dr hab. inż. Eligiusz Postek

Zakład Informatyki i Nauk Obliczeniowych (ZIiNO)
Zespół Komputerowych Analiz Zaawansowanych Konstrukcji (ZeKAZK)
stanowisko: specjalista
telefon: (+48) 22 826 12 81 wew.: 131
pokój: 412
e-mail: epostek

Doktorat
1997-06-26Numeryczna analiza wrażliwości na parametry projektowe dużych nieliniowych układów konstrukcyjnych 
promotor -- prof. dr hab. inż. Michał Kleiber, IPPT PAN
533 
Habilitacja
2014-09-25Modelowanie numeryczne problemów sprzężonych wraz z paralelizacją 
Promotor prac doktorskich
1.2006
pomocniczy
Rosli Ahmad  
(Swansea UW)
Optimisation of the squeeze forming process 
2.2004
pomocniczy
Luo Chouping  
(Lulea UT)
Finite elements based on the piece-wise linear weight functions in contact problems 

Ostatnie publikacje
1.Postek E., Sadowski T., Distributed microcracking process of WC/Co cermet under dynamic impulse compressive loading , COMPOSITE STRUCTURES, ISSN: 0263-8223, DOI: 10.1016/j.compstruct.2018.04.014, Vol.194, pp.494-508, 2018

Streszczenie:

Cermet Materials (CM), for example, WC/Co, have very good mechanical, thermal and wear properties. They are used for manufacturing of cutting tools. However, their behavior under dynamic loads is still not properly understood.
Experiments, e.g. Siegl and Fischmester (1988) and Ravichandran (1994), indicate that the fracture energy of
WC/Co is expended through ductile failure of the Co: (1) close to the binder/tungsten carbide interface (Liu et al., 2017) [64] or by (2) dimple rupture across the interphase (Sigl and Exner, 1987) [22]. Stress concentrations around grain boundaries lead to initiation of microcracks which are dispersed by dynamic loading.
The main goal of the paper is to investigate the previously formulated models of the two-phase composite (Sadowski et al., 2005, 2006, 2007; Dębski and Sadowski, 2014, 2017) [47–51] in the case of dynamic compressive
pulses that are common in the case of cutting tools. 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 obtained results show that microcracking process and stress distributions are different for quasi-static and dynamic loadings. Early development of microcracks distribution revealed by damage parameter was observed.

Słowa kluczowe:

Cermet, Dynamic compressive impulse, Interface elements, Distributed microcracking process

Afiliacje autorów:

Postek E.-IPPT PAN
Sadowski T.-Lublin University of Technology (PL)
35p.
2.Postek E., Sadowski T., Dynamic pulse sensitivity of WC/Co composite, COMPOSITE STRUCTURES, ISSN: 0263-8223, DOI: 10.1016/j.compstruct.2017.10.092, No.203, pp.498-512, 2018

Streszczenie:

Cutting tools are manufactured among others from cermet (e.g. WC/Co) having excellent mechanical properties. Geometry of the internal microstructure is complex and mechanical response due to quasi-static or dynamic loading is difficult to be described. Particularly, the dynamic loading is not investigated enough precise up till now.
Experimental evidences, e.g. Siegl and Fischmester (1988), Ravichandran (1994), indicate that the fracture energy of WC/Co is expended through ductile failure of the Co: (1) near the binder/tungsten carbide interface or by (2) dimple rupture across the interphase. Concentrations of stresses around grain boundaries lead to initiation of microcrack system, which is dispersed for dynamic loading.
The aim of the paper is to extend the previously formulated models (Sadowski et al., 2005, 2006, 2007, Dębski and Sadowski, 2014, 2017) of the polycrystalline composite towards more advanced finite element formulation, applicable for description of the cermet behavior under dynamic pulses. The model takes into account: (1) spatial distribution of the cermet constituents, (2) system of grain boundaries/binder interfaces modeled by interface elements, (3) rotation of brittle grains.
The obtained results show that stress distributions and gradual microcracking processes are quite different for quasi-static and dynamic loadings. It was revealed by damage parameter indicating concentration of microcracks.

