. - IPPT PAN
Maj M. - IPPT PAN
Urbański L. - IPPT PAN
Kowalczyk-Gajewska K. - IPPT PAN
140p.
5.  Golasiński K.M., Pieczyska E.A., Maj M., Mackiewicz S., Staszczak M., Kowalewski Z.L., Urbański L., Zubko M., Takesue N., Anisotropy of gum metal analysed by ultrasonic measurement and digital image correlation, MATERIALS SCIENCE AND TECHNOLOGY, ISSN: 0267-0836, DOI: 10.1080/02670836.2019.1629539, Vol.36, No.9, pp.996-1002, 2020

Streszczenie:
The mechanical anisotropy of a multifunctional titanium alloy, Gum Metal, is investigated in this paper. The structural characterisation showed a strong <110> texture for Gum Metal, that is a result of the cold-swaging process applied during its manufacture. Gum Metal was treated as a transversally isotropic solid because of this texture. A significant difference from Young's moduli of the alloy was detected from the ultrasonic measurement of parallel and perpendicular directions to the alloy swaging direction. Samples of Gum Metal cubes were compressed in two different orientations. During the deformation process, two perpendicular walls of each sample were monitored by two visible range cameras for further two-dimensional digital image correlation analysis, this confirmed a strong plastic anisotropy in Gum Metal.

Słowa kluczowe:
gum metal, compression, mechanical anisotropy, digital image correlation, ultrasonic measurement, texture, titanium alloy, full-field deformation measurement

Afiliacje autorów:
Golasiński K.M. - IPPT PAN
Pieczyska E.A. - IPPT PAN
Maj M. - IPPT PAN
Mackiewicz S. - IPPT PAN
Staszczak M. - IPPT PAN
Kowalewski Z.L. - IPPT PAN
Urbański L. - IPPT PAN
Zubko M. - inna afiliacja
Takesue N. - Fukuoka University (JP)
70p.
6.  Staszczak M., Pieczyska E.A., Maj M., Urbański L., Odriozola I., Martin R., Thermomechanical Properties of Vulcanized Rubber investigated by Testing Machine and Infrared Camera, Measurement Automation Monitoring, ISSN: 0032-4140, Vol.61, No.6, pp.206-209, 2015

Streszczenie:
Experimental results of effects of thermomechanical couplings occurring both in natural vulcanized rubber and rubber with self-healing polyurethane subjected to tension at different strain rates are presented. Mechanical characteristics were recorded by testing machine, while the sample temperature changes accompanying the deformation process was measured by infrared camera. The goal was to investigate influence of self-healing polyurethane on the rubber mechanical and thermomechanical properties. It was found that the introduction of the self-healing polyurethane ensures the higher elasticity and the lower tensile strength of the rubber. It was also confirmed that the material is very sensitive to the strain rate; the higher the strain rate, the higher the values of the stress and temperature increases have been obtained.

Słowa kluczowe:
vulcanized rubber, self-healing polyurethane, tension test, thermomechanical couplings, temperature changes, infrared camera

Afiliacje autorów:
Staszczak M. - IPPT PAN
Pieczyska E.A. - IPPT PAN
Maj M. - IPPT PAN
Urbański L. - IPPT PAN
Odriozola I. - IK4-CIDETEC (ES)
Martin R. - IK4-CIDETEC (ES)
11p.
7.  Pieczyska E.A., Maj M., Kowalczyk-Gajewska K., Staszczak M., Urbański L., Tobushi H., Hayashi S., Cristea M., Mechanical and Infrared Thermography Analysis of Shape Memory Polyurethane, Journal of Materials Engineering and Performance, ISSN: 1059-9495, DOI: 10.1007/s11665-014-0963-2, Vol.23, No.7, pp.2553-2560, 2014

