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.Kowalewski Z.L., Advances in fatigue investigations of materials – state of the art and new challenges, 12th INTERNATIONAL ARMAMENT CONFERENCE, 2018-09-17/09-20, Jachranka (PL), pp.161-162, 2018
2.Jóźwiak-Niedźwiedzka D., Gibas K., Glinicki M.A., Petrographic evaluation of reactive minerals in selected crushed aggregates in Poland, 13th International Symposium on Concrete Roads, 2018-06-19/06-22, Berlin (DE), pp.1-4, 2018
Jóźwiak-Niedźwiedzka D., Gibas K., Glinicki M.A., Petrographic evaluation of reactive minerals in selected crushed aggregates in Poland, 13th International Symposium on Concrete Roads, 2018-06-19/06-22, Berlin (DE), pp.1-4, 2018

Abstract:
The long term performance of concrete pavements can be reduced due to improper selection of
aggregates, thus prevention of damage due to alkali-silica reaction (ASR) requires a detailed
examination of minerals in aggregates. The amount of reactive silica in the aggregate is an
important factor governing the severity of ASR, which depends critically on the nature of the
reactive aggregate.
In the present study the potential for ASR in selected rocks in Poland was evaluated using
petrographic methods. The tests were performed on crushed aggregates from different regions,
covering a variety of rock origin and their geological structure. The optical microscopy in
transparent light on thin sections was used as a principal tool to assess the mineral composition of
aggregates. The content of reactive siliceous minerals was assessed. The petrographic
examination concerned different forms of silica. Quartz grains were classified according to their
mean diameter so as to identify the reactive range.
The application of the petrographic method allowed for classification of aggregate for ASR
potential using RILEM recommendation. The results of the study allow to make a quick and
responsible decision to direct the aggregates to further detailed tests, reject or accept them as
concrete components for concrete pavements.

Keywords:
alkali-silica reaction, polymineral grains, petrographic analysis

3.Dąbrowski M., Jóźwiak-Niedźwiedzka D., Antolik A., Glinicki M.A., Effects of cyclic wet-dry- external alkali exposure on microstructure and water permeability of air-entrained pavement concrete, 13th International Symposium on Concrete Roads, 2018-06-19/06-22, Berlin (DE), pp.1-4, 2018
Dąbrowski M., Jóźwiak-Niedźwiedzka D., Antolik A., Glinicki M.A., Effects of cyclic wet-dry- external alkali exposure on microstructure and water permeability of air-entrained pavement concrete, 13th International Symposium on Concrete Roads, 2018-06-19/06-22, Berlin (DE), pp.1-4, 2018

Abstract:
Penetration of external alkalis from deicing salts into concrete pavement can promote deleterious alkali-silica reaction (ASR) and therefore reduce its long-term performance. In severe exposure
conditions (wet and heavy traffic load) the susceptibility of aggregates to ASR may be aggravated. To study this phenomenon on concrete specimens the combined cyclic exposure method was
developed at VDZ Düsseldorf. Such a cyclic wet-dry-external alkali exposure was used on air entrained concrete specimens to investigate its influence on the microstructure and the
permeability of concrete. Air voids characteristics, mercury intrusion porosimetry, porosity accessible to water and water absorption of concrete was tested. Concrete microstructure was
observed in scanning electron microscope to reveal the specific features. The applied cyclic wetdry-external alkali exposure induced a marked decrease of total porosity of concrete and the
appearance of ASR gel in cement matrix. An increase of the rate of water absorption of concrete was also found.

Keywords:
alkali-silica reaction, VDZ test, microstructure, permeability, water absorption

4.Szymczak T., Brodecki A., Makowska K., Kowalewski Z.L., Tow truck frame made of high strength steel under cyclic loading, 35 DANUBIA-ADRIA, 35th Danubia-Adria Symposium on Advances in Experimental Mechanics, 2018-09-25/09-28, Sinaia (RO), pp.145-146, 2018
5.Pieczyska E.A., Golasiński K., Maj M., Staszczak M., Kowalewski Z.L., Furuta T., Kuramoto S., Yielding and strain localization effects in gum metal - a unique ti alloy -investigated by digital image correlation and infrared thermography , 35 DANUBIA-ADRIA, 35th Danubia-Adria Symposium on Advances in Experimental Mechanics, 2018-09-25/09-28, Sinaia (RO), pp.57-58, 2018
6.Denis P., Sajkiewicz P., Electrospun nonwovens with poly(glycerol sebacate), BiPoCo 2018, 4th International Conference on Bio-based Polymers and Composites, 2018-09-02/09-06, Balatonfured (HU), pp.1-2, 2018
7.Golasiński K., Pieczyska E.A., Mackiewicz S., Staszczak M., Zubko M., Takesue N., Analysis Gum Metal crystallographic texture and misorientation in correlation to its mechanical behavior, CAC, XXIV CONFERENCE ON APPLIED CRYSTALLOGRAPHY, 2018-09-02/09-06, Arłamów (PL), No.OY1-5, pp.37-38, 2018
Golasiński K., Pieczyska E.A., Mackiewicz S., Staszczak M., Zubko M., Takesue N., Analysis Gum Metal crystallographic texture and misorientation in correlation to its mechanical behavior, CAC, XXIV CONFERENCE ON APPLIED CRYSTALLOGRAPHY, 2018-09-02/09-06, Arłamów (PL), No.OY1-5, pp.37-38, 2018

Keywords:
Gum Metal, EBSD, ultrasonic measurement

8.Blachowski B., Tauzowski P., Logo J., Topology optimization of elastoplastic structures: Stress intensity driven formulation and functor-oriented implementation, CST2018, The Thirteenth International Conference on Computational Structures Technology 2018, 2018-09-04/09-06, Sitges, Barcelona (ES), No.0090, pp.1-3, 2018
Blachowski B., Tauzowski P., Logo J., Topology optimization of elastoplastic structures: Stress intensity driven formulation and functor-oriented implementation, CST2018, The Thirteenth International Conference on Computational Structures Technology 2018, 2018-09-04/09-06, Sitges, Barcelona (ES), No.0090, pp.1-3, 2018

Abstract:
This study is devoted to a practical method for topology optimization of elastoplastic structures subjected to stress constraints. Instead of the classical compliance minimization problem the aim of this work is to find a minimum weight structure, which is able to carry given load and the corresponding stresses do not exceed an allowable limit. The general form of the problem is based on the classical limit design formulations of plasticity. The proposed method finds optimal structure in an iterative way using only stress intensity distribution and doesn’t require computing of any gradients or sensitivities.
Our method starts with determining representative stresses in every quadrilateral finite element. At first an elastoplastic analysis is performed to obtain stress values in four Gaussian points, then by the use of von Misses criterion and these stress values the resultant stress is calculated. Next, having obtained stress intensity distribution within the structure we apply penalization to avoid stress concentration issues. Finally, the material is removed proportionally to the stress intensities of individual finite elements. The above mentioned procedure is repeated until limit load capacity is achieved for a given loading vector. The checkerboard problem is solved by means of design filter. Two benchmark problems have been selected as illustrative examples. They are: cantilever and simply supported beam. For these examples parametric studies on different length to height ratios and support patterns are conducted. Additionally, the results of topology optimization for different values of filter radius and penalty parameter are presented.
Finally, efficient computer implementation based on functor-oriented programming is discussed. It is demonstrated how Functor and Template-based programming can be utilized to create versatile Finite Element environment. Within this environment computation of all element matrices and loading vectors can be called in the same way, this in turn allows for implementation of effective aggregation procedure.

