Eligiusz Postek, Ph.D., Dr. Habil., Eng.

Department of Information and Computational Science (ZIiNO)
Division of Computational Analysis of Advanced Structures (ZeKAZK)
position: specialist
telephone: (+48) 22 827 46 92
telephone: (+48) 22 826 12 81 ext.: 131
room: 412
e-mail: epostek

Doctoral thesis
1997-06-26Numeryczna analiza wrażliwości na parametry projektowe dużych nieliniowych układów konstrukcyjnych 
supervisor -- Prof. Michał Kleiber, Ph.D., Dr. Habil., Eng., IPPT PAN
533 
Habilitation thesis
2014-09-25Modelowanie numeryczne problemów sprzężonych wraz z paralelizacją 
Supervision of doctoral theses
1.2006
co-supervisor
Rosli Ahmad  
(Swansea UW)
Optimisation of the squeeze forming process 
2.2004
co-supervisor
Luo Chouping  
(Lulea UT)
Finite elements based on the piece-wise linear weight functions in contact problems 

Recent publications
1.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
Abstract:

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.

Keywords:

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

Affiliations:
Postek E.-IPPT PAN
Sadowski T.-other affiliation
2.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
Abstract:

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.

Keywords:

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

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

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.

Affiliations:
Postek E.-IPPT PAN
4.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
Abstract:

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

Keywords:

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

Affiliations:
Postek E.W.-IPPT PAN
Sadowski T.-other affiliation
5.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
Keywords:

Finite element analysis, Thermodynamics, Material‐deforming processes

Affiliations:
Postek E.W.-other affiliation
Lewis R.W.-University of Wales (GB)
Gethin D.T.-University of Wales Swansea (UK)
6.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
7.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
8.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
9.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
10.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

List of chapters in recent monographs
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
Editor of monographs
1.
370
Postek E., Kowalewski T.A., GRAFEN – IPPT PAN COMPUTER OF BIOCENTRUM OCHOTA GRID, IPPT Reports on Fundamental Technological Research, 3, pp.1-164, 2014

Conference papers
1.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
Abstract:

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.

Keywords:

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

Affiliations:
Sadowski T.-other affiliation
Postek E.-IPPT PAN
2.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
3.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
4.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
5.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
6.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
7.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
8.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
9.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
10.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

Conference abstracts
1.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
Keywords:

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

Affiliations:
Postek E.-IPPT PAN
Sadowski T.-other affiliation
2.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
Keywords:

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

Affiliations:
Postek E.-IPPT PAN
Dubois F.-Université de Montpellier (FR)
Mozul R.-Université de Montpellier (FR)
Canadas P.-Université de Montpellier (FR)
3.Postek E., Parameter sensitivity of a single layer tensegrity modelled tissue, Mecánica Computacional, ISSN: 2591-3522, Vol.XXXIII, No.43, pp.2797, 2014
4.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
5.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
6.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
7.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