Streszczenie:
Multifunctional new material—polyurethane shape memory polymer (PU-SMP)—was subjected to tension carried out at room temperature at various strain rates. The influence of effects of thermomechanical couplings on the SMP mechanical properties was studied, based on the sample temperature changes, measured by a fast and sensitive infrared camera. It was found that the polymer deformation process strongly depends on the strain rate applied. The initial reversible strain is accompanied by a small drop in temperature, called thermoelastic effect. Its maximal value is related to the SMP yield point and increases upon increase of the strain rate. At higher strains, the stress and temperature significantly increase, caused by reorientation of the polymer molecular chains, followed by the stress drop and its subsequent increase accompanying the sample rupture. The higher strain rate, the higher stress, and temperature changes were obtained, since the deformation process was more dynamic and has occurred in almost adiabatic conditions. The constitutive model of SMP valid in finite strain regime was developed. In the proposed approach, SMP is described as a two-phase material composed of hyperelastic rubbery phase and elastic-viscoplastic glassy phase, while the volume content of phases is specified by the current temperature.

Słowa kluczowe:
constitutive model, dynamic mechanical analysis, shape memory polyurethane, strain rate, temperature change, thermomechanical couplings

Afiliacje autorów:
Pieczyska E.A. - IPPT PAN
Maj M. - IPPT PAN
Kowalczyk-Gajewska K. - IPPT PAN
Staszczak M. - IPPT PAN
Urbański L. - IPPT PAN
Tobushi H. - Aichi Institute of Technology (JP)
Hayashi S. - SMP Technologies Inc. (JP)
Cristea M. - Petru Poni Institute of Macromolecular Chemistry (RO)
20p.
8.  Staszczak M., Pieczyska E.A., Maj M., Urbański L., Tobushi H., Hayashi S., Właściwości mechaniczne oraz zmiany temperatury polimeru z pamięcią kształtu w procesie rozciągania, POMIARY AUTOMATYKA KONTROLA, ISSN: 0032-4140, Vol.59, No.9, pp.1002-1005, 2013

Streszczenie:
This paper presents experimental evaluation of a new polyurethane shape memory polymer (PU-SMP) produced by SMP Technologies Inc. It discusses mechanical characteristics and temperature changes of the SMP specimens subjected to tension test performed at room temperature with various strain rates. Basing on the mechanical data and the relevant temperature changes, we have studied the thermomechanical properties of the PU-SMP and influence of the strain rate on the strain localization behavior. Finally, we have identified the material parameters for the one-dimensional rheological model of the SMP.

Słowa kluczowe:
shape memory polyurethane, tension test, dynamic mechanical analysis, infrared camera, temperature change, thermomechanical properties, rheological model

Afiliacje autorów:
Staszczak M. - IPPT PAN
Pieczyska E.A. - IPPT PAN
Maj M. - IPPT PAN
Urbański L. - IPPT PAN
Tobushi H. - Aichi Institute of Technology (JP)
Hayashi S. - SMP Technologies Inc. (JP)
7p.
9.  Oliferuk W., Maj M., Litwinko R., Urbański L., Thermomechanical coupling in the elastic regime and elasto-plastic transition during tension of austenitic steel, titanium and aluminium alloy at strain rates from 10-4 to 10-1 s-1, EUROPEAN JOURNAL OF MECHANICS A-SOLIDS, ISSN: 0997-7538, DOI: 10.1016/j.euromechsol.2011.08.007, Vol.35, pp.111-118, 2012

Streszczenie:
The temperature variation phenomenon during uniaxial deformation of materials with positive coefficient of linear thermal expansion is studied. The formula for a change in the specimen temperature during non-adiabatic tensile deformation is briefly derived. Thermomechanical behaviour of austenitic stainless steel, titanium and aluminium alloy during initial stage of tension at strain rates from 10−4 to 10−1 s−1 has been investigated. It was confirmed, that with increasing stress the temperature of each tested specimen first decreases linearly, reaches a minimum and then starts to rise. The decrease in the specimen temperature corresponds to elastic deformation whereas the temperature rise is related to the plastic one. Thus, the change in the specimen temperature can be used for study of elasto-plastic transition. From the viewpoint of strict theoretical analysis, the yield point will be defined as the stress corresponding to the lowest temperature, if tensile deformation process is adiabatic. The processes of deformation considered in this work are not adiabatic; there is a heat exchange between the specimen and the surroundings. The influence of this fact on the change in the specimen temperature vs. stress is discussed. The problem of yield point as the value of stress corresponding to minimum temperature of the specimen is considered. The influence of the strain rate on the yield point for tested materials is studied. Comparing of the obtained results with theoretical model, the limit above which the deformation process can be treated as the adiabatic one was determined. The values of the yield points determined on the basis of the thermoelastic effect were compared with the stress corresponding to the 0.2% of plastic strain.