Keywords:
topology optimization, minimum-weight design, functor-oriented programming, stress constraints

9.Jurczak G., Maździarz M., Dłużewski P., Dimitrakopulos G., Komninou Ph., Karakostas T., On the Applicability of the Theory of Elasticity to Very Thin Layers, EDS2018, 19th International Conference on Extended Defects in Semiconductors, 2018-06-24/06-29, Thessaloniki (GR), pp.1, 2018
Jurczak G., Maździarz M., Dłużewski P., Dimitrakopulos G., Komninou Ph., Karakostas T., On the Applicability of the Theory of Elasticity to Very Thin Layers, EDS2018, 19th International Conference on Extended Defects in Semiconductors, 2018-06-24/06-29, Thessaloniki (GR), pp.1, 2018

Abstract:
Theory of elasticity, a continuum model of a macroscopic material is commonly used to model a relaxation of a crystalline heterostructures. There are many reports on the successful application of theory of elasticity to nanometer crystalline heterostructures, even if the continuum condition for these structures is hardly fulfilled. On the other hand progress in epitaxial growth techniques allows to prepare the stable ultra thin layers with the thickness about a single monolayer. For such extremely thin layers the theory of elasticity seems to fail in describing the relaxation process. The results provided by theory of elasticity and experimental measurements or molecular statics/dynamics become diverging. The key problem in that case seems to be located at the interface between layers and related to composition change, which is problematic in classic, elastic approach. By applying a “substitutive” composition of the interface layers which is just an interpolation, it is possible to obtain a good agreement with molecular statics, even for 1 monolayer heterostructure. Instead of classic approach to the composition within the theory of elasticity, we propose another approach which takes into account the composition as an extra degree of freedom along with classical displacement. Such approach creates a chemo-elastic coupling with composition interpolated by use of the Vegard’s law. This allows to take into account a composition changes at the interface and avoid mesh refining necessary at the classic approach.

Keywords:
theory of elasticity, semiconductor, monolayer, relaxation

10.Pawłowska S., Pierini F., Kowalewski T.A., Highly flexible filaments in an oscillatory microchannel flow, EFMC12, 12th European Fluid Mechanics Conference, 2018-09-09/09-13, Wiedeń (AT), pp.1, 2018
11.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
12.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
13.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
14.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
15.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
16.Blachowski B., Tauzowski P., Lógó J., Elasto-Plastic Topology Optimization Under Stochastic Loading Conditions, EngOpt, 6th International Conference on Engineering Optimization, 2018-09-17/09-19, Lizbona (PT), DOI: 10.1007/978-3-319-97773-7_7, pp.70-79, 2018
Blachowski B., Tauzowski P., Lógó J., Elasto-Plastic Topology Optimization Under Stochastic Loading Conditions, EngOpt, 6th International Conference on Engineering Optimization, 2018-09-17/09-19, Lizbona (PT), DOI: 10.1007/978-3-319-97773-7_7, pp.70-79, 2018

Abstract:
Optimal topologies obtained for structures subjected to deterministic loading can be sensitive to loading variations in terms of both magnitude and direction. Therefore, in this study we consider problem of topology optimization for structures subjected to probabilistic loading. The proposed method applies basic findings from probability theory, which allow to transform the original problem of topology optimization under single probabilistic loading into analogous problem of topology optimization under multiple deterministic loading cases. After recalling the theoretical background of the method,’ its effectiveness is demonstrated on an examples of cantilever structure subjected to horizontally oriented load with randomly varying angle of action.

Keywords:
Topology optimization, Stochastic load, Elastoplastic FE analysis

17.Urbanek O., Kołbuk D., Sonochemical modification of electrospun fibres with hydroxyapatite nanoparticles, ESB2018, 29th European Conference on Biomaterials, 2018-09-09/09-13, Maastricht (NL), pp.523-524, 2018
18.Golasiński K., Pieczyska E., Maj M., Staszczak M., Takesue N., Superelastic-like behavior of Gum Metal under compression inspected by infrared thermography, ESOMAT 2018, 11th European Symposium on Martensitic Transformations, 2018-08-27/08-31, Metz (FR), pp.84, 2018
19.Faraj R., High Performance Pneumatic Shock-absorbers for aeronautical applications, ICAS2018, 31st Congress of the International Council of the Aeronautical Sciences, 2018-09-09/09-14, Belo Horizonte (BR), pp.1-10, 2018
Faraj R., High Performance Pneumatic Shock-absorbers for aeronautical applications, ICAS2018, 31st Congress of the International Council of the Aeronautical Sciences, 2018-09-09/09-14, Belo Horizonte (BR), pp.1-10, 2018

Abstract:
The paper is aimed at development of high performance shock-absorbers for aeronautical applications. This contribution concerns pneumatic dampers because of their lightweight, technical simplicity and low manufacturing costs. The concept of semi-passive devices is introduced and single reconfiguration technique is discussed for both single- and double-chamber shock-absorber. Presented general approach to optimal design of the semi-passive devices can be applied for design of different types of fluid-based absorbers, e.g. hydraulic or oleo-pneumatic dampers. The absorbers can be used as a suspension of light airdrop system as well as a part of landing gear of small UAV.

20.Postek E., Sadowski T., Temperature effect in 2 phase ceramic based composite during impact conditions, ICCS21, 21st International Conference on Composite Materials, 2018-09-04/09-07, University of Bologna, Bologna (IT), DOI: 10.15651/978-88-938-5079-7, pp.100, 2018
Postek E., Sadowski T., Temperature effect in 2 phase ceramic based composite during impact conditions, ICCS21, 21st International Conference on Composite Materials, 2018-09-04/09-07, University of Bologna, Bologna (IT), DOI: 10.15651/978-88-938-5079-7, pp.100, 2018

Abstract:
Cermet Materials (CM) are often used for manufacturing of different cutting tools. They have very good mechanical, wear and thermal properties. In our opinion, the dynamic load is still not enough thoroughly analysed, and the impact load as well. The tools are subjected to different dynamic effects.We have taken into account complex spatial distribution of cermet phases, grain/binder interfaces modeled by interface elements, possibility of cracks appearance within binders using interface elements as well, and rotation of brittle grains.
The main goal of the presentation is to develop further previously formulated models of two-phase composite [1-4] to capture effects of temperature due to impact. The source of the thermal loading is the conversion of plastic work into heat [5, 6]. The increase of temperature takes place in the Co interfaces. We investigate adiabatic and fully coupled solutions.
We note differences in the behaviour of the samples when the thermal loading is not considered. We have found that the thermal softening effect in the interface material is important as well. We enhance the description of the damage mechanism in the presence of temperature increase.
Acknowledgements
This work was financially supported by Ministry of Science and Higher Education (Poland) within the statutory research (IPPT PAN) and National Science Centre (Poland) project No 2016/21/B/ST8/01027 (Lublin University of Technology). The calculations were done at the Interdisciplinary Centre for Mathematical and Computational Modelling, University of Warsaw, Poland. The licenses for the MSC Patran and Abaqus programs were provided by Academic Computer Centre in Gdańsk, Poland.

References:
[1] Sadowski T, Hardy S, Postek E. Prediction of the mechanical response of polycrystalline ceramics containing metallic intergranular layers under uniaxial tension. Comput Mat Sci 2005;34:46-63.
[2] Sadowski T, Hardy S, Postek E. A new model for the time-dependent of polycrystalline ceramic materials with metallic inter-granular layers under tension. Mat. Sci. Eng. A 2006;424:230-238.
[3] Sadowski T, Postek E, Denis C. Stress distribution due to discontinuities in polycrystalline ceramics containing metallic inter-granular layers. Comput Mat Sci 2007;39: 230-236.
[4] Postek E, Sadowski T. Dynamic pulse sensitivity of WC/Co composite, (accepted in Composite Structures).
[5] Wriggers P, Miehe C, Kleiber M, Simo JC. On the coupled thermomechanical treatment of necking problems via finite element methods. Int. J. Num. Meth. Eng. 1992; 33:869–883.
[6] Rojek J, Onate E, Postek E. Application of explicit FE codes to simulation of sheet and bulk metal forming processes. J. Mat. Proc. Tech. 1998; 80–81: 620–627.