Słowa kluczowe:

Metal-ceramic composite, Interface elements, Crack propagation, Dynamic loading,

Afiliacje autorów:

Postek E.-IPPT PAN
Sadowski T.-Lublin University of Technology (PL)
35p.
3.Postek E., Sadowski T., Qualitative comparison of dynamic compressive pressure load and impact of WC/Co composite, International Journal of Refractory Metals and Hard Materials, ISSN: 0263-4368, DOI: 10.1016/j.ijrmhm.2018.07.009, Vol.77, pp.68-81, 2018

Streszczenie:

Degradation of Cermet Materials (CM) under impact and pulse pressure is not thoroughly investigated. In this
study, we qualitatively compare the behaviour of WC/Co samples under these types of loading.
The new models of impact and dynamic compressive load of a WC/Co plate were investigated. We developed two models of the composite plate, namely, a continuous model and a model with crack appearance possibility in the interfaces/binders.
We noted a qualitative difference of the shapes of the deformed structure due to different models and kind of loading. The differences also concern the Mises stress, equivalent plastic strains and damage parameter.
The proposed models are suitable for both impact and pressure load. The possibility of cracks appearance should not be neglected. In case of the model with discontinuities, for both kinds of loads, the grains rotation and sliding is more distinct than in case of the continuous model.

Słowa kluczowe:

Cermet, Impact, Pressure load, Interface elements, Distributed microcracking process, Numerical models

Afiliacje autorów:

Postek E.-IPPT PAN
Sadowski T.-Lublin University of Technology (PL)
35p.
4.Postek E., Sadowski T., Cracks in Interfaces and Around Their Junctions in WC/Co Composite, ENGINEERING TRANSACTIONS (ROZPRAWY INŻYNIERSKIE), ISSN: 0867-888X, Vol.64, No.4, pp.589-596, 2016

Streszczenie:

WC/Co ceramic metal-matrix composites are characterized by very high mechanical properties that allow for application of the composites mostly in production of different types of cutting tools. By combining in a composite structure a phase of brittle hard wolfram carbide (WC) grains with a metallic interface of cobalt (Co) that exhibits plastic properties, a geometrically complex microstructure with significantly different mechanical properties of the combined phases is created, see Fig. 1a. The presence of the elastic-plastic interface material, i.e. Co binder, in the composite structure is the reason for initiation of technological defects – mainly material porosity. During material loading pores start to coalesce and finally one can observe creation of microcracks system distributed along interfaces. The aim of the paper is to show the previously formulated model [1, 2] of the polycrystalline composite to be extended towards cracks development around the junctions of the interfaces. The obtained numerical results indicate that in the junctions high stress concentrations were observed, which leads to crack initiation and its further unstable propagation, and finally the composite failure. Results indicate that the first crack appears close to the junction and that the load carrying capacity of the sample is overestimated if a crack model in the interfaces is not assumed.

Słowa kluczowe:

metal-ceramic composite, interface elements, crack propagation at composite junctions

Afiliacje autorów:

Postek E.-IPPT PAN
Sadowski T.-Lublin University of Technology (PL)
15p.
5.Postek E., Parameter sensitivity of a monolayer tensegrity model of tissues, Journal of Coupled Systems and Multiscale Dynamics, ISSN: 2330-152X, DOI: 10.1166/jcsmd.2014.1054, Vol.2, No.4, pp.179-187, 2014

Streszczenie:

The state of stress in the tissue that we call mechanical environment is important for the cell behavior. In particular, the stresses may trigger the chemical pathways. Therefore, it is important to model structure of the cell. The part of the cell is the cytoskeleton that carries most of the loading. We believe that a good method to understand the importance of particular parts of the cellular structure is the parameter sensitivity analysis. In particular, it is interesting in the case of hierarchical structures. An example of such a structure is the tissue. The single cell is modelled as icosahedral based tensegrity structure. The constitutive model is viscous-elastic. The formulation of the parameter sensitivity problem is done in the Updated Lagrangian reference frame. We observe the sensitivity fields due to change of sizing parameters of the microtubules in a single cell and groups of cells. The change of the sizing parameters simulates the sensitivity to growth of group of cells. The tissue evolves continuosly since each cell undergoes cell cycle. In consequence, the state of mechanical fields evolves as well. The investigation of the rules of the cell cycle is the domain of the computational systems biology. The main novelty of the paper is the presentation of the parameter sensitivity algorithm with the application to a complex biological system.

Słowa kluczowe:

computer simulation of cell processes, finite-element and galerkin methods, modeling, sensitivity analysis, structures and organization in complex systems

Afiliacje autorów:

Postek E.-IPPT PAN
6.Postek E., Concept of an Agent-stress Model of a Tissue, TECHNISCHE MECHANIK, ISSN: 0232-3869, Vol.32, pp.518-529, 2012

Streszczenie:

This paper stands for a concept of coupling between agent modeling and stress analysis valid for a tissue. The stress analysis of evolving tissue is underestimated in previous studies. The experimental observations and numerical simulations of stress development in a single cell and in particular, in a growing tissue are still rare in the literature. We use a tensegrity model for a single cell that serves for stress evaluation in a growing tissue. We propose to couple the mechanical modeling with the agent one using a staggered scheme for two exemplary scenarios. The first example is devoted to scratching of the epithelium, and the second one to the pins and slits.
We observe the systems sensitivities with respect to the selected groups of design parameters. The groups of parameters have been associated with clusters of cells. We have found that the sensitivities may be used for comparing the complex structures of the tissue.

Afiliacje autorów:

Postek E.-IPPT PAN
7.Postek E.W., Sadowski T., Assessing the influence of porosity in the deformation of metal-ceramic composites, COMPOSITE INTERFACES, ISSN: 0927-6440, DOI: 10.1163/092764410X554049, Vol.18, No.1, pp.57-76, 2011

Streszczenie:

The aim of the paper is to develop the previously formulated model [19, 20] of the polycrystalline composite to include porosity growth at metallic interfaces of metal-ceramic composites (MCCs). Examples of this kind of MCCs are: (1) a two-phase material composed of brittle grains WC joined by the plastic binder Co, which can contain a small degree of porosity introduced during the cooling process [31], (2) TiC-Mo2C hard phase grains surrounded by tough binder phase Ni [12]. This work focuses on the description of the deformation of the MCC material including the modelling of a real material internal structure taking into account porosity growth during the loading. Experimental observations of the WC/Co composite [10] indicate that the majority of the fracture energy of MCC is expended through ductile failure of the plastic binder Co (dimple rupture across the binder or in the binder near the binder/carbide interface). This process is preceded by porosity growth at metallic interfaces and finally leads to inter-granular cracks propagation.

This paper presents micromechanical modelling of the MCC response in the case of uniaxial tension of 3-D Representative Volume Element (RVE) with the application of the Finite Element Analysis (FEA). The MCC material includes: elastic grains and inter-granular metallic layers containing technological pores that create its real complex internal structure. The quasi-static deformation process of the material comprises elastic deformation of brittle grains, elasto-plastic deformation of inter-granular layers (of different thickness: 2-4 mu m) and additional deformation due to micro-porosity development in the layers. A micro-sample analysis leads to the conclusion that a small amount of technological porosity changes the qualitative behaviour of the MCC including deformation, rotation of grains, roughness, and level of plastic strains. (C) Koninklijke Brill NV, Leiden, 2011

Słowa kluczowe:

Interface porosity, Gurson-Tvergaard model, polycrystalline ceramic composites, INTER-GRANULAR LAYERS, POLYCRYSTALLINE CERAMICS, FRACTURE, GROWTH, PREDICTION, STRENGTH, BEHAVIOR, TENSION, CERMETS, MODEL

Afiliacje autorów:

Postek E.W.-IPPT PAN
Sadowski T.-Lublin University of Technology (PL)
25p.
8.Postek E.W., Lewis R.W., Gethin D.T., Finite element modelling of the squeeze casting process, INTERNATIONAL JOURNAL OF NUMERICAL METHODS FOR HEAT AND FLUID FLOW, ISSN: 0961-5539, DOI: 10.1108/09615530810853619, Vol.18, pp.325-355, 2008

Słowa kluczowe:

Finite element analysis, Thermodynamics, Material‐deforming processes

Afiliacje autorów:

Postek E.W.-other affiliation
Lewis R.W.-University of Wales (GB)
Gethin D.T.-University of Wales Swansea (UK)
9.Sadowski T., Postek E., Denis Ch., Stress distribution due to discontinuities in polycrystalline ceramics containing metallic inter-granular layers, COMPUTATIONAL MATERIALS SCIENCE, ISSN: 0927-0256, Vol.39, pp.230-236, 2007
10.Sadowski T., Hardy S., Postek E., A new model for the time-dependent behaviour of polycrystalline ceramic materials with metallic inter-granular layers under tension, MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING, ISSN: 0921-5093, Vol.424, pp.230-238, 2006
11.Lewis R.W., Postek E.W., Han Z., Gethin D.T., A finite element model of the squeeze casting process, INTERNATIONAL JOURNAL OF NUMERICAL METHODS FOR HEAT AND FLUID FLOW, ISSN: 0961-5539, Vol.16, No.5, pp.539-572, 2006
12.Sadowski T., Hardy S.J., Postek E.W., Prediction of the mechanical response of polycrystalline ceramics containing metallic intergranular layers under uniaxial tension, COMPUTATIONAL MATERIALS SCIENCE, ISSN: 0927-0256, Vol.34, pp.46-63, 2005
13.Postek E.W., Lewis R.W., Gethin D.T., Ransing R.S., Influence of initial stresses on the cast behaviour during squeeze forming processes, JOURNAL OF MATERIALS PROCESSING TECHNOLOGY, ISSN: 0924-0136, Vol.159, pp.338-346, 2005

Lista rozdziałów w ostatnich monografiach
1.
402
Postek E., GRAFEN – IPPT PAN COMPUTER OF BIOCENTRUM OCHOTA GRID, rozdział: Parameter Sensitivity of a Tensegrity Model of a Tissue, IPPT Reports on Fundamental Technological Research, Postek E., Kowalewski T.A. (Eds.), 3, pp.81-92, 2014
2.
403
Postek E., GRAFEN – IPPT PAN COMPUTER OF BIOCENTRUM OCHOTA GRID, rozdział: Generic Models of Linear and Non-linear Visco-elastic Surface Deformation above a Fault, IPPT Reports on Fundamental Technological Research, Postek E., Kowalewski T.A. (Eds.), pp.92-101, 2014
3.
404
Postek E., GRAFEN – IPPT PAN COMPUTER OF BIOCENTRUM OCHOTA GRID, rozdział: Reliability Analysis of Reinforced Concrete Structures, IPPT Reports on Fundamental Technological Research, Postek E., Kowalewski T.A. (Eds.), pp.105-127, 2014
4.
405
Postek E., GRAFEN – IPPT PAN COMPUTER OF BIOCENTRUM OCHOTA GRID, rozdział: Development of a Concept of an Agent-stress Model of a Tissue, IPPT Reports on Fundamental Technological Research, Postek E., Kowalewski T.A. (Eds.), pp.127-134, 2014

Prace konferencyjne
1.Postek E., Design Sensitivity of a Tensegrity Model of a Tissue, CMM 2011, 19th International Conference on Computer Methods in Mechanics, 2011-05-09/05-12, Warszawa (PL), pp.1-6, 2011

Streszczenie:

The design sensitivity algorithm for visco-elastic tensegrity structures is presented. We adopt Updated Lagrangian formulation. We have possibility of grouping of the design variables what is particularly useful in the case of hierarchical structures. In our case, the structure is the tissue built of elementary cells. The design sensitivity procedure is implemented with parallel solver.

