Instytut Podstawowych Problemów Techniki
Polskiej Akademii Nauk

Pracownicy

dr inż. Przemysław Sadowski

Zakład Mechaniki Materiałów (ZMM)
Zespół Modelowania Materiałów (ZeMM)
stanowisko: adiunkt
telefon: (+48) 22 826 12 81 wewn.: 453
pokój: 140
e-mail:
ORCID: 0000-0001-7699-4222

Doktorat
2009-02-26 Modelowanie przepływu ciepła przez powierzchnię kontaktu ciał chropowatych w procesach przeróbki plastycznej 
promotor -- dr hab. inż. Stanisław Stupkiewicz, IPPT PAN
 

Ostatnie publikacje
1.  Rezaee-Hajidehi M., Sadowski P., Stupkiewicz S., Deformation twinning as a displacive transformation: Finite-strain phase-field model of coupled twinning and crystal plasticity, JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS, ISSN: 0022-5096, DOI: 10.1016/j.jmps.2022.104855, Vol.163, pp.104855-1-30, 2022

Streszczenie:
A finite-strain phase-field model of coupled deformation twinning and crystal plasticity is developed in the paper. Twinning is treated as a displacive transformation characterized by a volume-preserving stretch rather than a simple shear, the latter considered in the conventional approach. It is shown that the two approaches are equivalent in the sharp-interface description, but not in the diffuse-interface description. In the proposed stretch-based kinematics, each pair of conjugate twinning systems is represented by a single twin deformation variant, and thus a single order parameter suffices to consistently describe the two conjugate twinning systems, thereby treating them equally. The model is formulated in the framework of incremental energy minimization, which, upon time discretization, leads to a quasi-optimization problem due to the specific form of the incremental potential within the diffuse interfaces. To facilitate finite-element implementation, a micromorphic formulation of the model is employed. As an application, tensile twinning in HCP magnesium alloys is examined, and a set of comprehensive 2D plane-strain problems is studied to illustrate the features of the proposed approach.

Słowa kluczowe:
deformation twinning, microstructure, phase-field method, crystal plasticity, magnesium alloy

Afiliacje autorów:
Rezaee-Hajidehi M. - IPPT PAN
Sadowski P. - IPPT PAN
Stupkiewicz S. - IPPT PAN
140p.
2.  Sadowski P., Kowalczyk-Gajewska K., Stupkiewicz S., Spurious softening in the macroscopic response predicted by the additive tangent Mori–Tanaka scheme for elastic–viscoplastic composites, EUROPEAN JOURNAL OF MECHANICS A-SOLIDS, ISSN: 0997-7538, DOI: 10.1016/j.euromechsol.2021.104339, Vol.90, pp.104339-1-17, 2021

Streszczenie:
The Mori–Tanaka (MT) scheme is a well-established mean-field model that combines simplicity and good predictive capabilities. The additive tangent MT scheme is a popular variant of the method that is suitable for elastic–viscoplastic composites. This work is concerned with the analysis of some intrinsic features of the additive tangent MT scheme, in particular, of spurious softening in the macroscopic response that may be encountered when the Perzyna-type viscoplasticity model is used. The resulting non-monotonic macroscopic stress–strain response is clearly non-physical, but it also has a negative impact on the efficiency and robustness of the MT model when it is used as a local constitutive model in concurrent multiscale finite-element computations. As shown in the paper, the spurious softening is more pronounced when the so-called soft isotropization is employed to compute the viscoplastic Hill tensor, but it is also observed, although for a much narrower range of material parameters, in the case of the hard isotropization and when no isotropization is applied. Moreover, the softening is promoted at low strain rates, for high elastic contrast, and for high volume fractions of inclusions. Nevertheless, if the soft isotropization is avoided, the additive tangent MT scheme proves to be a feasible and computationally robust mean-field model that can be successfully employed in finite-element computations.

Słowa kluczowe:
mean-field homogenization, Mori–Tanaka method, isotropization, composite materials, viscoplasticity

Afiliacje autorów:
Sadowski P. - IPPT PAN
Kowalczyk-Gajewska K. - IPPT PAN
Stupkiewicz S. - IPPT PAN
100p.
3.  Sadowski P., Stupkiewicz S., Friction in lubricated soft-on-hard, hard-on-soft and soft-on-soft sliding contacts, TRIBOLOGY INTERNATIONAL, ISSN: 0301-679X, DOI: 10.1016/j.triboint.2018.08.025, Vol.129, pp.246-256, 2019

Streszczenie:
Friction in lubricated soft contacts is examined using a ball-on-disc tribometer with the focus on the effect of configuration. In the soft-on-hard and hard-on-soft configurations, one of the contact-pair members is soft while the other one is hard. In the soft-on-soft configuration, both members are soft. For a soft disc, time-dependent viscoelastic deformations contribute to friction. Upon correction for the hysteretic losses, estimated using a theoretical model, the friction coefficient in the full-film regime does not depend on configuration. This holds also for high loads, when the deformations are finite. The combined effect of configuration and surface roughness on the transition from the full-film to the mixed lubrication regime is also examined.

