Publications in journals ranked by Journal Citation Reports (JCR) 
Publications in other journals ranked by Ministry of Science and Higher Education
Conference publications indexed in the Web of Science Core Collection
Publications in other journals and conference proceedings
Affiliation to IPPT PAN

1.Dulnik J., Sajkiewicz P., Crosslinking of bicomponent nanofibres from alternative solvent system, Electrospin2018, Electrospin2018 International Conference, 2018-01-16/01-18, Stellenbosch (ZA), pp.71, 2018
2.Urbanek O., Sajkiewicz P., Pierini F., Cell response on fibres surface properties induced by process parameters and post-treatment of electrospun nonwovens, Electrospin2018, Electrospin2018 International Conference, 2018-01-16/01-18, Stellenbosch (ZA), pp.62-63, 2018
3.Sajkiewicz P., Dulnik J., Kołbuk-Konieczny D., Denis P., Structure dependent cell activity on pcl/gelatin and pcl/collagen nanofibers electrospun from various solvents, Electrospin2018, Electrospin2018 International Conference, 2018-01-16/01-18, Stellenbosch (ZA), pp.45-46, 2018
4.Pierini F., Lanzi M., Nakielski P., Pawłowska S., Urbanek O., Kowalewski T.A., Electrospinning of polythiophene with pendant fullerene nanofibers for single-material organic solar cells, Electrospin2018, Electrospin2018 International Conference, 2018-01-16/01-18, Stellenbosch (ZA), pp.19-20, 2018
5.Pawłowska S., Nakielski P., Pierini F., Electrospun polyacrylamide hydrogel nanofibers: from nanocarriers to stimuli responsive nanomaterials, Electrospin2018, Electrospin2018 International Conference, 2018-01-16/01-18, Stellenbosch (ZA), pp.39, 2018
6.Enayati M.S., Behzad T., Sajkiewicz P., Rafienia M., Bagheri R., Ghasemi-Mobarakeh L., A novel electrospun three-component Bionanocomposite for bone tissue engineering, ICNS7, 7th International Conference on Nanostructures , 2018-02-27/03-01, Teheran (IR), pp.1-3, 2018
Enayati M.S., Behzad T., Sajkiewicz P., Rafienia M., Bagheri R., Ghasemi-Mobarakeh L., A novel electrospun three-component Bionanocomposite for bone tissue engineering, ICNS7, 7th International Conference on Nanostructures , 2018-02-27/03-01, Teheran (IR), pp.1-3, 2018

Abstract:
In the present study, a full bionanocomposite scaffold from poly (vinyl alcohol) (PVA), nanohydroxy apatite (nHAp) and cellulose nanofibers (CNF) was fabricated by electospinning and its potential application for bone tissue engineering was investigated. Morphology of the electrospun scaffolds was seen by field emission scanning electron microscope (FE-SEM). Both nHAp and CNF enhanced the tensile modulus of the scaffolds; however, both tensile strength as well as slongation at break showed reduced behaviour. Porosity measurement showed that scaffolds had porosity more than 70% which is appropriate for tissue engineering scaffolds. Contact angle test proved high hydrophilicty of electrospun mats while nanofiller incorporation promoted hydrophilicity. Biodegradability was investigated in phosphate buffer saline (PBS). In vitro biomineralization in simulated body fluid (SBF) and MTT cytotoxicity analysis showed that addition of nHAp and CNF increased bioactivity and cell viability of the scaffolds. The obtained results offered a 3-component promising scaffold for bone tissue engineering.

Keywords:
Bionanocomposite, Scaffold, Electrospinning, Poly (vinyl alcohol) and Bone tissue engineering

7.Marszałek A., Burczyński T., Ordered Fuzzy GARCH Model for Volatility Forecasting, Includes the proceedings of the 10th Conference of the European Society for Fuzzy Logic and Technology (EUSFLAT-2017), 2017-09-11/09-15, Warszawa (PL), No.XI, pp.480-492, 2018
Marszałek A., Burczyński T., Ordered Fuzzy GARCH Model for Volatility Forecasting, Includes the proceedings of the 10th Conference of the European Society for Fuzzy Logic and Technology (EUSFLAT-2017), 2017-09-11/09-15, Warszawa (PL), No.XI, pp.480-492, 2018