Keywords:
cermet composites, coupled solutions, thermomechanics

21.Dąbrowski M., Glinicki M.A., Gibas K., Antolik A., Dziedzic K., Influence of Surface Retarders on Texture Profile And Durability of Upper Layer of Exposed Aggregate Concrete Pavement, ICDCS-6, Sixth International Conference on Durability of Concrete Structures, 2018-07-18/07-20, University of Leeds, Leeds, West Yorkshire (GB), No.PSE17, pp.451-456, 2018
Dąbrowski M., Glinicki M.A., Gibas K., Antolik A., Dziedzic K., Influence of Surface Retarders on Texture Profile And Durability of Upper Layer of Exposed Aggregate Concrete Pavement, ICDCS-6, Sixth International Conference on Durability of Concrete Structures, 2018-07-18/07-20, University of Leeds, Leeds, West Yorkshire (GB), No.PSE17, pp.451-456, 2018

Abstract:
Exposed aggregate concrete (EAC) pavement technology is used in Poland for construction of major highways and expressways. When properly executed, it is an efficient technique to provide desired friction for skid resistance without compromising the noise limitations. Concrete mix uniformity, proper dosing of retarding agent and optimal time to brush with a mechanical broom are supposed to have a major impact on the properties of the upper pavement layer. An experimental investigation was performed on exposed aggregate concrete specimens manufactured in the laboratory in a way to simulate the industrial production of two-layer concrete slab with exposed aggregate. The texture depth was determined using a laser profiler. The compressive strength of concrete, the water absorption rate, and permeability of chloride ions through concrete were also determined. The freeze-thaw resistance and surface scaling resistance were tested and analyzed with respect to air void characteristics. Results revealed an increase in surface scaling for EAC slabs with higher w/c ratio and slabs simulating local bleeding. The most efficient method to determine indirectly the durability of EAC slabs was the set of permeability tests comprised of measurements of chloride migration and rate of water absorption. The change of macrotexture depth with increase of w/c ratio and retarding admixture type was found.

Keywords:
highway pavement, exposed aggregate concrete, surface retarder, durability, concrete preparation parameter, water absorption, chloride migration, surface scaling, macrotexture

22.Pieczyska E., Golasiński K., Maj M., Staszczak M., Mackiewicz S., Zubko M., Takesue N., Gum metal in compression – investigation of mechanical anisotropy caused by texture, ICEM 2018, 18TH INTERNATIONAL CONFERENCE ON EXPERIMENTAL MECHANICS, 2018-07-01/07-05, BRUKSELA (BE), No.454, pp.1-2, 2018
23.Staszczak M., Pieczyska E.A., Odriozola I., Martin R., Investigation of functional properties of new shape memory polymer, ICEM 2018, 18TH INTERNATIONAL CONFERENCE ON EXPERIMENTAL MECHANICS, 2018-07-01/07-05, BRUKSELA (BE), No.199, pp.1-2, 2018
24.Ustrzycka A., Mróz Z., Kowalewski Z.L., Characterization of Damage Evolution Supported by ESPI Analysis, ICEM 2018, 18TH INTERNATIONAL CONFERENCE ON EXPERIMENTAL MECHANICS, 2018-07-01/07-05, BRUKSELA (BE), No.082, pp.1, 2018
25.Wang K., Kopeć M., Qu H., Wang Y., Wang L., Lin J., Li Z., A unified constitutive model for two-phase titanium alloys under hot stamping condition, ICNFT 2018, 5th International Conference on New Forming Technology, 2018-08-18/08-21, Bremen (DE), pp.1-1, 2018
26.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

27.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

28.Niemczyk B., Sajkiewicz P., Gradys A., The Effect of Chemical Composition on Crosslinking Kinetics of Methylcellulose/Agarose Hydrogel, ISBPPB 2018, 4th International Conference on Biomedical Polymers and Polymeric Biomaterials, 2018-07-15/07-18, Kraków (PL), pp.174, 2018
29.Dulnik J., Sajkiewicz P., The Comparison of Crosslinking Methods of Bicomponent PCL/gelatin Electrospun Nanofibres, ISBPPB 2018, 4th International Conference on Biomedical Polymers and Polymeric Biomaterials, 2018-07-15/07-18, Kraków (PL), pp.109, 2018
30.Walenta Z.A., Słowicka A.M., Detonation Waves in Narrow Channels of Various Shapes , ISIS23, 23rd International Shock Interaction Symposium, 2018-07-09/07-13, Kruger National Park (ZA), pp.135-140, 2018
Walenta Z.A., Słowicka A.M., Detonation Waves in Narrow Channels of Various Shapes , ISIS23, 23rd International Shock Interaction Symposium, 2018-07-09/07-13, Kruger National Park (ZA), pp.135-140, 2018

Abstract:
One of the important contemporary technological problems is connected with necessity of extinguishing detonation, which may occur in pipelines transporting gaseous fuels. To achieve this goal usually a matrix of very narrow channels is placed inside the pipeline, perpendicularly to its axis. In our recent paper (Walenta and Slowicka (2016)) we have shown, that channels with sharp changes of cross-section should be more efficient in this respect than traditionally used straight channels with constant cross-section area. In this paper we demonstrate how detonation behaves in the channels, in which gas flows under realistic conditions – when friction and heat exchange are present. We take into account the fact, that gas flowing through such channels accelerates and its density decreases considerably.

Keywords:
detonation waves, detonation damping, narrow channels

31.Błachowski B., Świercz A., Jankowski Ł., Virtual Distortion Method based optimal sensor placement for damage identification, ISMA 2018, The Leuven Conference on Noise and Vibration Engineering, 2018-09-17/09-19, Leuven (BE), pp.3689-3698, 2018
Błachowski B., Świercz A., Jankowski Ł., Virtual Distortion Method based optimal sensor placement for damage identification, ISMA 2018, The Leuven Conference on Noise and Vibration Engineering, 2018-09-17/09-19, Leuven (BE), pp.3689-3698, 2018

Abstract:
The paper presents a novel method for sensor placement optimized towards effective identification of structural damages. The derivation of the method is based on the concept of virtual distortions together with information provided by a set of strain gauges. Then, a gradient oriented optimization is applied to identify sensor locations, which are the most sensitive to potential damage scenarios. Steepest descent method is utilized to determine the optimal values of the objective function. Additionally, dependence of the method on the applied excitation signal is discussed. Finally, effectiveness of the proposed methodology is demonstrated on an example of optimal search for sensor placement on a 6-bay planar truss structure.

32.Mikułowski G., Semi-active damping of forced vibrations by means of pneumatic supports, ISMA 2018, The Leuven Conference on Noise and Vibration Engineering, 2018-09-17/09-19, Leuven (BE), pp.1051-1061, 2018
Mikułowski G., Semi-active damping of forced vibrations by means of pneumatic supports, ISMA 2018, The Leuven Conference on Noise and Vibration Engineering, 2018-09-17/09-19, Leuven (BE), pp.1051-1061, 2018

Abstract:
Vibration mitigation and vibration isolation are problems existing in a variety of industry branches. Pneumatic suspensions and isolators are a widely utilized technology, and in many applications they need to adapt their properties to a varying mass of the supported object, e.g., loaded or unloaded lorries. However, the pneumatic solutions posses limitations in the field of adequate damping. The change in mass results in a change in the required level of damping. This contribution presents and verifies a concept of an enhanced damping pneumatic device using an example of a Pneumatic Adaptive Absorber (PAA) adapted to the task of mitigation of forced vibrations. The investigation presents a concise introduction to the concept, as well as analytical and numerical modelling of the conceptual device. The contribution proposes a control algorithm based on performed analysis of mechanical energy dissipation process. The concept is verified experimentally in a laboratory. The proposed modelling seems to be in agreement with the demonstrator response.

