1. |
Majewski M., Wichrowski M., Hołobut P., Kowalczyk-Gajewska K., Shape and packing effects in particulate composites: micromechanical modelling and numerical verification,
ARCHIVES OF CIVIL AND MECHANICAL ENGINEERING, ISSN: 1644-9665, DOI: 10.1007/s43452-022-00405-9, Vol.22, pp.86-1-22, 2022 Streszczenie: The aim of this study is to analyse the joint effect of reinforcement shape and packing on the effective behaviour of particulate composites. The proposed semi-analytical modelling method combines the Replacement Mori–Tanaka scheme, by means of which the concentration tensors for non-ellipsoidal inhomogeneities are found numerically, and the analytical morphologically representative pattern approach to account for particle packing. Five shapes of inhomogeneities are selected for the analysis: a sphere, a prolate ellipsoid, a sphere with cavities, an oblate spheroid with a cavity as well as an inhomogeneity created by three prolate spheroids crossing at right angles. Semi-analytical estimates are compared with the results of numerical simulations performed using the finite element method and with the outcomes of classical mean-field models based on the Eshelby solution, e.g. the Mori–Tanaka model or the self-consistent scheme. Słowa kluczowe: composite material, micromechanics, computational modelling, packing effect, shape effect Afiliacje autorów:
Majewski M. | - | IPPT PAN | Wichrowski M. | - | IPPT PAN | Hołobut P. | - | IPPT PAN | Kowalczyk-Gajewska K. | - | IPPT PAN |
|  | 140p. |
2. |
Kowalczyk-Gajewska K., Majewski M., Mercier S.♦, Molinari A.♦, Mean field interaction model accounting for the spatial distribution of inclusions in elastic-viscoplastic composites,
INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES, ISSN: 0020-7683, DOI: 10.1016/j.ijsolstr.2021.111040, Vol.224, pp.111040-1-17, 2021 Streszczenie: A cluster interaction model has been proposed to account for the spatial distribution and morphology of particles when estimating the effective properties of elastic and thermoelastic composites (Molinari and El Mouden, 1996). In the present paper this approach is extended to elastic-viscoplastic composites. To this end the tangent linearization of the non-linear viscoplastic law and the concept of additive interaction equation are used. Although the extension is formulated for the non-linear case, first applications are considered for linear viscoelastic composites, a situation rich enough to evaluate the interest of the cluster interaction approach. Results of the model are compared to numerical homogenization for periodic
unit cells with two cubic configurations. Słowa kluczowe: homogenization, the cluster interaction model, elastic-viscoplastic composite, spatial configuration of inclusions, interaction between inclusions Afiliacje autorów:
Kowalczyk-Gajewska K. | - | IPPT PAN | Majewski M. | - | IPPT PAN | Mercier S. | - | Clermont Université (FR) | Molinari A. | - | Université de Lorraine (FR) |
|  | 140p. |
3. |
Majewski M., Hołobut P., Kursa M., Kowalczyk-Gajewska K., Packing and size effects in elastic-plastic particulate composites: micromechanical modelling and numerical verification,
International Journal of Engineering Science, ISSN: 0020-7225, DOI: 10.1016/j.ijengsci.2020.103271, Vol.151, pp.103271-1-18, 2020 Streszczenie: The issue of applicability of the Morphologically Representative Pattern (MRP) approach to elastic-plastic composites is addressed. The extension to the regime of non-linear material behaviour is performed by employing the concept of incremental linearization of the material response in two basic variants: tangent and secant. The obtained predictions are evaluated through comparison with the outcomes of numerical analyses. Finite Element simulations are carried out using periodic unit cells with cubic arrangements of spherical particles and representative volume elements (RVE) with 50 randomly placed inclusions. In addition to the analysis of the packing effect in two-phase composites, the size effect is also studied by assuming an interphase between the matrix and inclusions. It is concluded that the MRP approach can be used as an effective predictive alternative to computational homogenization, not only in the case of linear elasticity but also in the case of elastic-plastic composites. Słowa kluczowe: particulate composites, elastoplasticity, micromechanics, size effect, packing effect, morphologically representative pattern Afiliacje autorów:
Majewski M. | - | IPPT PAN | Hołobut P. | - | IPPT PAN | Kursa M. | - | IPPT PAN | Kowalczyk-Gajewska K. | - | IPPT PAN |
|  | 200p. |
4. |
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 Streszczenie: 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. Słowa kluczowe: Composite materials, Elasticity, Micro-mechanics, Packing and size effects Afiliacje autorów:
Majewski M. | - | IPPT PAN | Kursa M. | - | IPPT PAN | Hołobut P. | - | IPPT PAN | Kowalczyk-Gajewska K. | - | IPPT PAN |
|  | 45p. |
5. |
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 Streszczenie: 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. Słowa kluczowe: shape memory polyurethane, thermomechanical couplings, infrared camera, temperature change, dynamic mechanical analysis, strain rate, constitutive model Afiliacje autorów:
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) |
|  | 40p. |