Abstract:
A volatility forecasting comparative study between the most popular original GARCH model and the same model defined based on concepts of Ordered Fuzzy Numbers and Ordered Fuzzy Candlsticks is presented. These approaches offer a suitable tool to handle both imprecision of measurements and uncertainty associated with financial data. Therefore, they are particularly useful for volatility forecasting, since the volatility is unobservable and a proxy for it is used (realised volatility). In presented study, based on intra-daily data of theWarsaw Stock Exchange Top 20 Index (WIG 20), one showed that based on the adjusted-R squared and several prediction measurements, the fuzzy approach does perform better than the original GARCH model and forecasts more precisely in both the in-sample and out-of-sample predictions

Keywords:
Volatility forecasting, Realized volatility, Ordered fuzzy number, Kosinski’s fuzzy number, Ordered fuzzy candlestick, Ordered fuzzy GARCH model, Financial high-frequency data

8.Jóźwiak-Niedźwiedzka D., Dąbrowski M., Gibas K., Antolik A., Glinicki M.A., Alkali-silica reaction and microstructure of concrete subjected to combined chemical and physical exposure conditions, MATBUD'2018, 8th Scientific-Technical Conference on Material Problems in Civil Engineering MATBUD'2018, 2018-06-25/06-27, Kraków, Politechnika Krakowska (PL), DOI: 10.1051/matecconf/201816305009, No.163, pp.05009-1-05009-10, 2018
Jóźwiak-Niedźwiedzka D., Dąbrowski M., Gibas K., Antolik A., Glinicki M.A., Alkali-silica reaction and microstructure of concrete subjected to combined chemical and physical exposure conditions, MATBUD'2018, 8th Scientific-Technical Conference on Material Problems in Civil Engineering MATBUD'2018, 2018-06-25/06-27, Kraków, Politechnika Krakowska (PL), DOI: 10.1051/matecconf/201816305009, No.163, pp.05009-1-05009-10, 2018

Abstract:
Salt solutions are used to ensure safe driving conditions during winter. NaCl deicer is the most often used brine in Polish climatic zone. The chemical effects of this type of chloride-based deicer in wetting and drying (WD) and temperature cycles on concrete need to be better understood. This research was focus to study the microstructure of air-entrained pavement concrete after combined chemical (10% of NaCl) and physical (WD and 60°C) exposure conditions. The adopted WD and temperature regime was designed to verify the hypothesis that regularly alternating wetting and drying cycles with external alkali supply from deicer salt will provoke the Alkali-Silica Reaction (ASR). The aggregates varied their origin and mineralogical composition. The microscopic examination was carried out on concrete specimens using SEM with EDX. The microscopic analysis has shown that main reason for concrete deterioration during cyclic chemical and physical exposure conditions was both physical influence - WD cycles and the chemical influence – ASR (primarily, the fine aggregate which lead to form of alkali-silica gel). The expansive gel was shown to be capable of destroying the test specimens. Also differences in mineralogical composition of coarse aggregates influenced on the concrete prism expansion due to ASR.

9.Antolik A., Glinicki M.A., Gawlicki M., Effect of boron-containing aggregates on setting and hardening of Portland cement mortars, MATBUD'2018, 8th Scientific-Technical Conference on Material Problems in Civil Engineering MATBUD'2018, 2018-06-25/06-27, Kraków, Politechnika Krakowska (PL), DOI: 10.1051/matecconf/201816304003, No.163, pp.04003-1-04003-6, 2018
Antolik A., Glinicki M.A., Gawlicki M., Effect of boron-containing aggregates on setting and hardening of Portland cement mortars, MATBUD'2018, 8th Scientific-Technical Conference on Material Problems in Civil Engineering MATBUD'2018, 2018-06-25/06-27, Kraków, Politechnika Krakowska (PL), DOI: 10.1051/matecconf/201816304003, No.163, pp.04003-1-04003-6, 2018