33.Mikułowski G., Popławski B., Wiszowaty R., Mróz A., Jankowski Ł., An investigation on a semi-active damping of forced structural vibrations by means of controllable structural nodes, ISMA 2018, The Leuven Conference on Noise and Vibration Engineering, 2018-09-17/09-19, Leuven (BE), pp.189-201, 2018
Mikułowski G., Popławski B., Wiszowaty R., Mróz A., Jankowski Ł., An investigation on a semi-active damping of forced structural vibrations by means of controllable structural nodes, ISMA 2018, The Leuven Conference on Noise and Vibration Engineering, 2018-09-17/09-19, Leuven (BE), pp.189-201, 2018

Abstract:
Vibration mitigation in space structures creates a unique class of a technical problem where resistant for outgassing and non-fluidic solutions are preferable. Additionaly, a vibration induced by time-varying excitations needs to be effectively reduced. The vibration mitigation task is speciffically difficult in the case of light, slender and inherently flexible structures of various types, such as supporting structures, deployable structures, modular structures or wide-span skeletal roofing structures. This study presents a concept of a vibration attenuation method based on semi-active joints and dedicated to frame structures under forced vibration excitation. The presented investigation contains an analysis of the problem of the optimal control of a structure fitted with semi-active structural members. Furthermore, an adequate model of the semi-active joints is developed and a numerical example is presented. Finally, the research provides an experimental verification of the developed control algorithms, which is conducted on a test stand in a laboratory environment.

34.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.05009-1-10, 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.05009-1-10, 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.

35.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.04003-1-6, 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.04003-1-6, 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.

36.Golasiński K.M., Pieczyska E., Maj M., Staszczak M., Kuramoto S., Gum Metal under cyclic tension inspected by a fast and sensitive infrared camera, QIRT 2018, 14th Quantitative InfraRed Thermography Conference, 2018-06-25/06-29, Berlin (DE), pp.1-6, 2018
Golasiński K.M., Pieczyska E., Maj M., Staszczak M., Kuramoto S., Gum Metal under cyclic tension inspected by a fast and sensitive infrared camera, QIRT 2018, 14th Quantitative InfraRed Thermography Conference, 2018-06-25/06-29, Berlin (DE), pp.1-6, 2018

Abstract:
This work presents results of experimental investigation of recoverable deformation of a β-Ti alloy Gum Metal inspected by infrared (IR) thermography. To this end, a flat specimen of Gum Metal was subjected to cyclic tension with an increasing strain on a testing machine and was simultaneously monitored by a fast and sensitive IR camera. The IR measurements determined an average temperature accompanying the alloy deformation process for subsequent tension cycles and allowed to estimate thermoelastic effect, which is related to the alloy yield point. Thermomechanical couplings accompanying the loading-unloading cycles were analyzed for estimating the range of reversible deformation from mechanical and thermal perspectives as well as discussed in the view of Lord Kelvin’s formula.

37.Jóźwiak-Niedźwiedzka D., Antolik A., Glinicki M.A., Investigation of potential for alkali-silica reaction in granitic aggregates, SLD4, 4th International Conference on Service Life Design for Infrastructures, 2018-08-27/08-30, Delft (NO), pp.131-134, 2018
Jóźwiak-Niedźwiedzka D., Antolik A., Glinicki M.A., Investigation of potential for alkali-silica reaction in granitic aggregates, SLD4, 4th International Conference on Service Life Design for Infrastructures, 2018-08-27/08-30, Delft (NO), pp.131-134, 2018

Abstract:
Crushed granite aggregates due to good physical and mechanical properties are widely
accepted for production of durable concrete. This kind of aggregates are considered as not
alkali-silica reactive (ASR). However, all of them contain silica. In some of them SiO2 occurs
in a strained form or the crystals are small enough to be treated as microcrystalline, so they
can be prone to ASR.
Various granite aggregates taken from largest exploited Polish quarries were tested.
Petrographic analysis on thin sections and accelerated mortar-bar test were carried out to
assess potential of the alkali-silica reactivity.
The petrographic analysis revealed differences in mineral composition of the tested
granites. The strained quartz and microcrystalline quartz were the main potentially deleterious
mineral in analyzed granite aggregates. Also the myrmekites were particularly visible in the
granitic rocks. The results of the mortar-bar tests confirmed such predictions. The mortar
beams showed expansion more than 0.1% after 28 days of exposition in 1M NaOH and 80°C.
The bars made with RILEM cement showed fast and large elongation. In all cases the increase
in mortar beam elongation was linear. The SEM-EDS analysis confirmed the presence of the
ASR gel both, in the aggregate and in the matrix.

38.Cristea M., Ionita D., Oprea S., Pieczyska E.A., How loading type affects viscoelastic response in polyurethane structures, SolMech 2018, 41st SOLID MECHANICS CONFERENCE, 2018-08-27/08-31, Warszawa (PL), pp.342-343, 2018
39.Staszczak M., Pieczyska E.A., Matsui R., Takeda K., Estimation of energy storage and dissipation in Shape Memory Polymer during its deformation, SolMech 2018, 41st SOLID MECHANICS CONFERENCE, 2018-08-27/08-31, Warszawa (PL), pp.338-339, 2018
40.Pieczyska E.A., Dunić V., Slavkovic R., Kowalewski Z., Stress relaxation effects in TiNi SMA, SolMech 2018, 41st SOLID MECHANICS CONFERENCE, 2018-08-27/08-31, Warszawa (PL), pp.350-351, 2018
41.Pieczyska E., Golasiński K., Maj M., Mackiewicz S., Staszczak M., Zubko M., Takesue N., Mechanical anisotropy of Gum Metal analyzed by ultrasonic measurements and digital image correlation, SolMech 2018, 41st SOLID MECHANICS CONFERENCE, 2018-08-27/08-31, Warszawa (PL), pp.352-353, 2018
Pieczyska E., Golasiński K., Maj M., Mackiewicz S., Staszczak M., Zubko M., Takesue N., Mechanical anisotropy of Gum Metal analyzed by ultrasonic measurements and digital image correlation, SolMech 2018, 41st SOLID MECHANICS CONFERENCE, 2018-08-27/08-31, Warszawa (PL), pp.352-353, 2018

Abstract:
Experimental investigation of mechanical anisotropy in a multifunctional beta titanium alloy Gum Metal under compression is reported. Non-destructive and destructive techniques were used to analyze unique mechanical behavior of the alloy. Structural characterization showed a strong <110> texture of Gum Metal, which is a result of cold-swaging applied during its fabrication [1]. Due to this kind of texture Gum Metal can be treated as transversally isotropic solid. Ultrasonic measurements determined elastic constants with high accuracy. A significant difference between Young’s moduli of the alloy calculated for parallel and perpendicular directions to the alloy swaging direction was demonstrated. Compression of Gum Metal cube samples with two orientations was conducted on a testing machine. Two perpendicular walls of each sample were monitored by two visible range cameras during the deformation process for further 2-dimensional digital image correlation (DIC) analysis. Strong mechanical anisotropy of Gum Metal was confirmed by a detailed analysis of the stress vs. strain curves and strain distributions.

