arXiv subjects

Azdine Nait-Ali

Publications and source records attributed to Azdine Nait-Ali.

3 recordsLinked to original sources

arXiv2026

Variational modeling adapted to the medium with gradient properties

This study aims to develop a numerical homogenization method that can be applied to a heterogeneous stratified medium. Traditional scale transition methods are inadequate in capturing the essential gradient properties of some materials. Therefore, the focus of this work is to construct a homogenized model that considers the material property gradient. To achieve this, a two-step homogenization scheme is proposed. Firstly, the 3D model is decomposed into multiple 2D heterogeneous layers, and the behavior of each layer is estimated using a micro-mechanical model such as the Hashin-Shtrikman bounds. Secondly, a variational sum method is used to rebuild the behavior of the 3D environment. Finally, the method is applied to homogenize a thin plate with a porosity gradient.

math-ph↗

arXiv2021

Time resolved evolution of the 3D nanoporous structure of sintered Ag by X-Ray nanotomography: role of the interface with a copper substrate

The evolution of the nanoporous structure of cylindrical sintered silver samples during high temperature aging, ranging from 200 {\textdegree}C to 350 {\textdegree}C for 350 min, is studied through in-situ Computed X-Ray Tomography. Investigations were performed for two types of specimens: pure sintered silver and 2 specimens containing a silver-copper interface. It is shown that the overall pore evolution is driven by the evolution of very few large ones. The smaller pores, although being more numerous, do not really evolve before being absorbed by the few bigger ones. In pure silver, pore evolution is driven by diffusion (Ostwald ripening) but the presence of an interface promotes faster growth kinetics until the aging time reaches a threshold value, after which a deviation from Ostwald ripening occurs. The transition is a function of the aging temperature. This behavior is associated with the competition between elastic relaxation and surface energy minimization.

cond-mat.mtrl-sci↗

arXiv2020

Non-local modeling with asymptotic expansion homogenization of random materials

The aim of this study is to build a non-local homogenized model for three-dimensional composites with inclusions randomly embedded within a matrix according to a stochastic point process w in a bounded open set associated with a suitable probability space). Both phases were linear elastic. Asymptotic expansion homogenization (AEH) was revisited by taking into account the stochastic parameter representing the inclusion centers distribution. The macroscopic behavior was then studied by combining the variational approach with the mean-ergodicity.

cs.CE↗