Abstract:
Multicomponent cement-based composites are known as versatile structural materials for enhanced radiation shielding. The use of selected elements, like boron, cadmium, or rare earth elements, provides an increased neutron shielding capacity. Because of profusion, reasonable costs and large cross-section for neutron capture, boron containing minerals are suggested as aggregates for radiation shielding concrete. Despite many advantages, boron additives may act as cement setting retarders. Uncontrolled setting and hardening is not acceptable in radiation shielding concrete technology. In this work we present results from isothermal calorimetry measurements on cement mortars with boron-containing aggregates. Four types of boron aggregates were used in the studies: colemanite, ulexite, borax and boron carbide. Based on calorimetric curves, the beginning of setting time was determined. Additionally early mortar strength was investigated and linear relationship between the heat generated in the isothermal calorimeter and the early compressive strength has been observed. The use of isothermal calorimetry allowed us to estimate the limits for the content of boron compounds to be used cement mortar.

10.Wiśniewski K., Turska E., Recent improvements to nine-node shell element MITC9 with drilling rotations, SSTA 2017, Shell Structures: Theory and Applications, 2017-10-11/10-13, Gdańsk (PL), Vol.4, pp.399-402, 2018
Wiśniewski K., Turska E., Recent improvements to nine-node shell element MITC9 with drilling rotations, SSTA 2017, Shell Structures: Theory and Applications, 2017-10-11/10-13, Gdańsk (PL), Vol.4, pp.399-402, 2018

Abstract:
The paper describes our improved 9-node quadrilateral shell element MITC9i, which is derived for the Reissner-Mindlin shell kinematics, the extended potential energy functional and Green strain.
1. The MITCi technique is used to avoid locking and it is based on the improved transformations proposed in (Wisniewski & Panasz 2013) for a membrane element. Here, these transformations are extended to bending/twisting and transverse shear shell strains.
2. To reduce the shape distortion effects, the so-called corrected shape functions (CSF) of (Celia & Gray 1984) are used instead of the isoparametric ones, and we propose the method of computation the shift parameters for non-flat shell elements.
3. The drilling rotations are included via the drilling Rotation Constraint and the penalty method. This rotation is used in the multiplicative/additive update scheme valid for large (unrestricted) rotations.
The effect of the MITC9i technique and the CSF is that all three patch tests are passed, also for shifted side nodes along the straight edges and for arbitrary shifts of an interior node. The MITC9i shell element was subjected to a range of linear and non-linear numerical tests described in (Wisniewski & Turska 2017); here we provide additional examples illustrating its accurate and robust behavior.

Keywords:
9-node shell element MITC9,two-level approximation of strains, corrected shape functions, node shift parameters, drilling rotations

11.Postek E., Generation of a tumor model, Supercomputing Frontiers Europe wraz z XX Sesją Sprawozdawczą Użytkowników KDM, 2018-03-12/03-16, ICM UW, Warszawa (PL), pp.1-1, 2018
Postek E., Generation of a tumor model, Supercomputing Frontiers Europe wraz z XX Sesją Sprawozdawczą Użytkowników KDM, 2018-03-12/03-16, ICM UW, Warszawa (PL), pp.1-1, 2018

Abstract:
The physical environment of living cells and tissues, and more
particularly their mechanical interaction with it, plays a crucial
regulatory role in their biological behaviour such as cell
differentiation, apoptosis, proliferation, tissue growth,
remodelling, tumor growth, etc. However, the way that
mechanical forces at the cellular level (i) influence the cell
functions and (ii) govern the behaviour of cell assemblies as well
as their development, remains unclear and hard to model.
First of all, we investigate a tissue growth model. The model is
generated with PhysiCell [1, 2].

