The authors present an experimentation demonstration and a numerical simulation using structural finite element analysis of assembled honeycomb plates used for satellites design. A detailed comprehension of the dynamics of the coupled structures is essential for the design and the development of new structures and to give the solution to problems of noise and vibration on existing structures. This comprehension passes by the study of the modal analysis, which makes it possible to describe, include/understand and model the behavior of the coupled structures. The knowledge of the vibration behavior of the coupled structures being able to take into account its environment is a difficult problem and the engineer often has recourse to artefacts to give an estimate of it. A modal analysis of a coupled system composed of two and three sandwich plates with aluminum skins and hexagonal honeycomb core in free vibrations is presented in this study under the Clumped–Free–Free–Free boundary conditions. In this paper, the comparative study has been performed using the experimental data. The results obtained in this paper show that a good agreement is observed between the finite elements results and the experimental methods by accepting an error about less than 6%.