Słowa kluczowe:
Thermoelastic effect, Yield point, Non-adiabatic deformation

Afiliacje autorów:
Oliferuk W. - IPPT PAN
Maj M. - IPPT PAN
Litwinko R. - inna afiliacja
Urbański L. - IPPT PAN
30p.

Prace konferencyjne
1.  Musiał S., Maj M., Urbański L., Nowak M., Experimental analysis of energy conversion during deformation process based on coupled DIC and IRT results, BSSM, 15th International Conference on Advances in Experimental Mechanics, 2021-09-07/09-09, Swansea (GB), pp.1-2, 2021
2.  Staszczak M., Pieczyska E.A., Maj M., Urbański L., Odriozola I., Martin R., Właściwości termomechaniczne gumy wulkanizowanej badane za pomocą maszyny wytrzymałościowej oraz kamery termowizyjnej, 11th Conference on Thermography and Thermometry in Infrared, 2015-09-22/09-24, Ustroń (PL), pp.66-67, 2015

Streszczenie:
Praca przedstawia wyniki doświadczalnych badań efektów sprzężeń termomechanicznych w naturalnej, wulkanizowanej gumie z różną zawartością poliuretanu o właściwościach samo-naprawiania, tzw. „self-healing” podczas obciążania z różnymi prędkościami deformacji. Próbki rozciągano na maszynie wytrzymałościowej wysokiej klasy, co pozwoliło otrzymać charakterystyki mechaniczne z wysoką dokładnością, a szybka i czuła kamera termowizyjna pozwoliła otrzymać w sposób bezstykowy zmiany temperatury próbek związane z ich odkształcaniem. Stwierdzono, że im więcej dodatku poliuretanu, tym wyższa sprężystość gumy oraz niższa jej wytrzymałość. Ponadto, otrzymane wyniki potwierdziły wysoką wrażliwość materiału na prędkość deformacji: im wyższa prędkość, tym wyższe wartości naprężenia oraz zmian temperatury.

Słowa kluczowe:
efekty sprzężeń termomechanicznych, wulkanizowana guma, poliuretan self-healing, prędkość deformacji, maszyna wytrzymałościowa, kamera termowizyjna

Afiliacje autorów:
Staszczak M. - IPPT PAN
Pieczyska E.A. - IPPT PAN
Maj M. - IPPT PAN
Urbański L. - IPPT PAN
Odriozola I. - IK4-CIDETEC (ES)
Martin R. - IK4-CIDETEC (ES)