Słowa kluczowe:

computational biology, tensegrity structures, design sensitivity

Afiliacje autorów:

Postek E.-IPPT PAN
2.Postek E., Sadowski T., Description of the Behaviour of Cellular Composite with Weak Filling Material, IUTAM Symposium on Mechanical Properties of Cellular Materials, 2007-09-17/09-20, Cachan (FR), pp.181-188, 2009
3.Sadowski T., Postek E., An influence of the elastic properties of composite components on the mechanical response of polycrystalline structures at yield level, IUTAM Symposium on Scaling in Solid Mechanics, 2007-06-25/06-29, Cardiff (GB), DOI: 10.1007/978-1-4020-9033-2_19, pp.199-208, 2009

Streszczenie:

The aim of this paper is to present a constitutive model in the case of an uniaxial tension of the polycrystalline materials including the inter-granular metallic layers, creating its internal structure. The paper is focused on the discussion of the elastic properties of a composite components influence on the overall material response. The effective continuum model was applied to get the constitutive relations. Representative Volume Element (RVE) was analysed taking into consideration an initial internal structure of the material obtained from SME photographs. Owing to a high complexity of the internal structure of the composite material, FEA technique was used to get macroscopic stress-strain correlations. They include gradual changes of the internal structure of the material due to porosity and cracks development under tension.

Słowa kluczowe:

Polycrystalline ceramics, inter-granular layers, different elastic properties of components

Afiliacje autorów:

Sadowski T.-Lublin University of Technology (PL)
Postek E.-IPPT PAN
4.Postek E.W., Smallwood R., House R., Nodal positions displacement sensitivity of an elementary icosahedral tensegrity structure, COMPLAS X, X International Conference on Computational Plasticity, 2009-09-02/09-04, Barcelona (ES), pp.1-4, 2009
5.Postek E., Sadowski T., Denis C., Modelling of metallic inter-granular layers in polycrystalline ceramics, BMC 8, 8th International Symposium on Brittle Matrix Composites, 2005-10-23/10-25, Warszawa (PL), pp.495-506, 2006
6.Postek E., Sadowski T., Hardy S., Numerical modelling of mechanical response of a two-phase composite, IUTAM Symposium on Multiscale Modelling of Damage and Fracture Processes in Composite Materials, Lublin University of Technology, 2005-05-23/05-27, Kazimierz Dolny (PL), pp.193-200, 2006
7.Postek E.W., Hardy S.J., Dłużewski P., Stress analysis of a quantum dot region using an elastic anisotropic model, Plasticity 2006, 12th International Symposium on Plasticity and Its Current Applications, 2006-07-17/07-22, Halifax (CA), pp.304-306, 2006
8.Postek E.W., Hardy S.J., Sadowski T., Finite strain behaviour of a polycrystalline ceramic composite with intergranular layers, Plasticity 2006, 12th International Symposium on Plasticity and Its Current Applications, 2006-07-17/07-22, Halifax (CA), pp.205-207, 2006
9.Ahmad R., Gethin D.T., Lewis R.W., Ransing R.S., Postek E.W., Thermal optimisation of the squeeze-forming process using genetic algorithms, 3rd M.I.T Conference on Computational Fluid and Solid Mechanics, 2005-06-14/06-17, Boston (US), pp.1205-1208, 2005
10.Lewis R.W., Postek E.W., Gethin D.T., Ransing R.S., A model of microstructural solidification during mould filling for squeeze forming processes, 4th International Conference on Computational Heat and Mass Transfer, 2005-05-17/05-20, Cachan (FR), pp.1122-1125, 2005
11.Postek E.W., Lewis D.T., Gethin R.S., Ransing R.S., Celentano D.J., Stress analysis of squeeze forming processes, Plasticity 2005, 11th International Symposium on Plasticity, 2005-01-04/01-08, Kauai (US), pp.136-138, 2005

Abstrakty konferencyjne
1.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

Streszczenie:

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.