Słowa kluczowe:
soft-EHL, mixed lubrication, surface roughness, finite deformation

Afiliacje autorów:
Sadowski P. - IPPT PAN
Stupkiewicz S. - IPPT PAN
200p.
4.  Sadowski P., Kowalczyk-Gajewska K., Stupkiewicz S., Consistent treatment and automation of the incremental Mori–Tanaka scheme for elasto-plastic composites, COMPUTATIONAL MECHANICS, ISSN: 0178-7675, DOI: 10.1007/s00466-017-1418-z, Vol.60, pp.493-511, 2017

Streszczenie:
A consistent algorithmic treatment of the incremental Mori–Tanaka (MT) model for elasto-plastic composites is proposed. The aim is to develop a computationally efficient and robust micromechanical constitutive model suitable for large-scale finite-element computations. The resulting overall computational scheme is a doubly-nested iteration-subiteration scheme. The Newton method is used to solve the nonlinear equations at each level involved. Exact linearization is thus performed at each level so that a quadratic convergence rate can be achieved. To this end, the automatic differentiation (AD) technique is used, and the corresponding AD-based formulation is provided. Excellent overall performance of the present MT scheme in threedimensional finite-element computations is illustrated.

Słowa kluczowe:
Mori–Tanaka method, Composite materials, Elasto-plasticity, Finite element method, Automatic differentiation

Afiliacje autorów:
Sadowski P. - IPPT PAN
Kowalczyk-Gajewska K. - IPPT PAN
Stupkiewicz S. - IPPT PAN
45p.
5.  Sadowski P., Kowalczyk-Gajewska K., Stupkiewicz S., Response discontinuities in the solution of the incremental Mori–Tanaka scheme for elasto-plastic composites, ARCHIVES OF MECHANICS, ISSN: 0373-2029, Vol.69, No.1, pp.3-27, 2017

Streszczenie:
The incremental Mori–Tanaka model of elasto-plastic composites is discussed, and the corresponding finite-step formulation is shown to lead to discontinuities in the overall response at the instant of elastic-to-plastic transition in the matrix. Specifically, two situations may be encountered: the incremental equations may have two solutions or no solution. In the former situation, switching between the two solutions is associated with a jump in the overall stress. Response discontinuities are studied in detail for a special case of proportional deviatoric loading. The discontinuities constitute an undesirable feature of the incremental Mori–Tanaka scheme that apparently has not been discussed in the literature so far. Remedies to the related problems are briefly discussed.

Słowa kluczowe:
mean-field homogenization, Mori–Tanaka method, incremental scheme, composite materials, elasto-plasticity

Afiliacje autorów:
Sadowski P. - IPPT PAN
Kowalczyk-Gajewska K. - IPPT PAN
Stupkiewicz S. - IPPT PAN
25p.
6.  Stupkiewicz S., Lengiewicz J., Sadowski P., Kucharski S., Finite deformation effects in soft elastohydrodynamic lubrication problems, TRIBOLOGY INTERNATIONAL, ISSN: 0301-679X, DOI: 10.1016/j.triboint.2015.03.016, Vol.93, pp.511-522, 2016

Streszczenie:
Soft elastohydrodynamic lubrication regime is typical for many elastomeric and biological contacts. As one or both contacting bodies are then highly compliant, relatively low contact pressures may lead to large deformations which are neglected in the classical EHL theory. In the paper, the related finite-deformation effects are studied for two representative soft-EHL problems. To this end, a fully-coupled nonlinear formulation has been developed which combines finite-strain elasticity for the solid and the Reynolds equation for the fluid, both treated using the finite element method with full account of all elastohydrodynamic couplings. Results of friction measurements are also reported and compared to theoretical predictions for lubricated contact of a rubber ball sliding against a steel disc under high loads.

Słowa kluczowe:
Soft-EHL problem, Finite deformation, Finite element method, Monolithic scheme

Afiliacje autorów:
Stupkiewicz S. - IPPT PAN
Lengiewicz J. - IPPT PAN
Sadowski P. - IPPT PAN
Kucharski S. - IPPT PAN
35p.
7.  Sadowski P., Kowalczyk-Gajewska K., Stupkiewicz S., Classical estimates of the effective thermoelastic properties of copper–graphene composites, COMPOSITES PART B-ENGINEERING, ISSN: 1359-8368, DOI: 10.1016/j.compositesb.2015.06.007, Vol.80, pp.278-290, 2015

Streszczenie:
Significant research effort is concentrated worldwide on development of graphene-based metal-matrix composites with enhanced thermomechanical properties. In this work, we apply two classical micromechanical mean-field theories to estimate the effective thermoelastic properties that can be achieved in practice for a copper–graphene composite. In the modelling, graphene is treated as an anisotropic material, and the effect of its out-of-plane properties, which are less recognized than the in-plane properties, is studied in detail. To address the severe difficulties in processing of graphene-based metal-matrix composites, the copper–graphene composite is here assumed to additionally contain, due to imperfect processing, particles of graphite and voids. It is shown quantitatively that the related imperfections may significantly reduce the expected enhancement of the effective properties. The present predictions are also compared to the experimental data available in the literature.