Abstrakty konferencyjne
1.  Nabavian K.M., Staszczak M., Ziai Y., Urbański L., Pieczyska E., Effect of Shape Recovery and Cyclic Loading on the Evolution of Micro-Cracks in Shape Memory Polymers, IUTAM Symposium, IUTAM Symposium on Enhancing Material Performance by Exploiting Instabilities and Damage Evolution, 2022-06-05/06-10, Warszawa (PL), No.P040, pp.54-54, 2022
2.  Staszczak M., Nabavian Kalat M., Urbański L., Cristea M., Pieczyska E.A., INFLUENCE OF STRAIN RATE AND COOLING RATE ON THE MECHANICAL BEHAVIOUR SHAPE MEMORY POLYURETHANE WITH Tg = 65 °C, ICEM, 19th International Conference on Experimental Mechanics, 2022-07-17/07-21, Kraków (PL), pp.280-281, 2022
3.  Nabavian Kalat M., Staszczak M., Ziai Y., Gradys A., Urbański L., Pieczyska E.A., THE EFFECT OF SHAPE MEMORY BEHAVIOR ON THE MICROSTRUCTURE OF THE PU-SMP (Tg = 45°C), ICEM, 19th International Conference on Experimental Mechanics, 2022-07-17/07-21, Kraków (PL), pp.278-279, 2022
4.  Staszczak M., Pieczyska E.A., Urbański L., Odriozola I., Martin R., Shape memory polymer subjected to thermomechanical loading - investigation of application parameter, ISMMS, 10th International Symposium on Mechanics of Materials and Structures, 2019-06-02/06-06, Augustów (PL), pp.105-106, 2019

Słowa kluczowe:
shape memory polymer, shape fixity, shape recovery, thermomechanical loading program

Afiliacje autorów:
Staszczak M. - IPPT PAN
Pieczyska E.A. - IPPT PAN
Urbański L. - IPPT PAN
Odriozola I. - IK4-CIDETEC (ES)
Martin R. - IK4-CIDETEC (ES)
5.  Kowalczyk-Gajewska K., Frydrych K., Maj M., Urbański L., Micromechanical modelling of magnesium alloy and its experimental verification, PCM-CMM 2015, 3rd Polish Congress of Mechanics and 21st Computer Methods in Mechanics, 2015-09-08/09-11, Gdańsk (PL), pp.677-678, 2015

Streszczenie:
Micromechanical modelling of magnesium alloys is presented. The applied model combines the crystal plasticity framework accounting for twinning with the self-consistent grain-to-polycrystal scale transition scheme. The mechanical response of the material in the experiments involving the strain path changes is studied, together with the prediction of the accompanying texture evolution. It is demonstrated that the evolution of microstructure has an important impact on the overall material behaviour. The model predictions will be verified in experiments performed on the rolled sheets made of AZ31B alloy

Słowa kluczowe:
micromechanics, crystal plasticity, twinning, texture evolution

Afiliacje autorów:
Kowalczyk-Gajewska K. - IPPT PAN
Frydrych K. - IPPT PAN
Maj M. - IPPT PAN
Urbański L. - IPPT PAN
6.  Staszczak M., Pieczyska E.A., Maj M., Urbański L., Tobushi H., Hayashi S., Właściwości mechaniczne oraz zmiany temperatury polimeru z pamięcią kształtu w procesie rozciągania, TTP2013, X Konferencja TERMOGRAFIA I TERMOMETRIA W PODCZERWIENI, 2013-09-24/09-26, Lwów (UA), Vol.1, pp.91-92, 2013

Streszczenie:
W pracy przedstawiono wyniki badań efektów sprzężeń termomechanicznych poliuretanu z pamięcią kształtu podczas rozciągania z różnymi prędkościami. Zależności zmiany temperatury próbek od czasu wyznaczano za pomocą kamery termograficznej. Zaobserwowano dużą wrażliwość charakterystyk mechanicznych i zmian temperatury poliuretanu na prędkość deformacji. Wykorzystując efekt piezokaloryczny wyznaczano granice plastyczności dla różnych prędkości odkształcenia. Pokazano, że metoda bazująca na minimum temperatury próbki jest przydatna do wyznaczania granicy plastyczności materiałów polimerowych wykazujących nieliniową sprężystość.

Słowa kluczowe:
poliuretan z pamięcią kształtu, efekty sprzężeń termomechanicznych, kamera termograficzna, efekt piezokaloryczny, granica plastyczności

Afiliacje autorów:
Staszczak M. - IPPT PAN
Pieczyska E.A. - IPPT PAN
Maj M. - IPPT PAN
Urbański L. - IPPT PAN
Tobushi H. - Aichi Institute of Technology (JP)
Hayashi S. - SMP Technologies Inc. (JP)

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