Keywords:
computational biology, tumor growth

12.Postek E., Sadowski T., Impact modelling of cerment composite, The 7th International Conference on Advanced Materials and Structures, 2018-03-28/03-31, Timisoara (RO), pp.111, 2018
13.Ashraf W., Glinicki M.A., Olek J., Probablistic approach for selection of composition of freeze–thaw-resistant ordinary portland cement concrete, TRB 97th Annual Meeting, 2018-01-07/01-11, Washington, D.C. (US), No.18-00237, pp.1-24, 2018
Ashraf W., Glinicki M.A., Olek J., Probablistic approach for selection of composition of freeze–thaw-resistant ordinary portland cement concrete, TRB 97th Annual Meeting, 2018-01-07/01-11, Washington, D.C. (US), No.18-00237, pp.1-24, 2018

Abstract:
This paper features the development of a probabilistic model linking freeze-thaw (F-T) performance of concrete mixtures to their composition. As part of the process of model development, a sensitivity analysis was performed on several concrete mixture parameters to identify these factors that have strong correlations with the F-T resistance of concrete. This sensitivity analysis was performed on 128 sets of experimental F-T test results collected from the literature. The F-T performance level was defined as a discrete measure of the frost resistance of concrete. Finally, a new model to predict the F-T damage of concrete incorporating the variability of the concrete mix parameters (as selected from sensitivity analysis) was developed. This model was developed using only these data sets which contained the results of the relative dynamic modulus of elasticity (RDME) testing performed according to the ASTM C 666 (AASHTO T 161) specifications. Furthermore, only mixtures containing ordinary portland cement (OPC) as a sole type of the binder (i.e., mixtures that did not contain any supplementary cementitious materials) were considered. Additional experimental test results were utilized to validate the model. The reliability of the model was further demonstrated using several examples 1 of concrete mixtures of various compositions. Furthermore, the effects of the number of F-T cycles, air content, paste content, and w/c ratio on the F-T performance of the concrete mixes were demonstrated using the developed model. Accordingly, this model provides the opportunity to optimize the concrete mix proportion for the required performance level of concrete under F-T exposure condition.

Keywords:
Freeze-thaw, durability, concrete, pavement, sensitivity analysis, probabilistic design

14.Chojnacki A., Konowrocki R., Analiza numeryczna i eksperymentalna bezpieczeństwa przed wykolejeniem pojazdu szynowego w oparciu o różne metody wyznaczania kryterium oceny, XXIII Scientific Conference Railway Vehicles 2018, 2018-05-22/05-25, Szczyrk (PL), pp.8-9, 2018
Chojnacki A., Konowrocki R., Analiza numeryczna i eksperymentalna bezpieczeństwa przed wykolejeniem pojazdu szynowego w oparciu o różne metody wyznaczania kryterium oceny, XXIII Scientific Conference Railway Vehicles 2018, 2018-05-22/05-25, Szczyrk (PL), pp.8-9, 2018

Abstract:
W artykule przedstawiono wyniki badań eksperymentalnych i numerycznych dotyczących zagadnień wykolejenia wagonu towarowego. Przybliżono charakteryzację stanu wiedzy dotyczącej metod oceny bezpieczeństwa pojazdów szynowych przed wykolejeniem, w celu ich porównania. W pracy przeprowadzono teoretyczne analizy porównawcze według kilku metod, które ocenią bezpieczeństwo przed wykolejeniem porównane z badaniami eksperymentalnymi. Na potrzeby analiz teoretycznych powstał numeryczny model układu pojazd szynowy-tor. Model ten uwzględniał parametry dynamiczne elementów zastosowanych w rzeczywistym pojeździe. Wyniki analizy teoretycznej poparto badaniami eksperymentalnymi przeprowadzonymi na rzeczywistym obiekcie (wagon towarowy - tor testowy). Uzyskane wyniki pozwoliły określić stan zagrożenia bezpieczeństwa ruchu wagonu towarowego przy różnych kryteriach oceny oraz je porównać.

Keywords:
współczynnik wykolejenia, dynamiki pojazdów szynowych, bezpieczeństwo, badania eksperymentalne

15.Zbieć A., Konowrocki R., Wpływ prac konserwacyjnych na zużycie kół zestawów kołowych wagonów towarowych , XXIII Scientific Conference Railway Vehicles 2018, 2018-05-22/05-25, Szczyrk (PL), pp.12-13, 2018
Zbieć A., Konowrocki R., Wpływ prac konserwacyjnych na zużycie kół zestawów kołowych wagonów towarowych , XXIII Scientific Conference Railway Vehicles 2018, 2018-05-22/05-25, Szczyrk (PL), pp.12-13, 2018