42.Ustrzycka A., Irradiation creep damage in nuclear reactor components , SolMech 2018, 41st SOLID MECHANICS CONFERENCE, 2018-08-27/08-31, Warszawa (PL), pp.116-117, 2018
43.Ustrzycka A., Mróz Z., Kucharski S., Kowalewski Z.L., Analysis of fatigue crack initiation caused by cyclic microplasticity , SolMech 2018, 41st SOLID MECHANICS CONFERENCE, 2018-08-27/08-31, Warszawa (PL), pp.272-273, 2018
44.Postek E., Sadowski T., Temperature effects during impact of WC/Co composites, SolMech 2018, 41st SOLID MECHANICS CONFERENCE, 2018-08-27/08-31, Warszawa (PL), pp.1, 2018
Postek E., Sadowski T., Temperature effects during impact of WC/Co composites, SolMech 2018, 41st SOLID MECHANICS CONFERENCE, 2018-08-27/08-31, Warszawa (PL), pp.1, 2018

Abstract:
Generally, the papers on dynamic loading of composites more focus on the layered composites, for example [1]. High attention is paid to blast load. However, in our opinion, the process of impact a gap for analysis of WC/Co composite during impact conditions. During impact of WC/Co composite objects and the other composites with metallic binder heat of plastic work is generated. If the process is fast enough the problem can be treated as adiabatic. However, more common situation is slower process when the heat is generated in metallic interfaces and the neighbouring grains are heated due to conduction. The process should be rather considered as coupled [2]. We developed our model of WC/Co composite towards impact load, [3].

Keywords:
thermomechanics, coupled problems, composites

45.Postek E., Nowak Z., Pęcherski R., Impact resistance of crushable foam skeleton, SolMech 2018, 41st SOLID MECHANICS CONFERENCE, 2018-08-27/08-31, Warszawa (PL), pp.1-2, 2018
Postek E., Nowak Z., Pęcherski R., Impact resistance of crushable foam skeleton, SolMech 2018, 41st SOLID MECHANICS CONFERENCE, 2018-08-27/08-31, Warszawa (PL), pp.1-2, 2018

Abstract:
The analyses of the modern cellular materials due to complexity of their internal structure require efficient computer methods and codes. The new method that has been developed mostly in the last 10 years is peridynamics [1, 2]. The developments resulted in highly parallelized code [3] that we use in our analysis.
The subject of the study are alumina foams produced by gelcasting method. The results of microtomography of alumina foams are used to create the numerical model reconstructing the structure of foam skeleton. The numerical simulations of failure strength under compression for alumina foams are performed. The calculations with use of the numerical model are time consuming. Therefore, the simplified method of the assessment of failure strength is proposed. The 3D model of the foam structure is created. The detailed description of the model generation is presented in Nowak et al. [5].
The numerical models of real Al2O3 foam with porosity 96 %, and discussion of theirs mechanical properties have been presented. The method of the assessment of failure strength of real alumina foam produced by the gelcasting is proposed.
We attempt to present the mechanism of damaging of a crushable foam under impact.

Keywords:
foams, damage, impact, peridynamics

46.Tauzowski P., Blachowski B., Lógó J., Functor-Oriented Finite Element Programming with Application to Structural Topology Optimization, SolMech 2018, 41st SOLID MECHANICS CONFERENCE, 2018-08-27/08-31, Warszawa (PL), No.P076, pp.490-491, 2018
Tauzowski P., Blachowski B., Lógó J., Functor-Oriented Finite Element Programming with Application to Structural Topology Optimization, SolMech 2018, 41st SOLID MECHANICS CONFERENCE, 2018-08-27/08-31, Warszawa (PL), No.P076, pp.490-491, 2018

Abstract:
The subject of this study is an efficient approach to the development of a finite element framework, which is intended to be used for solving a variety of problems in computational solid mechanics. One of such problems, recently becoming an active field of research, is topology optimization of structures made of elastic-plastic materials. For finding the optimal topology of real, practical and complex structures the knowledge of a number of numerical algorithms is required, to mention a few: modification of finite element meshes, aggregation of tangent stiffness matrices, or direct and iterative solvers. The classical computer implementation of the original Classical Optimality Criteria method (COC) of the topology optimization problem given by Bendsoe and Sigmund is relatively simple and contains 99 lines of code in the MATLAB language. However, it assumes that there exists only a single loading case, single displacement (compliance) constraint, the material is linearly elastic and the optimal topology can be found using the so-called Solid Isotropic Material with Penalization (SIMP) algorithm, which is based on the original COC method. In reality, engineers face a slightly different problem. They need to find the topology of a minimum weight structure subjected to multiple loading cases, made of an elasto-plastic material, and with a limit on stresses. The above mentioned SIMP approach may not lead to an optimal solution.

Keywords:
functor-oriented programming, topology optimization, elastoplastic FE analysis

47.Ostrowski M., Blachowski B., Jankowski L., Pisarski D., Semi-Active Control of Mechanical Energy Transport Between Vibrational Modes , SolMech 2018, 41st SOLID MECHANICS CONFERENCE, 2018-08-27/08-31, Warszawa (PL), No.P136, pp.408-409, 2018
Ostrowski M., Blachowski B., Jankowski L., Pisarski D., Semi-Active Control of Mechanical Energy Transport Between Vibrational Modes , SolMech 2018, 41st SOLID MECHANICS CONFERENCE, 2018-08-27/08-31, Warszawa (PL), No.P136, pp.408-409, 2018

Abstract:
The vibration attenuation problem has been solved using many different methods, some of which involve the use of advanced control algorithms. The topic of harvesting the energy of structural vibrations is less explored. For that reason, this contribution studies the problem of conversion of mechanical energy of vibrations. The paper presents a method of semi-active control, which is applied to dynamically transfer the vibration energy into a selected vibration mode. The target mode is selected in such a way that the amount of energy that can be recovered during the vibration process is maximized. In other words, switching between two modes is not intended to dissipate the energy of vibrations, but rather to maximize the energy-harvesting potential of the overall system. The concept will be illustrated using an example of a simple frame structure, in which semi-actively controlled lockable joints modify the modal properties of the structure.

Keywords:
semi-active control, lockable joints, energy-harvesting

48.Dlugosz A., Pokorska I., Glinicki M.A., Jaskulski R., Application of evolutionary algorithms in identification of thermal properties of hardening concerte, SolMech 2018, 41st SOLID MECHANICS CONFERENCE, 2018-08-27/08-31, Warszawa (PL), pp.1-2, 2018
49.Szymczak T., Kowalewski Z.L., Visco-plastic effects due to deformation along circular loading path , SolMech 2018, 41st SOLID MECHANICS CONFERENCE, 2018-08-27/08-31, Warszawa (PL), pp.42-43, 2018
50.Makowska K., Kowalewski Z., Dudda W., Ziółkowski P., Badur J., Damage assessment of exploited turbine blades using barkhausen noise parameters , SolMech 2018, 41st SOLID MECHANICS CONFERENCE, 2018-08-27/08-31, Warszawa (PL), pp.270-271, 2018
51.Szymczak T., Kowalewski Z.L., Brodecki A., Mini-compact tension specimens for fracture toughness evaluation , SolMech 2018, 41st SOLID MECHANICS CONFERENCE, 2018-08-27/08-31, Warszawa (PL), pp.274-275, 2018
52.Popławski B., Mikułowski G., Wiszowaty R., Jankowski Ł., Semi-active mitigation of externally induced vibrations, SolMech 2018, 41st SOLID MECHANICS CONFERENCE, 2018-08-27/08-31, Warszawa (PL), No.P197, pp.1-2, 2018
Popławski B., Mikułowski G., Wiszowaty R., Jankowski Ł., Semi-active mitigation of externally induced vibrations, SolMech 2018, 41st SOLID MECHANICS CONFERENCE, 2018-08-27/08-31, Warszawa (PL), No.P197, pp.1-2, 2018