Słowa kluczowe:

cermet composites, coupled solutions, thermomechanics

Afiliacje autorów:

Postek E.-IPPT PAN
Sadowski T.-Lublin University of Technology (PL)
2.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

Streszczenie:

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].

Słowa kluczowe:

thermomechanics, coupled problems, composites

Afiliacje autorów:

Postek E.-IPPT PAN
Sadowski T.-Lublin University of Technology (PL)
3.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

Streszczenie:

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.

Słowa kluczowe:

foams, damage, impact, peridynamics

Afiliacje autorów:

Postek E.-IPPT PAN
Nowak Z.-IPPT PAN
Pęcherski R.-IPPT PAN
4.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

Streszczenie:

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].

Słowa kluczowe:

computational biology, tumor growth

Afiliacje autorów:

Postek E.-IPPT PAN
5.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
6.Postek E., Sadowski T., Impact Models of WC-Co Composite, CERMODEL 2017Modelling and Simulation Meet Innovation in Ceramics Technology, 2017-07-26/07-28, Trento (IT), pp.1, 2017
7.Postek E., Sadowski T., A Crack Model Around Junctions in WC/Co Composite, SolMech 2016, 40th Solid Mechanics Conference, 2016-08-29/09-02, Warszawa (PL), pp.1, 2016

Słowa kluczowe:

Metal-Ceramic Composite, Interface Elements, Crack Propagation at Composite Junctions

Afiliacje autorów:

Postek E.-IPPT PAN
Sadowski T.-Lublin University of Technology (PL)
8.Postek E., Dubois F., Mozul R., Canadas P., Modelling of a Collection of Non-Rigid Particles with Smooth Discrete Element Method, SolMech 2016, 40th Solid Mechanics Conference, 2016-08-29/09-02, Warszawa (PL), pp.1, 2016

Słowa kluczowe:

cell mechanics, smooth discrete element method, finite element method, finite motions

Afiliacje autorów:

Postek E.-IPPT PAN
Dubois F.-Université de Montpellier (FR)
Mozul R.-Université de Montpellier (FR)
Canadas P.-Université de Montpellier (FR)
9.Postek E., Parameter sensitivity of a single layer tensegrity modelled tissue, Mecánica Computacional, ISSN: 2591-3522, Vol.XXXIII, No.43, pp.2797, 2014
10.Postek E., A survey of tensegrity models of cells with design sensitivity analysis, III National Conference of Nano and Micromechanics, 2012-07-04/07-06, Warszawa (PL), pp.44-45, 2012
11.Postek E., Dubois F., Mozul R., Modeling of a collection of tensegrity particles with a nonsmooth discrete element method, SolMech 2012, 38th Solid Mechanics Conference, 2012-08-27/08-31, Warszawa (PL), pp.28-29, 2012
12.Postek E., Caliendo C., Latino P.M., Numerical model of ALN-based bulk acoustic high-frequency resonators, SolMech 2012, 38th Solid Mechanics Conference, 2012-08-27/08-31, Warszawa (PL), pp.316-317, 2012
13.Postek E., Concept of an Agent-stress Model of a Tissue, 2nd International Conference on Material Modelling, 2012-08-31/09-02, Paryż (FR), pp.297, 2011
14.Postek E., Smallwood R., Hose R., Finite deformation based model of cytoskeleton, ICCB2009, IV International Congress on Computational Bioengineering including the first European Symposium on Biomedical Integrative Research , 2009-09-16/09-18, Bertinoro (IT), DOI: 10.6092/unibo/amsacta/2646, pp.53-53, 2009