Abstract:
Artykuł dotyczy analizy nowo zdiagnozowanej przyczyny zużycia profili kół wagonu towarowego. W pracy przybliżono możliwe przyczyny nierównomiernego zużycia kół zestawów kołowych w wagonach towarowych znane z literatury, jak również podano nową hipotezę. Nowa rozpatrywana w pracy przyczyna nadmiernego zużycia kół zestawów kołowych dotyczy nieprawidłowej ich orientacji względem ramy wózka. Sytuację taką zdiagnozowano w wagonach towarowych posadowionych na wózkach z rodziny Y25, w wyniku niepoprawnego procesu naprawy ramy wózka i regeneracji maźnic. W pracy przedstawiono wyniki pomiarów przeprowadzonych na rzeczywistym wagonie towarowym oraz identyfikację zużyć i geometrii elementów pojazdu. W celu ilościowej analizy wpływu niepoprawnie zorientowanych osi zestawów kołowych na wielkość zużycia kół powstał model numeryczny, opisujący dynamikę ww. wagonu towarowego. Obliczenia numeryczne przeprowadzono przy różnych scenariuszach prędkości i geometrii toru oraz kilku wariantach zukosowania zestawów kołowych. Otrzymane z badań numerycznych wyniki wykazały istotny wpływ nierównoległości osi zestawów kołowych na nierównomierne zużycie profili kół. Zaprezentowana w pracy teza poparta wynikami badań może w znacznym stopniu wpłynąć na poprawę technologii wykonywania napraw układu biegowego oraz warunki utrzymania towarowego taboru kolejowego. Pozwoli także na redukując kosztów napraw zestawów kołowych i wydłużenie okresu ich eksploatacji.

Keywords:
zużycie kół, dynamiki pojazdów, badania numeryczne, transport towarowy

16.Bogacz R., Konowrocki R., Uszkodzenia pojazdów szynowych wywołane usterkami toru kolejowego , XXIII Scientific Conference Railway Vehicles 2018, 2018-05-22/05-25, Szczyrk (PL), pp.80-81, 2018
Bogacz R., Konowrocki R., Uszkodzenia pojazdów szynowych wywołane usterkami toru kolejowego , XXIII Scientific Conference Railway Vehicles 2018, 2018-05-22/05-25, Szczyrk (PL), pp.80-81, 2018

Abstract:
Praca zawiera omówienie wybranych zagadnień dynamicznych związanych
z kinematycznym wymuszeniem od usterek toru wpływającym na degradację elementów pojazdów szynowych oraz rozwój uszkodzeń infrastruktury. Wskazano zjawiska, które mogą być przyczyną dużych obciążeń współdziałającego ze sobą układu pojazd-tor oraz zagrożenia wypadkami spowodowanymi zmęczeniem materiału elementów takiego układu. Podano przyczyny powstawania i rozwoju pęknięć szyn i osi zestawów kołowych. Przedstawiono przykłady badań doświadczalnych wskazujących na występowanie obciążeń dynamicznych znacznie przekraczających obciążenia statyczne spowodowane oddziaływaniem pojazdu i jego układu napędowego. Omówiono i zamieszczono w pracy wyniki badań teoretycznych uzyskanych z numerycznego modelu napędu pociągu z uwzględnieniem elektromechanicznych sprzęgnięć pomiędzy silnikiem a zestawem kołowym. Model ten pozwolił na analizę niekorzystych drgań skrętnych zestawu kołowego towarzyszących podczas przejazdu przez szczeliny w pojedynczym toku szynowym toru.
Prezentowane w pracy wyniki odniesiono do badań eksperymentalnych. W pracy przedstawiono również zagadnienia dynamiczne związane z samowzbudnością wskazujące na zjawiska, które mogą być przyczyną dużych obciążeń osi zestawów kołowych, jak również toru i ich degradacji oraz uszkodzeń zmęczeniowych tych osi. Zasygnalizowane zostały prawdopodobne przyczyny powstawania wielokrotnie większych od powszechnie uznawanych obciążeń szyn kołami kolejowymi. Podano kilka przykładów eksperymentalnego zbadania dynamicznego oddziaływania zestawów kołowych z torem będącego alternatywnym podejściem do kinematycznego wyjaśniania tego zjawiska.