Abstract:
Almost all man-made structures are exposed to vibration. Regardless of whether these are large structures such as bridges or skyscrapers, machines with rotating parts such as engine shafts, frame structures or vehicle suspensions, excessive vibrations can be very harmful. From the perspective of their effects they can be seen as very spectacular (e.g., a collapse of a bridge) or not worth much attention (e.g., a failure of a motor shaft), but in each of these cases, the effect is the destruction of the structure and a negative impact on the users of these devices.
Several approaches can be used by the designers to overcome this phenomenon. The most basic, but often sufficient, method is to introduce changes in the mechanical parameters of the system affecting the severity of vibration in operational conditions, i.e., its mass or stiffness. If such design changes cannot be realized, or if vibration problems are detected after the system is manufactured, or if a vibration suppression system must be used for other reasons, one of the three basic types of such systems can be used.
The primary choice is usually a passive vibration damping system. These are relatively simple systems whose mode of operation is the passive dissipation of the energy of structural vibrations. Their design and simple functionality ensures that they are highly reliable, but their simplicity is reflected, unfortunately, in their limited efficiency. Their flexibility may be also considered as insufficient: once configured, even a small change in the specific operating conditions can result in a drastic loss of performance. This indicates a rather narrow spectrum (frequency range) of correct system operation.
Active systems constitute a much more effective damping approach. In this case, vibration attenuation is achieved not by means of dampers, but by actuators integrated into the structure. This approach allows to achieve very good results of vibration mitigation over a wide range of excitation frequencies. High efficiency, however, is burdened with a much higher degree of complexity of such a system as compared to the passive systems. In order to develop such a system, it is necessary to design the controller and install actuators that implement the control algorithm. During the vibration suppression, the actuators themselves require a large energy supply, which can be troublesome in some cases.
The compromise between these damping systems are semi-active systems, where the actuators are used to affect structural properties instead of exerting large external forces. In terms of reliability, semi-active systems can be compared with passive systems, while in terms of the efficiency of damping with active ones. They also do not require large amounts of electric energy to implement the control algorithm. Despite being a relatively new research area with less established design and development procedures, their advantages seem to be large enough to attract a growing number of scientists and engineers.
This contribution presents a strategy for semi-active reduction of forced vibrations in frame structures. Analogous damping technique proved to be effective in damping of free vibrations. The control strategy is based on the Prestress Accumulation–Release (PAR) concept and uses specially designed semi-active rotational nodes. Successive decentralization of the damping system demonstrates that apart from the global mechanism of the energy dissipation based on the PAR, it is also possible to disperse it locally to individual beams that are separate elements of the damping system.

53.Gawlicki M., Jankowski Ł., Identification of a load moving on a plate using the l1 norm minimization, SolMech 2018, 41st SOLID MECHANICS CONFERENCE, 2018-08-27/08-31, Warszawa (PL), No.P226, pp.1-2, 2018
Gawlicki M., Jankowski Ł., Identification of a load moving on a plate using the l1 norm minimization, SolMech 2018, 41st SOLID MECHANICS CONFERENCE, 2018-08-27/08-31, Warszawa (PL), No.P226, pp.1-2, 2018

Abstract:
There are two fundamental inverse problems in the field of structural health monitoring (SHM): identification of damages and identification of loads. Effectiveness of the related computational methods is crucial for maintaining integrity of the monitored structures. This contribution considers identification of unknown loads based on measurements of structural response. It is a relatively extensively researched problem: reviews of techniques used for off-line load identification can be found in [1,2], while techniques for online identification are reviewed in [3].
If the aim is to identify independent force histories in each of the excited degrees of freedom (Dofs), the uniqueness of the solution can be possible only if there are at least as many sensors (equations) as the excited Dofs (unknowns). Such a requirement can be satisfied in case of a few unknown stationary loads, but it becomes problematic if the unknown load is (even single but) moving in an unknown way across the structure. In such a case, a very large number of Dofs can be potentially excited and a limited number of sensors are available to measure the response. As a result, the naïve direct formulation of the inverse problem is underdetermined, and the solution is not unique.
This contribution is devoted to indirect identification of a single moving load that excites a 2D structure (plate). To attain the uniqueness, the solution space needs to be significantly constrained. However, instead of assuming a known trajectory of the load and identifying its value, the aim is to identify the trajectory only. Such a problem is important, e.g., in traffic monitoring and control [4,5]. Effectively, the approach is based on the assumption of sparsity of the excitation, which seems to suit the practice: even if the location of the load is unknown, at each time instant only a single (or a limited number of) Dofs is excited. Such an approach follows the methodology of compressed sensing [6], which includes such SHM-related applications as identification of impact load position [7]. The assumption of sparsity is usually expressed as a requirement of a bounded l1 norm of the solution [8].
The approach has already been verified numerically and experimentally using a flexible 1D structure (a beam) excited with a moving mass [9]. The cases considered there included single or multiple passes of the mass across the beam. The assumption of sparsity allowed the space-time trajectory of the load to be identified. Here, the goal is to test the approach in a much more complex problem that involves a 2D structure, e.g., a plate, subjected to a single moving load. In the fully dynamic case the task is computationally very demanding, thus we focus here on the quasi-static case. This abstract describes briefly the method and the experimental stand. Detailed results will be presented during the conference.

54.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

55.Mackiewicz S., Istota, znaczenie oraz metodyka wyznaczania parametru SNR w radiografii cyfrowej, STARY MŁYN, KRAJOWA KONFERENCJA BADAŃ RADIOGRAFICZNYCH - „STARY MŁYN 2018”, 2018-09-10/09-12, Bolesławiec (PL), pp.1-13, 2018
56.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, 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, 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

57.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
58.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

59.Popławski B., Mikułowski G., Suwała G., Jankowski Ł., Optimization of actuator placement for vibration damping in the Prestress-Accumulation release control approach, WCSCM, 7th World Conference on Structural Control and Monitoring, 2018-07-22/07-25, Qingdao (CN), pp.818-827, 2018
Popławski B., Mikułowski G., Suwała G., Jankowski Ł., Optimization of actuator placement for vibration damping in the Prestress-Accumulation release control approach, WCSCM, 7th World Conference on Structural Control and Monitoring, 2018-07-22/07-25, Qingdao (CN), pp.818-827, 2018

Abstract:
This contribution proposes a quantitative criterion for optimization of actuator placement for the Prestress–Accumulation Release (PAR) strategy of mitigation of vibrations. The PAR strategy is a semi-active control approach that relies on controlled redistribution of modal energy into high-frequency high-order modes, where it is effectively dissipated by means of the natural mechanisms of material damping. The energy transfer is achieved by a controlled temporary removal of selected structural constraints. An example is a short-time decoupling of rotational degrees of freedom in a frame node, so that the bending moments are no longer transferred between the involved beams. If it such a decoupling is performed at the maximum of the shear/bending strain energy of adjacent beams, it results in an almost instantaneous energy release into high-frequency local vibrations and quick dissipation of energy. We propose and test a quantitative criterion for placement of such actuators. The criterion is based on local modal strain energy that can be released into high-order modes. The numerical time complexity is linear with respect to the number of actuators, which facilitates quick selection of placements in large structures.

Keywords:
semi-active control, damping of vibrations, actuator placement, smart structures, Prestress-Accumulation Release (PAR)

60.Popławski B., Mikułowski G., Mróz A., Jankowski Ł., Decentralized algorithm for semi-active damping of forced vibrations using controllable truss-frame nodes, WCSCM, 7th World Conference on Structural Control and Monitoring, 2018-07-22/07-25, Qingdao (CN), pp.582-590, 2018
Popławski B., Mikułowski G., Mróz A., Jankowski Ł., Decentralized algorithm for semi-active damping of forced vibrations using controllable truss-frame nodes, WCSCM, 7th World Conference on Structural Control and Monitoring, 2018-07-22/07-25, Qingdao (CN), pp.582-590, 2018

Abstract:
Semi-active systems for mitigation of vibrations proved to be effective in many applications. Their prominent advantage is that they combine strong points of passive and active damping systems. Proper design can ensure their reliability, which is what passive systems are praised for. A high effectiveness in vibration damping links them with active systems. At the same time they do not have many deficiencies of active systems. They are adaptive, so they can stay effective in different environmental conditions, which is the factor that eliminates passive systems from many implementations. Their mass and energy consumption is very low, and the controlled structure can stay in the safe configuration even in case of power supply failure, which puts them in contrast to many active systems. The mentioned attributes make them a good choice for many structures subjected to vibrations, especially when there is a strong emphasis on maximization of the efficiency/mass ratio of the damping system.

