The structural properties of confined granular packings play a crucial role in catalytic fixed-bed reactors, where particle arrangement influences porosity distribution [1], flow dynamics [2], and overall reactor performance. These systems are particularly relevant in applications such as the catalytic conversion of ortho-to-para hydrogen, a necessary process for hydrogen liquefaction. In confined environments, wall effects lead to structural heterogeneities, modifying local packing fraction and coordination number, which in turn affect fluid-solid interactions [3]. Understanding these effects is essential for optimizing catalyst bed design and improving reaction performance. In this study, we investigate the influence of particle shape or density and external vibrations on packing structure within a catalytic bed using the Discrete Element Method (DEM). While confinement effects and vibrated granular packings have been studied separately, their interaction remains less explored. We conduct numerical simulations to analyse key structural parameters, such as radial and axial porosity distributions, local packing density, and contact networks. To validate the numerical approach, DEM results are compared with experimental data obtained through X-ray tomography of packed catalyst beds. This study aims to provide novel findings on how vibrations affect packing structures in confined environments, and how these effects might affect structural arrangement. By exploring this coupled effect, our work contributes to a better understanding of granular packing dynamics in catalytic reactors, for optimizing fluid-solid exchange in various industrial applications. [1] B. Gong, H. Cheng, J. Yan, et L. Zhang, « A method for the determination of local packing factor distribution of a packed pebble bed by the improved line-based averaging method », Fusion Engineering and Design, vol. 208, p. 114658, nov. 2024, doi: 10.1016/j.fusengdes.2024.114658. [2] V. Papkov, N. Shadymov, et D. Pashchenko, « Gas flow through a packed bed with low tube-to-particle diameter ratio: Effect of pellet roughness », Physics of Fluids, vol. 36, no 2, p. 027127, févr. 2024, doi: 10.1063/5.0183475. [3] D. Choi et al., « A DEM-CFD study of the effects of size distributions and packing fractions of pebbles on purge gas flow through pebble beds », Fusion Engineering and Design, vol. 143, p. 24‑34, juin 2019, doi: 10.1016/j.fusengdes.2019.03.068.