Keywords:
drgania skrętne, uszkodzenia pojazdu i toru, dynamiki toru, badania numeryczne

17.Konowrocki R., Dąbrowski A., Brona P., Application of longitudinal dynamics of the train in the simulator of catenary maintenance vehicles - experimental and numerical tests , XXIII Scientific Conference Railway Vehicles 2018, 2018-05-22/05-25, Szczyrk (PL), pp.19-20, 2018
Konowrocki R., Dąbrowski A., Brona P., Application of longitudinal dynamics of the train in the simulator of catenary maintenance vehicles - experimental and numerical tests , XXIII Scientific Conference Railway Vehicles 2018, 2018-05-22/05-25, Szczyrk (PL), pp.19-20, 2018

Abstract:
The paper presents results obtained from experimental and simulation tests of trains, treated as simplified one-dimensional models of railway vehicles. This approach to train dynamics enables to assess train forces and their impact on dynamic characteristics, for example related to some problems of rapid starting or emergency braking. These works were used to implement them as a solver mechanism in the simulator of catenary maintenance trains, whose features in the article are discussed. In the paper algorithm of operating vehicles by their drivers in different driving scenarios are presents. The algorithm described simulator must meet atypical requirements resulting from the specific properties of the simulated vehicles.The paper describes also the methodology of identifying driving system of modeled vehicles and the way of adaptation of parameters obtained experimentally. Then, in brief, issues related to the image animation and presentation in the simulator are discussed. Also the most important rules of operating rail vehicle simulator, selecting proper scenarios and using effective training methods are characterised. Results of operational and numerical tests presented in the paper reflect in details processes accompanying the operation of catenary maintenance trains. The experimental test methodology to the real railway vehicles to acquire some missing work parameters was allowed. Results of the presented research indicate a large convergence of theoretical results with the experiment.The obtained result allowed to validate the work of the simulator

Keywords:
training simulator, dynamics of the train, experimental test, VBS3 environmental

18.Konowrocki R., Modeling of dynamic aspects of operation railway vehicle traction drive system including the electromechanical coupling , XXIII Scientific Conference Railway Vehicles 2018, 2018-05-22/05-25, Szczyrk (PL), pp.46-47, 2018
Konowrocki R., Modeling of dynamic aspects of operation railway vehicle traction drive system including the electromechanical coupling , XXIII Scientific Conference Railway Vehicles 2018, 2018-05-22/05-25, Szczyrk (PL), pp.46-47, 2018

Abstract:
In the paper, a dynamic electromechanical interaction between the wheelset of railway vehicle and its driving electric motors is investigated. This is the high-speed train driven by the electric motors through elastic hollow shaft with linear characteristics. In particular, there is considered an influence of negative electromagnetic damping generated by the motor on a possibility of excitation of resonant torsional vibrations. Conclusions drawn from the computational results can be very useful during a design phase of these devices as well as helpful for their users during a regular maintenance.

Keywords:
electromechanical coupling, torsion oscilation, electric motor, high speed train drive

19.Konowrocki R., Groll W., Kukulski J., Walczak S., Badania doświadczalne i symulacyjne powstawania gorących obszarów w parach ciernych hamulca kolejowego pociągów dużych prędkości , XXIII Scientific Conference Railway Vehicles 2018, 2018-05-22/05-25, Szczyrk (PL), pp.20-21, 2018
Konowrocki R., Groll W., Kukulski J., Walczak S., Badania doświadczalne i symulacyjne powstawania gorących obszarów w parach ciernych hamulca kolejowego pociągów dużych prędkości , XXIII Scientific Conference Railway Vehicles 2018, 2018-05-22/05-25, Szczyrk (PL), pp.20-21, 2018