Słowa kluczowe:
Metal-matrix composites (MMCs), Mechanical properties, Thermal properties, Micro-mechanics, Graphene

Afiliacje autorów:
Sadowski P. - IPPT PAN
Kowalczyk-Gajewska K. - IPPT PAN
Stupkiewicz S. - IPPT PAN
40p.
8.  Sadowski P., Stupkiewicz S., Combined effect of friction and macroscopic deformation on asperity flattening, TRIBOLOGY INTERNATIONAL, ISSN: 0301-679X, DOI: 10.1016/j.triboint.2010.04.011, Vol.43, pp.1735-1741, 2010

Streszczenie:
The combined effect of friction and macroscopic plastic deformation on asperity flattening is studied. Crushing of a periodic array of wedge-like asperities is formulated as a rigid-viscoplastic periodic indentation problem with superimposed macroscopic deformation. A micromechanical framework is developed and the corresponding boundary value problem is solved using the finite element method. An anomalous regime of asperity flattening is predicted at low flattening rates, in which the effect of friction on asperity flattening is opposite to that observed in the absence of macroscopic deformation and also at high flattening rates. An incremental elastoplastic analysis confirms this finding.

Słowa kluczowe:
Asperity flattening, Real contact area, Surface layer, Metal forming

Afiliacje autorów:
Sadowski P. - IPPT PAN
Stupkiewicz S. - IPPT PAN
32p.
9.  Sadowski P., Stupkiewicz S., A model of thermal contact conductance at high real contact area fractions, WEAR, ISSN: 0043-1648, Vol.268, pp.77-85, 2010

Streszczenie:
Thermal contact conductance (TCC) is studied in the whole range of real contact area fractions between zero and unity. For this purpose, a two-scale model is developed in which the effective (macroscopic) TCC coefficient is obtained from the solution of the heat conduction problem at the scale of asperities. Additional thermal resistance at the real contact spots is included in the model. The model is applied for several real 3D roughness topographies for which the effective TCC coefficient is determined as a function of the real contact area fraction and the local TCC coefficient at real contact spots. An analytical function is found which approximates this relationship in the whole range of parameters, and a characteristic length-scale parameter is introduced which characterizes the effective TCC properties of a rough surface.

Słowa kluczowe:
Roughness topography, Real contact area, Thermal contact conductance, Characteristic length

Afiliacje autorów:
Sadowski P. - IPPT PAN
Stupkiewicz S. - IPPT PAN
32p.

Lista rozdziałów w ostatnich monografiach
1. 
Stupkiewicz S., Sadowski P., Analysis and simulation of contact problems, Lecture notes in applied and computational mechanics, rozdział: Micromechanical analysis of deformation and temperature inhomogeneities within rough contact layers, Springer, Wriggers P., Nackenhorst U. (Eds.), 27, pp.325-332, 2006

Abstrakty konferencyjne
1.  Rezaee-Hajidehi M., Sadowski P., Stupkiewicz S., Phase-Field Model for Spatially Resolved Deformation Twinning Coupled with Crystal Plasticity, IUTAM Symposium, IUTAM Symposium on Enhancing Material Performance by Exploiting Instabilities and Damage Evolution, 2022-06-05/06-10, Warszawa (PL), DOI: 10.24423/iutam2022warsaw, No.P029, pp.42-42, 2022
2.  Sadowski P., Kowalczyk-Gajewska K., Stupkiewicz S., Micromechanical modelling of elasto-plastic composites: efficient and robust finite-element implementation of Mori-Tanaka model, CNM, 5th Conference on Nano- and Micromechanics, 2017-07-04/07-06, Wrocław (PL), No.O-08, pp.31-33, 2017

Słowa kluczowe:
Mean-field homogenization, Mori-Tanaka method, Composite materials, Finite element method

Afiliacje autorów:
Sadowski P. - IPPT PAN
Kowalczyk-Gajewska K. - IPPT PAN
Stupkiewicz S. - IPPT PAN
3.  Sadowski P., Kowalczyk-Gajewska K., Stupkiewicz S., Efficient algorithmic treatment of the incremental Mori–Tanaka scheme for elasto-plastic composites, SolMech 2016, 40th Solid Mechanics Conference, 2016-08-29/09-02, Warszawa (PL), No.P070, pp.1-2, 2016
4.  Sadowski P., Kucharski S., Lengiewicz J., Stupkiewicz S., Soft elastohydrodynamic lubrication problems in the finite deformation regime: experimental testing and modelling, SolMech 2014, 39th Solid Mechanics Conference, 2014-09-01/09-05, Zakopane (PL), pp.323-324, 2014
5.  Sadowski P., Stupkiewicz S., Estimation of the effective properties of composites with inclusions of diverse shapes and properties, SolMech 2014, 39th Solid Mechanics Conference, 2014-09-01/09-05, Zakopane (PL), pp.139-140, 2014
6.  Lengiewicz J., Sadowski P., Stupkiewicz S., Finite element modelling of elastohydrodynamic lubrication in the finite deformation regime, SolMech 2014, 39th Solid Mechanics Conference, 2014-09-01/09-05, Zakopane (PL), pp.43-44, 2014

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