This contribution presents a decentralized closed-loop control strategy and applies it in a frame structure equipped with controllable truss-frame nodes. Such nodes can be switched between frame-like and truss-like states in a controllable manner. In the frame-like state the node transmits all forces and moments, while in the truss-like state only axial and shearing forces are transmitted. These nodes allow for structural reconfiguration, which can be utilized by semi-active control strategies for the purpose of vibration damping. The implemented control algorithm applies the Prestress-Accumulation Release (PAR) strategy based on the transmission of the accumulated potential energy to high modes of vibration, which are highly dissipative. Strain measurements are conducted locally on selected elements. A similar strategy proved its effectiveness in mitigation of free structural vibrations. This research studies the concept of its application to mitigation of forced structural vibrations, caused by variable external conditions.

Keywords:
Semi-active damping, Truss-frame nodes, Prestress-Accumulation Release (PAR), Decentralized control

61.Hou J., Wang S., Jankowski Ł., Structure damage localization of the slab track by adding virtual masses, WCSCM, 7th World Conference on Structural Control and Monitoring, 2018-07-22/07-25, Qingdao (CN), pp.1368-1373, 2018
Hou J., Wang S., Jankowski Ł., Structure damage localization of the slab track by adding virtual masses, WCSCM, 7th World Conference on Structural Control and Monitoring, 2018-07-22/07-25, Qingdao (CN), pp.1368-1373, 2018

Abstract:
In this paper, a damage localization method based on additional virtual mass and dynamic test of simple harmonic excitation is proposed. Firstly, when additional masses are added to the structure, a large number of virtual structures can be constructed; then the virtual construction formula is derived in order to obtain the dynamic response of virtual structures without adding real mass. After dynamic test of simple harmonic excitation, the dynamic response of virtual structures can be obtained using the acceleration response and virtual construction formula. Furthermore, when the applied harmonic excitation frequency is close to the natural frequency of the structure, the structural response can reach a maximum by adding advisable mass and the mass value can be calculated. When the local structure is damaged, the extreme value and the corresponding position of the additional mass are found by adding mass at different positions in the structure. Thus, the approximate location of the damage is determined according to the results. Finally, the numerical simulation of the elastic foundation beam model simplified by track structure is carried out, and the results show that the damage can be localized.

Keywords:
structural health monitoring, damage identification, slab track, virtual mass

62.Faraj R., Graczykowski C., Mikułowski G., Wiszowaty R., Holnicki-Szulc J., Control techniques for adaptive absorbers, WCSCM, 7th World Conference on Structural Control and Monitoring, 2018-07-22/07-25, Qingdao (CN), pp.1-9, 2018
Faraj R., Graczykowski C., Mikułowski G., Wiszowaty R., Holnicki-Szulc J., Control techniques for adaptive absorbers, WCSCM, 7th World Conference on Structural Control and Monitoring, 2018-07-22/07-25, Qingdao (CN), pp.1-9, 2018

Abstract:
The paper is aimed at discussion of various control techniques developed for adaptive impact-absorbers protecting structures and machines. Different approaches to the problem of optimal damper design are presented and systems comparison is provided with the example of pneu-matic shock-absorber. The influences of selected control strategy on the absorber characteris-tics, its efficiency and adaptation capabilities are shown. The contribution includes both numerical and experimental examples. The authors highlight the fact that the final design of the device should be elaborated simultaneously with the development of dedicated control system. In some cases properly assumed architecture of the control system enables significant simplifi-cation of the absorber. The paper covers analyses of semi-passive devices with single reconfig-uration to identified excitation conditions and semi-active absorbers capable of adaptation to unknown impact loading. Adaptation mechanisms of such devices and their robustness are com-pared in reference to volatility of system parameters and variety of loading conditions. Limita-tions of smart devices (e.g. piezo-electric valve in pneumatic absorbers) used in practice for absorbers’ control are described in relevant mathematical models. Technological challenges in the design and manufacturing of absorbers are identified and methods of their overcoming are proposed.

Keywords:
Adaptive Impact Absorption, adaptive control, adaptable system, damper

63.Pisarski D., On optimal distributed semi-active control of vibrating structures, WCSCM, 7th World Conference on Structural Control and Monitoring, 2018-07-23/07-26, Qingdao (CN), pp.3148-3149, 2018
Pisarski D., On optimal distributed semi-active control of vibrating structures, WCSCM, 7th World Conference on Structural Control and Monitoring, 2018-07-23/07-26, Qingdao (CN), pp.3148-3149, 2018

Abstract:
A novel semi-active control method for mitigation of structural vibration is studied. The method relies on distributed state information patterns and solutions to optimal control problem that aims at replicating the structures of the optimal open-loop switched stabilizing controls. The performance of the designed method is validated by means of numerical experiments performed for a double cantilever system equipped with a set of semi-active elastomers with controlled viscoelastic properties.

64.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

65.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

66.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

67.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

68.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

69.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

70.Kowalewski Z.L., Szymczak T., Badania wytrzymałościowe połączeń spawanych w elementach wybranych konstrukcji, XXIV Seminarium NIENISZCZĄCE BADANIA MATERIAŁÓW, 2018-03-14/03-16, Zakopane (PL), pp.21-50, 2018
71.Mackiewicz S., Badania ultradźwiękowe w sprzężeniu powietrznym, XXIV Seminarium NIENISZCZĄCE BADANIA MATERIAŁÓW, 2018-03-14/03-16, Zakopane (PL), pp.135-153, 2018
72.Dobkowska-Chudon W., Wrobel M., Karłowicz P., Dabrowski A., Krupienicz A., Targowski T., Nowicki A., Olszewski R., Detecting cerebrovascular changes in the brain caused by hypertension in atrial fibrillation group using acoustocerebrography, PLOS ONE, ISSN: 1932-6203, DOI: 10.1371/journal.pone.0199999, pp.1-10, 2018
Dobkowska-Chudon W., Wrobel M., Karłowicz P., Dabrowski A., Krupienicz A., Targowski T., Nowicki A., Olszewski R., Detecting cerebrovascular changes in the brain caused by hypertension in atrial fibrillation group using acoustocerebrography, PLOS ONE, ISSN: 1932-6203, DOI: 10.1371/journal.pone.0199999, pp.1-10, 2018

Abstract:
Acoustocerebrography is a novel, non-invasive, transcranial ultrasonic diagnostic method
based on the transmission of multispectral ultrasound signals propagating through the brain
tissue. Dedicated signal processing enables the estimation of absorption coefficient, frequency-
dependent attenuation, speed of sound and tissue elasticity. Hypertension and atrial
fibrillation are well known factors correlated with white matter lesions, intracerebral hemorrhage
and cryptogenic stroke numbers. The aim of this study was to compare the acoustocerebrography
signal in the brains of asymptomatic atrial fibrillation patients with and
without hypertension. The study included 97 asymptomatic patients (40 female and 57
male, age 66.26 ± 6.54 years) who were clinically monitored for atrial fibrillation. The
patients were divided into two groups: group I (patients with hypertension) n = 75, and group
II (patients without hypertension) n = 22. Phase and amplitude of all spectral components
for the received signals from the brain path were extracted and compared to the phase and
amplitude of the transmitted pulse. Next, the time of flight and the attenuation of each frequency
component were calculated. Additionally, a fast Fourier transformation was performed
and its features were extracted. After introducing a machine learning technique, the
ROC plot of differentiations between group I and group II with an AUC of 0.958 (sensitivity
0.99 and specificity 0.968) was obtained. It can be assumed that the significant difference in
the acoustocerebrography signals in patients with hypertension is due to changes in the
brain tissue, and it allows for the differentiating of high-risk patients with asymptomatic atrial
fibrillation and hypertension.