Abstract:
Pracę poświęcono eksperymentalnym i numerycznym badaniom dotyczącym występowania gorących punktów w elementach hamulców tarczowych stosowanego w pojazdach szynowych dużej prędkości. W pracy zaprezentowano wyniki eksperymentalnych badań przeprowadzone na rzeczywistym układzie hamulcowym dedykowanym do takich pojazdów. W badaniach eksperymentalnych wykorzystano technikę termografii w podczerwieni, która pozwoliła scharakteryzować omawiane zjawiska cieplne. Uzyskane wyniki badań doświadczanych potwierdzono analizami numerycznymi, przy wykorzystaniu z walidowanego modelu układu hamulcowego. Wykorzystano w tym celu metodę elementów skończonych. Otrzymane wyniki numeryczne ilustrują zjawisko powstawania gorących obszarów na powierzchni tarczy hamulcowej wywołane przez termoelastyczne zaburzenia występujące na jej powierzchni.

Keywords:
gorące obszary, badania numeryczne, badania eksperymentalne, układ hamulcowy, pociągi dużych prędkości

20.Nowak Z., Nowak M., Widłaszewski J., Kurp P., Experimental and Numerical Investigation on Laser-Assisted Bending of Pre-Loaded Metal Plate, AIP Conference Proceedings, ISSN: 0094-243X, DOI: 10.1063/1.5019148, Vol.1922, pp.140006-1-7, 2018
Nowak Z., Nowak M., Widłaszewski J., Kurp P., Experimental and Numerical Investigation on Laser-Assisted Bending of Pre-Loaded Metal Plate, AIP Conference Proceedings, ISSN: 0094-243X, DOI: 10.1063/1.5019148, Vol.1922, pp.140006-1-7, 2018

Abstract:
The laser forming technique has an important disadvantage, which is the limitation of plastic deformation generated by a single laser beam pass. To increase the plastic deformation it is possible to apply external forces in the laser forming process. In this paper, we investigate the influence of external pre-loads on the laser bending of steel plate. The pre-loads investigated generate bending towards the laser beam. The thermal, elastic-plastic analysis is performed using the commercial nonlinear finite element analysis package ABAQUS. The focus of the paper is to identify how this pattern of the pre-load influence the final bend angle of the plate

Keywords:
Laser forming, Force-assisted laser forming, Laser-assisted bending, Thermo-mechanical simulations, Finite element analysis

21.Wcisło B., Pamin J., Kowalczyk-Gajewska K., Menzel A., Numerical analysis of ellipticity condition for large strain plasticity, AIP Conference Proceedings, ISSN: 0094-243X, DOI: 10.1063/1.5019150, Vol.1922, No.1, pp.140008-1-140008-8, 2018
Wcisło B., Pamin J., Kowalczyk-Gajewska K., Menzel A., Numerical analysis of ellipticity condition for large strain plasticity, AIP Conference Proceedings, ISSN: 0094-243X, DOI: 10.1063/1.5019150, Vol.1922, No.1, pp.140008-1-140008-8, 2018

Abstract:
This paper deals with the numerical investigation of ellipticity of the boundary value problem for isothermal finite strain elasto-plasticity. Ellipticity can be lost when softening occurs. A discontinuity surface then appears in the considered material body and this is associated with the ill-posedness of the boundary value problem. In the paper the condition for ellipticity loss is derived using the deformation gradient and the first Piola-Kirchhoff stress tensor. Next, the obtained condition is implemented and numerically tested within symbolic-numerical tools AceGen and AceFEM using the benchmark of an elongated rectangular plate with imperfection in plane stress and plane strain conditions.

22.Ranachowski Z., Schabowicz K., Gorzelańczyk T., Kudela Jr S., Dvorak T., Visualization of Fibers and Voids Inside Industrial Fiber Concrete Boards, Material Science & Engineering International Journal, ISSN: 2574-9927, DOI: 10.15406/mseij.2017.01.00022, Vol.1, No.4, pp.1-4, 2018
Ranachowski Z., Schabowicz K., Gorzelańczyk T., Kudela Jr S., Dvorak T., Visualization of Fibers and Voids Inside Industrial Fiber Concrete Boards, Material Science & Engineering International Journal, ISSN: 2574-9927, DOI: 10.15406/mseij.2017.01.00022, Vol.1, No.4, pp.1-4, 2018