Streszczenie:

The cytoskeleto is modelled as a tensegrity structure. It consists of tendons and struts [Stamenovic, 2005]. The basic tensegrity structures are developed from icosahedron.
The cells undergo finite deformations behaviour and their response to loading conditions is visco-elastic,
These types of structures are sensitive to initial prestressing what it intuitively natural since without the initial stress state they would not exist, The other factors affecting the mechanical behaviour of the cell are constitutive parameters and positions of the nodes, in fact, the shape of the cell.

Słowa kluczowe:

cytoskeleton, visco-elasticity, finite strains, prestressing

Afiliacje autorów:

Postek E.-IPPT PAN
Smallwood R.-other affiliation
Hose R.-other affiliation
15.Postek E., Parallel version of a design sensitivity tensegrity code, TAM 2009, Transnational Access Meeting, HPC-Europa2 2009, 2009-10-14/10-16, Montpellier (FR), pp.1-1, 2009

Streszczenie:

The cytoskeleton is a tensegrity structure, The mechanics is important to the cells: "change the mechanical stresses on cancer cells and they can start to behave like healthy ones" [1] . The displacements and stresses change in the biological materials due to the growth, division and death of the cells. The cells receive signals for the actions. This constitutes the agent-stress based models of the tissue. [1] C. Ainsworth. Stretvhing the examination, Nature, 456, Dec., 696-699, 2008.

Słowa kluczowe:

cell mechanics, signals, design sensitivity

Afiliacje autorów:

Postek E.-IPPT PAN
16.Postek E.W., Houseman G.A., Jimack P.K., Aspects of Non-Newtonian Viscoelastic Deformation Produced by Slip on a Major Strike- slip Fault, AGU FALL MEETING 2008, American Geophysical Union Fall Meeting 2008, 2008-12-15/12-19, San Francisco (US), pp.1-1, 2008

Streszczenie:

Non-Newtonian flow occurs in crustal deformation processes on the long
timescales associated with large- scale continental deformation, and also
on the short time-scales associated with post-seismic deformation. The
co-seismic displacement is determined by the instantaneous elastic
response of the rocks on either side of the fault surface to the
distribution of slip on the surface of the fault. The post-seismic
deformation is determined by some combination of visco-elastic relaxation
of the medium and post-seismic creep on the fault. The response of the
crust may depend on elastic moduli, Poisson's ratio, temperature, pressure
and creep function parameters including stress exponent, activation
energy, activation volume and viscosity coefficient. We use the von Mises
function in describing the non-linear Maxwell visco-elastic creep models.
In this study we examine a model of a strike-slip fault crossing a 3D
block. The fault slips at time zero, and we solve for the viscoelastic
deformation field throughout the 3D volume using a 3D finite element
method. We perform parametric studies on the constitutive equation by
varying these parameters and the depth of the fault event. Our findings
are focused on the fact that the system is very sensitive to the above
mentioned parameters. In particular, the most important seems to be the
temperature profiles and stress exponent. The activation energy and the
pressure are of lower importance, however, they have their meaning. We
investigated the relaxation times and the deformation patterns. We took
the material properties as typical to dry quartzite and diabase. Depending
on the parameters the surface can be deformed permanently or the
deformation can decrease. We attempt to compare qualitatively the
calculated post-seismic response in terms of the post-seismic displacement
history of the earth's surface with InSAR patterns determined from recent
major strike-slip earthquakes. Quantitative comparison of the observations
with these numerical model results can in principle provide a better
understanding of the physical properties of the sub-surface and further
insight into the diagnostic properties of the earthquake cycles of major
fault systems.