Keywords:
changes in the brain, hypertension in atrial, acoustocerebrography

73.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

74.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.140008-1-8, 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.140008-1-8, 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.

75.Lewandowski M., Walczak M., Witek B., Rozbicki J., Steifer T., Demonstrator przenosnego systemu Phased-Array z funkcją Full-Matrix Capture, BADANIA NIENISZCZĄCE I DIAGNOSTYKA, ISSN: 2451-4462, Vol.3, pp.70-71, 2018
Lewandowski M., Walczak M., Witek B., Rozbicki J., Steifer T., Demonstrator przenosnego systemu Phased-Array z funkcją Full-Matrix Capture, BADANIA NIENISZCZĄCE I DIAGNOSTYKA, ISSN: 2451-4462, Vol.3, pp.70-71, 2018

Abstract:
Ultradźwiękowe systemy Phased-Array (PA) umożliwiają detekcję i ocenę wad za pomocą wieloelementowych głowic ze skanowaniem elektronicznym. Zaawansowane metody kierowania wiązki oraz wizualizacji znacznie ułatwiają badania obiektów o skomplikowanej geometrii. Należy jednak pamiętać, ze klasyczna metoda PA bazuje na tych samych zasadach fizycznych, co skanowanie standardowymi głowicami jednoelementowymi i posiada te same ograniczenia. W naszym laboratorium pracujemy nad implementacją nowej klasy metod obrazowania UT, które wykorzystują technikę Full-Matrix Capture (FMC) oraz Total Focusing Method (TFM). Metody te dają zupełnie nowe możliwości rekonstrukcji obrazów wad i pozwalają na uzyskanie jednorodnej rozdzielczości poprzecznej w całej głębokości badania. W tym celu zbudowaliśmy demonstrator przenośnego systemu PA wyposażony w funkcje FMC i TFM. Akwizycja pełnej macierzy ech oraz przetwarzanie softwarowe na wbudowanym procesorze GPU (Nvidia Tegra) zapewniają duże możliwości przetwarzania i analizy sygnałów. Demonstrator jest wyposażony w 32-kanały akwizycji w konfiguracji 32:128 i współpracuje ze standardowymi głowicami PA firmy Olympus.

Keywords:
UT, Phased-Array, akwizycja pełnej macierzy, GPU

76.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

77.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

78.Kopeć M., Wang K., Wang Y., Wang L., Lin J., Feasibility study of a novel hot stamping process for Ti6Al4V alloy, MATEC Web of Conferences, ISSN: 2261-236X, DOI: 10.1051/matecconf/201819008001, Vol.190, pp.1-5, 2018
Kopeć M., Wang K., Wang Y., Wang L., Lin J., Feasibility study of a novel hot stamping process for Ti6Al4V alloy, MATEC Web of Conferences, ISSN: 2261-236X, DOI: 10.1051/matecconf/201819008001, Vol.190, pp.1-5, 2018

Abstract:
To investigate the feasibility of a novel hot stamping process for the Ti6Al4V titanium alloy using low temperature forming tools, mechanical properties of the material were studied using hot tensile tests at a temperature range of 600 - 900°C with a constant strain rate of 1s-1. Hot stamping tests were carried out to verify the feasibility of this technology and identify the forming window for the material. Results show that when the deformation temperature was lower than 700°C, the amount of elongation was less than 20%, and it also had little change with the temperature. However, when the temperature was higher than 700°C, a good ductility of the material can be achieved. During the forming tests, parts failed at lower temperatures (600°C) due to the limited formability and also failed at higher temperatures (950°C) due to the phase transformation. The post-form hardness firstly decreased with the temperature increasing due to recovery and then increased due to the phase transformation. Qualified parts were formed successfully between temperatures of 750 - 850°C, which indicates that this new technology has a great potential in forming titanium alloys sheet components.

Keywords:
titanium, hot stamping, metal forming

79.Kecik K., Zaszczyńska A., Mitura A., Experimental Investigations of Energy Recovery from an Electromagnetic Pendulum Vibration Absorber, Journal of Vibration Testing and System Dynamics, ISSN: 2475-4811, DOI: 10.5890/JVTSD.2018.09.002, Vol.2, No.3, pp.209-219, 2018
Kecik K., Zaszczyńska A., Mitura A., Experimental Investigations of Energy Recovery from an Electromagnetic Pendulum Vibration Absorber, Journal of Vibration Testing and System Dynamics, ISSN: 2475-4811, DOI: 10.5890/JVTSD.2018.09.002, Vol.2, No.3, pp.209-219, 2018

Abstract:
The paper presents an experimental study of a special non−linear low frequency system dedicated to vibration mitigation and energy recovery. The dual−function design was based on an autoparametric vibration system, which consists of an oscillator with an added pendulum vibration absorber. Its structure includes an energy harvesting device: a levitating magnet in a coil. The pendulum motion shows simultaneously the effects of vibration reduction and energy recovery. The influences of the magnet−coil configurations, and load resistances on vibration reduction and energy harvesting were studied in detail.

Keywords:
Experiment, Energy recovery, Pendulum, Vibration mitigation

80.Papliński P., Wańkowicz J., Ranachowski P., Ranachowski Z., Microstructure and degree of degradation of ZnO varistors in surge arresters due to operation , ARCHIVES OF METALLURGY AND MATERIALS, ISSN: 1733-3490, DOI: 10.24425/123800, Vol.63, No.3, pp.1267-1273, 2018
Papliński P., Wańkowicz J., Ranachowski P., Ranachowski Z., Microstructure and degree of degradation of ZnO varistors in surge arresters due to operation , ARCHIVES OF METALLURGY AND MATERIALS, ISSN: 1733-3490, DOI: 10.24425/123800, Vol.63, No.3, pp.1267-1273, 2018

Abstract:
The paper presents the test results for the microstructure of ZnO varistors comprising high voltage gapless surge arresters. The tests were performed on varistors produced in different periods and by various manufacturers. The research was inspired by different characteristics of changes in values of current flowing through surge arresters as a function of changes in values of system voltage in a 220 kV substation, and the temperature in a multi-year cycle. Furthermore, the effects of varistor microstructure degradation following a failure of an unsealed surge arrester were investigated. The results provided the grounds for assessment of ZnO varistor microstructure parameters in terms of their durability and resistance to degradation processes. Keywords: surge arrester, MO varistor, microstructure of ceramics, ceramic material degradation

81.Jóźwiak-Niedźwiedzka D., Dąbrowski M., Brandt A.M., Burakowska A., Baran T., The results of the concrete shield of the EWA nuclear reactor/Wyniki badania betonu z obudowy reaktora jądrowego EWA, CEMENT, WAPNO, BETON, ISSN: 1425-8129, Vol.3, pp.226-238, 2018
Jóźwiak-Niedźwiedzka D., Dąbrowski M., Brandt A.M., Burakowska A., Baran T., The results of the concrete shield of the EWA nuclear reactor/Wyniki badania betonu z obudowy reaktora jądrowego EWA, CEMENT, WAPNO, BETON, ISSN: 1425-8129, Vol.3, pp.226-238, 2018

Keywords:
nuclear reactor, concrete shield, radiation influence