Displacement Influence on Frequencies and Modal Deformations of a Sandwich Beam

Abstract

Composite structures are used in the aerospace, stars and automotive especially the structures made of composite sandwich panels which are subject to vibration harmful sources of noise and mechanical failures. In this paper, we propose to analyze the influence of the shapes of displacement fields on the vibration behavior of a sandwich beam. For this energy method based on the minimum energy is used to achieve the equations frequencies and a sandwich beam modes. The kinetic and potential energies of the skins are, in turn, derived from the classical laminate theory. Several fields of polynomial movements are tested. Other parts will study the effects of rotational inertia, taking into account the bending energy of the body of sandwich NIDA. We analyzed the frequencies and modes based on different parameters. The experimental data are obtained for recessed-free conditions limits exciting near underrun using an impact hammer. The vibrational response is measured with a laser vibrometer. The natural frequencies are obtained experimentally by modal analysis. Numerical simulations complete this work for two types of sandwich Nomex paper and aluminum. The natural frequencies obtained from the theoretical formulation for numerical solution of the system are compared with experimental results and the results of numerical simulation. The very good agreement between the results shows that the model is correct.