Abstract:
Fiber cement boards (FCB) microstructure and methods of fabrication are described. The method of X-ray microtomography in application for investigating of FCB microstructure is presented. The cellulose fibers constituting the remarkable reinforcement of the FCB are colorless and too small to be seen applying the standard optical methods. The X-ray microtomography method however enabled the authors to realize three goals within the investigation of the properties of FCB. The length and shape of the fibers could be assessed on specimens’ cross-sections. Applying the pseudo 3D visualization it was possible to visualize the cracked regions inside the specimen volume. The case of non-uniform fibers distribution in respect to the board thickness which was impossible to recognize applying the standard visual inspection, was also performed by merging the multiple cross-section images into a single graph

23.Leyva-Mendivil M.F., Lengiewicz J., Limbert G., Skin friction under pressure. The role of micromechanics, Surface Topography: Metrology and Properties, ISSN: 2051-672X, DOI: 10.1088/2051-672X/aaa2d4, Vol.6, No.1, pp.1-14, 2018
Leyva-Mendivil M.F., Lengiewicz J., Limbert G., Skin friction under pressure. The role of micromechanics, Surface Topography: Metrology and Properties, ISSN: 2051-672X, DOI: 10.1088/2051-672X/aaa2d4, Vol.6, No.1, pp.1-14, 2018

Abstract:
The role of contact pressure on skin friction has been documented in multiple experimental studies. Skin friction significantly raises in the low-pressure regime as load increases while, after a critical pressure value is reached, the coefficient of friction of skin against an external surface becomes mostly insensitive to contact pressure. However, up to now, no study has elucidated the qualitative and quantitative nature of the interplay between contact pressure, the material and microstructural properties of the skin, the size of an indenting slider and the resulting measured macroscopic coefficient of friction. A mechanistic understanding of these aspects is essential for guiding the rational design of products intended to interact with the skin through optimally-tuned surface and/or microstructural properties. Here, an anatomically-realistic 2D multi-layer finite element model of the skin was embedded within a computational contact homogenisation procedure. The main objective was to investigate the sensitivity of macroscopic skin friction to the parameters discussed above, in addition to the local (i.e. microscopic) coefficient of friction defined at skin asperity level. This was accomplished via the design of a large-scale computational experiment featuring 312 analyses. Results confirmed the potentially major role of finite deformations of skin asperities on the resulting macroscopic friction. This effect was shown to be modulated by the level of contact pressure and relative size of skin surface asperities compared to those of a rigid slider. The numerical study also corroborated experimental observations concerning the existence of two contact pressure regimes where macroscopic friction steeply and non-linearly increases up to a critical value, and then remains approximately constant as pressure increases further. The proposed computational modelling platform offers attractive features which are beyond the reach of current analytical models of skin friction, namely, the ability to accommodate arbitrary kinematics, non-linear constitutive properties and the complex skin microstructure.

Keywords:
skin friction, contact mechanics, pressure, microstructure, finite element, homogenisation, material properties

24.Maździarz M., Rojek J., Nosewicz S., Molecular dynamics study of self-diffusion in stoichiometric B2-NiAl crystals, Philosophical Magazine, ISSN: 1478-6443, DOI: 10.1080/14786435.2018.1480838, Vol.98, No.24, pp.2257-2274, 2018
Maździarz M., Rojek J., Nosewicz S., Molecular dynamics study of self-diffusion in stoichiometric B2-NiAl crystals, Philosophical Magazine, ISSN: 1478-6443, DOI: 10.1080/14786435.2018.1480838, Vol.98, No.24, pp.2257-2274, 2018

Abstract:
Self-diffusion parameters in stoichiometric B2-NiAl solid state crystals were estimated by molecular statics/dynamics simulations with the study of required simulation time to stabilise diffusivity results. An extrapolation procedure to improve the diffusion simulation results was proposed. Calculations of volume diffusivity for the B2 type NiAl in the 1224–1699 K temperature range were performed using the embedded-atom-model potential. The results obtained here are in much better agreement with the experimental results than the theoretical estimates obtained with other methods.

Keywords:
NiAl; nickel–aluminium; diffusivity; molecular dynamics; molecular statics; embedded-atom method; sintering