Michał Majewski, M.Sc., Eng.

Department of Mechanics of Materials (ZMM)
Division of Micromechanics of Materials (PMM)
position: doctoral student
telephone: (+48) 22 826 12 81 ext.: 435
room: 141
e-mail: mmajew

Recent publications
1.Majewski M., Kursa M., Hołobut P., Kowalczyk-Gajewska K., Micromechanical and numerical analysis of packing and size effects in elastic particulate composites, COMPOSITES PART B-ENGINEERING, ISSN: 1359-8368, DOI: 10.1016/j.compositesb.2017.05.004, Vol.124, pp.158-174, 2017
Abstract:

Effects of particle packing and size on the overall elastic properties of particulate random composites are analyzed. In order to account for the two effects the mean-field Morphologically Representative Pattern (MRP) approach is employed and an additional interphase surrounding inclusions (coating) is introduced. The analytical mean-field estimates are compared with the results of computational homogenization performed using the finite element (FE) method. Periodic unit cells with cubic crystal-type arrangements and representative volume elements with random distributions of particles are used for verification purposes. The validity of the MRP estimates with respect to the FE results is assessed.

Keywords:

Composite materials, Elasticity, Micro-mechanics, Packing and size effects

Affiliations:
Majewski M.-IPPT PAN
Kursa M.-IPPT PAN
Hołobut P.-IPPT PAN
Kowalczyk-Gajewska K.-IPPT PAN
2.Pieczyska E.A., Maj M., Kowalczyk-Gajewska K., Staszczak M., Gradys A., Majewski M., Cristea M., Tobushi H., Hayashi S., Thermomechanical properties of polyurethane shape memory polymer–experiment and modelling, SMART MATERIALS AND STRUCTURES, ISSN: 0964-1726, DOI: 10.1088/0964-1726/24/4/045043, Vol.24, pp.045043-1-16, 2015
Abstract:

In this paper extensive research on the polyurethane shape memory polymer (PU-SMP) is reported, including its structure analysis, our experimental investigation of its thermomechanical properties and its modelling. The influence of the effects of thermomechanical couplings on the SMP behaviour during tension at room temperature is studied using a fast and sensitive infrared camera. It is shown that the thermomechanical behaviour of the SMP significantly depends on the strain rate: at a higher strain rate higher stress and temperature values are obtained. This indicates that an increase of the strain rate leads to activation of different deformation mechanisms at the micro-scale, along with reorientation and alignment of the molecular chains. Furthermore, influence of temperature on the SMP's mechanical behaviour is studied. It is observed during the loading in a thermal chamber that at the temperature 20°C below the glass transition temperature (Tg) the PU-SMP strengthens about six times compared to the material above Tg but does not exhibit the shape recovery. A finite-strain constitutive model is formulated, where the SMP is described as a two-phase material composed of a hyperelastic rubbery phase and elastic-viscoplastic glassy phase. The volume content of phases is governed by the current temperature. Finally, model predictions are compared with the experimental results.

Keywords:

shape memory polyurethane, thermomechanical couplings, infrared camera, temperature change, dynamic mechanical analysis, strain rate, constitutive model

Affiliations:
Pieczyska E.A.-IPPT PAN
Maj M.-IPPT PAN
Kowalczyk-Gajewska K.-IPPT PAN
Staszczak M.-IPPT PAN
Gradys A.-IPPT PAN
Majewski M.-IPPT PAN
Cristea M.-Petru Poni Institute of Macromolecular Chemistry (RO)
Tobushi H.-Aichi Institute of Technology (JP)
Hayashi S.-SMP Technologies Inc. (JP)

Conference abstracts
1.Majewski M., Hołobut P., Kursa M., Kowalczyk-Gajewska K., Micromechanical modelling of packing and size effects in particulate elastic-plastic composites, SolMech 2016, 40th Solid Mechanics Conference, 2016-08-29/09-02, Warszawa (PL), No.P099, pp.1-2, 2016
2.Majewski M., Hołobut P., Kursa M., Kowalczyk-Gajewska K., Description of packing and size effects in particulate composites by micromechanical averaging schemes and computational homogenization, PCM-CMM 2015, 3rd Polish Congress of Mechanics and 21st Computer Methods in Mechanics, 2015-09-08/09-11, Gdańsk (PL), pp.571-572, 2015
Abstract:

Different approaches to model packing and size effects are studied to model overall properties of particulate composites of different morphological features of phase distribution. The micromechanical schemes originating in the composite sphere model and its extension by morphologically-based pattern approach are taken as a basis. Analytical predictions are compared with results of computational homogenization performed on the generated representative volume elements of prescribed statistical characteristics.

Keywords:

micromechanics, morphologically representative pattern, computational homogenization, size and scale effect

Affiliations:
Majewski M.-IPPT PAN
Hołobut P.-IPPT PAN
Kursa M.-IPPT PAN
Kowalczyk-Gajewska K.-IPPT PAN
3.Kowalczyk-Gajewska K., Pieczyska E.A., Maj M., Staszczak M., Majewski M., Cristea M., Tobushi H., Two-phase model of shape memory polymers at finite strains: formulation and experimental verification, SolMech 2014, 39th Solid Mechanics Conference, 2014-09-01/09-05, Zakopane (PL), pp.259-260, 2014
Abstract:

A constitutive model of SMP, formulated at large strain format, is developed. SMP is described as a two-phase material composed of a soft rubbery phase and a hard glassy phase. The volume fraction of each phase is postulated as a logistic function of temperature. Identification of model parameters has been performed using the experimental tensile loading-unloading tests with different strain rates conducted at thermal chamber at different temperatures.

Keywords:

shape-memory polymers, two-phase model, large strain framework

Affiliations:
Kowalczyk-Gajewska K.-IPPT PAN
Pieczyska E.A.-IPPT PAN
Maj M.-IPPT PAN
Staszczak M.-IPPT PAN
Majewski M.-IPPT PAN
Cristea M.-Petru Poni Institute of Macromolecular Chemistry (RO)
Tobushi H.-Aichi Institute of Technology (JP)