Cite as: Author(s) (2008), Title, Eos Trans. AGU, 89(53), Fall Meet.
Suppl., Abstract T44B-07

Słowa kluczowe:

rheology, crust, litosphere

Afiliacje autorów:

Postek E.W.-IPPT PAN
Houseman G.A.-University of Leeds (UK)
Jimack P.K.-University of Leeds (UK)
17.Postek E.W., Houseman G.A., Jimack P.K., Generic Models of Linear and Non-linear Visco-elastic Surface Deformation above a Fault, EGU 2008, European Geosciences Union General Assembly 2008, 2008-04-13/04-18, Vienna (AT), pp.1-1, 2008

Streszczenie:

The ground displacements measured in the vicinity of a large strike-slip earthquake are
potentially important in diagnosing the state of stress on the fault and in the medium
surrounding. The co-seismic displacement is determined by the immediate elastic response
of the medium and the slip function on the fault-surface. The post-seismic
displacement is determined by a combination of post-seismic creep on the fault, viscoelastic
relaxation in the surrounding medium, and possibly poro-elastic deformation.
There are strong indications from previous earthquake studies that the visco-elastic
relaxation involves non-linear mechanisms, which produce faster deformation in the
early stages and slower deformation in the later stages than would occur with a linear
creep mechanism. In this study we examine a simplified model of a strike-slip fault
cutting a 3D block, and compute the surface displacement versus time functions for
a range of different constitutive relations. We examine linear and non-linear Maxwell
visco-elasticity, and compare with the generalized linear Maxwell visco-elasticity. The
effect of non-linearities in the elasticity (finite strain theory) is also considered.We use
the von Mises flow function in describing the non-linear Maxwell visco-elastic creep
models in which viscous creep strain-rate is proportional to the nth power of the deviatoric
stress (formulated using the 2nd invariant of the stress tensor). We describe
analytical solutions used to validate the 3D code, and then consider the effect of the
exponent n on the time histories of the surface displacement fields above the fault.
We aim here to compare these numerical models with observations from actual fault
systems obtained using InSAR and GPS data. Among the factors affecting the surface deformation patterns are near-surface layering, and lateral variation of material
properties, as well as irregularities on the fault surface. In principle, the comparison
of observations with theory should provide a better understanding of the physical response
of the sub-surface, together with a better understanding of the earthquake cycle
as it operates on specific fault systems.

Słowa kluczowe:

surface deformation, seismic cycle, visco-elasticity, numerical models

Afiliacje autorów:

Postek E.W.-other affiliation
Houseman G.A.-University of Leeds (UK)
Jimack P.K.-University of Leeds (UK)
18.Postek E., Houseman G.A., Jimack P.K., Surface deformation during earthquake cycle for a layered visco-elastic crust, Ada Lovelace Workshops on Modelling Mantle and Lithosphere Dynamics 10th International Workshop on Modeling of Mantle Convection and Lithospheric Dynamics, 2007-09-02/09-07, Carry-le-Rouet (FR), pp.1, 2007

Słowa kluczowe:

surface deformation, viso-elasticity, seismic cycle

Afiliacje autorów:

Postek E.-other affiliation
Houseman G.A.-University of Leeds (UK)
Jimack P.K.-University of Leeds (UK)
19.Postek E.W., Houseman G.A., Jimack P.K., The effect of geometrical nonlinearity in visco-elastic deformation, EGU 2007, European Geosciences Union, General Assembly 2007, 2007-04-15/04-20, Vienna (AT), No.9, pp.03087, 2007
20.Postek E., Houseman G.A., Jimack P.K., Nonlinear effects during post-seismic visco-elastic deformation, IUGG XXIV 2007, International Union of Geodesy and Geophysics General Assembly Earth, Our Changing Planet, 2007-07-02/07-13, Perugia (IT), No.JGS003, pp.207, 2007

Słowa kluczowe:

deformation, viscosity, power law

Afiliacje autorów:

Postek E.-other affiliation
Houseman G.A.-University of Leeds (UK)
Jimack P.K.-University of Leeds (UK)