2026-01-27
S. Nishad, K.P. Madasu
The present study examines the thermophoresis of a cylindrical particle in a direction perpendicular to its axis in the Brinkman medium. To describe the behaviour of micropolar fluid driven by a thermal gradient within such a porous medium, the modified Brinkman’s equation is applied while considering low Reynolds and Péclet numbers. The governing equations for both the particle and the medium are solved using the separation of variables technique. The boundary conditions applied at the particle surface are thermal jump and heat flux continuity, with viscous slip, thermal creep, thermal stress slip and microrotation slip. The main objective of the research is to derive the expressions for thermophoretic velocity and thermophoretic force of a cylindrical particle. Graphical representations illustrate the thermophoretic velocity and force of the particle for various physical parameters, including the permeability, micropolarity parameter, thermal stress slip parameter, viscous slip parameter, Knudsen number, and thermal conductivity parameters. The results show that an increase in the micropolarity parameter decreases both the thermophoreti velocity and the force. Additionally, thermophoretic velocity increases with higher permeability, while the thermophoretic force decreases with increasing permeability and the thermal conductivity ratio. The findings of this research align with previously published studies and hold potential applications in industrial processes, including filtration, heat exchangers, air cleaning, and manufacturing thermal precipitators.
2025-10-22
J. Rojek
This issue of the Archives of Mechanics contains a selection of papers presented at the 43rd Solid Mechanics Conference (SolMech 2024) held in Wrocław, 16–18 September 2024.
2025-10-22
K. Cichocki, F.J. Dominguez-Gutierrez, E. Wyszkowska, L. Kurpaska, K. Muszka
We performed molecular dynamics simulations to investigate the mechanical response of face-centered cubic (FCC) nickel under uniaxial compression and nanoindentation using traditional interatomic potentials, including the embedded atom method (EAM) and the modified embedded atom method (MEAM). By calculating the generalized stacking fault energy (GSFE), we analyzed the dissociated slip paths responsible for stacking fault formation and partial Shockley dislocations during mechanical loading. Our findings highlight the critical importance of selecting appropriate interatomic potentials to model compression and nanoindentation tests accurately, aligning simulations with experimental observations. We propose a practical methodology for identifying empirical interatomic potentials suitable for mechanical testing of single-element materials. This approach establishes a benchmark for FCC nickel simulations and provides a basis for extending these methods to more complex Ni-based alloys, facilitating comparisons with experimental results such as those from electron microscopy.
2025-10-22
B. Wcisło, J. Pamin, K. Kowalczyk-Gajewska, A. Menzel
The paper deals with the notion of stability for thermo-elastoplastic materials undergoing large strains. The stability analysis is performed by using the perturbation approach applied to a comprehensive material model derived in a thermodynamic format. As the main contribution of this paper a stability condition for a material model incorporating geometrical and material non-linearities under full thermo-mechanical coupling, without typical simplifying assumptions, is derived, and a hybrid analytical-numerical verification of the stability condition at a material point is investigated for the three-dimensional case. Special emphasis is placed on the quasi-static case, for which a specific stability criterion is derived. The theoretical analysis is followed by the numerical verification of the obtained condition. The implementation of the model in the finite element method, using the numerical-symbolic package AceGen, is also presented in the paper. Two representative three-dimensional examples are solved, namely a cube under simple shear and a plate with imperfection, subjected to tension. The obtained results reveal that the type of softening, i.e., thermal or material softening, has a significant influence on the stability at a material point level.
2025-07-13
K.R. Rajagopal, A. Wineman, P. Alagappan
In this short paper, we extend the seminal study by Berker [4] of pseudoplanar flows that occur in an orthogonal rheometer, essentially two parallel disks rotating about non-coincident axes at the top and bottom, to the case of an electroactive elastic solid. We obtain the expression for the stress, which is a function of the deformation as well as the electric field, in an electroactive elastic solid using standard representation theorems. We show that in the case of elastic solids, pseudoplanar displacements can take place, with each layer z = constant rotating about a distinct center of rotation. We determine the nature of the locus of the centers of rotation, which can take on profiles that are distinctly different, based on the nature of the electric field, the applied pressure gradient and the rotation of the top and bottom plates.
2025-06-01
A. Menasria, R. Slimani, A. Bouhadra, S. Refrafi, M. Chitour, M. Ali Rachedi, N. Himeur, K. Zerari
This study introduces a simplified approach to assess the buckling and static bending of advanced composite beams, including those composed of functionally graded materials (FGMs) with various porosity models. The technique utilizes a straightforward integral quasi-3D approach based on the advanced shear deformation theory. This approach offers several advantages: it simplifies the analysis by reducing the number of unknowns and equations required, improves accuracy by considering the stretch effect across the entire depth of the beam, resulting in more reliable results, and accurately represents shear by satisfying the zero-traction boundary conditions on the beam’s surfaces without the need for a shear correction factor. Additionally, it captures the parabolic pattern of transverse shear strain and stress throughout the depth of the beam. The governing equations are obtained by applying the concept of virtual work, and the Navier solution is employed to calculate analytical solutions for the buckling and static bending of FGM porous beams under different boundary conditions. The approach is in line with and builds upon existing research on FGMs and other sophisticated composite beams, further enhancing its validity and reliability. Finally, computational analyses demonstrate how the distribution of materials, such as power-law functionally graded materials (FGMs), geometry, and porosity, affect the deflections, stresses, and critical buckling load of the beam.
2013-01-03
B. Amirian, R. Hosseini-Ara, H. Moosavi
This paper presents a new model to consider the thermal effects, Pasternak's shear foundation, transverse shear deformation and rotary inertia on vibration analysis of a single-walled carbon nanotube. Nonlocal elasticity theory is implemented to investigate the small-size effect on thermal vibration response of an embedded carbon nanotube. Based on Hamilton's principle, the governing equations are derived and then solved analytically, in order to determine the nonlocal natural frequencies. Results show that unlike the Pasternak foundation, the influence of Winkler's constant on nonlocal frequency is negligible for low temperature changes. Moreover, the nonlocal frequencies are always smaller as compared to their local counterparts. In addition, in high shear modulus along with an increase in aspect ratio, the nonlocal frequency decreases.
2011-02-27
J. Jamali, M.H. Naei, F. Honarvar, M. Rajabi
In this paper, the method of wave function expansion is adopted to study the scattering of a plane harmonic acoustic wave incident upon an arbitrarily thick-walled, functionally graded cylindrical shell submerged in and filled with compressible ideal fluids. A laminate approximate model and the so-called state space formulation in conjunction with the classical transfer matrix (T-matrix) approach, are employed to present an analytical solution based on the three-dimensional exact equations of elasticity. Three models, representing the elastic properties of FGM interlayer are considered. In all models, the mechanical properties of the graded shell are assumed to vary smoothly and continuously with the change of volume concentrations of the constituting materials across the thickness of the shell. In the first two models, the rule of mixture governs. The main difference between them is the set of elastic constants (e.g., Lamé's constants in model I and Young's modulus and Poisson's ratio in Model II) which are governed by the rule of mixtures. In the third model, an elegant self-consistent micromechanical model which assumes an interconnected skeletal microstructure in the graded region is employed. Particular attention is paid to backscattered acoustic response of these models in a wide range of frequency and for different shell wall-thicknesses. The results reveal a technical comparison between these models. In addition, by examining various cases (i.e., different shell wall-thicknesses, various profiles of variations and different volume concentration of constituents), the impact of the overall volume concentration of constituents and also the profile of variations, on the resonant response of the graded shell is investigated. Limiting cases are considered and good agreement with the solutions available in the literature is obtained.